Here are the simple facts: If it breaks the timing belt or shucks a few teeth off of it, it will break or bend either half or all of the rocker arms before the engine stops spinning. You will be lucky if only rocker arm damage occurs; some poor souls have even had catastrophic engine damage occur including having a valve break off, destroy the head, the piston, bust the piston liner, and crack the block. Search LOST, there are horror stories.
You will then be forced to repair all the damage if you want the engine to run again or replace the entire engine.

This is an "Interference" engine, which means that if the valve to piston timing gets far enough out of time, valves will contact the tops of the pistons and damage will occur.
This WILL happen with timing belt failure!

But as always, it's your engine, how lucky do you feel?
Members on here and all the free advice is simply trying to help you prevent a very possibly costly mistake!
Whether or not you take heed, is up to you.....

They say a picture or two is worth a thousand words:

_________________
Supporting Vendor and Moderator of LOST
05 Jeep Liberty CRD Limited
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount
98 Dodge Cummins 24 Valve

Hahaha I am aware of what an interference engine is. I have repaired two alh tdis with junkyard heads that went thousands of miles after until a deer destroyed (and the other I still have). Usually the block stays in tact if your lucky and valve doesn’t fall. These engines don’t have the best valve reputation tho! [SMILING FACE WITH OPEN MOUTH AND COLD SWEAT][SMILING FACE WITH OPEN MOUTH AND COLD SWEAT][SMILING FACE WITH OPEN MOUTH AND COLD SWEAT]

I’ll have to look into timing but don’t currently have the funds. I’ll just do the fancy thermostat.


Sent from my iPhone using Tapatalk Pro

If it were me, I'd get a cheap thermostat now,
https://www.amazon.com/5142601AA-Coolant-Thermostat-49012026F-Compatible/dp/B07JMXFLNB/ref=sr_1_4?keywords=crd+thermostat&qid=1573846831&sr=8-4
and do the timing belt NOW.

Get the fancy thermostat later.

The engine will continue to run with the thermostat it already has.
It will NOT run with a broken timing belt.

Rockauto.com lists a STANT thermostat for $40 plus shipping.
https://www.rockauto.com/en/catalog/jeep,2005,liberty,2.8l+l4+diesel+turbocharged,1431569,cooling+system,thermostat+housing+/+water+outlet,10337

_________________
U.S. Army Retired

The torque to yield bolts are NOT "failing"... they are doing their job as a sacrificial part and stretching to beyond their limits to keep the cylinder head that is warping from cracking. There is a valid reason why TTY bolts are employed in aluminum head/iron block internal combustion engine architecture.

The entire narrative on this subject has been skewed by a man who makes a lot of money travelling around the U.S. and repairing CRD engines with questionable upgrades. Take careful note of geordi's two LOSTJEEPS threads on head studs and exhaust valves.... NOTHING conclusive has ever been proven to support his theories.

Nobody is doing proper research on this subject. Other than myself, who has been asking why cylinder head gasket failures seem to be a big problem here in North America, but not in other parts of the world, (they occur there as well, just not to the degree that they seem to be occurring here in Canada and the U.S.). The engine is architecturally no different in all markets around the world; why are head gaskets a problem here?

I have called ARP directly on two separate occasions and inquired both times about recommended upgrade studs for CRD engines. THEY DO NOT HAVE ANY RECOMMENDATIONS, BECAUSE THEY HAVE DONE NONE OF THE RESEARCH THEMSELVES. Because of this, they do not recommend any of their products or offer any kits for the CRD engine. If someone wants to pony up the money to get this research done, then a kit can POSSIBLY be developed.

Just because I.D. Parts, Sasquatch Parts and geordi recommend them does not mean that they are appropriate upgrades.

So bolts that stretch, causing a head gasket leak, is a good thing?
A LOT of 6.0 Powerstroke users would highly disagree. The ONLY way to fix those engines was to fasten the heads down with ARP studs.
Myself, when I replace a head gasket I'd like to never have to do it again.


