New member

Re: IMAT high temperature

Thank you very much AIH.


The ambient temperature is hot,  which is around 40 degree C, I observed the IMAT temperature only decrease when there is a cold wind blowing.

The engine was set up at offshore open area with no rooftop.


I will check your recommendation and other possible caused.


Best Regards,



Trusted Contributor
Trusted Contributor

Re: IMAT high temperature

You don't mention just how hot the ambient temperature is in your location but if the ambient temperature increases to over 100 deg F, that certainly could cause the engine IMAT to increase.  Other conditions that could affect the IMAT is the engine air/fuel ratio.  If the air/fuel ratio is too rich, this might increase the inlet air temperature.  For a 2 gram NOx engine, the exhaust should show 310 ppm NOx; for 1.5 gram NOx rating, you should see 240 ppm; for 1 gram NOx you should see 140 ppm and for 0.5 gram NOx, you should see 60 ppm NOx.


Another item that could cause high IMAT, is if the auxiliary cooler cannot cool the coolant for the aftercooler.  The engine is designed for nominal 130 deg F coolant temperature.  If the auxliliary cooler section is experiencing debris plugging on the outside, this hinders the air flow through the cooler and the coolant will heat up, causing higher IMAT.


The engine aftercooler core could have some plugging on the air flow side.  You can check this by measuring the pressure differential across the a/c core.  A clean core would have only 1 psi restriction.  If the pressure differential across the core is 4 psi or higher, then the a/c core cannot cool the air coming from the turbocharger.  If this is occurring, you will have to remove the a/c core and clean or replace it.


These are some items to be checking on for your recent IMAT increase.


Best Regards,

Al Hunt

New member
Accepted Solution

IMAT high temperature



I'm an operator for gas compressor, we use Cat G3516 Tale engine coupled to Ariel Comp JG-2. 


Recently the engine developed high IMAT temperature which the value was around 68-70 degree C, and cause the engine shutdown. Normally the IMAT temperature was around 56-62 degree C.


What are the caused other than the hot weather? Are the air intake prob sensor dirty? Do we need to replace the sensor?


I hope for a good feedback soon.


Sorry for my bad English.