I have been noticing that my manifold temperature has been creeping higher on my ISL 370 w/80K miles. It used to be 10-14 degrees F higher than ambient temperature. But now I'm seeing (via Silverleaf) 18-20 degrees higher than ambient temp. Fuel milage is decreasing too. Ambient temp today was from 88-92F. Anyone have any insight of possible causes? TIALarry

How clean is the charge air cooler (CAC) and has the engine coolant temp been holding at normal average?

Yup, blockage of air flow through the CAC is the most likely cause.With a side radiator, could also be that the hydraulic fan or fan control is failing to provide needed RPM. But, that would normally also lead to higher engine coolant temperatures.

Failed to mention/tranny Temps are normal. 180-195

Thanks for the inputs. I'm going to try changing the air filter and see what that does. It's been a while since I changed it. Indicator looks good but, I'm told unreliable. Also have noticed increased black soot on tail pipeLarry

The air filter minder is easy to test. Pull the hose off the filter/pipe between filter and turbo. Suck on it. The indicator should peg at highest reading and stay there until you push the reset button. Reset.BUT, you are absolutely correct, a high air filter minder reading is just one of the reasons for replacing the air filter. Remember, if the filter pleats have a crack in them (that is why you NEVER remove and bang a filter to remove dirt) the air filter minder reading will always be low.Filters are made of paper. They degrade with time. Good idea to replace every three years whether they filter minder suggest a problem or not.

Intake manifold temperature creeping higher | Good Sam Community

14 Replies

lfeather
Explorer
Jun 22, 2015
Thanks for the inputs. I'm going to try changing the air filter and see what that does. It's been a while since I changed it. Indicator looks good but, I'm told unreliable. Also have noticed increased black soot on tail pipe

Larry
lfeather
Explorer
Jun 22, 2015
Failed to mention/tranny Temps are normal. 180-195
wolfe10
Explorer
Jun 22, 2015
Yup, blockage of air flow through the CAC is the most likely cause.

With a side radiator, could also be that the hydraulic fan or fan control is failing to provide needed RPM. But, that would normally also lead to higher engine coolant temperatures.
Dale_Traveling
Explorer II
Jun 22, 2015
How clean is the charge air cooler (CAC) and has the engine coolant temp been holding at normal average?

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Intake manifold temperature creeping higher

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