Actually, A LOT of research was done towards selecting the ARP studs.
VM Motori even contributed some data and that data was presented to ARP for a recommendation, to which ARP obliged.
You can read about the whole process here:
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=65524&start=20
And still further research was performed by popular CRD parts retailers who determined that the popular VW TDI head studs were a little too short, so longer length studs were identified and sold as kits.
Why do we here on LOST only hear about head gasket problems in N. America?
Because the vast majority of posters on LOST live in N. America.


Duh.
The market isn't big enough for ARP to do all the research for such a small amount of CRD owners.
But, if you provide them with all the necessary specifications for a bolt they WILL provide you with a recommendation for appropriate sized stud as a replacement.


Careful there.
The exact same thing could be said about you and your "theories"

_________________
U.S. Army Retired

"Actually, A LOT of research was done towards selecting the ARP studs.
VM Motori even contributed some data and that data was presented to ARP for a recommendation, to which ARP obliged.
You can read about the whole process here:
viewtopic.php?f=5&t=65524&start=20
And still further research was performed by popular CRD parts retailers who determined that the popular VW TDI head studs were a little too short, so longer length studs were identified and sold as kits.
Why do we here on LOST only hear about head gasket problems in N. America?
Because the vast majority of posters on LOST live in N. America."

GETTING HEAD STUD SPECIFICATIONS FROM THE O.E. MANUFACTURER AND PROVIDING THOSE SPECS TO ARP IS NOT THE SAME AS ACTUALLY HAVING ARP PERFORM R&D WORK ON UPGRADE HEAD STUDS FOR ANY GIVEN ENGINE. You making the case that retailers are performing R&D work by merely determining that VW head studs are too short for use in the R428 is kind of like saying that Samsung did their due diligence in some of their battery powered devices. If I.D. Parts, Sasquatch Parts or geordi has some REAL engineering data to prove that the kits they sell are a genuine upgrade that will not harm the cylinder head, then I will admit that I am wrong here... but I do not think that will happen, and at least two LOSTJEEPS members have ended up with cracked cylinder heads after installing ARP head studs.

And yes; I am well aware that heads have cracked for other reasons, but clamping an aluminum head down on an iron block with studs that will not stretch at all - NO accommodation for the the larger thermal expansion factor of aluminum - is just asking for trouble.

If you TRULY want a reliable R428, someone has to pony up for development of an iron cylinder head... then you can get ARP to R&D proper head studs for an iron head/iron block engine. NO commercial diesel engine I know of runs iron block/aluminum head architecture, and that is why the R428 and all other diesel engines like it are relegated to a consumer grade status.

Retailers are eager to sell you whatever you think will make your engine perform better or last longer... history is filled with speed shops and aftermarket manufacturers selling the equivalent of snake oil to gullible buyers.

In my quest to expand my business I have spoken to people all over the world about the R428 and its predecessor, the R425. Not once while inquiring about the cylinder head issues of these engines have I heard been complaints from people in those markets about this being a big problem. Do cylinder head issues occur over there? Most certainly the answer is yes, but not with any more frequency than other engines of a similar architecture.



"Duh.
The market isn't big enough for ARP to do all the research for such a small amount of CRD owners.
But, if you provide them with all the necessary specifications for a bolt they WILL provide you with a recommendation for appropriate sized stud as a replacement."

CORRECTION... ARP has performed NO RESEARCH on the V.M. Motori R428 engine. And yes; ARP did mention in both phone calls that they will sell you whatever you want and make up a kit for you according to your exacting specifications. That is most definitely not the same as having them perform any research on the engine you want upgrade studs for. Call them yourself if you do not believe me.... ARP HAS NO HEAD STUD RECOMMENDATIONS FOR THE V.M. MOTORI R428 ENGINE BECAUSE THEY HAVE NOT TOUCHED THE ENGINE THEMSELVES... END OF STORY.



"Careful there.
The exact same thing could be said about you and your "theories"

My so-called theories are not theories... what I have written here on LOSTJEEPS and elsewhere is basic engine architecture 101... you can look up and do your homework regarding ANYTHING I have written and discover that it is fact. Just do your homework when researching upgrades on any engine, and do not completely rely on online forums or other peoples' advice.

Precisely. All parties included.



