Okay guys, here's a new one......

My daughter's 1986 240GL isn't producing any heat.
The car warms up to operating temperature, (right in the middle of the gauge or slightly above center), but the heater is only blowing slightly warm air.

I replaced the thermostat thinking that might be the problem. Unfortunately that didn't fix the issue.

I also tried the following: I removed the radiator cap and allowed the engine to run. When I did that, I started getting really warm air but of course the temperature gauge started to rise and the car began to overheat. As soon as I put the radiator cap back on the tank, the temperature fell and the warm air stopped flowing out of the vents.

Could my radiator cap be causing this problem?
If not, what could be the cause of no heat?

I live in Illinois and the temps are starting to get pretty cold. A good working heater is a must, especially if you are a 17 year old girl.

Thanks in advance for any help you can give.


Dave
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I dream of a world where a chicken can cross the road without having its motives questioned.