What happened in my engine?

[Bimmer Nut Ed]

OK, the strangest thing just happened to my 1999 Z3 M52 i6. After driving it and turning it off, then trying to start it 10 minutes later, it would not start. It tried, the starter motor engaged, turned the engine over only a hair where you could just see the the fan blade move maybe an inch.

OK, I towed the car home, assumed it was the starter motor, replaced the starter motor. BTW, a real pita in a 6 cyl z3.

Still no start, still same symptoms.

I charge the battery overnight, try in morning, hear a pop, then the car starts up. Now white smoke, big time. That's all I have now, it ran well, while a ran it, but it's burning coolant.

Could the water pump somehow locked up, now somehow throwing coolant into the intake. Does not make sense. Any Ideas?

[Ross]

Just saw this same scenario, it was a head gasket.
After shutdown the pressure in the cooling system forces coolant into the effected cylinder hydro-locking it.
Did it run ragged when it started?? That's the coolant burning off.
Hope I'm wrong.

[whiskychaser]

Any black stuff in the expansion tank? I'd be taking out the plugs to see if any are wet. I've had one motor drop so much coolant into the cylinders it wouldnt turn over. Spun it with the plugs out and water spurted out of the plug holes. HG was shot. Sincerely hope this is not the case.

[ryan roopnarine]

IIRC, i don't believe that the intake on your iteration of the bmw I6 has any reason to have coolant passages that run through the intake. good luck, in any event.

[Bimmer Nut Ed]

Yeah, I'm thinking head gasket, and hydro-lock causing the no start symptom. I'll go pull the plugs and let you all know. Good call.

Yay, I get to do a head gasket. :( Have not done one on a bimmer yet.

Wonder if my daughter who was driving it at the time noticed anything like overheating or such.

Thanks guys.

[Ross]

"Wonder if my daughter who was driving it at the time noticed anything like overheating or such."

Ha!

[Bimmer Nut Ed]

She's usually pretty good about these kinda things, you forget, she has me for a daddy. I'll have to interrogate her when she gets home! doh

[whiskychaser]

Lets be really cheerful : isnt it more likely the HG went because it overheated and not the other way round? If its gone I'd be looking for the cause: coolant leak, duff pump, stat stuck etc. Then the buttock clenching moment: you have backed off the head bolts and hope that they hold when you do the re-torque test. And if not you are looking for these: http://www.timesert.com/
Fingers crossed.

[Tiger]

Do a coolant system pressure test.

[bsell]

So OP, what did the combustion chamber spies look like?

Spark plugs, that is.

I figure you will find one very clean spark plug of the six...:(

[Bimmer Nut Ed]

Here's three of the plugs:
http://mymotorsport.com/head/DSCF0017.JPG

Only one was not wet.

[Bimmer Nut Ed]

I took the valve cover off and I'm going to start the process to replace the HG.

http://mymotorsport.com/head/DSCF0016.JPG

http://mymotorsport.com/head/DSCF0022.JPG
This milkyness is not a sign of overheating, it's a sign of tstat being stuck open, and never heating, isn't it?

http://mymotorsport.com/head/DSCF0025.JPG
POS, now I got to do the HG after busting my knuckles replacing the starter motor for no good reason. frig

[bsell]

Does your engine have a dipstick? If so, does the oil look like chocolate milk?

I pulled the head of my '73 240z needlessly...there was a coolant leak into the intake manifold at the throttle body warming plate.

So I replaced the head gasket and put on 3 two barrels and went about my business! I taught that pesky leaker a lesson! :p

I don't know if your intake has coolant available to it. If it does, can I suggest pulling the intake manifold first and see if there is coolant in there? Could save you a head gasket job.

If the intake is dry, you are in for more work...

[whiskychaser]

If the car stood for, say a few weeks and you just fired it up you may get a bit of mayo. Or if its only used for very short runs. Bearing in mind its refusal to start, I'd stick a length of wooden dowel down each plug hole. I bet one comes out wet. A compression test will confirm.

[ryan roopnarine]

I forgot to mention something that brian brought up. Your engine does have a potential for water ingress at the throttle body--at least I think it does, as my plain jane non vanos m50 has plate warming coolant passing through it. I would think that your engine has the same.

and..do you ever drive the car? do you notice the coolant fluctuating between cooler than normal and illogically cool? The ford taurus over here has a tendency to rust apart thermostats, and in one instance, one of the two metal branches that hold the spring in came apart. the result was relatively normal temperature in the city and on the highway that would suddenly start fluctuating and indicating cooler than usual when one slowed down and stopped at a toll plaza. made me feel good about the generic stant cheapie that i put in there, as it proved that it would fail open rather than closed.

