I agree, and that's what I did to my daily driver, well, I had an almost new head in the rotation, and I saved it for my personal rig. Now I just wished I would have marked, and then replaced the valves next to the broken rocker that head had. The rocker looked like it had a stamp in it from the top of the valve stem.

Another bit of data. I showed Geordi the head that came off that engine the other day, and it had 2 or 3 indents where a piece of glow plug was smacking around. Even though it was on the outer circumference of the valve, that valve held up for tens of thousands of miles, a boil over, and many 3/4 temp gauge runs. My guess is it's either warped heads that bind the guides, or just occasional weak valves. Maybe those valves weren't machined perfectly concentric to the stem, and eventually fatigued to death?

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05 CRD: H.D.S2 stat,WW Ironrock trilink&LCA's, OX rear,ARB front, 4.10's, ARB bumper, Suncoast,OME 3.5, JBA UCA,rock rails, Moabs&265/75 Duratracs, GDE tunes ,FFD fan,ARP's, 2 micron fuel, new valves,sasquatch battery tray & grid heater, tensioner relocated
Mech fan, VH & AC delete

What about a methanol/water injection system? It cools EGTs so it should also cool valves? Anyone running one of these?

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JBA 4" lift, IRO Tri-link w/ wwdiesel bracket, JBA sliders, 235/85-16 Goodyear Wrangler Duratracs, Mercedes Benz forged ultralight wheels, Weeks stage 1 and 2, Weeks lift pump and harness, Weeks battery tray and AGM battery, GDE tune, Suncoast TC, updated front pump, HDS 001 T-stat, ARP studs, Front and rear Detroit/Eaton Truetrac LSD.

In order to test my theory about the rear cylinders running hotter than the front cylinders, I installed a temperature probe on the cylinder head.
Near the back of the head, between cylinders 3 and 4, is a threaded plug in the water jacket. I removed that plug and attached the temp probe to it.







After a good hard run to get everything up to temperature, it appears that this part of the head does not run any hotter than the rest of the head.

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U.S. Army Retired

If these are the temperatures you are getting fully warmed up, you are still running too cool. Modern diesel engines should be running over 200 degrees for long term reliability and better fuel economy.

A very good solution to dropped exhaust valves is to run sodium filled valves, but this is a very expensive option.

With the thermostat I am using, 185-195 is normal.
It's now summer time here in Florida. No need to run any hotter.

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U.S. Army Retired

This is a really interesting thread, I'll throw in my data. Had a small water pump hose fail on Frwy and engine overheated briefly but too late, HG failure, Warped over spec. Replaced head with VM rebuilt, timing belt kit, ARP studs, ERG delete, etc. Did all work myself, started right up, ran fantastic for 4200mi after new Head. Exited Frwy after 2hours at 70mph, engine died, no noise, cranks normally but no start. Couldn't figure it out, took to dealership here in Houston, they kept it 6 weeks, replaced a bunch of fuel parts and sensors but couldn't make it run, gave it back to me without diagnosis and comp'd a $3000 invoice, since I had never approved any repairs. Anyway took it back to my shop, pulled head and #4 exhaust valve embedded in center of piston.

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06 CRD Limited/#2
Full OME suspension/Sway Bar Disconnects
ARB Bumper/ LEDs
SS Cat Back
Warn 8000
KC HID Daylighters (2)
Sasquatch EGR delete kit
ARP stud kit
Safari Snorkel
Suncoast TC
Alpine/ JL Audio
Clifford Remote Start
Netto Terra Grapplers 265/75/16
GDE Hot
Lift Pump
Sasquatch Battery Kit

Jeff, I disagree with you regarding running 200+ is good for reliability. 185-195 is not hurting reliability. At least I do not have any data that would support your statement. On your thermostat unit I went with a cooler 190F thermostat just because I want to have peace of mind of not getting over 200F, mainly because I do not want the coolant warming too high and running higher pressure in the cooling system. Plus when you're offroading you want to take extra precautions of not going overheated, offroading can be tougher on an engine than towing. But I do agree that running hotter will decrease fuel consumption.

