LOST JEEPS :: View topic - Coolant will not get to temp in cold weather

Hi All,
I purchased an 06 CRD march of last year, it wasnt getting up to temperature so when i did the head gasket,timing, water pump, egr delete I replaced the thermostat as well with a new Stant one from Rock auto. It seemed to be working fine but by now the temperature outside has warmed up, so fall came again and when it's cold outside, my coolant temperature only gets between 118 and 131F at highway speeds 100 kms/hr 1900 RPM. If i am towing or rev the vehicle up to 3000 rpms going up steep hills, the temp will go to 178 and then drop right back down when RPM go back to under 2000. The heater seems to work fine, I thought maybe it was a bad Thermostat from Rock auto, so I again replaced it with an OEM thermostat from a vehicle where the thermostat worked. I am stumped, does anyone have any suggestions? I have tried putting a rubber membrane in front of the grill, that seems to help a little but only a few degrees.
Thanks,

Billybob wrote:

Does not set a CEL on US models. Mine on an 05 has been out for several years now and no DTC.

You can pull out the relay for the viscous heater from the fuse/relay box (PDC) under the hood.
This let's the pulley run free.

It will post a CEL but try this out for a while to see if it makes a difference.

Thermostat installed facing in the right direction?
I have never worked in this area so I do not know if doing this would make it run hotter or cooler.

Ok looks like I will be driving like this from now on. I installed a clear hose from TS to RAD with the hose capped off, when jeep is cold, the hose filled up with coolant but did get to temperature. I would assume this should only happen when the TS is open. I bought a new Thermostat (this is the 3rd replacement), did the hose test, same thing. I installed everything the way it should be yet still not getting up to temperature with the yet again new thermostat. This is my first and last GM vehicle, I am gong back to German engineering. Am i missing something? does anything need to be done with the new thermostat prior to installation? some sort of calibration?

Author:	xsfpns [ Sat Feb 01, 2020 11:34 am ]
Post subject:	Coolant will not get to temp in cold weather
Hi All, I purchased an 06 CRD march of last year, it wasnt getting up to temperature so when i did the head gasket,timing, water pump, egr delete I replaced the thermostat as well with a new Stant one from Rock auto. It seemed to be working fine but by now the temperature outside has warmed up, so fall came again and when it's cold outside, my coolant temperature only gets between 118 and 131F at highway speeds 100 kms/hr 1900 RPM. If i am towing or rev the vehicle up to 3000 rpms going up steep hills, the temp will go to 178 and then drop right back down when RPM go back to under 2000. The heater seems to work fine, I thought maybe it was a bad Thermostat from Rock auto, so I again replaced it with an OEM thermostat from a vehicle where the thermostat worked. I am stumped, does anyone have any suggestions? I have tried putting a rubber membrane in front of the grill, that seems to help a little but only a few degrees. Thanks,

Author:	TKB4 [ Sat Feb 01, 2020 11:49 am ]
Post subject:	Re: Coolant will not get to temp in cold weather
Curious if the absolute max temp you can get it to is 178 F then that would seem like the thermostat is opening when it should and therefore cannot be stuck all the way open. The only explanation I can think of is the thermostat is being bypassed through the radiator all the time and therefore doesn't need to open unless the bypass flow isn't enough to keep it below 178F . If this is the case its possible a coolant hose from head, block could have been plumbed in after the thermostat. WW diesel has a good coolant flow diagram here that might help diagnosis. viewtopic.php?f=5&t=90894 Did you try to eliminate something like the viscous heater etc besides the normal EGR delete process?

Author:	xsfpns [ Sat Feb 01, 2020 12:05 pm ]
Post subject:	Re: Coolant will not get to temp in cold weather
Thank you for your response. No extra hoses were plumbed in after the egr delete and head gasket. All i did was remove the Y hose and joined it directly and put a plug in the head where the hose used to go. I did not try to eliminate the viscous heater, how would one do that? just join the two hoses going in and plug the holes on the viscous heater? Thanks,

Author:	WWDiesel [ Sat Feb 01, 2020 3:06 pm ]
Post subject:	Re: Coolant will not get to temp in cold weather
Have you tried seeing what the thermostat housing temperature is reading using an IR gun. Maybe your gauge sender (temperature sensor) or gauge is not reading correctly. Just a thought....

Author:	PZKW108 [ Sat Feb 01, 2020 3:40 pm ]
Post subject:	Re: Coolant will not get to temp in cold weather
xsfpns wrote: Hi All, I purchased an 06 CRD march of last year, it wasnt getting up to temperature so when i did the head gasket,timing, water pump, egr delete I replaced the thermostat as well with a new Stant one from Rock auto. It seemed to be working fine but by now the temperature outside has warmed up, so fall came again and when it's cold outside, my coolant temperature only gets between 118 and 131F at highway speeds 100 kms/hr 1900 RPM. If i am towing or rev the vehicle up to 3000 rpms going up steep hills, the temp will go to 178 and then drop right back down when RPM go back to under 2000. The heater seems to work fine, I thought maybe it was a bad Thermostat from Rock auto, so I again replaced it with an OEM thermostat from a vehicle where the thermostat worked. I am stumped, does anyone have any suggestions? I have tried putting a rubber membrane in front of the grill, that seems to help a little but only a few degrees. Thanks, Where do you get the temperature reading from, OEM gauge, aftermarket gauge, ir gun, OBDII ? If your temp reading are good it looks like a thermostat stuck open !

