Okay sorry to keep posting but still need help. Have a 1989 190E with the 2.6L in it, it has no heat no matter how hot I let the car get it still blows room temp air, any ideas? does this car have a monoblock valve like the 1980s 123 diesels? I flushed the coolant system twice, and changed the T-stat. Also the fan will run for a while and then shut off, it just goes click and then nothing have to turn the car off and then it will work again. Are these two things related? Also the fan control the one in the middle of the dash does not turn all the way up agian maybe a spearate issue but might be worth mentioning. Have done a forum search to no avail, any help you might give would be great thanks in advance

That car uses a vacuum heater valve under hood. IF you disconnect the vacuum line the heater MUST work.

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MERCEDES Benz Master Guild Technician (6 TIMES)
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190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
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Thanks M.B. Doc, where under the hood is this vaccum valve? on the firewall or? thanks again

Under the plastic air intake beneath the wiper area.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Thanks M.B. Doc will try that as soon as I get home any idea about the heater/ac fan going click and then not working?