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I suspect you have a bad fan clutch they are notorious on this vehicle for having problems under load when they get worn. Here are the procedures to test it. Most likely you will need to replace the fan clutch to fix the problem. If this was helpful please take a moment to press ACCEPT. Thanks in advance Danny
The fan clutch was just replaced
Did they do a coolant pressure test?
Not sure ! I have gauges in my truck ( aftermarket )
Nothing that checks the pressure though
What would that determine ?
There are two options causing this if the clutch is for sure good. You have a leak in the system or blockage or the engine coolant temp sensor is faulty, You should have a coolant pressure test done to see if there is a leak then have the radiator removed and ensure proper flow. If this checks out I would replace the temp sensor
There is a picture which shows the location of the coolant temp sensor
The temp backs down quick after dropping rpm's
I suspect there is a problem with the radiator having a blockage or the water pump is no longer performing like it should
Both of these can cause this to happen
The water pump was replaced last spring !
Leaves the radiator
Let me know if you have any further questions. If this was helpful please take a moment to press ACCEPT. Thanks in advance Danny
replace or ?
You can have it removed and checked for flow and ensure its not just a blockage that can be cleared
Would not want to waste money on something that can be fixed easily
What about egr valve not working properly ?
Not going to cause this
Thanks dude I hope your right , i am replacing EGR valve anyway and thermostat !
Ok just make sure you check that radiator I also recommend a pressure test they can pressurize the coolant system with the vehicle off and see if there are any small pin leaks
First thing I do with every cooling issue at the shop