Yet this, your research, is precisely what many of us, including Geordi, have done, contributing to the stud issue, but when it's not you, you say it's not research. Hypocritical much?


FACT: Actually, the R4 series, as well as the current A4 series are Widely used around the world in commercial applications, including Marine, stationary and mobile Generator sets, commercial welding units, Trucks, Tractors, construction equipment, and many others. And yes, they do have head gasket issues there as well as here. Why we seem to have a higher rate of failure here, there are so many possibilities yet unexplored no one could say for sure, but many people are working on the most obvious improvements, including you, and your HDS. Likewise, many others, not just a few, have found reduced failure with studs which are pretty universally used with MLS head gaskets, in applications from Cummins gen sets to 10,000 HP Nitromethane burning drag engines.
Aluminum heads have been used with iron blocks on various engines since the 1960s, and many things have been learned since then, including when using TTY head bolts, If you push the limits, the head gaskets fail. Some quickly, but all eventually, when the limits are explored.

Iron blocks
Aluminum Heads
MLS head gaskets
TTY bolts - gasket failures
Studs - gasket failures nearly eliminated

Regarding pushing the limits, it's kind of the American Way. It's what we do. It's in our DNA. In all truthfulness, it is, I believe, the #1 main reason why the TTY bolts fail so often. And for decades, the fix that works, is studs with higher clamping capacity.

Pushing the limits is, I believe, also part of the reason behind the exhaust valve issue.

One of the things I noticed about the EU and UK applications, is they usually have speed governors set lower than what we have here. In this application, when we're "having fun" these generally shift up between 4000 and 4400 rpm. A tractor engine, a gen set, a welder, a London cab, are mostly all governor-limited in the 3500-3600 rpm range. Sometimes lower. This means lower temps and less stress everywhere. In most applications, there is no Hot Tuning either, So naturally there is less component failure in overseas applications.

All these things that you and others have done, is in an interest of making an already good thing, BETTER.
What is BETTER?
To one guy it's more reliability.
To another it's getting his vehicle to 500K miles
To yet another, it's fuel efficiency
Another one looks for comfort, that it heats up fast and doesn't overheat.
A yet different crowd wants acceleration and lower ETs
Someone else just wants to surprise the driver in that loud-ass Honda/Toyota/fill-in-space at the light in the lane next to you.

The point is, every "car guy/gal" is wanting to make the Libby they love/hate but drive as much as possible, BETTER in their own way. What really irks me, is when there is this war between the different kinds of BETTER. It accomplishes nothing. It is nether positive nor helpful in any way.

Jeff has produced and brought to market a vastly superior product. Jeff has many happy customers that absolutely love his product. Jeff also has people that deeply dislike him for whatever reason, and would never buy his product no matter how rich they are. Harsh, yes, but also true.

Geordi has accrued experience, and sharpened his skill into a service he has brought to market. Geordi has many happy customers that absolutely love his service, and the convenience and expertise he brings, and find it absolutely worth the price. Geordi also has people that deeply dislike him for whatever reason, and would never have him touch their vehicle no matter how rich they are or how much it needs fixing. Harsh, yes, but also true.

This is life. Let the animosity go. This verbal swordfight is SO VASTLY unnecessary and damages you both, as well as a forum that is one of the best for helping everyday people with problems that stump them, find hope, solve their issues and get on with life.

If you can't get along, Focus on your own skills, products, etc. Let the other guy focus on his, and get on with life.

_________________
'06 Lbrty Sprt CRD 150K

Sasquatch
DSS Turbo
CAT-elimntr
Weeks Stg1&2 EGRfix
PV-200
BLING
vent gauges

IDParts
head
cams
rockers
Timing set
ARP studs
eTn1 GX2123 5v GPs

YETI Custom Tune
Flowmaster 8325508
Carter P76611M
GM 12611872
Hayden 2986
GM 15976889
PATC Custom Billet
2010 Ram Hemi Trans
Sonnax 44957
Transgo kit
Cooper 51770

Good lord....the results speak for themselves. ARP=no head gasket failures. TTY Bolts=head gasket failure.... Blah Blah.....change your head gasket on a regular basis if you must. I will be happy to send you my original TTY head bolts.