To Flash, this is a personal thought and I don't have any data to back it up. I believe the valve issues are from one or more of the following: running with egr, low quality oil, in-line thermostats, hard working the engine, improper maintenance. Most of our crds didn't see a gde tune (egr off and better pilot injection) till years after manufacturing date, so most crds were running with egr in them which probably smoked the #3 valves more than the other cylinders. I believe even segr was made over a year later since production. Many people do run those engines like a gasoline, start and step on it, drive it like you stole it then turn off w/o cool down. Even the oil that is in the valve stems can cook when shutting down an engine with cylinder temps in excess of 1000F.

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2005 kj CRD, samco, suncoast tc, provent, Kennedy lift pump, GDE ECO full torque, 2nd gen filter head, 245/70/16 a/t tires, mopar light bar, fumoto oil valve, OEM Skid Plates, ARB Front bumper and HD OME, tru cool LPD47391 40k GVW tranny cooler (stock cooler delete), FF Dynamics e-fan and shroud, rocker arms replaced, HDS2 190F thermostat.

thermorex & flash7210:

All of the research I have conducted to develop the Hot Diesel Solutions Model 001 engine thermostat assembly points to diesel engines running better over 200 degrees. I have consulted with a cooling system engineer, diesel technicians, and even a chemical engineer who specializes in engine oils, (can the base stocks and additive packages handle the heat?), to determine what the ideal operating temperature for a modern turbo-diesel engine should be.

There is some variance in the ideal engine temperature - most certainly - depending upon the type of engine, great changes in ambient temperature, what the engine is being used for and the loads it will encounter. However, everyone I discussed this with was in agreement that there should be no problems running just over 200 degrees Fahrenheit. Running 180 to 186 degrees is still running too cool, summer in Florida notwithstanding.

My own personal experience running commercial diesel vehicles as a Class 1 driver tells me that running over 200 degrees is the right thing to do. The Mack triple drive axle tractor I drove to haul 80,000 lb loads of pipe up North of Fort McMurray to the giant oil sand projects would regularly run over 220 degrees loaded, and over 210 degrees empty. I called Mack about this issue once, as I was concerned about the high temperatures... the response was that those temperatures are normal, and help the pollution control systems to function properly.

I have already written in other threads and on Facebook that you would have to be 4x4ing or towing in Death Valley to require a change to a lower temperature Hemi thermostat valve. The caveat here is that the rest of your cooling system needs to be healthy as well. If you have a weak hose, you will probably blow that hose even if you are running at 176 degrees.

I am fully aware that this higher running temperature for the R428 engine brings it closer to the overheat redline. Our main concern when designing the H.D.S. Model 001 was not if we could get the engine to run hotter, but how do we address any potential overheat concerns. This is why I fussed so much with the design of the Model 001 and it took so long to develop a prototype. I consulted with that cooling system engineer on the issue of increasing coolant flow in the thermostat assembly to compensate for running a hotter valve; his reply was that increasing flow was the safe thing to do.

Anyone who has a Model 001 can compare it with the O.E. thermostat assembly and immediately see that the Model 001 is significantly larger. This is not simply to accommodate the Hemi thermostat, but to also increase coolant flow at every opportunity...

1) The main intake port in the Model 001 has diverging angles in the upper and lower ramped walls, verses the parallel walls in the O.E. housing. Thus the Model 001's intake port is huge in comparison to the O.E.'s intake port.

2) The hose barbs in the Model 001 that lead to the viscous heater and the heater core in the cabin are a full 0.500" I.D., verses 0.470" I.D. in the O.E. assembly.

3) Even the 90 degree steel hose barb leading to the overflow tank has a significantly larger I.D. than the 90 degree barb in the O.E. assembly.

4) The upper radiator hose was determined to be more than large enough to accommodate increase flow, and therefore the upper radiator hose barb of the Model 001 remains unchanged in size from the upper radiator hose barb on the O.E. assembly.

5) The chamber in the main housing of the Model 001 that the Hemi thermostat sits in is properly sized for for that specific valve, and allows an appropriate amount of coolant to flow around the valve and the bypass portion of the valve. This chamber is significantly larger than the chamber in the housing of the O.E. assembly, and is properly matched to the significantly larger Hemi thermostat valve. THIS CAN NOT BE SAID OF THE BASTARDIZED SARGE INDUSTRIES RIP-OFF OF MY DESIGN, BY THE WAY.

All of these things were accomplished on the Model 001 without having to try and source larger coolant hoses to fit to it.

