I've been having issues with my 1998 C280 (has about 113,000 Miles) heating and cooling. When it heats, it doesn't heat like it's supposed to. And when it cools, it doesn't cool as it's supposed to. Today I took some readings with a thermometer in the air vent. Could anyone please look at these readings and help me diagnose the issue.

I did the test at night, the atmosphere temperature was about 55 F.

I drove the car around for about 30+ minutes in the city and had set the air to MAX heat (HI) and the max temperature the thermometer could read was 110 F (I had stuck the thermometer int he air vent).

Then I drove it again for another 30 minutes with the temp set to LO (AC) and the coolest temp I could record was 50 F.

Here's the kicker, which I drove for about an hour, the coolant temperature gauge barely made it to the 60 mark. It mainly stayed close to the 50 mark. Isn't that a little too low? or is it normal?

Thanks for your help and time.
Bullish.


I did the same tests on my 1995 Geo metro, the max heat it blew was 1140 F and max Cool air was around 35-40 F.