I am getting a very strong coolant smell inside the cabin of my E34 540. Car does not appear to be using coolant (havent had to fill it, no warning lights, car is not overheating, there is no coolant in the oil, there is no coolant in the interior.

This has me kind of miffed. My gut tells me the heater core is leaking but I am not seeing anything inside that would indicate that.

Got any ideas.

One note, I do not have the auxilary water pump connected at this time because the last time I replaced it it made so much noise I couldnt bare it. BTW, is that normal? I have gone through 2 OE auxilary water pumps in 4 months because the noise was was loud. It sounded like the bearing inside was shot. Since the part has a 6 mo warranty I need to take it back again.

mine had a slight coolant smell right before a coolant hose split near the fire wall. im guessing it had a little leak before it filnally blew. might want to check that, it is the one coming out of the back of the intake manifold.

It only takes a few drops to make the whole car smell. It might be the heater core. It might just be something in the engine bay getting sucked into the car.

Run the car for a while then lift the hood, if you get a good smell from under the hood then it's not the heater core.

Thanks for the suggestions guys. I will check it. The only hoses that have not been replaced are the ones from the block to the heater core. I would expect to see some leakage outside the car though. I suppose it could be and I could be missing it. I dont get the smell under the hood.

Anyone know what the book time for the heater core is? I do my own work as I have on the Porsche and Mazda but I dont have FSMs for this car.

See if you get the smell with heat on and off. Then try AC on and off. See if these both work correctly, report back. :)

Under the car there is a drain tube/hole for the heater box. Stick your finger in then lick your finger. If its sweet, its the core leaking. Go get a breath mint. And to all you people that are going to say that coolant is poisonous, its a tiny lick. Won't kill you.

Under the car there is a drain tube/hole for the heater box. Stick your finger in then lick your finger. If its sweet, its the core leaking. Go get a breath mint. And to all you people that are going to say that coolant is poisonous, its a tiny lick. Won't kill you.
Alan,thank God this is not a plumber's forum. :)

See if you get the smell with heat on and off. Then try AC on and off. See if these both work correctly, report back. :)

Will check in the morning. I am 100% sure I get it with the heat on, it hasnt been warm enough to try the AC :)

See if you get the smell with heat on and off. Then try AC on and off. See if these both work correctly, report back. :)


OK checked this morning. There really doesnt appear to be a smell when the AC is on but the second the climate control knob is turned past 72 (into the "heat" section) the smell is very definite. It also seems to be worst on defrost.

Best I can tell it points to heater core.

Anyone know how long a job it is?

I am looking at the same job.

In Canada here, one guy at work paid $1000 at a local shop. I had the heater core quoted as $180 and the labour at $300 from a guy at a local online BMW club.

Here are some details on the job....it ain't pretty!!

http://www.homeofsbc.com/Fixes/Heater/heater.htm

I just had the center console out in mine, replacing the condenser. It's not as bad of a job as it seems. Just lots of screws to take out and remember where they go back. If you've worked on your own stuff before, you should take it apart and make sure you have a leak before ordering the part. Probably take you 4 hours to tear it apart if you've never had it apart before. Bentley manual is a big help.

I just had the center console out in mine, replacing the condenser. It's not as bad of a job as it seems. Just lots of screws to take out and remember where they go back. If you've worked on your own stuff before, you should take it apart and make sure you have a leak before ordering the part. Probably take you 4 hours to tear it apart if you've never had it apart before. Bentley manual is a big help.

Mike, I can certainly handle taking it apart...sure dont want to however! Not to mention, if I get it apart then the car is undrivable until the core comes in. Is this common enough that a dealer should have it in stock?

BMA can probably get it to you within 3 days. (much cheaper than dealer usually) I tore mine apart thinking it was the heater core, but it turned out to be the condenser. It also could be the hard pipes that connect to the heater core. You just won't know what it is until it's apart. If you're driving it now, you can certainly drive it with the center console out. Just looks wierd ;)

Under the car there is a drain tube/hole for the heater box. Stick your finger in then lick your finger. If its sweet, its the core leaking. Go get a breath mint. And to all you people that are going to say that coolant is poisonous, its a tiny lick. Won't kill you.
Heh. All the antifreeze I've ever tasted has been bitter and foul as shit. It won't leave your mouth for a long time. I don't know how these people call it 'sweet' - I went straight to the listerene to get that shit OUT of my mouth.

And it takes a teaspoon to kill a small cat - a lot more to kill a human. Tasting is fine, but don't chug the stuff. :)