Overheating 05

TByram · **Joined:** Thu May 14, 2015 10:21 am **Posts:** 8

My 05 keeps overheating when I take it on the highway or am going up large hills I've checked my antifreeze and just replaced my fan clutch and it still happens. Any ideas as to what's wrong/ how to fix it?

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dennyb · **Joined:** Wed Aug 13, 2014 4:27 pm **Posts:** 110

Maybe radiator dirty internally. Or fins outside plugged. We have a very thick stack with all the coolers up front. Bugs or fine dirt (cottonwood fluff) in fins? Temp gun in and out manifolds. See what temperature drop. Is factory thermostat opening fully (mine failed open)? Has the system been flushed and refilled yet?

flash7210 · **Posted:** Fri Sep 18, 2015 12:09 pm

Are you frequently having to add coolant?
Are you using the correct coolant?
The correct coolant is Zerex G-05. DexCool and typical green coolants are not correct and will cause problems.

If you turn the air conditioning off does it still overheat?
Do you have mud or dirt caked in and around the radiator or anything blocking air flow?
Are you towing or carrying a heavy load?

When it overheats, is coolant boiling/venting out of the overflow tank?
Have you ever replaced the thermostat?
Do you have access to a infrared temp gun or other temperature probe to verify actual temperature at the thermostat outlet?
On some CRDs, the temperature gauge is calibrated incorrectly and even though the needle may get all the way to the red, it is not actually overheating. Most of the time the needle should stay right near the 12 o clock position on the gauge.
This is why its helpful to have another tool available to verify actual temperature.

TByram · **Joined:** Thu May 14, 2015 10:21 am **Posts:** 8

I am not having to frequently add coolant usually only once a year.
I am using the correct coolant.
It is overheating without a/c
I have always stopped to let it cool before it completely overheats. So I don't know and haven't noticed any boiling.
I don't have anything blocking the radiator or mud caked in it
And I have replaced the thermostat

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TByram · **Joined:** Thu May 14, 2015 10:21 am **Posts:** 8

And I do not have access to a temp gun

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thermorex · **Posted:** Fri Sep 18, 2015 11:33 pm

Replace the thermostat. It may be stuck on semiopened

papaindigo · **Posted:** Sat Sep 19, 2015 9:08 am

The most common tstat failure mode is semiopen or opening early which will not cause overheating rather it causes over cooling. It is possible the tstat has failed partially closed though which will cause overheating.

IR temp gun $19.95 on Amazon, buy one.

racertracer · **Posted:** Sat Sep 19, 2015 6:29 pm

TByram wrote:

And I have replaced the thermostat

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Well here is what I have to say about this scenario.

1. You replaced the Thermostat buttoned everything up and added coolant to top it off.

2. You didn't remove the trapped air that was in the head.

3. Temp rise due to the trapped air in the head.

4. Head Gasket is about to fail if it hasn't already and possibly a cracked head.

Is this serious ...you ubet your zzz it is.

Ask me how I know.

Procedure on how to properly drain and refill the cooling system.

1. open radiator cap at top of expansion tank.

2. Drain all coolant via the petcock drain at the bottom of the radiator.

3. DO NOT - Open the twist valve at the top of the radiator EVER ... I repeat EVER. opening that valve will permit coolant to flow down from the expansion tank and below the head Allowing air ot set in and all your effort to remove air from the system is for naught.

4. Close petcock valve and fill the sytemwith coolant via the expansion tank.

This procedure is what must be done prior to removing the thermostat.

There is a way to remove the trapped air in the head.

By allowing the air to escape via a cooling system flush T that is placed / cut into the upper most part of the the 5/8" coolant hose at the front of the engine. This hose leads into the egr valve.

http://www.walmart.com/ip/16817507?wmls ... 12&veh=sem

Also, consider any possible air that got into the heater core to be removed.

Or park the car on a steep hill, point the nose to the sky and remove any trapped air via the flushing T .

Good luck......

thermorex · **Posted:** Sat Sep 19, 2015 9:11 pm

papaindigo wrote:

The most common tstat failure mode is semiopen of opening early which will not cause overheating rather it causes over cooling. It is possible the tstat has failed partially closed though which will cause overheating.

IR temp gun $19.95 on Amazon, buy one.

