I need help
 

how do i get heat in a 1988 sel mercedes 650?

I just got the car not too long ago and cannot seem to get heat. I have changed the thermostat thinking that was the problem but its not. I can only get cold air....please help.....:confused:

Do a search on monovalve. Sounds like you may need to replace it.

Touch the hoses on the monovalves, ie before from engine and after to the heating radiator , if that one before is warm (be carfull temperature can reach 85°c) and the other not, there is the problem.
if there is an auxillairy pump you should ear the sound and feel pressure schocks on the hose.

Good luck