_________________
2005 CRD Limited
SEGR
WEEKS Kit (removed EGR, FCV),
Gen 2 Fuel Head
GDE Eco Tune
ARP studs
Etechno (7v) Glow Plugs
F37
Kap 193 thermostat
Carter Lift Pump (Modified wiring harness)
Fumoto (CRD-108)
Bypass oil filter (2 micron)
Samco
Provent
Sears P-1 Battery
Secondary 2 micron fuel filter

taroo: "Good lord....the results speak for themselves. ARP=no head gasket failures. TTY Bolts=head gasket failure.... Blah Blah.....change your head gasket on a regular basis if you must. I will be happy to send you my original TTY head bolts."

...Seriously? There have been plenty of CRD owners that continue to have cylinder head issues after installing ARP head studs. Head gaskets can still fail, and now you run the risk of cracking your head.

The CRD parts guy in Sherwood Park has had at least 7 CRDs that he has owned/currently owns; 1 that he just sold had over 400,000 km rolled up on it. He has not performed ANY head gasket work on any of them. ALL of his CRD engines have original TTY bolts in them.

Joker... TTY bolts can only be used 1 time.

What all of you ARP head stud fans keep overlooking is the plain fact that American Racing Products - the very same manufacturer who makes the studs you all are so slavishly devoted to - does not recognize or recommend the very same ARP head stud kits that are being sold by I.D. Parts and Sasquatch Parts; the very same kits that are recommended by geordi.

Keep in mind that ARP makes products for RACING. The primary goal of RACING is to be the first vehicle to cross the finish line... often it is the case where reliability is the sacrificial lamb to achieving this. Did it ever occur to any of you that perhaps the additional clamping force offered by ARP head studs and bolts so engine builders can up the horsepower and torque of the engine - with the goal of getting to the finish line first without the engine flying apart - works AGAINST long-term reliability because you now have no ability of the aluminum head to thermally expand properly over the iron block it is clamped to?

People who build racing engines don't care about long-term reliability... they simply want to win races.



GordnadoCRD: "All these things that you and others have done, is in an interest of making an already good thing, BETTER.
What is BETTER?
To one guy it's more reliability.
To another it's getting his vehicle to 500K miles
To yet another, it's fuel efficiency
Another one looks for comfort, that it heats up fast and doesn't overheat.
A yet different crowd wants acceleration and lower ETs
Someone else just wants to surprise the driver in that loud-ass Honda/Toyota/fill-in-space at the light in the lane next to you."

Sooo, are you now making the claim that all of the CRD head gasket/cylinder head/head stud/exhaust valve threads on all of the Jeep forums everywhere on line are NOT about reliability, (or lack thereof)? That, somehow Mr.LOSTJEEPS.com member is trying to "push the limits" of his Daughter's daily driver CRD?

EVERY thread I have seen on this subject is from a CRD owner who wants his or her engine to be reliable; don't try to spin the narrative here by stating otherwise.



"TURBO-DIESEL-FREAK: I have spoken to people all over the world about the R428 and its predecessor, the R425..

GordnadoCRD: Yet this, your research, is precisely what many of us, including Geordi, have done, contributing to the stud issue, but when it's not you, you say it's not research. Hypocritical much?"


This is not hypocritical at all; I merely stated that I have made telephone calls to customers all over the world and I did NOT claim that those telephone calls amounted to "research" of any kind. The calls were made to satisfy my suspicions that the head gasket and exhaust valve issues in North American market CRDs were caused by other factors than "bad head studs" or "bad exhaust valves".

Developing the HDS Model 001? Yes, to do that you require genuine research.

GordnadoCRD: "This is life. Let the animosity go. This verbal swordfight is SO VASTLY unnecessary and damages you both, as well as a forum that is one of the best for helping everyday people with problems that stump them, find hope, solve their issues and get on with life."


When we have people becoming members of this forum and other online entities to get answers on how to keep their vehicles running reliably; FACTS MATTER... you have just said it yourself, ("a forum that is one of the best for helping everyday people with problems that stump them"). If that means there is inevitably going to be a clash of personalities, then so be it.

