help with my heater!!!

[Chris]

So I spent a few hours last night trying to get the heater to work in the E30. I'll try and keep this short, any help would be greatly appreciated as driving on the track with no heat in February is going to be painful!!


blower fan works only on highest speed (not a big deal for now)

I pulled a heater valve and heater core from a junk yard car the other weekend. A common problem is the coolant hoses (inlet and outlet) from the engine bay through the firewall can be reversed- I checked and the top hose goes to the back of the head, which I believe is correct.

I pulled out and swapped the heater valve from the junk yard car, since I read the heater valve can fail. It blows a little hot air, but almost all of the air blows COLD from the large hole that is left from where I pulled out the a/c condenser. I don't get it...

My next step might be to replace the heater core, but I don't understand why air is blowing out of where the a/c condenser was. Could it be something unrelated to the heating components, or maybe the thermostat??

thanks in advance!

[Chris]

pictures for reference:

where the cold air is blowing out, passenger floor in the large hole:




a/c condenser I took out of the hole:

[.RJ]

Where does the heater core sit in relation to that big hole? Does that hole need to be sealed to push air through the vents?

[Andy]

Do you have a schematic for the HVAC air flow?

Is the recirculation door closed? If it's left open, it would allow cold air to be pulled in and possibly not be forced to travel through the heater core because of that hole. But this is all guesswork unless someone is intimately familiar with E30 (Chan) or if you could provide the schematic.

The easiest way to check the heater core is to feel both inlet and outlet hoses after the engine is warmed up. If both hoses are hot, then the core is good. If the inlet is signifcantly warmer than the outlet, you've got a clogged core. If neither hoses are cool or not hot after the engine is hot, and you've opened the heater control valve, then you've got a bad valve.

Are E30 valves cable actuated or do they use a solenoid?

[Mike]

i'll have bj chime in, he's out right now, but should know the hvac system like the back of his hand.

[NTIman]

As far as your heater fan issue, it sounds like you need a new Blower motor Resistor. when they burn out, it will only work on high speed. Should be located in your heater box somewhere.

Chances are, if it was your thermostat, your car would never drop off of high idle due to low Coolant temperature. Sounds too me like its most likely some sort of blend door problem, but don't hold me to it.

[Chris]

Do you have a schematic for the HVAC air flow?

Is the recirculation door closed? If it's left open, it would allow cold air to be pulled in and possibly not be forced to travel through the heater core because of that hole. But this is all guesswork unless someone is intimately familiar with E30 (Chan) or if you could provide the schematic.

The easiest way to check the heater core is to feel both inlet and outlet hoses after the engine is warmed up. If both hoses are hot, then the core is good. If the inlet is signifcantly warmer than the outlet, you've got a clogged core. If neither hoses are cool or not hot after the engine is hot, and you've opened the heater control valve, then you've got a bad valve.

Are E30 valves cable actuated or do they use a solenoid?

you may have answered one part of the problem... the inlet was hot and the outlet wasn't, so the core is probably clogged. I"ll try replacing that but there is still the issue of the air flow.

RJ, the heater core sits in the box directly in front of that a/c hole. I'll try plugging the a/c hole, good idea.



here is some info from e30 tech, no schematics of air flow, but some of the parts involved:

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[.RJ]

You can "plug" the hole with duct tape and/or cardboard. I did that when I took out my a/c box out of the integra - although I could put the box back in and just patch up a few holes with racer tape.

[Andy]

Get that shit fixed or you'll be hypothermic before you even get near VIR.

Swap out the heater core, plug the hole and go from there. The blend door is another possibility. That's why I was asking about the recirc button or pull tab.

[Beej]

Word, I've had a lot of problems with the red car.

Fan problem: Definitely the resistor. They commonly fail, but high speed works because it bypasses the resistor and sends all 12 volts to the motor. I replaced mine before finding out it wasn't the problem...I still may have the old one, which I believe is good. They're pretty easy to replace on M20 cars (fucking a pain on 24v swaps though). I can send it to you and maybe save you the $20 or so they cost. If you take the plate thing off the firewall, it's underneath the motor, right in the middle. It'll take some tugging, but pull it straight out (it's not your traditional looking resistor).

No heat problem: I'll have to double check my car when it's not snowing, but my heater core hoses were reversed when I got the car, and I got zero heat. I'm 99% sure the one from the head goes to the bottom, and the top one goes to the spider hose. Once I swapped them, it started working fine.