[Bimmer Nut Ed]

The Z3 never really sat long, daughter drove it to school every day. But school is not far at all, so I think that would account for the mayo.

Yep, I'll have to do a compression test. I woulda hated to do the HG for nothing, like I just did the starter motor. Good suggestion.

When I take the manifold out, I'll see if there's a warming plate with coolant. We'll see.

And no, I don't drive it, I don't fit in that little toy of a car! But yes, the tstat has stuck in the open position and not warmed up in the past. I replaced the tstat for exactly that once already. I think daughter woulda complained about no heat to me though, she's good for that. She readily complained about that in the 535 e34 she drove prior to the z3, in which I had to replace the tstat for her.

Thanks for all your thoughts and suggestions.

[Tiger]

Gee Ed. I thought you were ready to rip out the head when you took off the cover... scared the heck out of me for going so far without diagnostic.

Do coolant pressure check and compression check.

The spark plug looks horrible... is that even factory plug? It is so wet, that it is possibl you got leaky injectors.

[Bimmer Nut Ed]

Yeah, the car wasn't going anywhere, so I ripped off the valve cover. That's the easy part. I have to research tools and what not before I take the next step. But yes, a compression test I'll likely still get to today. I'll post the results.

BTW, anyone have carsoft here in the North of Chicago, by the WI boarder, area. The 1997 M3 EWS is out of sync with the DME, so it won't start. I'll post a new thread on that one! Down two bimmers! I'm beginning to have my doubts about these cars, not!

[Ross]

If you were able to run the engine long enough to build any cooling system pressure pull the plugs(look for the one(s) without any soot) and spin it over. If coolant spits out you know what you are up against.
M50, I'll bet you find a water pump with a loose impeller too.

[Bimmer Nut Ed]

Compression test is fine.

And guess what, the other daughter sent her other M3 keys home in the mail, and the M3 started. Very strange. It would not start with one key, that worked perfectly well, but it starts with the other key. They both looked like master keys. The one that did not work was even a key with the light in it. I have a third key that does not have the etch running down the side, which is not a master. Very strange, but now only down one bimmer. It's nice when they repair themselves.

[Bimmer Nut Ed]

So if the compression test is fine, does that mean it's not the head gasket? Do I need to do a leak down test.

[Jr ///M5]

No. I believe you have a blown PCV. On the M52 and 54 it's located underneath the intake manifold. The oil in the engine is being sucked up through the dipstick because the valve froze in the closed position because of all the condensate that didn't drain back into the block. It's why your plugs are fouled. There is an updated version that is insulated and runs about $400 from the dealership, this includes an updated dipstick that is about $200. There's a trick to cleaning out the dipstick tube, but replacement is up to you. You need to call me and I'll help you through it. Do a search on BMW Cyclone Valve and you'll see what I'm talking about.

JR

[Ross]

^^this makes sense.
Too late to run it now but do you remember if it pressurized the cooling system before it would get hot? Was it fuel, oil or coolant on those plugs? I don't see five cylinders loosing the gasket at once.
Did you smell coolant in the exhaust?
Let me know if you would like to borrow a cylinder leakage tester

[Tiger]

This seems more probable for cyclone valve problem. I remember another guy had similar problem and the oil ran down but caught it before it ran dry.

[Jr ///M5]

Just ask me how I know....it's happened twice to my wife's car. It can fail one of two ways, we've experienced both.

[Tiger]

Ahh... so it is you... I wasn't sure. I did remember you told you wife to shut it down right away and tow it home.

[Bimmer Nut Ed]

But, but, but, seems the engine would not turn over because of hydro-lock, and when it did start, it poured clouds of white smoke out the exhaust. The coolant level is down, and the oil level is fine.

I know the oil separator issue too, and it sucks oil into the intake.

So I'm still in the dark. I kinda plan to take the intake manifold off and take a look see inside there. It's the first step towards further removal of the head anyway. Is there a specific test that will tell me if it's a head gasket? Shouldn't the compression test have failed if it was a head gasket?

Thanks

[Bimmer Nut Ed]

My oil separator froze up two Chicago Auto shows ago on me. I was downtown, drove home, and finally getting close to the house, I noticed clouds of smoke coming out the exhaust. I get home, engine oil all over my engine compartment, adn down to about 2 quarts of oil. Had it towed in to knauz, and they fixed it under warranty.