I for one am not willing to let people like geordi spin false or misleading narratives. Remember that geordi is the guy who fully endorsed in inline thermostat "upgrade". That little BS backyard fix was the cause of innumerable cylinder head warps and head gasket failures. geordi may be good at replacing parts under the hood, but he knows nothing about basic engine architecture and thermodynamics.

Clarification to OP:
I edited my post from idlers to rockers, sorry.
At least change the timing belt alone its not expensive
https://www.amazon.com/Gates-T336-Timin ... 976&sr=8-3

I will add a small 1 cent worth because I don't like reading these types of posts whether correct or not as far as I am concerned that is one of the things PM can be used for. I don't know that it has or even could be proven that the in-line thermostat with some bypass/hole etc has been proven to cause anything since our sample size is likely to be too small to reach statistical significance and we only hear the bad experiences but I believe it does lead to more failures. We all learn from whatever information we have at the time which continually changes. I also believe and it seems there is much better evidence for the ARP studs overall being a benefit. I have 8 years of post graduate education and majored in Math and Chemistry and had multiple physics classes had courses in statistics and logic etc. I do not have any work experience in the auto industry or related services. I have learned several useful things from education and various real world experiences one of the most important being:

I don't know what I don't know and some things I can never know for sure and to try to recognize what these things are and act accordingly as best I can.

I also believe we can state our opinions without naming or demeaning others that may have differing opinions whether there are facts or not.

I know this keeps the thread going but I hope it doesn't continue.

_________________
05 Blu LIM, OME GDE Tbo, wk II 245/75/17, KC Lights, bull bar, 195K H TC
05 Blu Lim, Dayton, GDE HT, 255/75/18 , 210K , H TC
06 Bla Lim, GDE Eco, Destination AT 245/75/17, 151K, H TC
06 D Khaki Lim 126K wkII Eur TC
05 D khaki Lim 145k refurbishing
All CRDS: Fumoto, Lift , Fan Shroud mod, fuel head Gen II, SAMCOS,self TB, 2 Mic filt, Hayden

Not so fast hoss.
Show me how many CRDs running ARPs have 150-200k miles and 14 yrs of thermal cycles on them. There are still plenty, mine included, that have oem bolts and gasket on them. EVERY head gasket will eventually fail with enough thermal cycles and corrosion, just some sooner than others. One HUGE variable we will never know is if VM had a torque monitoring malfunction and there were batches of engines built with under/over torqued head bolts. Good luck getting that data from an overseas manufacturer, if it was ever recorded to begin with.

And spec'ing a bolts torque is not as simple as fastener material, thread pitch and base metals. The spreading of the load and distortion of the base material is more important. To measure clamp force distribution you'd need a gasket with multiple pressure sensors imbedded for real time results. This is where you'll find the clamp pressure that will actually start causing reduced clamp forces in certain areas and long before you even reach the yield strength of a premium fastener like an ARB stud.

Now I'm not a anti-ARB person. Put a set in my sons 12V along with o-ringing the head for potential twins and 50 psi+.
I see this same thing on other diesel sites, ARP everything! 6.5TD groups are notorious but there is a few guys running 20 psi+ on original bolts/gaskets. In those cases it's more about keeping the drive pressure down and good tunes that don't cause extreme cylinder pressures.

IMO, one thing this VM engine shares with the Ford 6.0 is poor head bolt spacing. However the 6.0 has iron heads vs the AL of these little engines so they can handle higher bolt torques.

Also, over the years I've seen people blame TTY head bolts for head gasket failures when in fact it was their workmanship that was the culprit. Not singling ANYONE out because I've seen it in AG/snowmobile/gasoline/diesel applications.

BTW, I like the idea of an upgraded T-stat housing allowing a serviceable T-stat too.

_________________
2006 Liberty CRD
2006 GMC LBZ

If you’ve got over 200k miles and never had a head gasket problem, that’s awesome. And consider yourself lucky.
I certainly wouldn’t go through the trouble of pulling off intake manifold just to perform some preventative bolt-stud replacement. But if the rockers are worn out/broken, then why not also do the head bolts?

