heat all the time on my 74 450sl

[daxter]

wow heat all the time...i have the 4 lever type controlls..i know the vent must be open..it wasnt before..should i take it all apart and see if its a rod?..anyone have this before and know how to fix it? thanks

[jerryb]

The control valve for hot water is under the hood on the fire wall. The valve may be bad or you could have a vacuum leak.
You can unhook the linkage and tie it closed.

[daxter]

well i spent a few hours under the pass side...took it apart..not much going on there..i saw one controll and it was working..so this is what happened..all was good untill last week...then tons of hot air would come into the car specially while driving down the road..the defrost works..but never had hot air pumping into the car while driving before..stuck something? think maybe the vent door seal went bad maybe? and can i fix it or do i need the shop to take my life savings...was going to stop the water going into the heater box but that wont stop all the air...help...thanks

[LOWMILE]

Hey Daxter I feel your pain my 72 350SL has the same levers as your car! I had to remove the lower dash panels you know the ones that run from your foot to your knee and are the color of your interior...after removing these panels on both side of center console you will see the lever rods that move the heat on off valves. In my case even though you moved the levers towards "cool" heat would rush in at speed...I lubed up and then worked the levers carefully so as not to damage them...then I loosend up the nuts on each clevis pin (joints on lever assembly) then sprayed a little more wd 40 and spray lithium on links and rods and retightened. This takes a little trial and error. The first time I tried this the levers were stuck "heat on" and would not move all the way (heat stuck in on position) If they are not tight enough the rods will not open and shut heat valves properly. In thes old 107's the balance of tight enough can be reached with trial and error so leave the interior trim panels off for a couple of days until you get the levers working just right. I would take some pictures but my car is at the paint shop. Good luck Daxter let me know if this help's or if you need some pictures.
Ernie

[daxter]

thanks ernie...i chickened out and dropped it at the shop to see what they think...they probably think 1000 bucks..but least ill get an estimate...maybe they wont rip me and tell me the truth...i will be sure to post what my problem was so the next guy can have a heads-up about it...thanks to everyone that has had this heat-ache

[LOWMILE]

I have a money nazi at home that hates when I spend money on my 107 so I try with the help of this wonderful site to fix things on my own. Good for you that you can afford to just drop your car off! Ask your mechanic what the problem was and then post. I am curious my heat stuck on problem went away after adjusting the clevis pins and lube of same. You have to work the lever as I remember and loosen and then retighten the very short 8 or 10 millimeter nut and bolts as you work the lever towards on then off...what happens is the lever feels like it is doing something but it isn't it all becomes very easy to adjust and try, if you get the nut and bolt to tight the lever works hard to loose and the lever stays towards one position or the other. I wish I had my car here I would take pictures for you. Good luck with your mechanic Daxter let me know how you end up.
Ernie

[LOWMILE]

Hello Dax
How did you make out with the heat problem?

[LOWMILE]

whoops I must remember to proof read

[daxter]

had it fixed...shop said it was a vacuum leak under the hood on 2 lines...when he fixed that it fixed it all....wish i knew that...so now it all works..guess it was keeping the valve open with no vac and that let in the water which caused the heat...now all i need is a valve job...sucks to fix anything..but thats how it goes