Heat, but no heat

[spyderg0d]

The winter 328is finally has an issue.
No heat. Well, only after being at OT for 15 minutes AND at around 2k rpm does it blow mildly warm air. I flushed and bleed the cooling system properly with heat on full blast. Just installed a metel impeller water pump and the original was good. Installed a new thermostat.

From my understanding the heater valve either sticks open or closed not somewhat open. Lol. Is there something I can just add to the coolant to maybe dissolve any possible gunk or blockage?

[scooper]

if valve is stuck you won't get heat at all. Try bleeding again and again. Would take a good 20 minutes for the car to warm up fully.

[Eric93se]

Bleeding won't fix a stuck heater valve. I've taken mine apart but it was a long time ago, if you not careful you can ruin it. They sell brand new aftermarket on ebay for $40. Mine didn't look dirty or gunked inside but it worked fine after taking it apart and cleaning, there are guides out there maybe even on pelican.

https://www.ebay.com/itm/HVAC-Heater...2/172797109099

- - - Updated - - -

Try raising and lowering the temp a few times, maybe the valve will wake up.

[Nanniepoo]

Yes there's coolant system cleaner. But I would flush it out after using it.

Neither of my E36s have been particularly quick to get the cabin warm. Thank God this one has heated seats. Mine will start blowing warm around when I get on the highway (a mile from my house, all neighborhood), on auto it starts with the windshield and then will kick on the face vents. I wouldn't call the cabin warm when I get to work 10 minutes later.

[jmo69]

Sounds like the t-stat is opening early, mine seems to be doing the same. I've got another temp gauge and it's climbing slower than usual.

[spyderg0d]

Its got a new thermostat. And the water pump is metel impeller and good. Now the car gets to temp faster with the new thermostat. Maybe its just me, but the pandemic will spew hot air when the temp guage is barely above the quarter dash line. This 328 has to be at ot for 10 minutes before I get heat while driving. And it goes cold when at idle.

[LockDots]

Cold at Idle and heat while driving sounds like your valves are stuck. When you're driving (engine revving higher than idle) your coolant is pushed around a lot faster and can therefore transfer more heat to your heater core or help push the valves open a little more. I would start with coolant cleaner but keep in mind, that you may be opening up otherwise gunk-closed leaks and holes. Otherwise the best bet would be to remove the valves to inspect and clean, then replace if need be while it's out.

[Mless5]

I should've went for this instead of rebuilding mine with a $35 kit .

Bleeding won't fix a stuck heater valve. I've taken mine apart but it was a long time ago, if you not careful you can ruin it. They sell brand new aftermarket on ebay for $40. Mine didn't look dirty or gunked inside but it worked fine after taking it apart and cleaning, there are guides out there maybe even on pelican.

https://www.ebay.com/itm/HVAC-Heater...2/172797109099

- - - Updated - - -

Try raising and lowering the temp a few times, maybe the valve will wake up.