# HELP... Diesel not warming up at ALL



## BlakeCary (Jan 11, 2017)

I would say yes to thermostat, When they fail they fail open which doesnt allow it to warm up.


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## jblackburn (Apr 14, 2012)

Yes, sounds like a thermostat. It may flag a CEL for it eventually if it continues.


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## Texas17 (May 25, 2017)

Any info out there on Diesel thermostat changes?


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## boraz (Aug 29, 2013)

or shutter failure


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## [email protected] (Mar 16, 2017)

Texas17 said:


> Any info out there on Diesel thermostat changes?


I can't find a how-to or anything like that but the GM number is 12647027. It comes with the housing and is #37 in this break down.









I will try to do some more digging tomorrow for you when I have a chance.


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## sailurman (Sep 29, 2016)

Texas17 said:


> 2015 Cruze diesel with approx. 90,000... noticed its started to take longer to warm to temp. Now it doesn't want to come up to temp at all. I commute 54 miles to and from work, and if outside temp is cooler than 50 degrees she wont get past a quarter on gauge. Could it be thermostat hung open? Or something else? no codes, and *running tune and delete*.....


Texas17, is this something that just happened? When did you do your tune? I know that when I tuned my Sonic the water temp was set at a lower temp by design (20F lower).


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## Texas17 (May 25, 2017)

Sailurman, no tuned at 18,000 and just started a few days ago, started noticing it taking longer then not at all. only if your in throttle heavy does it build heat......


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## thebac (Jul 29, 2017)

As the others have said, its the thermostat.


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## steveg241 (Jul 18, 2013)

As said above, probably the thermostat. I've had this happen in a couple cars and it's usually just a replacement and you're good to go. Your fuel economy may tank before you get it fixed so getting it fixed sooner is better for your wallet.


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## Texas17 (May 25, 2017)

WTF.... Noticed oil leak so started checking, coolant res is full of engine oil.... what do i look at now? runs fine, not sure whats going on....


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## jblackburn (Apr 14, 2012)

Texas17 said:


> WTF.... Noticed oil leak so started checking, coolant res is full of engine oil.... what do i look at now? runs fine, not sure whats going on....


Uhhhh...oil cooler? Don't think weve seen this yet on a diesel here. 

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## MRO1791 (Sep 2, 2016)

Texas17 said:


> WTF.... Noticed oil leak so started checking, coolant res is full of engine oil.... what do i look at now? runs fine, not sure whats going on....


Oil in coolant, that is a big problem. My Saturn had extended coverage for a casting flaw that affected some cars (not mine, thankfully). That casting allowed oil to get into the coolant, and it was quite the hassle to get it cleaned up if it happened. Not sure of anyone else who's seen this. Could also be a head gasket failure, where the oil is getting past that gasket and into the coolant channels, it would be odd to have no other symptoms, but it is possible.


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## Texas17 (May 25, 2017)

Whats in the coolant tank isn't milky, so its got me pretty confused....Lots of videos of gas Holdens with this but no diesels


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## Cruzator (Dec 31, 2014)

My initial response is the same as Jblackburn's - possible oil cooler failure. Since you are tuned, if you are running high boost, could be the head gasket.


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