[mjpd1]

I've been noticing a slight coolant smell through my vents while driving, probably for a few weeks now. Noticed last week that my reservoir tank was below minimum, so I refilled that up to max. I'm not seeing any fluids at all under the car or in the engine bay. I always check the driveway first thing in the morning, and then the parking lot when I leave work at the end of the day. Always dry. But it's obvious that I'm losing coolant somewhere. Any thoughts?

 

[07lmnt]

Heater core

 

[mjpd1]

Thanks for pointing me in the right direction, but any chance you can expand on that? Heater core going bad, ie needs replaced? Do I need to flush the coolant system? At 50,000 miles, is this a warranty repair? A little more info would be appreciated. I'm an IT guy, not a car guy :-D

 

[1fastvx]

If you are not seeing coolant on the floor in your E the heater core is most likely OK. Coolant leaks can be a little hard to spot. Remember that while you are driving the system is under much more pressure. Keep looking for traces of coolant under the hood.

PS...I am an IT guy and a car guy :-D

John

 

[ramblerdan]

If the heater core is beginning to leak, in addition to smelling it, you'll find yourself washing the inside of the windshield more often. That greasy film is coolant.

OTOH it's possible you have a leak under the hood, and the smell is coming in through the cowl vents. Look for a puddle under your parking spot in the morning.

 

[Cyclist_306]

It still could be heater core with the coolant leaking draining on to the road via the condensate drain (the same place water from the AC drains), a small leak in the engine compartment, or a small leak in the head gasket.

Check the oil for any discoloration.
Any white smoke from the exhaust (have a friend follow) while flooring it from a stop.
Once cooled down, run you hand over all rubber hoses in the engine compartment for a 'sticky feel'.

 

[mjpd1]

Thanks for all the advice. I'll continue checking under the hood and car for leaks, but so far have not seen anything.

Is this the kind of thing I can have the dealer test? Or will they invariably "find something wrong" and charge me to replace it?

 

[ramblerdan]

No need to go to a dealer, unless you're still under warranty.

 

[ApriliaGuy]

small leaks are tough to find.

Usually you get some visable drippage or puddle.

Maybe the coolant is dripping onto the exaust system and evaporating (thus making the smell more noticeable besides.)

Check around the back of the motor where the hoses go into the heater core.

Check all the connections/hose clamps. That is a common area for leaks.

Check the radiator cap....and the radiator real good. You might have a pin hole in one of the fins.

Was the car ever damaged...like a deer hit or a low speed bump of a car in front of you? There could be a crack in the radiator housing.

Just some ideas that come to mind....good luck w/ the search. Be sure to keep the level topped up in the meanwhile, you don't want to let it overheat and cause some expensive damage. If you're not carefull it can sneak up on you.

 

[yoda13]

I am not sure about the E, but my Dad's Jeep appears to have sprung a leak around the thermostat housing, smells and acts just like this...is this possible on the E?

 

[bmwrider]

From you description my first guess is heater core. Turn the heat on and see if the smell gets worse. My '77 Eldorado had a slightly leaking heater core for months but never showed any signs of a coolant leak like water coming inside but turn the defroster or heater on and that sickly sweet smell would fill the car and cloud the windshield. It was almost 2 day job to replace a $40 heater core in that car and get the dashboard back together, I took a sledge hammer to the leaking core when I was done.....

I don't know if on the E if it is easy to bypass the heater core by simply connecting the input and output hoses together with a straight fitting but that would be an old school way of seeing if the smell goes away once the core is bypassed.

 

[desinia]

Another vote for a pinprick leak in or around the heater core. Could be in the core or just a hose connection seeping, but you don't need to spill very much to smell it.

Can anyone advise if the heater core can be seen through the opening for the cabin air filters, and does the OEM fluid have a UV die in it? A cheap black light should show where the leak is.