I had the issue of a partially open thermostat, summer regular driving was fine. As soon as you hit a slope longer than couple miles, it overheated. Not a whole lot, just couple ticks past vertical. I realized it is bad in the fall, when it wouldn't heat up the engine past 1/4 mark. I don't think it's a rule on how the thermostat can fail, as I don't see anything inside the assembly that would favor getting stuck on open more than on close, I believe it's just a matter of luck.

On the other hand, I either missed it at the beginning, either the post had been edited, but if the thermostat is new, what I said doesn't apply anyways ☺

seawheeler · **Posted:** Sun Sep 20, 2015 6:52 am

Same problem here. Without a/c running gauge will not go past 1/4. I suspect thermostat is not fully seating. I'm a new owner and am starting to understand this thermostat issue on the CRD. So you have to buy the entire housing just to replace the thermostat, correct? And this will leave you with an unreliable product with the wrong temperature opening. Who said it's the wrong temperature? So you can install an inline stat and retain the old housing after gutting it. This gives you somewhat of a Rube Goldberg looking solution with additional hose clams (read leaks). I've also seen within this forum a guy who mills the top off a stock housing and places a standard goose neck housing on it. This solution gives you the option of installing most any off the shelf stat. And finally if you want to go full Monty you can buy the totally redesigned CNC milled aluminum housing $$$. Did I miss anything?
Has anyone fully tested these modifications for correct water flow? I was wondering about bypass water flow vs a factory housing? And fully opened stat modified vs factory.

95Z28A4 · **Joined:** Sun Mar 30, 2014 9:53 am **Posts:** 297

seawheeler wrote:

And finally if you want to go full Monty you can buy the totally redesigned CNC milled aluminum housing $$$. Did I miss anything?
Has anyone fully tested these modifications for correct water flow? I was wondering about bypass water flow vs a factory housing? And fully opened stat modified vs factory.

I've gone with the "full Monty" and ordered a Hot Diesel Solutions thermostat. The factory stat in my wife's CRD is failing. The engine will only reach normal temp on the hottest of days with the A/C running. I hope to have the HDS thermostat installed before the end of October.

flash7210 · **Posted:** Tue Sep 22, 2015 9:25 am

seawheeler wrote:

So you have to buy the entire housing just to replace the thermostat, correct?

Correct

Quote:

And this will leave you with an unreliable product with the wrong temperature opening. Who said it's the wrong temperature?

Well, it will be equally reliable to the factory thermostat.
The factory opening temperature is somewhere around 176 F. Whether or not this is wrong is open for discussion. But the general consensus is that this engine operates more efficiently in the 190-200 F range.

Quote:

So you can install an inline stat and retain the old housing after gutting it. This gives you somewhat of a Rube Goldberg looking solution with additional hose clams (read leaks).

This is exactly what I have done and I have had no problems with leaks.
I gently cracked open the thermostat housing, removed the thermostat thingy from inside, and then sealed it back up with JBweld. I have a Meziere in-line thermostat housing that holds a 192 F thermostat. I've gone through the entire Florida summer like this with zero problems.

Quote:

Has anyone fully tested these modifications for correct water flow? I was wondering about bypass water flow vs a factory housing? And fully opened stat modified vs factory.

No, no one has tested water flow.
If you know of a way to conduct this kind of test, I'm sure many here would be interested to hear about it.

Depending on how you drive or use your CRD, good airflow through the radiator is very important for keeping the engine cool. The factory fan clutch is known to fail early and engage at too high of a temperature.
Some here, including myself, have been successful with just removing the mechanical fan and only using the factory electric fan. But if you tow heavy loads or drive through steep mountains, a good mechanical fan and heavy duty fan clutch is best.

seawheeler · **Posted:** Sun Sep 27, 2015 7:04 am

Good info Flash, thanks. After considering all the options I really feel the hot diesel housing is the way to go. Not the cheapest initially but over the long run worth it. Next issue on the cooling side will be dealing with the fan.

Flash, do you know what temp your electric fan turns on?

Thanks

WWDiesel · **Posted:** Sun Sep 27, 2015 1:52 pm

A fan clutch issue can cause overheating under loads and / or uphill runs??? :roll:

For a better and cheaper mechanical fan / clutch option, view this thread:
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=82941
:wink:

Overheating 05

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