Hey all, another heater question regarding the family car, an '87 Mondial. I've asked a few before, and gotten some good responses, as well as checking previous threads. If there is a problem with the system, I've narrowed it down to the valve, as it is getting the appropriate power pulses, the heater circulation pump works, etc etc. I've rebuilt this type of valve before on my old 5-series BMW, where the location was more....convenient. In the meantime, I've been bleeding the cooling system, and the heat has started to work a little bit. Possibly the valve is partially clogged--it's presently not connected to the wiring so it should be wide open--or do Mondials just not get much heat output? After running for a while, the temperature tends to stay right at 160, which I suppose it should. At that point, loads of cool to tepid air will come out of the vents. Last weekend I pushed a bit harder at times, and the temperature would briefly come up to about 195, at which point the heat would actually work, although very briefly. Is this normal? I think I had to be over 3,500 rpm to get either the temperature or the heat up. I know it's meant to rev, but.... As a note, it's been from about 36 to 45 degrees since I've begun bleeding the system in earnest. A lot of air has come from the radiator, very little from the thermostat housing, even when hot. Maybe it's still burping air out of the heater core, which could take a while given the slow coolant flow and the long paths. The basic question is: Do I actually have a problem, or Mondial heaters just not perform like a more modern American or northern European car? Or is it time for a new thermostat? Thanks in advance for any insights. Peter
My 82 Mondial-8 heater puts out more heat than I can stand when the engine is warmed up. I would think either the water valve isn't opening for some reason, or you don't have any coolant flow through the line.
i hae an 88 3.2, and the heater works quite well. it sounds like you are doing everything right - i would just add the electrical control is always very slow to respond on mine. i know mine has an auxiliary electric water pump to move hot water better through the heater - it is located on the port side of the car in the engine bay. check this as well - if not working it could act to add resistance to flow instead of augmenting it. good luck, and let us know
Thanks so much--knowing that the heat can work well tells me there's still a problem. I think I can reasonably narrow it down to the valve now, since I've checked pretty much everything else. Fixing it should take the edge off top down rides. Peter
I had a similar problem, and went through the elaborate assessment of all the components of the system. For me, it was solved by repeated bleeding of the system, this car is hard to get air pockets out, but once one does, the heat becomes reguilar and more than one can stand. Open up the rad vent valve when hot, when cold, with heater on, and off, topping up repeatedly to keep more air from getting in. Ater three or four bleeds the problem was solved. Hope your fix is as straightforward.
Ahh.. more insight. Thanks. Now I'm sure something is off, but maybe I'll hold off a bit and keep bleeding it. The previous owner seems to have changed the fluids annually, so maybe it's been two years since it was last flushed and bled. So far there has been an incredible amount of air in the system so either it hasn't been bled in years or there is an internal problem and new air is introduced every time it is driven. The car doesn't leak coolant, and I just replaced the plugs--none of which were "steam cleaned", so I'm hoping there are no gasket issues. First I bled it at the radiator and thermostat about twice a day 4 days in a row, although it didn't get driven long distances in that time. I then drove around for about 1-1/2 hours and repeated the bleeding process, primarily at the radiator, about 4 times. The thermostat housing didn't have much air come out, although the radiator did. I was running the engine pretty hard, which I assumed would flush air out of the heater core. This is when it actually began to produce some heat. The heater valve has been disconnected the entire time, so it should be wide open unless it is clogged with debris. I rebuilt this valve on my BMW and vaguely recall that it has a thin rubber diaphragm that had turned into mush and clogged a fine screen inside it. Either revving the engine hard gets fluid past this screen, or it is in good shape and there is still a lot of air to go. Anyone out there ever installed a flushing T in the heater line?
