One Hot Car

[neotab]

Just got a "deal" on an '81 380 SL, my first Mercedes.  But it's too hot to drive! Second owner had it for 10 years (and put 14,000 mi. on it; 109,000 total).  A/C hasn't worked for 10 yrs; that's OK, but there's HOT AIR coming out of vents on the dash (near windshield and out of the two outside-air vents); the hot air starts blowing about a minute after it's started.  I have the temp control on auto-lo; didn't think I should turn it off completely. Any way to turn off the heat?

 

[Neil Eglintine]

Sounds like a vaccuum leak to me. The heater controls are worked by vaccuum, and any leak on the system can cause a problem here. Is your central locking working OK as this works on the same system?

 

[Andy]

Hullo Neotab

Check this out. Drop both of the under trays down. Held up with 10or8mm bolts and some self tappers. (I say both as I cant remember which side the nut comes loose on. You will see what I mean.) Close to the centre console you will see a 10mm nut. Tighten this nut which comes loose. Tighten when the heater flap is in the hot position. Then turn to cold position. This should cure your problem. IE. The nut which holds the heater flap tight comes loose causing the flap not to switch off.

For the rest of you which may have heater problems with your merc. The above repair is only for SL'S & SLC'S

Good luck
Andy @mercedesservicing.com

 

[neotab]

Thank you, Neil and Andy.  I'll try the "vacuum-angle" first, as I can't make the master locking system work, and that may be the problem.  The other suggestion is a bit beyond me, but I'll at least sound as though I know something about the problem when I bring the car in to the shop.  Thank you!

 

[petermwatts]

Hi. havent got my mercedes yet, but looking at 380 sel supercharged, see other posts. but on A/C I have porsche 928, and Saab, 9000's all with A/C . I think that with the A/C ON the system heats the air, to remove moisture, and then the A/C cools it to the correct temperature, therefore the the A/C gas is not cooling it this will give the effect of the heater being on. It certainly did in the porsche when the A/C gas needed recharging. so although vacuume leaks etc may well be a factor, I believe that teh air through A/C will always be warm unless the A/C gas is charged, and the system fully working.

Any other thioughts welcome

peter

 

[graham fawkner]

I think I had your problem last month, i.e. VERY hot air in all positions of the temperature and a/c selector. The problem was traced to a coroded fuse which energises the heater valves and, on my car, a 200 TE, also the reversing light. Wire brushing the corosion off the fuse cured the problem. Certainly worth looking at and incidentally made me clean up all the other fuses!!