No surprise, you guys were dead on...







*Clearly* a dual poppet thermostat. How detrimental running an inline thermostat probably depends on how far the second poppet moves and how well it seals, but clearly the risk is exactly as TDF indicated - when the stock thermostat is open, the bypass path is compromised. Whether that happens because the stock thermostat is failed open or because it's opened normally is just degrees of potential damage... adding an inline thermostat is at best not good and at worst quite bad.

To be clear, I'm no expert but it's pretty obvious how & why this is true.

Yes... it does not take a genius to realize that - for more than 1 reason - the Renualt 5 hack is a terrible idea.

However, some people are absolutely wedded to the idea that the cheaper the fix, the better. There is also a serious level of arrogance going on with these same people who think they know more than the engineers who designed the engine.

I am sending a link to the owner of CoolCat Express Corp., a company dedicated to proper upgrades for vintage Jaguars and the company you posted a link to earlier. He is the fellow whose website I bookmarked and had a discussion with long ago about coolant bypass circuits in engines. I spoke to him yesterday via telephone, and he may be willing to add some commentary to this important topic.

Some of us don't have that sort of money floating about...I lost my job due to Covid 19 back in March and haven't had a job since, so money is too tight to mention...The Renault 5 hack is all I can afford.
I should also mention that there are some on here, and you know who you are, that have nothing better to do than scaremongering by trying the rubbish the Renault 5 hack, simply because they are trying to sell their own alternative thermostat replacements to the OEM version, but which cost more than twice the price of a used 2.8 CRD!
I can get a used 2.8 CRD, with all the ancillaries still on it (including an OEM thermostat!) for £200 on ebay, half the price of one of these ridiculously priced replacement stats!
So it should be no surprise that it is only those who have a vested financial interest in making money from selling hyper expensive thermostat replacements that are the first to try and pour scorn on a simple and ultra cheap mod that works perfectly, but that they see as taking money out of their pocket...If you read my earlier post you will have seen where I said some KJ owners have been running the Renault 5 hack for over 6 years and have run up over 100,000 miles with one installed, with no ill effects to their engine at all...That should tell you all you need to know!
So the Renault 5 hack is a perfectly safe mod for the 2.8 CRD, and anyone that says otherwise should be ignored as they obviously haven't tried it for themselves, or they are just trying to fleece money from the gullible.
There are larger diameter thermostats with the same overall design, which could be used instead of the Renault 5 stat, giving better flow, you just need to modify the hose, to fit them, but don't expect them to work any better.

Stant #50388 is only £34.04 shipped o the UK.... I can't imagine taking a risk like that for thirty quid.

https://www.ebay.co.uk/itm/Thermostat-W ... SwOZNckwqz

Ignoring advice based on the long term experiences and knowledge freely shared by members on this forum can be very costly on these vehicles and have severe negative consequences.
Many posters have "been there and done that" and learned the hard way through experimentation what actually works and what does not work, some at a very high cost and have freely shared their experiences and sometimes failures to prevent others from making a similar mistake.
If you choose to ignore their learned advice and generous willing help, you probably should consider a different forum.
Advising owners to do something that has already been proven problematic and possibly detrimental or costly to one of these unique vehicles is not good.
Do not belittle members for their freely shared advice for trying to help others, it certainly will not be tolerated.

_________________
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

I am not belittling anyone...I'm just letting other members, like myself, know that there is at least one con man on here (it is the exact same member that is peddling their ridiculously overpriced wares on the Facebook KJ CRD group too) trying to fleece people out of their hard earned money...I am referring to one particular member who charges more than $500 for a CNC machined replacement for the OEM thermostat!!! So I'm sorry, but their "freely shared advice" can often be completely fabricated lies in order to take down the ultra cheap competition that they see as taking money out of their pocket. The only difference is here they hide behind a nickname whereas on facebook they use their real name.
If the Renault 5 hack was really as bad for the engine as they claim then everyone that has tried it would have quickly reported multiple issues with blown head gaskets, warped heads, dropped valves, overheating etc etc...The fact is the vast majority of owners who have reported overheating and blown head gaskets, did so when using the OEM thermostat, not a Renault 5 inline thermostat.
So you will forgive me if I see their advice as amounting to nothing more than deliberate scare mongering.
Unlike them, I have actually installed the Renault 5 thermostat, and so far it is working perfectly...The minute I get an issue that could only have been caused by it I will let you know...Till then, I will repeat my own freely given advice...I see nothing wrong with the Renault 5 hack.

