The OFFICIAL heater core hose thread/answer

[328ijunkie]

Got tired of reading back and forth about this so decided to tear one apart and see. As you can see the arrow points toward the valve from the core (IE: Top hose return, bottom from head).
This is confirmed by looking at the design of the valve. Coolant flows into the valve from the core, goes up through the exit hole and leaves if the valve is open. When the valve is closed the hole is closed and the coolant force is being blocked by the plunger. if the coolant flow is reversed, when the valve is open the coolant flow will force the piston closed thus messing up your heat as youll get a fluttering sound as the valve continually opens and closes by the coolant flowing past it. You will also have intermittent/not working heat
Unsure as to why BMW engineers designed the system to have hot coolant sitting in the core at all times but yeah.
Also the solenoid is normally open. When voltage is applied it closes. (from the TIS its around the last 15-20 deg of the cold section of your temp selector on the heater control panel)







So abridged version: CYL head hose goes to BOTTOM pipe of heater core. Hose coming from back of thermosat, whether spider hose or metal pipe goes to the TOP heater core pipe

This is all assuming you have the common valve on top heater valve setup.


Correct Install:

[Philo]

Thanks for the definitive answer. Let's hope BMW kept this as a standard throughout E30 models.

[328ijunkie]

Ninja Edit

[herlsy]

This topic has caused me a headache over the past week or so. Had my hoses hooked up correctly, had an issue bleeding so the heater core pipes weren't getting hot which caused me to second guess myself and browse forums....bad idea. Switched them up, no difference.

The other e30 board has a terrible 24v thread telling you that the hose from the back of the head must go to the valve.

Not to be one of those to cause confusion, i will reiterate what the OP said:

CYL head hose goes to BOTTOM pipe of heater core (without valve). Hose coming from back of thermosat, whether spider hose or metal pipe goes to the TOP heater core pipe

Valve pipe: OUTLET
Staight pipe: INLET

[browntown]

Now for all of us that never label anything or take pictures before a swap, we need a similar thread on which hard fuel line goes to which end of the fuel rail.

[hammslice]

Now for all of us that never label anything or take pictures before a swap, we need a similar thread on which hard fuel line goes to which end of the fuel rail.

I took some pictures and it was discussed in my "won't start" thread.

http://e30sport.com/board/showpost.php?p=2446625&postcount=14
http://e30sport.com/board/showpost.php?p=2446661&postcount=16

[Pussy30]

Ughhhh and make sure you do this when you put the motor. I bought my swapped car with it looped and running the hoses was impossible, theres no clearance unless you pull the intake manifold.

[328ijunkie]

Yup!

[justin_l_]

The other e30 board has a terrible 24v thread telling you that the hose from the back of the head must go to the valve.

Bash it all you want, it is better than any thread you have ever contributed to the E30 community.:ohsnap:

[Mr.SWISS]

Now for all of us that never label anything or take pictures before a swap, we need a similar thread on which hard fuel line goes to which end of the fuel rail.

No we don't. It depends on if the rail is OBD1 or 2, and then its's pretty easy to deduce which line is the feed if you follow it from the fuel filter, and then LOOK at the rail and the line that DOESNT come from the regulator is the feed, on OBD2 the round metal tube on top is the return.

JEESUS FUCKING CHRIST This shit isnt that damn hard!!!!!!! HEAD TOP SPIDER BOTTOM !!!!:hitler:

[328ijunkie]

No we don't. It depends on if the rail is OBD1 or 2, and then its's pretty easy to deduce which line is the feed if you follow it from the fuel filter, and then LOOK at the rail and the line that DOESNT come from the regulator is the feed, on OBD2 the round metal tube on top is the return.

JEESUS FUCKING CHRIST This shit isnt that damn hard!!!!!!! HEAD TOP SPIDER BOTTOM !!!!:hitler:

Uh did you just read the thread? Thats wrong.

[FredK]

Yeah, if it's TL;DR, then

SPIDER TOP
HEAD BOTTOM

[herlsy]

Bash it all you want, it is better than any thread you have ever contributed to the E30 community.:ohsnap:

Glad you took the time to browse my posts to justify your statement. Makes me feel worthy. Now be a good lad and update that other thread.

[e30s50dan]

....I can just smell antifreeze from reading this thread lol!

[samiam3356]

For everyone in Australia its reversed!


What about the people with the Valve on the bottom? Is the valve made to flow different on those?