Engine heat

[Holden Lewis]

I have recently purchased a 1966 230SL that recently had a 280 engine put in it.  The car seems peppy, but puts out a lot of heat back into the passenger compartment and is very uncomfortable.  It is an automatic transmission.  What is causing this heat?  I am new and this is my first posting.  Thank you.

[Cees Klumper]

Is this heat coming out of the vents? If it is (most likely it is) then your heater controls are not operating properly. The controls on my car work fine and I can regulate the temperature inside the cabin just like I want to - except when it gets very cold in winter, I would like just a little bit more heat.

[Rolf]

I too have a similar problem with the heat in the cabin. Until I get around to getting it fixed, I have the heat directed through the defrosters. It helps a lot.

[seattle_Jerry]

Rolf...why not turn the flow off to the heater core by hand in the engine compartment? Isn't there a valve that might be too stiff for the dash knobs to turn but turnable with a wrench, mallet etc. when addressed directly?

Holden...even if it isn't coming out of the vents make sure the duct that attaches to the vent isn't unattached and blowing heat from behind the dash.

The only other thing I could think of from other than SL experience is maybe something is off in the engine setup and your "headers" are glowing red creating a lot of heat (not that they aren't a little hot already).

[Holden Lewis]

This is holden.  I am not sure if I am replying properly to your comments.  The heat seems to come in from under the dash.  I do note that the heater control knobs seem stuck, but the heat does not seem to come in from the dash.  It sort of sneaks in from underneath the dash.

[seattle_Jerry]

If it is coming from high on the dash I would think it is a disconnected heat duct or one with a hole in it.

Exhaust heat would be a bit lower...just above the footwell

[Richard Madison]

Just to add that there should be a heat shield under the car between the exhaust pipes and the floor under the passenger seat. Not sure if this is your problem but without the shield, the passenger floor can  can get quite warm.

The shield is a steel plate about 1/8 inch thick, maybe 3 feet long. The slightly curved left edge fits between the pipes and the floor while the right side is screwed to the floor pan. It goes above the exhaust pipes where they pass below the passenger seat area.

The shield is in 280SL's...not sure if it was installed in the earlier cars.

Probably a good idea to fashion one from scrap plate if it is missing.
 
The arrow in the photo points to the edge of the shield.
 
Richard M, NYC

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