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Author:	TKB4 [ Sat Feb 01, 2020 5:30 pm ]
Post subject:	Re: Coolant will not get to temp in cold weather
Without much detail the few that have totally remove Viscous Heater replaced it with a different pulley and/or serpentine belt length but didn't gain much if anything in the way of mileage or power. You would do as well bypassing the hoses and disabling the clutch. You can search for threads . Flash and I think Mountain Man have posted about it. you could also see if the temp guage will actually work by performing the instrument cluster test. Doing this u should see all the gauges function I think the temp goes from low to about 1/4 and about 1/2 and high during the test if it has the capability of reacting appropriately . Perhaps temp sensor is intermittent or just miscalibrated especially if the heat seems to be working normally. That seems most likely since its unlikely that the second thermostat suddenly malfunctioned just because it was swapped. I had a short in wire harness going to the thermostat that caused intermittent hot reading and could be stopped for a while by wiggling the wires. It seems prudent to get an infrared reading though unless you find a short or guage doesn't function

Author:	Billybob [ Sun Feb 02, 2020 2:47 am ]
Post subject:	Re: Coolant will not get to temp in cold weather
You can pull out the relay for the viscous heater from the fuse/relay box (PDC) under the hood. This let's the pulley run free. It will post a CEL but try this out for a while to see if it makes a difference. Thermostat installed facing in the right direction? I have never worked in this area so I do not know if doing this would make it run hotter or cooler.

Author:	WWDiesel [ Sun Feb 02, 2020 2:53 am ]
Post subject:	Re: Coolant will not get to temp in cold weather
Billybob wrote: You can pull out the relay for the viscous heater from the fuse/relay box (PDC) under the hood. This let's the pulley run free. It will post a CEL but try this out for a while to see if it makes a difference. Does not set a CEL on US models. Mine on an 05 has been out for several years now and no DTC.

Author:	flash7210 [ Sun Feb 02, 2020 1:53 pm ]
Post subject:	Re: Coolant will not get to temp in cold weather
Lets back up a bit here... Exactly how cold is it? Yes, the factory type thermostat sucks but its likely functioning normally. Plus you say the heater is working great. Well, the heater is actually a small radiator. So if your heat is running full blast, its gonna cool your engine temperature. I remember one time, driving up a mountain in Tennessee, below freezing and snowing, heater at full blast... Going up the hill engine stayed at full operating temp. Coming down the other side, coolant temp dropped to about 130F.

Author:	Billybob [ Mon Feb 03, 2020 3:11 am ]
Post subject:	Re: Coolant will not get to temp in cold weather
WWDiesel wrote: Billybob wrote: You can pull out the relay for the viscous heater from the fuse/relay box (PDC) under the hood. This let's the pulley run free. It will post a CEL but try this out for a while to see if it makes a difference. Does not set a CEL on US models. Mine on an 05 has been out for several years now and no DTC. Cool!...mine definitely sets a CEL which is a bit of a pain...I tried breaking the wire from the relay to the viscous heater and that likewise sets a CEL

Author:	xsfpns [ Mon Feb 03, 2020 1:35 pm ]
Post subject:	Re: Coolant will not get to temp in cold weather
Thank you everyone for the input. I removed the Viscous Heater relay and took it for a test spin, still no difference. I used my IR gun on the hoses just after parking and the hose from Thermostat briefly read 130F as well as both hoses going to viscous heater/cabin. The hose coming directly from the degass bottle read 178. after approx 10 minutes of idling, all hoses dropped to 118F. Yes i am getting heat however it is not as hot as my friend's CRD. it is still warm enough for me. I just don't like the engine not being up to optimal running temperature. Just after doing the head, i don't want any other issues. In response to one person mentioning if i have the tstat in wrong, it can't go in wrong, it's all in one housing (horrible design). Also, considering this is three different tstats, i don't think that is the issue lol.

Author:	flash7210 [ Mon Feb 03, 2020 5:51 pm ]
Post subject:	Re: Coolant will not get to temp in cold weather
It is absolutely a thermostat problem. The factory style thermostats suck. Period.

Author:	xsfpns [ Mon Feb 03, 2020 7:00 pm ]
Post subject:	Re: Coolant will not get to temp in cold weather
I find it hard to believe that it is a thermostat problem... I replaced with new one and didn't work... Sure it's possible it was a faulty one but then I replaced it with one from a jeep where I knew it was working. I replaced sensor and all. My new one I thought was faulty I gave to a friend and it works in his Jeep.

