1991 BMW 318 no heat?

I was looking at a 1991 BMW 318I today and the one thing that held me back from making an offer was the lack of heat. The car had coolant and did not overheat or run hot on the test drive and the hoses were hot, but no heat, not even a little bit. Any clue what it could be other than a heater core if it's the heater core how difficult is the repair?

Thanks, Paul B

Dumb question. But, did you let it get up to operating temperature? 

I'd check to see if the heater core has been bypassed, I'm not as familiar with E30's as E28's but it should be obvious where the lines go through the firewall and if things have been tampered wiht. If it is not bypassed then the heater core is likely okay and it could be problems with the heater valve or climate control.

Adam

Donebrokeit said:

I was looking at a 1991 BMW 318I today and the one thing that held me back from making an offer was the lack of heat. The car had coolant and did not overheat or run hot on the test drive and the hoses were hot, but no heat, not even a little bit. Any clue what it could be other than a heater core if it's the heater core how difficult is the repair?

 

Thanks, Paul B

Is that the red one in Maryland? I know the guy selling it and recall him saying it didn't have heat.

e30 heater cores replacement basically requires removal of the dash. Which isn't THAT bad but is time-consuming. Mine blew up a couple years ago during a rallycross lol. I use a Summit Racing aftermarket heater now.

If it is plugged up and not leaking you could probably fix it by flushing the heater core with a garden hose. No removal required.

My money is on the heater valve.  They aren't as prone to failure as the one in an e28 but it can happen.  If that's it, the fix should pretty simple.  There are various troubleshooting guides online, here's one : https://blog.bavauto.com/9009/bmw-no-heat-or-low-heat-e30-and-others-318i-325e-325i-m3/

E30 heater core removal does not require removing the dash. I just did mine a bit ago. 45min job or so.

Also it is probably not the heater valve unless it is clogged up. E30 heater valves are designed to open upon failure.

My money is on the system not being properly bled. They are notoriously hard to bleed. Ask me I know. I drove my last E30 around for days with no heat because I didn't get coolant into the heater core. Never once did the car even think about overheating.

Daeldalus said:

E30 heater core removal does not require removing the dash. I just did mine a bit ago. 45min job or so.

 

Also it is probably not the heater valve unless it is clogged up. E30 heater valves are designed to open upon failure.

My money is on the system not being properly bled. They are notoriously hard to bleed. Ask me I know. I drove my last E30 around for days with no heat because I didn't get coolant into the heater core. Never once did the car even think about overheating.

Yeah, I think I got it mixed up with the HVAC in my 924, on second thought. Which is a lot tighter under the dash.

I did the e30 heater while I had the dash out anyhow to cage the car, now that I think about it.

Too many cars + too much whiskey, apparently :/

Just sorted out a similar problem on our '87 325i. If it's not the heater core itself my money is on the system being properly bled. It took many, many tries for me to get heat again after replacing the timing belt. The only alternative thought would be something mechanical such as the blend door/flap mechanism. 

None of these would prevent me from making an offer so long as there were no signs the car was burning or mixing coolant.

After reading the post and recalling my conversation with the seller I think the system might be air bound for a number of reasons, the engine was up to temperature, coolant lines are hooked up and I see no funny business, and the seller said this happened after he replaced the thermostat at an event.

Irish, this is the car in Maryland, the seller is waiting for the title to come from the MVA or to be found before we move forward.

irish44j said:

Too many cars + too much whiskey, apparently :/

Thanks for all the information.

Paul B

Ah, well he's a good guy. Surprising he hasn't diagnosed it as he's a "car guy" and rallycrossed this car.

Question: does it have a GRM "DORK" sticker on the rear door quarter window? If so, that's from my car....we had to break one of his windows at a rallycross because he locked his keys inside, and I gave him one off of my rally car to replace it - and it had the GRM sticker on it :)

In reply to Daeldalus :

Hi there...i just put a heater core and valve in my 89 325i convertible.  (Original valve was leaking and did core while I was at it.)  Now I have no heat...warm at higher speeds.  Temp gauge is straight up and no overheating.  Tried bleeding several times. Any tips??

Brerat01 said:

In reply to Daeldalus :

Hi there...i just put a heater core and valve in my 89 325i convertible.  (Original valve was leaking and did core while I was at it.)  Now I have no heat...warm at higher speeds.  Temp gauge is straight up and no overheating.  Tried bleeding several times. Any tips??

double-check that you didn't reverse the heater hoses from the engine. Otherwise likely an air pocket. Get the front of the car up as high as possible when bleeding it. 

In reply to irish44j (Forum Supporter) :

Its on jack stands!  Hoses are correct...how long should it take to bleed....days of driving like daeldalus mentioned?  

In reply to Brerat01 :

You should be able to get it fully bled without moving the car. 

The trick to it usually is making sure to get the front end of the car as high in the air as you can safely get it. At the very least you need the bleeder screw to be about 6 inches higher than the top of the heater. 

After that just remember to keep the heater on full heat while you are bleeding.