December 21, 2009 05:20PM
I have had an issue with my 86 325es for a couple of years now in that the heater output does not get hot even though the car if fully up to temp and the stat is functioning properly. It does get warm though, but not like my other cars. I think it is the mixing valve not opening all the way. Is there anything I can do other than replace the valve to fix this? Thanks!
December 22, 2009 04:08PM
if your temp is truly up to the middle on your car, then yea the valve isn't opening. you might consider changing the tstat just for good measure, see my thread about the split rack boot.

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rkj
December 24, 2009 03:52PM
Grab both hoses (at the motor side of the firewall), if you have the inlet going in hot and the return cold your problem is in the car (heater valve more than likely). Don't forget, you might have one of those valves on the motor side of the firewall in one of the heater hoses, those go bad too. Another thing to check is the core itself; are both sides coming out cold (where the warm air exits the plenum at the foot-well) or whatever temp you can get.

Rick
December 30, 2009 11:08PM
Update - I spent most of the day out in the shop and took out the heater core and valve. Much to my surprise the valve seemed to be fully opened and water flowed through that pipe quite freely. The heater core was a different story. When I tried to flush it out the water did not go through it very well and even though it did have some flow it was not even close to the flow of the spare core I had to replace it with. I think this explains the problem. I put everything back together and took it for a spin and the heat was much warmer but then it went cold again. I think I need to re-bleed the system as it probably has an air bubble blocking the flow.

Anyway, just wondered if there was a way I could clean out the gunk inside the core as it did not leak and if it is still usable I might want to flush it out and save as a spare. Maybe not worth the time or money, I don't know!
rkj
January 02, 2010 12:56AM
Quote
wodcutr
Update - I spent most of the day out in the shop and took out the heater core and valve. Much to my surprise the valve seemed to be fully opened and water flowed through that pipe quite freely. The heater core was a different story. When I tried to flush it out the water did not go through it very well and even though it did have some flow it was not even close to the flow of the spare core I had to replace it with. I think this explains the problem. I put everything back together and took it for a spin and the heat was much warmer but then it went cold again. I think I need to re-bleed the system as it probably has an air bubble blocking the flow.

Anyway, just wondered if there was a way I could clean out the gunk inside the core as it did not leak and if it is still usable I might want to flush it out and save as a spare. Maybe not worth the time or money, I don't know!

Well, cores usually have a useful life and when they're done (clogged or leaking), they are done for.... usually sad smiley

Rick
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