Well first of all i am new to these forums and hope to find a lot of information about the little gem i just purchased. I just bought a 1991 850i V12 and i am having some coolant issues. First of my questions is where can I find a service manual online (.pdf) that I can download to work on this car......also if anyone can post a diagram of the coolant flow or any diagram that has to do with the coolant I would appreciate it. Thanks, chris

www.wuffer.net has all of the manuals in downloadable form.

Welcome to the club.:)

The first operation on the coolant system is Bleed Bleed and Bleed again unless of course you have water running across the ground :(

Thanks wuufer for the quick and helpful responce. I have heard that these cars have trouble with the heater cores going bad. And I have also read that i can bypass the heater core by connecting a tube that runs down the valley of the engine to the water pump to keep it from over heating is there any truth to that and also what would you recommend to fix my over heating issue......thanks for the help in advance~Chris

I have the same problem, cooling fluid sprayed true the vents today. I turned off the heating i turned off the car i went out, the cooling fluidf pored out on the road in about 20 sec. I waited an hour , car started fine, i was 2 km from home, vapor of cooling fluid was coming from the vets and under the dash.

Anyone know what I am looking at fixing??

Thanks you

Nik

I have the same problem, cooling fluid sprayed true the vents today. I turned off the heating i turned off the car i went out, the cooling fluidf pored out on the road in about 20 sec. I waited an hour , car started fine, i was 2 km from home, vapor of cooling fluid was coming from the vets and under the dash.

Anyone know what I am looking at fixing??

Thanks you

Nik
Heater core.......good luck your going to need it......that's why i was wanting to know if anyone had ever bypassed the heater core as a quick fix but noone has answered so far.....

Heater was bypassed at the back of the engine in my car. Heater core replacement was my first DIY. Turned out to be quite an experience. I didn't follow the manual on this one, but rather used an "unorthodox" approach at getting to the heater core (will only work if you can weld). Anyway, took the better part of a complete day to repair and it still works to this day.

Heater was bypassed at the back of the engine in my car. Heater core replacement was my first DIY. Turned out to be quite an experience. I didn't follow the manual on this one, but rather used an "unorthodox" approach at getting to the heater core (will only work if you can weld). Anyway, took the better part of a complete day to repair and it still works to this day.

any pictures on how you did the heater bypass? and what you used to do it?

Heater bypass is a piece of metal pipe (get at HomeDepot) and a pair of hose clamps. Connect the supply hose to the return hose. They are the 2 hoses that come off the rear of the engine - it is a tight fit, be prepared.

Here is the info on the heater core replacement (unorthodox version)


Basically remove the seats (drivers side at the least)
Remove instrument cluster
Remove center console with radio, A/C controls, MID
Remove console at e-brake
Take ALOT of digital pictures
mark all connectors with masking tape and write where they go
Remove knee knee bolsters
Cut dashboard support (big black metal tube that runs from the left side of the center console up towards the instrument cluster) right below where it starts to curve toward the steering column.
Weld a "plug" into the short piece of support pipe you just cut out.
Re-fit the cut tube with welded plug back into the remaining support tube and drill a hole through the tube for a bolt and nut when you reassemble.
The tube is cut, so you can access the heater core cover which is held on by 7 or so little metal clips (you will see when you get there)
Remove heater core cover (black plastic lid) and there you have it.
Replace the core and remember to replace the black double pipe as well (these are known to fail - it is plastic after all)
Reinstall in reverse order
Drink 20 beers!
Good luck

the two hoses that come off the back of the engine? I had heard that they came off of the firewall, do you have a pic of these tubes........?

The firewall is pretty much the back of the engine. Will look for a rerouted hose pic/diagram that i seen a while ago.

The firewall is pretty much the back of the engine. Will look for a rerouted hose pic/diagram that i seen a while ago.
Thanks if you could I would appreciate it!!

you need to connect part # !2 with part #13 in the diagram

you need to connect part # !2 with part #13 in the diagram
I'm sorry part number 12 or nuber 2?

12, sorry, fat-finger syndrome

Heater bypass is a piece of metal pipe (get at HomeDepot) and a pair of hose clamps. Connect the supply hose to the return hose. They are the 2 hoses that come off the rear of the engine - it is a tight fit, be prepared.

Here is the info on the heater core replacement (unorthodox version)


Basically remove the seats (drivers side at the least)
Remove instrument cluster
Remove center console with radio, A/C controls, MID
Remove console at e-brake
Take ALOT of digital pictures
mark all connectors with masking tape and write where they go
Remove knee knee bolsters
Cut dashboard support (big black metal tube that runs from the left side of the center console up towards the instrument cluster) right below where it starts to curve toward the steering column.
Weld a "plug" into the short piece of support pipe you just cut out.
Re-fit the cut tube with welded plug back into the remaining support tube and drill a hole through the tube for a bolt and nut when you reassemble.
The tube is cut, so you can access the heater core cover which is held on by 7 or so little metal clips (you will see when you get there)
Remove heater core cover (black plastic lid) and there you have it.
Replace the core and remember to replace the black double pipe as well (these are known to fail - it is plastic after all)
Reinstall in reverse order
Drink 20 beers!
Good luck
Drink the beer before you start

thanks for the help,bypass is done as youll see today.this car is sooooooo cool!.it isnt quite as fast as the S500 but it's looks make up for it.