Non-MB heat problem - PeachParts Mercedes-Benz Forum

vwbuge · #1 02-05-2006, 01:57 PM

A friend's Dodge Dakota. No heat. I pulled the old thermostat and put a new one in. I noticed he was low on coolant so I added at that time and told him to drive it and check the coolant again and add if needed. I put a little more in today but the heat is still not there. Just lukewarm. I slid the control a few times and it seems to be working. Do you think the heater core is clogged? The lines going to and from are hot but seems to have no pressure. Any ideas?

Brian Carlton · #2 02-05-2006, 02:01 PM

Usually they are real basic systems. The valve is cable operated and it does not fail very often. No heat is simply a bad heater core. Common among vehicles with poor maintenance.

The fact that both sides of the hose are hot, around the valve, tells you that the valve is working. Since there is no heat in the cabin, you must conclude that the flow is very low.

Take a shot and try to backflush it with a garden hose. Be careful, however, because the core is not designed for line pressure from a garden hose. But, I suppose that if you blow it up.......you'd be taking it out anyway.

vwbuge · #3 02-05-2006, 07:58 PM

That is what I was thinking. It is not leaking so I'm thinking it must be clogged? I'll just remove the two lines under the bonnet and try to flush a few times.

redassag00 · #4 02-05-2006, 10:04 PM

Check to see if it has one of those vacuum shut off valves that closes coolant flow when AC setting is on MAX. Fords use this valve and often it fails, causing low coolant flow.

vwbuge · #5 02-05-2006, 10:32 PM

I did peek under the dash and saw a wire going to a diapragm type thing. Put a multimeter to the disconnected wire and toggle the A/C switch on and off?