Author:	APC9199 [ Mon Feb 03, 2020 7:36 pm ]
Post subject:	Re: Coolant will not get to temp in cold weather
Just tossing my 2 cents in the ring. Has the entire coolant system been properly flushed using a solvent designed for coolant systems? Are you positive that only the proper coolants have ever been used and that no two different kinds have ever been mixed? Have you taken steps to ensure that there are no air bubbles/pockets in the system? Does your coolant cap seal properly? Have you checked all the hoses for kinks? Also, I would go back and read the EGR delete instructions again and TRIPLE check that you router everything correctly. Coolant that is routed too heavily through the radiator will be too cool throughout the entire system, which ultimately will not do much damage. Coolant that is NOT circulating properly in the system will absolutely lead to catastrophic engine failure eventually. This is something you want to get figured out quickly. The fact that you seem to have already eliminated what most of us would consider the 95% most likely cause means something potentially more sinister is happening.

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Author:	thesameguy [ Mon Feb 03, 2020 11:25 pm ]
Post subject:	Re: Coolant will not get to temp in cold weather
Is it possible the fan clutch is stuck engaged? That happened on an old Suburban. Couldn't really tell from inside the cabin, but with your head under the hood it was obvious. The fan would have minimal impact at freeway speed, and in fact could make cooling worse, but it would keep temps pretty low at lower speed.

Author:	TKB4 [ Tue Feb 04, 2020 7:34 am ]
Post subject:	Re: Coolant will not get to temp in cold weather
A stuck fan clutch seems like a viable possibility. You could check temp of block and head with IR and compare that to the friends when fully warm. The reason I say that if there is some blockage in the coolant system its not significant in the radiator or it would be too hot and though unusual if it was blocked somewhere in the engine itself so that it isn't exchanging the heat well then there might be an indication by the IR but not necessarily. Unplugging the viscous heater will make it run cooler if anything and not heat cabin as well when cold. Unless you find something causing it , I would just keep closing off flow to radiator till it stays warmer but doesn't overheat. You could also remove the fan at least for a while. I have the fan totally removed from one of mine all the time even in 95 degrees running the ac it doesn't overheat, but I only tow with that one in the winter.

Author:	xsfpns [ Wed Feb 12, 2020 7:39 pm ]
Post subject:	Re: Coolant will not get to temp in cold weather
Update The fan clutch seems to be working properly, I am able to stop the fan with the core of a paper towel roll. After an hour drive, I checked the temperature of the block by where the thermostat is with my gun and it's showing 165 F, it's 130 just after the thermostat where it does to the Rad. As i was taking the temperature after my run I noticed the clutch on the viscous heater would cut out at 3 second intervals and then run for 5 seconds. I am not sure if it's supposed to be doing that or not.

Author:	xsfpns [ Tue Feb 25, 2020 5:40 pm ]
Post subject:	Re: Coolant will not get to temp in cold weather
Ok looks like I will be driving like this from now on. I installed a clear hose from TS to RAD with the hose capped off, when jeep is cold, the hose filled up with coolant but did get to temperature. I would assume this should only happen when the TS is open. I bought a new Thermostat (this is the 3rd replacement), did the hose test, same thing. I installed everything the way it should be yet still not getting up to temperature with the yet again new thermostat. This is my first and last GM vehicle, I am gong back to German engineering. Am i missing something? does anything need to be done with the new thermostat prior to installation? some sort of calibration?

Author:	TURBO-DIESEL-FREAK [ Tue Feb 25, 2020 7:36 pm ]
Post subject:	Re: Coolant will not get to temp in cold weather
Billybob wrote: You can pull out the relay for the viscous heater from the fuse/relay box (PDC) under the hood. This let's the pulley run free. It will post a CEL but try this out for a while to see if it makes a difference. Thermostat installed facing in the right direction? I have never worked in this area so I do not know if doing this would make it run hotter or cooler. It is impossible to install the thermostat in the wrong direction as it is in it's own housing. xsfpns: You could be dealing with more than one problem. One thing I can tell you is that it is highly unlikely that the viscous heater is the problem. I also do not think that the modifications to the EGR system are to blame, either. WWDiesel makes a good point; and I will elaborate on what he wrote. There is an issue from time to time with the O.E. temperature sending unit. To eliminate that possibility, please get an actual temperature reading in degrees using an OBDII reader or a Torque Pro app with your mobile device. Cross-reference that temperature reading with a reading from an infrared temperature gun pointed st the top of your thermostat. These two readings should be the same or within a couple of degrees of each other. If they are significantly different, (10 degrees or more), then it is likely that your O.E. temperature sending unit is malfunctioning and must be replaced. This test assumes that the IR gun is functioning accurately. DO NOT trust the O.E. temperature gauge. It is neither accurate or linear. You have the classic signs of a failed thermostat, but even a new thermostat does not operate the engine at a high enough temperature. The rest of the world gets a 195 degree Fahrenheit thermostat; all North American Liberty CRD vehicles get a ridiculously low 176 degree Fahrenheit to meet the Environmental Protection Agency's NOx pollution control standards. This is the crux of the problem with CRD engines running too cool; the quality of the O.E. thermostat that fails too often is also a major contributing factor.