m42 radiator + m50 = problem

[1990m3]

it's got to be an air bubble. It's a bitch to bleed that radiator fully, took me a full day once. Then when I figured out how to do it it went much quicker the second time.

Search bimmerforums for how to bleed an e36 radiator. There are some good threads over there. Their radiators have the same bleeder design as the m42 radiator and a lot of people had problems with it. Takes patience.

[FredK]

Spider hose is going to the top heater core pipe, right? If it is on the bottom, coolant won't go into the heater core and it the heat will never get hot.

[AL GReeNeRy]

Spider hose is going to the top heater core pipe, right? If it is on the bottom, coolant won't go into the heater core and it the heat will never get hot.

oohhh boy. lemme double check that one. hope this is it!! itll be an easy fix.

[AL GReeNeRy]

nope spider hose connected to top pipe on heater core. is it possible that its clogged?

[1990m3]

it's possible that the aluminum pipe is crimped and bent where it goes through the firewall. Mine is a little crimped from bending it down when I did the swap but it still flows...

[AL GReeNeRy]

i attempted to bleed the system again today, heres what i did..

m50 + m42 radiator - no thermostat

1. key on, ignition off
2. heater full hot, fan high speed
3. filled radiator to cold line (cap open, bleeder open)
4. let sit for 10 min (temp guage began rising)
(at this point the coolant in the expansion tank was not moving at all)
5. cap on, bleeder open, reved and held engine at 2000rpm
(temp gauge raised to half way and coolant began spilling out of bleeder)
6. closed bleeder, reved and held engine again at 2000rpm
(temp gauge raised to full hot)

what am i doing wrong? should i just let the car idle with both cap and bleeder open for an hour or something? if i rev the car the temp gauge shoots straight up to hot at which point coolant starts shooting out of either the bleeder or expansion tank, depending on which is open. again i have no thermostat and hot air is not flowing out of my vents at all. i have a spare heater core ready to go, but i really dont want to swap it unless i have to

[1990m3]

search the files from bimmerforums for an e36 radiator. there is a completely different procedure. It worked for me but i can't remember the specifics anymore.

[Frog]

DaveMarkert told me that the M42 radiator wasn't ideal for the M50/M52/S50/S52 because it is very difficult to bleeding the system due to the difference in the M42 and the other motors' water level. If the M50/M52/S50/S52 has a M42 radiator, you will need to jack the front up at a steep angle to be able to correctly bleed it.

Could this be the reasons for the difficulties you had?

[matthugie]

I'm pretty sure this was taken care of 6 years ago...

[Frog]

I'm pretty sure this was taken care of 6 years ago...

I knew someone would say that... But can your head grasp the idea that there are people today that are running into the same issue and search the internet/forums to find answers and run into this thread?

[matthugie]

I knew someone would say that... But can your head grasp the idea that there are people today that are running into the same issue and search the internet/forums to find answers and run into this thread?

Yes, and it can also grasp the numerous other threads that address the issue. And by that I mean all the more recent ones that say that it ISN'T and issue.