I think I have a blown head gasket (M62TU). Symptoms:
- Big puff of white/grey smoke on start-up (intermittent),
- Rough idle at start-up (intermittent),
- CHECK COOLANT LEVEL warning (every 3-4 months, refill needed [not faulty sensor]), no coolant on garage floor,
- No codes or CEL.
What's baffling is these problems are intermittent -- sometimes the car starts beautifully, other times it balks. It could be oil smoke and I actually hope it's an oil leak instead. (But isn't oil smoke black in color?) The VCG have been replaced, so no oil in spark plugs. Car going into shop next week.
Wish me luck.
Last edited by Frankie; 05-11-2017 at 11:12 AM.
Have you replaced the OSV/CCV on the rear of the intake yet? The coolant has to be going somewhere. Is it in the oil? You may have a small coolant as well. Do a pressure test on the cooling system and see if the leak shows...
https://youtu.be/kKNeN8tR3wM
Here's what happens but I'd recommend replacing the whole piece with the intake off along with all intake gaskets...
Last edited by purplecty; 05-11-2017 at 11:19 AM.
The intermittent white smoke is what would worry me most in terms of the head gasket.
I've also had a slow coolant leak (low coolant message every 3-4 weeks) until it got worse last week. However I've only ever seen a small puddle of coolant once in all that time. Shop yesterday found that the radiator has a slow leak and will be replacing it. It seems to me that a lot of the time slow leaks in our cooling systems will only really leak under pressure/heat, where the coolant comes out while hot and the car is moving, so you don't see the evidence under the car when it is parked.
I think u have a combo problem. U have a slow leak in your system. Possibly the valley pan as it is my understanding that the coolant will burn off before hitting the ground.
Head gasket issue are extremely rare on this car.
2nd, your Osv/ccv in the back of the engine probably has a hole in it.
Slow down and read the forums for the more obvious reasons.
If you really want to get to the bottom of it, do a compression test. If one or two cylinders are abnormally low then that might indicate a bad head gasket. It's extremely uncommon with these engines though.
1995 525i 5-speed - Thread
Did the smoke problem start straight after one of the repairs above. How about straight after you did the timing cover gaskets? The only reason I am asking is that the following part if messed with can cause you problems like blowing smoke out the back...
01 Oil separator 1 09/1998 11151705272
When I had my guides done, they did not change this out and it was disturbed when the mechanic was replacing the guides. Every morning I would blow out smoke out of the exhaust. Had to take it all apart again and replace it.
Last edited by tomloans; 05-11-2017 at 08:32 PM.
It's highly doubtful it's the gasket. I agree that the OSV is bad along with a possible very slight coolant leak.
If the guy says head gasket get a second opinion.
I spend thousands on my BMW the rest I pissed away.
I've spent most of my money on this car the rest I just pissed away
Head gasket doesn't fail intermittanly.
It either fails or not.
I spend thousands on my BMW the rest I pissed away.
I've spent most of my money on this car the rest I just pissed away
Here is my best guess for both. When changing out the timing cover gasket, the oil separator was disturbed. Or the OSV you changed out is an aftermarket cheapy that broke early.
The leak could be from the Valley Pan or also a possibility is the hoses in the back of the engine that lead to the firewall and engine. I think there are four of them if I remember correctly. If one is leaking slowly, it would probably burn off before it hit the ground. Be sure to replace all four if one is leaking.
Also, the coolant will stain when it burns off so with a good flashlight, you should be able to see it. I also find that the coolant temp gauge at the lower radiator hose often will leak slowly too. Take a close look at that as that is an easy fix. You will need a green o-ring.
best wishes.
Just something else to check - see if your cooling system is building pressure. I had a slow coolant leak, and repaired/replaced every part of my cooling system - water pump, sensors, thermostat, radiator, hoses and o-rings in my car. Eventually I discovered that after driving it a couple of days when I removed the radiator cap I could hear a rush of escaping gas that smelled a little like exhaust fumes. I had either a bad head gasket or a cracked head that was allowing exhaust gas into the cooling system, and it was displacing coolant. Once other clue was the radiator hose always stayed hard, even when the engine sat overnight. I got a used engine for cheaper than tearing apart my engine, and ever since I installed it I haven't lost a drop of coolant, radiator hose gets soft when the engine is cool. I also had the rough start up, it has also gone away.
Keep in mind that the back plate, AKA OCV, PCV, CCV, is often called OSV in error on the forums, but is most often the cause of smoke on start up.
You guys were correct: large PCV vacuum leak coupled with valley pan gasket coolant leak. My wallet is about $1K lighter.
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