E30 S54 HVAC Heat issues

[8920vt]

So i finished my s54 swap 3 years ago. Love the swap and the e30 but I never drove it in cold climates. I now have a short term need to run the car for part of this winter while looking for a new car.

I go to fix the heat in the car over the past weeks and am coming up unsuccessful.

I have a new heater core, new heater shut off valve new hoses and new thermostat bypass and still have no heat.

This shows my current routing:


I must disclose i have changed the hose routing on other parts of this engine. I will try to get photos to show this later, but i still have my factory e30 1990 325i coolant jug in the factory location and i welded in tubing to make this work. I also am running factory e30 radiator and factory s54 thermostat, all new and functioning well.

My concern is that some hose routing i have changed may be affecting the flow characteristics to my heater core preventing sufficient flow giving me no heat inside.

How have others run theirs and how well does your heat work? Thanks in advance.

-Ian

[8920vt]

Here are a few photos that KIND OF show other pipe routing.

[2mAn]

Thats a clean looking engine bay. Sorry I cant help. Good luck!

[jink0619]

How do you have the heater core hoses connected?

[8920vt]

The hoses are connected using the quick connect fittings on the engine and run directly to the core and hose clamped on to the heater core aluminum tubes. The only thing in between is the E30 heater core thermostatic bypass.

[dude8383]

I believe he's asking where the hoses are coming from and connecting to.

[jink0619]

I believe he's asking where the hoses are coming from and connecting to.

Yes this^

I'm thinking you may have the hoses routed wrong from motor to heater core.

[diesekte]

per s54swap.com:

For the heater core lines, connect the hose from behind the cylinder to the bottom pipe on the heater core line on the E30. The top line is connected to the metal pipe coming off the thermostat.

[8920vt]

Oh yes.... The aluminum "thermostat tube" that is attached to the head is connected to the top heater core tube.

The black steal tube on the block below the head is connected to the lower heater core hose.

[diesekte]

Any other hoses that coolant runs through in non stock locations? Your heater core isn't blocked with debris? Not trying to be stupid but does your blower motor work? I have mine hooked up as above and my heat works really really really well and pretty quickly too

[8920vt]

I appreciate any and all input because this is driving me nuts. I flushed my first heater core and have since installed a brand new core and new heater shut off valve.

The one thing i have changed is i have welded a tube off of the lower black line that runs to my expansion tank, but as a trial, I clamped off that line, mimicking the stock orientation and ran it. Still no heat

Yes the blower motor works. When I did the swap, I installed AC and the AC works wonderfully in the summer

[8920vt]

diesekte do you have the e30 heater core thermostatic bypass installed in yours as well?

[diesekte]

Um... No? I looked up a picture of it and I've never seen anything like that in my engine bay. My heater core hoses are hooked up like yours. I have the expansion tank on the passenger side just kinda thrown in the battery tray lol

[M3PO]

Just an FYI, welding the tube on like you did that goes to the expansion bottle is exactly how the Z3M is plumbed so that's not it. I plan to do the same or buy the OEM hardline from the Z3M.

[328ijunkie]

hoses at core backwards. Top of Hcore is OUT bottom is IN.
S54 Alum Tube on cyl head is OUT to core
Metal pipe is IN FROM core.