I have been having some issues with the heater in the car not getting hot enough when it was working good it would almost burn you if you held your hand on the vent now it is about half is hot. I have changed the mono valve and replaced the recirculation pump about a year ago and it is still working does anybody have any ideas what might be the problem I suspect the climate control unit I have replaced all the vaccum units in the dash and have also tried to remove the connector at the mono valve to give it full heat but it is still just warm not hot air blowing out.

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84 300 Turbo / 320,000
96 E300 D / 55,000

Does it start of hot, then cool down?

What is the condition of the foam hose that takes sample air to the temp sensor?

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

I replaced the foam hose about a year ago from what I can tell if you take the connector off the mono valve it should give you full heat, it stays the same temp. it does not cool down it just does not get hot enough on really cold days.

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84 300 Turbo / 320,000
96 E300 D / 55,000

When you replaced the monovalve, was it with a new one or a boneyard one? I would at least check to see if there is a tear in the diaphragm that may be causing your woes. Another thing I did to help the climate control was to remove the unit from the dash and resolder all of the connection points.