Actually it's only £16.87 on UK ebay, with free postage...But that is still way too much money for me ...I have been out of work for months...The Intermotor 75035 on the other hand is only £4.27 with free postage, so it was my only option:

https://www.ebay.co.uk/itm/Thermostat-A ... SwMQ5e-uvF

https://www.ebay.co.uk/itm/Coolant-Ther ... SwgFxe9aln

LOL
We all know exactly who you are talking about.
I totally understand about not wanting to spend that much money on a stupid thermostat.
Its my money and I'll choose how to spend it.
So instead, I performed my own modification.
Its not as good as the $500 aluminum piece but it works for me and the bypass outlet will never be blocked. Again, emphasis on the bypass outlet as that has been the key point of this whole discussion.

I have no idea where you live but if you live in a warm climate just toss the in-hose and stick with the factory stuck open thermostat. An engine running too cool is a nice problem to have. Here in Florida, running too hot is a frequent problem for most drivers.


No.
Not quickly.
I ran my in-line thermostat for almost 5 years before any problems start to show.
Started with a small mysterious loss of coolant with no obvious signs of a leak.
Later developed into obvious signs of coolant in the exhaust and quick loss of coolant.

Go ahead and ignore TurboDieselFreak, WWdiesel, and others.
They haven't personally dealt with the problem.
I have.
And I too once sung the praises of the in-line thermostat.
And mine never ever once overheated.
Yet, the head was indeed cracked. The cracks were around the exhaust valve seats of cylinders 2, 3, and 4.
I concluded that the culprit was a coolant flow problem causing 2, 3, and 4 to run hotter than cylinder 1.
The best logical conclusion was my choice of thermostat(s) and the function of the bypass valve (or lack there of).
If you can think of a better conclusion I'd like to hear it.
And no, it was not a improperly installed head gasket from the factory.
Sure, maybe there were other contributing factors but I dont want you to go through what I went through.

The choice is yours.
I wish you the best and enjoy your holidays.

_________________
U.S. Army Retired

I suggest you get rid of the Jeep and get a Renault 5

Just a friendly reminder; name calling of a fellow member of this forum will not be tolerated.
Keep discussions courteous and respectful.

_________________
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

Point noted.

I live in the UK where the average temperature is somewhat cooler that Florida. How many miles had yours done when you discovered the problem?...Mine is still only done under 67,000 miles from new.

I think you may have just gotten closer to the nature of the issue. Where you drive and how you drive will certainly have an impact on the side effects you see or don't see from ad hoc modifications to a complicated engine.

The conceptual issue with the inline thermostat is that it prevents water from circulating as intended until it opens. Normally, when cold, the pump circulates water around the block and head using the bypass. If that bypass is blocked, water cannot circulate during this time. It is *clearly* defeating a feature every engine since the '60s has - and has for good reason.

What's the fallout from this? If your vehicle is only driven short trips, maybe none. Maybe the engine never warms to the point it matters. If you drive at very low speeds, maybe nothing bad happens. Maybe temperature comes up slowly and evenly enough that this lack of circulation poses no issue. But perhaps you merge your from driveway directly onto the motorway and you develop hot spots very quickly due to lack of coolant circulation through the bypass. Maybe it's the opposite of these things. Nobody knows save some VM engineer somewhere. What is being said, however, is that it's understood what the bypass does, why it's there, and why it's important. So we can also intuit that defeating it carries some risk.

Saying "my barely driven Jeep which exists in a cool climate has no issues, therefore it's a good modification" is a lot like saying "I turned the boost up to 50psi, did a quarter mile, and had no issues therefore 50psi is a safe number." Your sample is very narrow, very specific. It's luck and anecdotes not good engineering and repeatability.

Saving ten pounds and risking thousands in damage feels like the definition of penny smart, pound foolish. I get the financial constraints but, man, seems like I'd sign up for uber or mechanical turk or something to make that tiny amount of cash before putting transportation I can't afford to lose at risk.

