Engine not getting up to temperature.

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Erskine

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My transmission cooler, which is integral to the main coolant radiator, developed a leak about 6 months ago. I couldn't stump up for a new rad at the time so I fitted an aftermarket external transmission cooler up behind the front grill. Since then my gauge stays closer to a 1/4 rather than up at 1/2. It fluctuates a lot depending on the driving, going vertical on big climbs, but then dropping down. Is the transmission oil temp important to the equation or is this a thermostat issue. All received wisdom welcome! I can borrow a laser thermometer, I also have an OBD reader. I'm unclear what to point it at to get the readings to test the thermostat other than the intake hose, where do I go for the second reading, will the ODB give me the second, i.e. where is the the temp sensor in the flow sequence?
 
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turblediesel

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Temp sensor is on the thermostat housing. The original CRD thermostats are overpriced junk. Look into TURBO-DIESEL-FREAK's CRD thermostat. It allows the thermostat to be replaced without buying the housing every time it's replaced. Expensive with a long lead time though.

I don't think transmission temps would affect engine coolant temps much.
 

Erskine

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Temp sensor is on the thermostat housing. The original CRD thermostats are overpriced junk. Look into TURBO-DIESEL-FREAK's CRD thermostat. It allows the thermostat to be replaced without buying the housing every time it's replaced. Expensive with a long lead time though.

I don't think transmission temps would affect engine coolant temps much.
I have neither loads of money or time to wait. Here in the UK we can get new pattern thermostats from between £40 and £70, which I think is less than you guys in the land of the brave and free? The VM engine has been used by a few other vehicles in Europe, mainly commercial vehicles, not just jeeps.
Do you know if the temp sensor measures the temp before it goes in to the thermosat or after, I need to find if it is stuck open.
 

turblediesel

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Temp sensor is in the bottom of the thermostat housing so it's reading just before the thermostat. No heat sounds like it's stuck open. Mine never made much heat at idle. My standard practice to produce heat was to put it in 4wd, lock out the overdrive, and drive like a maniac for a minute.

New oem thermostats were $170.00 in the US last time I looked. Glad you have better prices.
 

Erskine

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Temp sensor is in the bottom of the thermostat housing so it's reading just before the thermostat. No heat sounds like it's stuck open. Mine never made much heat at idle. My standard practice to produce heat was to put it in 4wd, lock out the overdrive, and drive like a maniac for a minute.

New oem thermostats were $170.00 in the US last time I looked. Glad you have better prices.
I have ascertained that it IS a stuck open thermostat. I have found a supplier here that sells a 88 degree one, most of the ones over here are only set at 80 degrees. Fingers cross that will get me up more vertical.
 

mrhemi

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Whichever replacement T stat you can source, hotter is better. The OEM's in North America were way to cold (for emissions reasons). I run HDS1 thermostats in both of my CRD's, 203 deg.f temperature. One of them I have put over 150000 miles with no issues.
 

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