Replacing the E30 Heater Core and Valve

[JinormusJ]

Kind of...

During idle, the engine never actually gets to rated operating temperature. Say, the thermostat is rated at 80*: the engine, at idle, gets to about 75 or so, and is not hot enough to open the thermostat after a fresh bleed. Normally, idling the the engine at 3k increases flow and temperature enough to open the thermostat. Driving the car after a fresh bleed is much the same concept

Top off coolant
Bleed
Rev to 3k rpm til heat blows
Enjoy fresh heater

[blazinxpk]

So if you bleed the air out of the cooling system and allow the vehicle to get fully warmed up(halway on the temp gauge) after replacing the core and valve but DONT drive the car you wont have heat? That's what happened on mine.

i replaced my heater valve a few weeks back. after putting everything back together, i started my car and filled up coolant. it felt like the air still wasnt hot, so i thought the valve that i replaced wasnt the problem. i still continued with filliing up coolant and went for a drive. the air was now getting hot and this was the solution to my problem.

so i guess you and i had the same issue.

[DatUtahGuy]

So if you bleed the air out of the cooling system and allow the vehicle to get fully warmed up(halway on the temp gauge) after replacing the core and valve but DONT drive the car you wont have heat? That's what happened on mine.

[JinormusJ]

Thermostat has to reach a certain temperature to open and allow coolant flow to enter the heater core if the system has been allowed to depressurize (you've allowed a large amount of coolant to drain/escape). Air trapped in the system almost ALWAYS gets stuck in the heater core and will not allow heat to blow; a working heater is one of the things that you can use to verify you've bled your system correctly and your thermostat functions

[ttrreevvoorr]

Just got around to replacing the heater core valve (shoutout to buttchuzz for hooking me up with the parts) and I have a NOOB question.
After replacing the valve and reinstalling everything, I bled the system and allowed the car to get to idling temp. I tried my heat and still had nothing, so I walked out to the engine and felt the hoses that go to the core, both were cold. However, as I followed the top hose down it got hotter and hotter.
I revved the engine for a few minutes, still no heat, top of hose cold, bottom hot.

Started driving home thinking what I could have missed and about 5 min into my drive I tried my heat and viola, hot as can be. So what do I not understand about how the thermostat or core works?

Because you didn't wait long enough for your car to warm up. You know how when you start your car on a cold morning the heat doesn't work immediately? It's the same thing.
/myguess

[DatUtahGuy]

Just got around to replacing the heater core valve (shoutout to buttchuzz for hooking me up with the parts) and I have a NOOB question.
After replacing the valve and reinstalling everything, I bled the system and allowed the car to get to idling temp. I tried my heat and still had nothing, so I walked out to the engine and felt the hoses that go to the core, both were cold. However, as I followed the top hose down it got hotter and hotter.
I revved the engine for a few minutes, still no heat, top of hose cold, bottom hot.

Started driving home thinking what I could have missed and about 5 min into my drive I tried my heat and viola, hot as can be. So what do I not understand about how the thermostat or core works?

[blazinxpk]

heat did not work in my car. replaced heater valve with one from junkyard, now i can finally feel warm air.

i didnt replace any of the o-rings and didnt see any leak. all works well so far.

[kmarei]

Coolant light is normally a bad coolant sensor

[ttrreevvoorr]

Good DIY. However my coolant light is still goes on from time to time. Doesn't over heat or leak though. Any ideas on what it might be?

[JinormusJ]

Where are you all getting the o rings from? Local BMW dealer is out

I bought them from Patrick at BMA Auto

About $.35 each or so; you only need 3

[Kershaw]

my ex didnt replace her o-rings. she has no problems and it's in the middle of winter. she uses the heat all the time since she weighs 90lbs.

[DatUtahGuy]

Where are you all getting the o rings from? Local BMW dealer is out

[DatUtahGuy]

I get to do this soon, crossing my fingers that it doesnt leak after.

Oh did I mention I dont have a garage and will be doing this with a lovely temperature of about 5 degrees? Challenge accepted

[JinormusJ]

Mine moves right where the red starts (3-4 range); from what I can tell, you can also hear the valve open (it's like a clicking sound)
If it really irritates you, you might need a new valve. If your looking to fix it up, PM me, I have an extra that I purchased accidentally when I thought my valve was busted

[quickervicar]

Mine only moves in the 4-5 range. If we combine the power of our valves we could take over the world!