[Landiah]

Originally Posted by RockCrusher

Glad to read it was nothing serious.

My Cayman S came with a heavy coating of rust protection. (See pic below.)

No signs of any protection on the exhaust but the pic was taken at ~750 miles and if any had been on the exhaust it would have burnt off with that many miles of engine run time.

I imagine it’s a similar thing here. Tech said it was cosmolene.

[Cj1]

Originally Posted by Landiah

I imagine it’s a similar thing here. Tech said it was cosmolene.

That doesn't look like cosmolene. It looks like coolant. Have you ran your defrost or heat since you've had the car? There is no area where cosmoline would heat up and drip onto that area of exhuast. There is however an AC condensate drain hose over that exact location. It is a little to the aft (maybe a half inch) to be getting so much over that section, unless it's puddling maybe? Anyway, yes condensate is water and that's what you'll see most likely if you run your AC. But I'd run you're defrost and heat and see what happens. Look at fluid and smell around area. It will be outside only. So if you drive with windows up, you'd never know. Heater cores can leak into condensate line from pan on some vehicles. Especially if it's leaking at a hose fitting/connection. Lastly, cosmolene, when heated or cool is usually sticky, not hard, and cosmolene is easily removed with something like goo gone or parts cleaner (it is a grease after all). Baked on coolant is usually harder almost like a calcified material.
I could be absolutely incorrect, I am not trying to make you nervous, if I were you I wouldn't trust me as I am no mechanic, just a forum member. But, I would not put complete trust into mechanics these days, or anyone for that matter. Pessimist, sorry

[Tag]

Originally Posted by kaysonb

i had a queston about my bmw its a 2008 328 xi i bought a window washer fluid pump thinking that was the reason why it wouldnt work, but yesterday i was doing my window alternator and hit my window washers, i heard the pump run then notice a leak coming from the drivers side front, i tried to look up if the hoses go that far out and couldnt find anything, not sure if you would know but thought it was good to ask, thanks.

Wrong place to ask your question. This is the G87 M2 forum, not the E9x forum.

Try https://www.e90post.com/forums/

[gcmak]

Originally Posted by Landiah

Got the car checked out by the dealer. It’s nothing to worry about. Something to do with some kind of rust protectant.

Yep undercoating. Why they couldn't do a cleaner job is another question haha.

[RockCrusher]

Originally Posted by gcmak

Yep undercoating. Why they couldn't do a cleaner job is another question haha.

Don't need to.

My new Cayman S had some rust protection (cosmoline) sprayed onto the under carriage, engine, transmission.

I'm sure the exhaust manifolds got some spray but by the time I bought the car the few miles it had accumulated and engine run time this required I'm sure burned off whatever over spray was on the exhaust.

[RockCrusher]

Originally Posted by Landiah

I imagine it’s a similar thing here. Tech said it was cosmolene.

I'm reluctant to disagree with a tech's diagnosis/opinion.

But I have to question blaming that stain on cosmoline. Now my Cayman S had plenty of cosmoline sprayed on the engine, drive train, some suspension hardware and probably on the exhaust.

I just recalled I took some pics of my M2 on the lift during its first service.

Won't take the time to transfer the pics from my phone to my MacBook Pro and post the pics, but I reviewed each one and I see no real sign of cosmoline -- at least as it appeared on my Cayman S -- in the pics.

Could be BMW uses a lighter treatment? I can't say. I'd have to be under the car with this in mind and look more closely for a more translucent rust preventative.

I will refer back to my first post and restate I believe the stains are coolant. It is quite normal for coolant to after hitting a hot exhaust for the water to evaporate (to state the obvious) and (maybe less obvious) leaving behind white stain. It is the antifreeze residue. White? Yes, in small amounts and dry the color will be white. Only when the coolant leak is wet (as I have observed several times over the years from water pump seals and radiators) there will be antifreeze color (green-ish or red-ish) to what one sees.

See attached pic of my Turbo's leaking water pump.

And I've attached a pic of my Boxster's leaking water pump and you can make out the light/white stain on the housing under/below the pulley.

But even if I'm right this does not necessarily mean there is a leak. It could be that in filling the engine with coolant or perhaps topping it up during its PDI some coolant was spilled.

An active coolant leak and especially one that is suspected of dripping coolant on a hot exhaust would have the car stinking of antifreeze.

Absent the odor of antifreeze from the hot vehicle and after it has sat a bit, absent any signs of coolant under the car, or the stains changing, and with careful monitoring of the coolant level and no change in the level then I would offer there is no active leak.