actbadtothis

So I recently grabbed a 2008 550i with 147k miles on it, found what I thought was one coolant leak, (very small very slow) and a slight oil leak that the last person must of had for a while and never fixed because the engine is so caked in oil its hard to watch for the leak to see where it's at.

Anyway, not just 1 leak but alot of leaks, upper hose above the rad, i'm pretty sure the water pump failed, and the return hose from water pump to rad were all really bad, so ordered all those parts and will be installing them, but another issue keeps bugging me and I've looked everywhere to see if someone has had it but none just like mine so i'll share, after the engine has gotten to temp and not every time but only sometime, sometimes i'll go an entire day without seeing it, I will be at a stop light for a bit in the hot sun, press the gas, and pump more smoke out of my back end then a person vaping in their mom's WRX, and of course its coolant, got the sweet smell and light smoke, but cracked head/bad gasket, cylinder would always push smoke, or at least be consistent right? I have herd people say there are other ways coolant can get into the exhaust i would like to ask if anyone knows what exactly does before I bury this poor puppy. I have checked for oil in the coolant, and coolant in the oil, and neither are a factor, once I get the car apart for the other parts ill probably just take the damn thing apart and check myself for bad gasket, cylinder's ect, but if anyone knows of another reason I'd really like to know what you think so i can check as well.

dingolfing

It's oil burning more likely than coolant, especially since you said you didn't see any coolant in the oil. Our N62 engines have valve stem seal issues where oil is allowed to leak past and into the combustion chamber.

I had this exact same problem. No smoke on cold idle, but when at operating temp and idling for a minute or more, press the gas and you'll see the light blue smoke.

I fixed it by switching to a high mileage oil with rubber seal conditioners. I previously used Mobil One synthetic 0W-40 and now use Mobil One synthetic 5W-30 high mileage. It takes awhile, as in 6-12 months and normal accrued mileage for the seal conditioners to restore the internal oil seals.

Now I can idle for quite awhile and do not emit any smoke when accelerating.

I tried this after reading someone on a forum do the exact same thing by switching to high mileage oil. Your other alternative is tearing apart the head to replace all 32 valve stem seals!

actbadtothis

awesome man, I'll give it a switch and see if that works, also got one last question, just replaced all the hoses and the water pump, tossed coolant with a pan under just in case (good thing i did) and as i was pouring, it took a little bit for it to flow but as it was getting to the block i started hearing water swishing around from the block, then i noticed all the coolant i just added was just dripping out from a hole in the second splash guard, took it off and started seeing it dripping from up by the mid of the block, am I safe to guess that's the "amazing" BMW coolant transfer pipe leaking or might it be something else? just want to make sure before i buy a collapsible one

dingolfing

There are several common failure prone cooling system components on our cars. Take a look at this diagram of the cooling system:

https://www.realoem.com/bmw/enUS/sho...diagId=17_0286

Both vent pipes (#10 and #12) have flexible rubber tubes (not problematic) and hard plastic pipes. The plastic parts are where these vent pipes fail. Since this pipe is located high up in the cooling system circuit, it won't show any leakage until you fill the circuit near full of coolant. To me it sounds like your #12 vent pipe is leaking. Take off your engine acoustic dampening top cover and look underneath the intake manifold. Start where #12 vent pipe connects to the coolant tank and follow it to where it connects to both cylinder heads underneath the intake manifold. If you see dried blue coolant around any part of the pipes, there's your coolant leak.

I just replaced this vent pipe on my car.

actbadtothis

well it was the coolant transfer pipe, got that replaced, also looked and everything else externally on cooling system is good, but now that coolant makes it rounds it has brought me to a awkward predicament, started the car up, let it idle for about 5 minutes them clouds of sweet smelling white smoke just started pouring out of the tailpipe, unsure if it was build up or not, I drove on it under 2k rpm for 10 or so minutes, then pulled back into the house, got out while it was still running, and no smoke, let it idle for about 5 minutes, reved to 2.5k rpm, still no smoke, so I turned the car off let the engine cool for an hour, came back out and started the engine, and 5 minutes in, white smoke came back. I know everyone is so quick to say head gasket, and maybe they are right, but the fact the smoke goes away insted of getting worse as I drive has me questioning if it is, a current gasket with an "install kit" cost's in total 340 bucks I got a place and a couple people with over 40 years working on cars (but not BMW cars) to help me switch it, I just want some other opinions before i commit to that to find out it wasn't even the head gasket.