With the first prototype, we torture-tested it in 30 degree Celsius weather in July of 2014. My partner loaded up his high mileage, (295,000 kms) CRD with his wife, 3 kids, luggage, and towing a 2500.00 lb travel trailer, (the largest we had available to us). He took it on vacation with his OBDII reader hooked up to it, traveling at about 120 KPH, (about 75 miles per hour); the installed prototype Model 001 running with a 203 degree Hemi thermostat valve in it. The results, after the valve settled in during initial warm-up - was a rock-steady 203 degree reading.

Essentially, all of the research I conducted to create the Model 001 tells me that - unless the driving and ambient temperature conditions are quite extreme - the hotter you can safely run your CRD engine, the more efficient and more reliable it will be. All of the testing I have conducted and all of the feedback I have received from customers running the Model 001 with the 203 degree Hemi valve support this assertion.

I'd like to add that I have finally put the HDS to the test, and although it isn't July yet, I am very impressed. I've been trying to get the needle to move, and only once did I get it to move a little past center, and that was at the very top of the grade, towing 6500 lbs. I am glad to say that I am impressed, and the extra flow must be doing it's job. The FFD fan is keeping up wonderfully now with the HDS stat. I'm running the 203 degree flavor. I think if I pulled that same load in July, that a 190 degree stat might make sense (or a mechanical fan, or both), but I'd just drive much slower, I have been pushing it to find my limits, or when I need to pay attention to the temp gauge...

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05 CRD: H.D.S2 stat,WW Ironrock trilink&LCA's, OX rear,ARB front, 4.10's, ARB bumper, Suncoast,OME 3.5, JBA UCA,rock rails, Moabs&265/75 Duratracs, GDE tunes ,FFD fan,ARP's, 2 micron fuel, new valves,sasquatch battery tray & grid heater, tensioner relocated
Mech fan, VH & AC delete

Mountainman... a little clarification is in order here. Do you mean to say that the FFD electric fan was not keeping the engine temperatures down in these driving conditions with the O.E. thermostat in place? Or perhaps you had some modification to the O.E. thermostat that we need to know about?

I am also wondering if you can hook up an OBDII reader to your CRD and get actual engine temperature measurements the next time you want to haul heavy loads up hills. "A little past center" only gives us a ball-park idea of how hot the engine is running.

Thank you for the feedback, by the way!

Nobody is saying that you're wrong. Its just not for me.
I prefer to err on the side of caution and run my engine cooler. Especially in the summer.

You know that old saying about leading a horse to water?
I'm THAT horse.

_________________
U.S. Army Retired

Regarding broken valves...

I still believe that its all related to heat.
Maybe not the head itself, although good coolant flow through the head is important.
But maybe its high EGTs?
Nearly all the broken valves have been exhaust valves.
Is it because of the EGR?
Seems most likely. But does the EGR cause an increase in EGT?
Opening up the exhaust to get those hot gasses out quicker could help too.

Regarding cracked heads...

The root cause of cracked heads seems to be the use of a in-line thermostat with a factory thermostat. The in-line thermostat creates a restriction to coolant flow prior to its opening temperature. This causes hot spots within the head.

The cylinder head temperature probe I installed above tells me that my cooling system is doing a good job of keeping the head cool. When fully warmed up at idle, my temp probe is 3-5 degrees cooler than the coolant temp sensor in the thermostat housing. Then once I start moving again and rpms come up, the temp probe slowly drops to about 20 degrees cooler than coolant temp. This tells me that the water pump is flowing much better at higher rpms and the coolant is doing a good job of transferring heat away.
My cylinder head temp probe is not perfect and has some flaws but its the best I could do.

_________________
U.S. Army Retired

Yeah, it's not very scientific. But, I am comparing this to 3 CRDs, one with mechanical fan and "functional" stock thermostat, one with FFD fan and stock stat w/inline, and one with failed stock thermostat and no fan. Just some various configurations I've driven over these mountain grades. The addition of the HDS cools much better than all three, with, and without the heavy load. The mountain grade in question is steep and long enough to make any CRD run hot without anything being towed. I can't get it to budge the temp gauge now without a trailer I will get some readings this summer and get back to you with the temps.

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05 CRD: H.D.S2 stat,WW Ironrock trilink&LCA's, OX rear,ARB front, 4.10's, ARB bumper, Suncoast,OME 3.5, JBA UCA,rock rails, Moabs&265/75 Duratracs, GDE tunes ,FFD fan,ARP's, 2 micron fuel, new valves,sasquatch battery tray & grid heater, tensioner relocated
Mech fan, VH & AC delete

Outstanding... this is the kind of feedback I have been looking for. THANK YOU, MOUNTAINMAN!