Sure, head gaskets fail, but I would expect a lot more from a quality MLS gasket.
In my case, at 160k miles it wasn’t the gasket that failed, it was the head.
I’m not blaming the factory head bolts for that but the ARP studs made me feel confident about not having to go back to pull the head again to replace the head gasket later.
I’ve got 70,000 miles on my ARP head studs.

I’m sure many errors were made at the factory assembling these engines.
But we will never know exactly what was done wrong or right. All we can do react and try to fix it better than what the factory could.

Lastly, I’ve got two complete sets of never used head bolts sitting in a box that I’ll never use. If you think the factory head bolts are so great and you want some new ones, just let me know.

_________________
U.S. Army Retired

I think a lot of head gasket failures reported on this forum are probably due to abuse ,tunes, modification, especially cooling system mods.

As per Geordi , I think is putting a lot more effort to keep is business going...… than getting the facts straight about the CRD.

Like he says, he is "THE" CRD mechanic...…… even if he has no certification !!!!!



My 2 cents

Your comments regarding factory errors assembling engines are highly unlikely... this engine had already been manufactured for years in both 2.5L and 2.8L displacements before we got them over here. Most mistakes are made in the initial production runs.

The much more likely reasons for CRD engine problems in North America are the following....

1) Poor driving and maintenance habits.... many people over here do not know how to operate and properly care for a diesel powered vehicle. GordnadoCRD said it best... "Regarding pushing the limits, it's kind of the American Way. It's what we do. It's in our DNA. In all truthfulness, it is, I believe, the #1 main reason why the TTY bolts fail so often." I would add to this the fact that many people drive their diesel vehicles like their gasoline vehicles, and that is hard on diesel engines.

2) Crappy upgrades to the engines that are not well thought out and make fundamental changes to how the engine operates in ways never intended by the engineers who originally designed the engine.

Send those head bolts MY way, and I will make use of them when I set up to rebuild someone else's engine... are they still in the package?

I agree that many of the problems many CRDs are likely related to poor maintenance such as wrong oil etc. by inexperienced and neglectful owners but many are not. The great majority of tunes from members appear to be GDE tunes which in my understanding are engineered and designed not to raise pressures etc above factory specs. Many including me rarely use the extra HP etc and mainly wanted a more economical vehicle. I do know that two of my CRDs have no apparent explanation for the HG failures except engine design and one non functioning part that I won't disclose at present but you should know what it is . These two CRD s had maintenance records and one was a person in military who had his friend a certified diesel mechanic do all the maintenance. I got both of these Crds with around 80,000 miles and they had meticulous maintenance after that . One had a GDE tune when I got it and the other has original post F37 tune. Both had HG failures. The GDE tune one at about 190,000 and the stock one at 94,000. This is of course anecdotal but I feel much more confident with ARP studs and I have not seen where many if any had head gasket leaks after properly torqued ARP s and I believe there should be now that many users probably have close to 100,000 on their ARP studs if they were not better but only more time and miles will tell. Remember we are aware of only a few CRDs over 300,000 and it should not be unusual for these to reach 500,000 but I will be surprised if more than a handful last that long even with meticulous maintenance and babying.

_________________
05 Blu LIM, OME GDE Tbo, wk II 245/75/17, KC Lights, bull bar, 195K H TC
05 Blu Lim, Dayton, GDE HT, 255/75/18 , 210K , H TC
06 Bla Lim, GDE Eco, Destination AT 245/75/17, 151K, H TC
06 D Khaki Lim 126K wkII Eur TC
05 D khaki Lim 145k refurbishing
All CRDS: Fumoto, Lift , Fan Shroud mod, fuel head Gen II, SAMCOS,self TB, 2 Mic filt, Hayden

Half a million miles is entirely possible, if proper maintenance is maintained and proper driving habits for diesel engines is employed.

These engines do not like being revved to high RPM, and prefer to operate in the fat part of their torque curve. I have seen online videos of people starting and driving their CRD engines and it makes me want to cringe; in the videos I have seen, people were revving the little diesel like it was a 2-stroke racing engine. There was also that whole episode online where people are having a contest to see how cold the weather is where their CRD engine will still start unplugged.... VERY hard on the engine.