Do NOT take the blower motor out if you can avoid it. It's turning, so it ain't broke. Getting it aligned and back in, and then that fucking clip back on was a big pain for me (though again, probably easier on an M20 car).

[white_2kgt]

Just rip it out, save the weight and use this for the drive down,

<!-- m --><a class="postlink" href="http://www.autobarn.net/halinheat.html">http://www.autobarn.net/halinheat.html</a><!-- m -->

[Andy]

Just rip it out, save the weight and use this for the drive down,

<!-- m --><a class="postlink" href="http://www.autobarn.net/halinheat.html">http://www.autobarn.net/halinheat.html</a><!-- m -->

The cigarette lighter doesn't work either :lol:

[D_Eclipse9916]

I Dont know anything about heat, im just going to tag along.

You could just get a space heater and "hard-wire" it in. LOL it just two simple wires to the adapter plug.

[.RJ]

You could just get a space heater and "hard-wire" it in. LOL it just two simple wires to the adapter plug.

He could just use the same battery for the space heater as the power windows!

[white_2kgt]

Just rip it out, save the weight and use this for the drive down,

<!-- m --><a class="postlink" href="http://www.autobarn.net/halinheat.html">http://www.autobarn.net/halinheat.html</a><!-- m -->

The cigarette lighter doesn't work either :lol:

I can fix that in 5 minutes.

[Chris]

You could just get a space heater and "hard-wire" it in. LOL it just two simple wires to the adapter plug.

He could just use the same battery for the space heater as the power windows!

haha pretty soon that 12v battery will power the whole car!

[Chris]

Word, I've had a lot of problems with the red car.

Fan problem: Definitely the resistor. They commonly fail, but high speed works because it bypasses the resistor and sends all 12 volts to the motor. I replaced mine before finding out it wasn't the problem...I still may have the old one, which I believe is good. They're pretty easy to replace on M20 cars (fucking a pain on 24v swaps though). I can send it to you and maybe save you the $20 or so they cost. If you take the plate thing off the firewall, it's underneath the motor, right in the middle. It'll take some tugging, but pull it straight out (it's not your traditional looking resistor).

No heat problem: I'll have to double check my car when it's not snowing, but my heater core hoses were reversed when I got the car, and I got zero heat. I'm 99% sure the one from the head goes to the bottom, and the top one goes to the spider hose. Once I swapped them, it started working fine.

Do NOT take the blower motor out if you can avoid it. It's turning, so it ain't broke. Getting it aligned and back in, and then that fucking clip back on was a big pain for me (though again, probably easier on an M20 car).

awesome thanks for the info. Let me know when you have some time to check the hoses... if its how you stated, then mine are reversed. I'll try that before pulling the heater core. I'd rather not have coolant spill all over if I can avoid it.

[Beej]

Let me know when you have some time to check the hoses... if its how you stated, then mine are reversed.

I'm pretty sure of it, but don't count on me checking my car. I don't get home until after dark, and it's been way too butt cold to check it in the mornings (not to mention it's a real pain in the ass to see them through the intake manifold holes).

Do a couple searches on r3v...in the 24v/M50/S50 motorswap forum, I know it's been answered a few times.

[Chris]

well still no luck, and I only have this week to figure it out. Any more help would be greatly appreciated!!


completed so far in hopes of fixing heat:

-swapped heater valve, then switched back to the original because I tested it with a multimeter and it read 12 volts (its a 12v unit)

-pulled the heater core and flushed it out with water

-checked the inlet/outlet hoses to see if they were swapped, both are hot now

-replaced the thermostat

-have bled the coolant (ran with cap off)

-blocked the hole from removing the A/C condenser with duct tape and cardboard to direct air onto heater core

-adjusted cable that controls hot/cold from temp dial


The car will blow some hot air once it reaches operating temp, but only when idiling. Once driving, it starts to blow cold air again and then never blows heat. This sucks. Could it be a damper or something allowing too much fresh air in? Have I not blocked the air enough to force it onto the heater core?

[Andy]

Could it be a damper or something allowing too much fresh air in? Have I not blocked the air enough to force it onto the heater core?

These seems to be the only two options left. Make sure the blend door is shut and that air is being forced over the heater core. The only caveat is that even if the blend door was wide open, the heater core should still be able to heat the air up unless the air isn't being channeled across the core properly.