Jeff, your thermostat is a fine piece of engineering. The temperature is stable, within few degrees more or less, but is way less variance than with stock thermostat. I absolutely love it, and I do not regret getting it at all. I also highly recommend it to everybody that plans on keeping the crd. Regarding temperatures, I'm sure you did your homework and I do not disagree with you regarding your research. I just want to make sure I do not run into overheating issues. Even if that means to run a bit less efficient. I may never run into overheating regardless, but since I want to take extra cautions, I installed the 190F start. 185-195 will give me that peace of mind and also put less heat and expansion (pressure) in my cooling system. That's all I am saying, everybody with each own preferences.

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2005 kj CRD, samco, suncoast tc, provent, Kennedy lift pump, GDE ECO full torque, 2nd gen filter head, 245/70/16 a/t tires, mopar light bar, fumoto oil valve, OEM Skid Plates, ARB Front bumper and HD OME, tru cool LPD47391 40k GVW tranny cooler (stock cooler delete), FF Dynamics e-fan and shroud, rocker arms replaced, HDS2 190F thermostat.

thermorex, you wrote:

Jeff, your thermostat is a fine piece of engineering. The temperature is stable, within few degrees more or less, but is way less variance than with stock thermostat. I absolutely love it, and I do not regret getting it at all. I also highly recommend it to everybody that plans on keeping the crd. Regarding temperatures, I'm sure you did your homework and I do not disagree with you regarding your research. I just want to make sure I do not run into overheating issues. Even if that means to run a bit less efficient. I may never run into overheating regardless, but since I want to take extra cautions, I installed the 190F start. 185-195 will give me that peace of mind and also put less heat and expansion (pressure) in my cooling system. That's all I am saying, everybody with each own preferences.

I say... O.K.

I had been expecting to drop ~$120 on the Mopar part but for a fraction of the cost I preformed that mod 3 weeks ago and have nothing but good things to say about it's performance, ease of implementation and cost effectiveness viewtopic.php?f=5&t=84571 It's been in the high 80's here last week and I've been hauling loads of topsoil around, roughly 6000lb per load, with no issues or notable difference from the factory thermostat. It's a great alternative to the Mopar thermostat and I believe it provides equivalent performance with the added benefit of being able to easily replace the thermostat element or select a different temperature. Admittedly, it's not for everybody because you need access to a relatively well equipped shop to fabricate and assemble the parts.

Now, accusing him of ripping off your design is a serious allegation to make in a public forum and I'm curious how you came to this conclusion? As far as I can see the similarity starts and ends at the choice of thermostat which is a commercially available part. That thermostat is used in a number of other Chrysler applications and the bypass plate just happens to be the same diameter as the factory thermostat element on the CRD which would make an obvious first choice. Since his isn't a scratch design his choice of thermostats was somewhat limited and the selection of one that has the same size bypass plate to mate with the existing seat was clearly essential to the simplicity of the implementation. Maybe he was motivated to consider that thermostat first because you had incorporated it into your housing. On the other hand he maybe went to the Gates application guide and compiled a shortlist of thermostats that where dimensionally suitable to fit in the factory housing, only he knows. Accusing him of ripping off your design because it happens to use the same thermostat element when in reality it's a completely different beast is libel. Of course, even a small child could look at the two side by side and see that they're very different and he's clearly not ripped you off. Although many parts are designed for a specific application there are also many generic parts that are common across multiple vehicle manufacturers and models. If someone else uses the same part as you it doesn't mean they've ripped you off.

Finally, I'm not suggesting that you've not designed a better mouse trap but it's ridiculously expensive for a thermostat housing. For most of us it's probably approaching a whopping 10% of the value of our vehicle. Sometimes you just can't avoid high parts costs but in this case you can.