(And I will toss in the way I got my Jeep was the guy who had it before me did some questionable repairs, broke it, and couldn't afford to fix it. Had he just done it right in the first place - spending US$50 - he wouldn't have taken a $2500 bath on the sale)

Excellent post thesameguy.
Doing anything to one of these vehicles that has already been proven to be possibly risky and very, very, costly for repairs is not the smartest thing to do or worse yet advise others to make similar mistakes.

_________________
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

Er...You obviously don't realise that I can get used VM 2.8 CRD engines, with all the ancillaries fitted, for between £200 and £250 here in the UK, not thousands! So if something ever cracks or breaks, it's cheap to fix it...

How is £250 cheap but £15 too much to swallow?

Where in the UK are all these cheap engines?
For that amount you may get a head!

_________________
Australian KJ CRD 2006

jeepsterkj's mathematics skills leave a lot to be desired, like simple addition and subtraction; even if you were to take him at his word that he can get used junkyard engines at the prices he is stating.

He also clearly does not value his own time because his line of thinking is to buy as cheap as possible and to do the work yourself. He thinks that making major repairs to an engine and the overall vehicle is just par for the course and thinks that the rest of us are O.K. with "Hack" upgrades because we can spend all day repairing our vehicles also. Newsflash, Alf; most of us do not care that you can get a used up junkyard engine core for 250 Pounds Sterling because you are going to have to spend a LOT of money rebuilding it anyway... to compare this with a brand new, extreme quality upgrade part that is properly engineered is nonsensical and shows your overall lack of understanding of manufacturing and market values of parts, both new and used.

December 3, 2020 addendum: I have noticed that jeepsterkj, (A.K.A. Alf Beharie), has not answered thesameguy's question quoted above. This is not surprising because Alf Beharie's method of maintaining vehicles is, ultimately indefensible. What is the point of getting cheap parts - new or used - if you have to put major time and/or money into those parts to make things work correctly, not ONLY in the short term, but years down the road?

Alf Beharie's refusal to even properly replace an O.E. part with another O.E. part when it is available at a rock-bottom price absolutely DEFINES the depth of this man's cheapness, and it will cost him in the end. That is O.K. with me, he can do what he wants with his vehicles... the sooner his CRD self-destructs the better, as far as I am concerned. Perhaps he will then leave Jeep forums such as this and we will no longer have to endure his ridiculous posts.

jeepsterkj, (Alf Beharie):

You are indeed belittling me... which is rather ironic seeing as you have not even tried my product and 100% of my entire customer base have been very happy with their purchase of a Model 001. That is a win/loss record of over 300/0. Every single one of my customers have had nothing but praise for the quality, the design and the outstanding performance of their Model 001 thermostats. You essentially have no basis for your claims other than your own misinformed opinion.

Your opinions on this topic and of me are harsh; it is therefore natural to conclude that you think my customers who think the same as I are fools and have been "taken in" by my slick advertising and "scare-mongering". As such, I hereby welcome all of my customers to now confess on this forum and on the Liberty CRD Facebook Page that I completely pulled the wool over their eyes.

You making accusations that I am a con-man because you cannot understand simple irrefutable principles of cooling system design is patently ridiculous. Your suggestion that I am lying and making complete fabrications about the dangers of the inline thermostat - even after you have been also informed by multiple LOSTJEEPS members of their own experiences and expertise that mirrors mine - show both your ignorance of the topic and a penchant for wilful blindness.

My product is NOT overpriced given the high cost to manufacture it. I have seen the cheap crap you have purchased from China and posted on Facebook, Alf Beharie. You repeatedly brag about how little you spend, even on critical fluids such as engine oil, so there is therefore no point in trying to convince you. However, your insults will not go without repercussions.

As mentioned earlier in this post, my win/loss record is over 300/0. You can not have a better record than that. On the other hand, your record is not so good... I already know from messaging Andy Barrett - the Administrator of the Jeep 4X4 UK Facebook Page and other Jeep Forums - that he has punted you from at least two online forums for your arrogance and your rude behaviour. This is a quote from him... "He put a lot of backs up in my groups, being rude and arrogant. He thinks he's an expert and talks with great authority - and was talking down to some of the guys who have been taking jeeps apart and putting them back together for 30 years - the irony is, he doesn't have a clue what he's taking about - he just googles something, reads half an article then thinks he is a master. He's an idiot."

Please don't feed the troll !