crasher wrote:
Thermostat housing was replaced in 2015 when the timing belt job was done.
I had to replace the leaking thermostat gasket last fall before I decided to get TURBO-DIESEL-FREAK's housing.
Then I put the housing replacement off waiting for decent weather when I could make the time for the swap.
I don't drive the CRD very often, I don't need to drive much lately, I have about 4K miles on in the last year, so I've been putting off the housing replacement until I had time in warmer weather to tackle the job. Old guys like me aren't as limber and agile as we were back when we were doing musclecar engine swaps years ago....
I changed the oil and rotated the tires yesterday, which reminded me what it was like when I used to do stuff like that without needing to plan for a good day.
Anyway, I'm guessing that the temp gauge suddenly reading 'lower' is due to the stock thermostat failing open, and it's time to do the swap NOW?
It's still hovering in the upper 40's most days around here when I have time, it's just starting to warm up on a regular basis.
Does the LostJeep Hive Mind believe that the thermostat housing swap will most likely solve my temp gauge issue at this time?
I'm assuming I need to kick my motivation up a few notches in the next few days.
Thanks for any ideas or comments.
Hello, Crasher:
Before jumping to any conclusions and rushing to get another thermostat, I think it would be prudent to see if either the O.E. temperature sending unit or the O.E. temperature gauge has failed first.
Please perform both of the following operations to determine exactly what your engine's actual measured temperature is once fully warmed up. I do not trust the O.E. temperature gauge as it is neither accurate or linear.
1) Use either an OBDII reader or the Torque Pro Application on your mobile device to measure engine operating temperature through the engine's computer. Take and record a reading after the engine is fully warmed up.
2) Once the engine is fully warmed up, take a cross reference engine temperature reading by aiming an infrared temperature gun at the top of the thermostat.
The two temperatures should be the exact same or almost exactly the same. If they are not, it is therefore likely that your O.E. temperature sending unit is malfunctioning. All of this assumes, of course, that your infrared temperature gun is accurate.
The temperature readings not only need to be the same or almost the same; they need to be "in agreement" with the known needle position for that temperature on the O.E. temperature gauge. Years ago, somebody posted a photo on LOSTJEEPS of the O.E. temperature gauge with the image of the needle at various positions on the gauge and the measured temperature readings of the engine at each needle position. If your temperature readings correspond to a different needle position that what is indicated in this image, (or, different than what another CRD vehicle indicates is correct for that measured temperature), then your temperature gauge is likely malfunctioning.
I really need to hunt this image down and store it on my computer for future reference. If a member has this image, I would really like it e-mailed to me, (INTCOMBUSTION2@hotmail.com). The engine operating temperature for your CRD engine should be at least 175 - 176 degrees Fahrenheit with a functioning O.E. thermostat assembly. As I have said many times before this is way too cool for long term reliability of the CRD engine, which is why people have been trying various methods to get the engine operating temperature up higher for years now. Any significant amount lower than 175 - 176 degrees, (say, 160 degrees or lower), then I would say that your O.E. thermostat has prematurely failed, and should be replaced.
I require some more information regarding the thermostat assembly currently on your CRD engine... How many miles have you put on since you replaced the thermostat in 2015? Was the replacement O.E. thermostat assembly an item purchased through a dealer or through I.D. Parts? Was this part purchased online, and is perhaps a Crown knock-off part?
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