I one don't consider sarge variant a ripoff of Jeff's thermostat, more likely a variant of kap's thermostat. I understand that jeff spent lots of time and money for his unit and I also understand his frustration. In history, there are many great ideas that didn't catch up with their times. I believe, from an investment point of view, that a thermostat for such a short run of Jeep diesels has not been a good investment. I'm also grateful, personally, to Jeff that he put so much resources to develop such a masterpiece. I also believe that going into a larger run, like the 3.0 diesel in ram and grand cherokee might be a better idea. Maybe the 2.8 vm from Canyon could change the tables. It's one thing to spend $500 for an up to $10,000 jeep, another to spend $500 for a vehicle that's well over 30k, and also come in bigger production numbers. Don't get me wrong, Jeff's hds thermostat is well worth the money, but not everyone is willing to shed money for an expensive part that is available, granted, at lower quality and performance, at a lower cost.

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2005 kj CRD, samco, suncoast tc, provent, Kennedy lift pump, GDE ECO full torque, 2nd gen filter head, 245/70/16 a/t tires, mopar light bar, fumoto oil valve, OEM Skid Plates, ARB Front bumper and HD OME, tru cool LPD47391 40k GVW tranny cooler (stock cooler delete), FF Dynamics e-fan and shroud, rocker arms replaced, HDS2 190F thermostat.

This is starting to spin off topic, but it doesn't really matter which thermostat you use. It can be the HDS, Sarge's, Kap's, or Mopar/VM.
DO NOT USE THESE:
1. a in-line thermostat combined with a factory thermostat
2. a thermostat manufactured by Crown

Do your research and figure out which one works best for you.

_________________
U.S. Army Retired

I stand by my comments regarding Sarge's design... I did the research necessary to determine that the Hemi thermostat valve was the right valve to use in this application, and had a working prototype at least a year before Sarge even started on his project. I even had a first production run completed before he even thought about his version. There were no notions from Sarge about starting an alternative thermostat solution until several people decided they didn't want to pay for a properly engineered upgrade thermostat assembly.

Yes, he most certainly did steal an idea or two from me. It would be the proper thing to do for Sarge to admit that he did so; at least I would have a little more respect for him.

All you have to do is look at the LOSTJEEPS.com thread timelines to confirm all of this. If Sarge has the gonads to launch a lawsuit against me, I say "bring it on"; I will SHRED him in court.

For the record, I am NOT claiming that Sarge ripped off my total design, but that he ripped off the my research that determined that the Hemi thermostat valve was the correct valve to use. While I am angry about this, I am well aware that there is nothing I can do about it except point out to people where he has cut corners in his design and where it is inferior to the Model 001.

ceeardeedriver, your claims that the Hemi thermostat valve fits properly into the O.E. thermostat housing are incorrect; it is in fact too large.

Sarge's design is not similar to Kapalczynski's because he is using a valve too large for the housing, and is welding everything together. Kap's design uses a valve similar in size to the O.E. valve, and is bolted together.

Time will tell if Sarges design is O.K. or not, but I have strong suspicions that his bypass valve does not work properly and/or the flow is severely restricted. The welding may not last either, being on a heated pressure vessel mounted on a vibrating engine.

Given the quality of my product, the price is actually quite reasonable, and I offer features like the threaded accessory ports that Sarge's design can not offer.

Ceearedeedriver, your statement that my prices are ridiculous shows an appalling lack understanding of what it takes to bring a new product, especially one that is produced in limited numbers, to market. Furthermore, your support of someone else's rip-off product creates a huge dis-incentive to anyone else who wants to try making another product for the CRD. Your statement that the Model 001 is too high because it now makes up about 10% of the value of the average CRD is totally meaningless; no manufacturer in any area of industry, whether it is automobiles, dishwashers, or widgets lowers the price of their parts just because the part is for an old piece of machinery. Have you checked out the dealer prices on CRD parts lately, or even the jobber parts? There have been no price drops just because the vehicle is old, in fact some prices have actually increased, (probably the Auto Industry's way of getting you out of your old vehicle to purchase a new one).

thermorex, I have already looked at developing an aftermarket thermostat for the V.M. Motori A428 engine in Chrysler vehicles in Europe, and the G.M. version of that engine the Colorado/Canyon. It is still a thermostat assembly like that in the CRD, but it is a totally different design that requires a clean-sheet development. It will be needed because the A428 engine thermostat assembly is even worse than that of the CRD, but a serviceable, upgraded thermostat assembly will cost at least another $20,000.00 to develop.

Given the problems the Germans are having with their Wranglers that have the A428 engine right now and the fact that G.M. is being totally ridiculous with the prices of the Colorado/Canyon series, I do not expect that there will be many of those vehicles over here in North America.