Need Help

[cajunboyla]

Okay Guys; its been awhile since my last post. But as usual I need some help. My 89 735il is leaking coolant from under the driver's side bottom of the car. Is this a heater core problem? Temperature gauge displayed hot temp, then coolant started to leak out...

Cajunboyla

[lincolnmaster80]

The heater core is inside the cabin, behind the dash. To replace, you'd have to take apart your entire dash if I remember correctly. So, you have to be a bit more specific. Is the leak coming from under the engine? If so, is the leak near the front or the rear of the engine. We already know it's on the drivers side.

If it was the heater core, your windows would be fogging up with a mist that is hard to get rid of, you'd have no heat, and a constant smell of coolant in the cabin.

[cajunboyla]

Hey Lincolnmaster80; thanks for the info... There is no smell of coolant in the cabin and there are no leaks above or below the engine. The leak seems to be coming from the left side of the floor board above the transmission. Like there is a busted hose or something. I can see it pouring out just as soon as I add water or coolant to the reservoir. Is there a by hose or something in this area?

[lincolnmaster80]

Originally Posted by lincolnmaster80

If it was the heater core, your windows would be fogging up with a mist that is hard to get rid of, you'd have no heat, and a constant smell of coolant in the cabin.

My bad: you will still have heat....

Anyways, this might help you answer your question.

http://bmwfans.info/parts/catalog/E3...xpansion_tank/

The pipe running along where part 14 is goes to the heater core. This pipe of course, runs through the fire wall. It might be worth a shot taking the access cover off and having a peak with a flashlight if needed and see what you can see. Maybe have someone pour in some water (straight water won't hurt) to see if you can reproduce the problem if you can't find anything. I don't want to sounds alarms just yet, but you may have to take apart the dash if you can't get to it. Although, having a 735 is great help; more room to work with in the engine bay...with a V12, not so easy.

http://bmwe32.masscom.net/
Left side go:
Fixes (which should already be expanded) --> Body & Interior --> Dashboard removal

[cajunboyla]

Hey Lincolnmaster80; you are a lifesaver. This definitely seems to look like where the water is coming from. I'll jump right on it. You are right, I truely love this car... Thanks again... If I have anymore question, I hope you don't mind my asking...

Sincerely,
Cajunboyla

[lincolnmaster80]

Ask away dude!

[cajunboyla]

Hey Lincolnmaster80; you are definitely right. The hose does go thru the firewall. But its one of the hoses leading from the auxillary coolant pump. Now, is this a problem with the auxillary coolant pump or is this a heater core issue? The leak is right at the end of a pipe extending down from the transmission bay just like you said. What should be my next course of action?

Sincerely,
Cajunboyla

[lincolnmaster80]

Well, I don't think it's the heater core. You'd be smelling coolant inside the car, even more so when you turn on your fans. The aux water pump could be at fault. They can be had for about $50 if you can find them (will supply some of the part sources I use at the end).

http://forums.bimmerforums.com/forum....php?t=1158755

I wouldn't rule out the age of the piping, being an '89 and assuming it's never been replaced, the piping is 21 years old and probably pretty hard due to age and heat. I can't get a good look on my car (V12, no room), but most of the pipes that I can see are rubber. I'm would imagine they would be after all. Can you see if the leak is coming from a split in the tubing or a split in any metallic or plastic parts? If you can/want, pics might help.

If it is as simple as a split in the pipe work, you could simply call up BMW with the part number from the link above and order up a form fitted pipe, but a cheaper course of action would be to take the pipe off and inspect for any splits. If there are any, pop into your local parts store and buy a length of tubing. You can sort of eye ball the length you need when you get home, but you need to make sure the inner diameter of the new pipe is the same as the old one. Often they will sell in foot lengths, even if all you need is 3 inches you have to buy 12 inches, but that's okay, you'll have some left over for next time and a pair of large wire/side cutters or a sharp knife will be fine to cut to length.

If the pipes are fine on inspection, then I'd take the aux pump out and have a closer look and see what I can see.

Some parts sources:
http://www.autohausaz.com
http://www.bavauto.com <-- a little more expensive but OEM stuff.

[lincolnmaster80]

Let's try this link instead...not the one above...

http://bmwfans.info/parts/catalog/E3...ve_water_hose/

[lincolnmaster80]

Just thinking that it might be the heater core if one of the inlet/outlet pipes to the heater core or the hoses to it are split, which would explain why you have fluid leaking inside the cabin, but no smell of coolant through the vents...

...still, one would think you'd smell the fluid though, not necessarily through the vents.

[cajunboyla]

Lincolnmaster80; I really appreciate all your help. After reading your response I will look closer. My initial inspection revealed the leak comes directly from the pipe leading thru the floor board and its just like you said, its metal... I will follow your directions and see what happens...

Thanks again
Cajunboyla

[cajunboyla]

Hey Lincolnmaster80; its me again... Here's what I found! The pipes leading thru the firewall are still solid and good. There are no leaks inside the cabin. What is causing the coolant to run completely out as soon as I refill the reservoir? Is it the heater core? Strange, because there is no odor of anti-freeze and the core is isn't leaking. Oh and I changed the auxillary pump and the outcome was the same. Need more advice

Sincerely,
Cajunboyla

[lincolnmaster80]

Originally Posted by cajunboyla

Hey Lincolnmaster80; its me again... Here's what I found! The pipes leading thru the firewall are still solid and good. There are no leaks inside the cabin. What is causing the coolant to run completely out as soon as I refill the reservoir? Is it the heater core? Strange, because there is no odor of anti-freeze and the core is isn't leaking. Oh and I changed the auxillary pump and the outcome was the same. Need more advice

Sincerely,
Cajunboyla

This is where the heater core is:
http://twrite.org/shogunnew/fixes/cl...ce_Heater_Core

The expansion tank is removable. There should be one nut type jobbie on either side (part #4)
http://bmwfans.info/parts/catalog/E3...xpansion_tank/

This might be the culprit right here:


Remove the expansion tank and have a poke around:
http://www.bimmerboard.com/forums/posts/415525

The temp guage going hot is probably do to air lock and low coolant.

[cajunboyla]

Hey Lincolnmaster80; I've poked around the expansion tank and no clogs, leaks or blockage. I'm just puzzled about this. Should I replace the heater core? Because there is no odor, no leak in the cabin. Does pouring coolant in the expansion tank go directly to the radiator or to the heater core? Because it seems to go directly to the hose leading thru the firewall to the transmission bay and on the ground... Am I missing anything else to check? Getting desperate now!!! Help

Sincerely,
Cajunboyla

[lincolnmaster80]

It looks like it goes to both the rad and the heater core. Without looking at your car myself, it's hard to say, but it looks like there is a T-joint from where Part #13 (in the link I provided of the expansion tank) it goes toward part #12 and toward part # 14. Maybe the that "T-joint" is at fault? Best I can figure from what you have described is the leak is somewhere along that line where you see it leaking.