A proper warm-up and proper cool-down are essential to long diesel engine life; employment of a Webasto heater, even in warm/hot climates would go a long way to cutting down idling time and allow the engine to be started hot every time... this is very good for the engine.

When I write about improper upgrades, I was not referring to engine tunes; although I suppose some radical tune designed for competition would be detrimental to engine longevity. I was referring to modifications like inline thermostat upgrades and the employment of unapproved ARP head studs.

It would not take many CRD owners employing the use of an inline thermostat to skew head gasket failure rates in North America and make things worse than they seem. Use of ARP head studs may make a positive difference in head gasket failures, but it will very likely increase catastrophic failure rates of the cylinder head itself later due to cracking as the cylinder head will not be allowed to thermally expand properly above the iron block it is clamped to. In both cases these modifications will not result in bad outcomes overnight; it takes hundreds and hundreds of heat/cool cycles for the damage to become apparent... but make no mistake, the damage will occur.

I love everything you've written here. My '05 CRD was taken down for an oil leak at 180,000 miles. The head gasket is flawless. Sample size of one, but there's certainly not some inherent flaw in VM's approach it seems.

One of my vehicular passions is Saab, and '00 through '02 Saabs have a problem with TTY bolts... wrong metallurgy results in stretched bolts and premature head gasket failure. Saab offered a TSB on a retorque, but it's not even 50% effective. The long term solution is simply replace them with "new style" bolts which did not suffer the same problem. Pretty sure certain BMW V8s have the same issue. Nothing says VM didn't screw the pooch on '05/'06 CRDs and that their replacement bolts will outlast their car. You'd need to find a bunch of people with 150,000 miles on them to know.

There are numerous instances of overly optimistic coolant change intervals leading to head gasket failure as well. I can name half a dozen cars where marketing and engineering didn't agree on coolant guidelines and marketing won. Maybe diesel and G05 aren't a good mix, or maybe VM didn't adequately test their gasket with G05, or maybe US owners don't change coolant frequently enough (seriously, they don't - we are terrible at that!)

Another one of my passions is 2.3 Fords, and for a long time people insisted you needed ARP studs to put up with high boost. Then Ford revised the head gasket, and Felpro revised their version, and suddenly everyone stopped talking about ARP studs. The problem was never the bolts.

I'm not saying ARP studs aren't better, but without a high dollar failure analysis the only thing you can say is that they might cure a problem. It's also possible that VM's revised bolts might too.

There are numerous instances of overly optimistic coolant change intervals leading to head gasket failure as well. I can name half a dozen cars where marketing and engineering didn't agree on coolant guidelines and marketing won. Maybe diesel and G05 aren't a good mix, or maybe VM didn't adequately test their gasket with G05, or maybe US owners don't change coolant frequently enough (seriously, they don't - we are terrible at that!)

thesameguy

You would be surprise to see how many of the CRD don't use HOAT coolant !

There are in fact A LOT of commercial diesel engines that utilize the iron block/aluminum head architecture. If we're talking about on-highway applications sold in North America only...

2001 to present - 6.6L Duramax used in the Chevy/GMC 2500 through 5500 truck applications.
2011 to present - 6.7L Powerstroke used in F-250 through F-750 truck applications.
2002 to present - Mercedes/Dodge Sprinter Vans in four different engines - 2.7L (two variations), 3.0L, 2.1L.

All of these applications utilize an iron block/aluminum head architecture, are sold in a commercial capacity with capabilities that far exceed that of our VM, and have been produced in the millions.

_________________
2005 KJ CRD Limited 4x4
ARP Head Studs
GDE Hot Tune / Trans Eco Tune
HDS Model 001 Thermostat (203°F)
Suncoast TC / Transgo Kit
Full EGR Kit
Bosch 5V Glow Plugs
NAPA HD Fan Clutch / GM 11-Blade Fan
Samco Silicon Charge Air Hoses
Carter In-tank Fuel Pump
Provent 200 with Sasquatch Install Kit
Sasquatch Silicon Turbo Inlet Hose
Bilstein Shocks