I could see that causing hydro lock, as is sucked a ton of oil. But oil level looks good on the Z3. And the clouds of smoke seemed to be burning coolant, not blue oil smoke.

[Jr ///M5]

I would think you would smell the oil burning. The hydrolock can also occur with oil being pumped into the intake manifold. This is exactly how Rob experienced his cyclone valve failure in Roundel a couple months ago. He ended up getting Ben Thongsai (just happened to be in that part of the country) to get it sorted out for him.

The cyclone valve can freeze shut or in the open position. One of the failure modes will blow off the valve cover and pour oil all over the exhaust because it overpressurizes the crankcase. The other failure mode is sucking the oil out of the pan and into the intake manifold. I'll bet Lori's car sucked 4 quarts up through the intake and into the exhaust while she was driving in a period of about 5 miles. Had she not seen it smoking, it would have almost sucked the sump dry before complete engine failure. I believe the hydraulic tappets will collasp, and that's why a compression test will not be true in this case. I believe that is what saves the engine from punching a hole in something.

[whiskychaser]

Can I just confirm the symptoms are loss of coolant, water on plug(s) and water under valve cover? Any evidence coolant escaped from the expansion bottle cap?

[Bimmer Nut Ed]

Can I just confirm the symptoms are loss of coolant, water on plug(s) and water under valve cover? Any evidence coolant escaped from the expansion bottle cap?

Yes, loss of coolant, possible hydro lock, when car did start (after installation of new starter motor, and charged battery), a ton of white smoke out of exhaust. It ran rough for maybe a minute, then ran fine, but still white smoke out of exhaust. I turned car off then and have not started it since.

No evidence of coolant excaping from expansion tank.

Only some mayo inside of valve cover, probably explained from daughter not driving far during recent winter months here.

Compression test checked out OK, 185 on all cyl.

And yes, the plugs, all of them, seem to have coolant on them.

Thanks guys.

Oh, Oil level is normal, and coolant level is low.

[whiskychaser]

OK, theory time. Well its actually based on me changing the head gasket twice. Not because I had low compressions. But because I had a leak at the joint between the cylinder head and the timing chain cover. So, unlike mine (which leaked out and I could see it) perhaps yours is leaking in? Water vapour escapes up by the timing chains and is drawn out of that handy vent in the valve cover. From there it goes into the inlet manifold and is distributed evenly between all cylinders. That would account for the loss of coolant, the mayo and the water on the plugs. The only flaw is that you dont mention the head has been disturbed. I had to take mine off to replace some bent valves. I dont know the motor in question but is this plausible?

[Bimmer Nut Ed]

Hmm, talked to a tech here at Knauz. I'm leaning towards Oil Separator now.

The burning coolant could perhaps have been oil/moisture mixture. A blob of that mayo getting sucked into the intake. Burning moisture laden white blob of oil might make me think coolant. Smoke did not smell sweet, but it did not necessarily smell oily, and I did not run it very long to let it warm up.

The plugs should be clean if it was straight coolant, they look oily, so another clue about it being the oil separator.

Also, daughter does not drive far, so moisture laden oil separator freezing up makes sense.

And it was cold as heck the day it died, and would not start.

A glob of that moisture laden oil coulda caused the hydro lock I guess.

If the car overheated, hopefully my daughter would have known to tell me, and at least she says to me specifically that the needle did not move past center.

And if it over heated it should have thrown a code, or provided an error message.

So, i'll likely still do a leak down test, a cooling system presure test, but I'll first take a look at that oil separator. I will let y'all know what I find.

[Sailor]

If you have good compression, but seemingly obvious coolant leak. it could quite easily be a crack in the head in the coolant jacket to intake manifold some where. It seems to be common in the chev 350 and I had it happen in a 735i long time ago. My coolant was not quite good enough to get to -40, I surmise. God knows what gas air mixture the computer is going to throw at the plugs when the o2 sensor gets the coolant to confuse it. Might explain the look of the plugs.

[Jr ///M5]

Replace the Oil Seperator Valve with the cold weather version from BMW. This kit also includes the dipstick tube. The TIS for the X5 shows a neat trick by using the metal insert from a wiper blade to clean out the drain passage on the dipstick tube. Followed with a few squirts of carb cleaner. The dipstick is removed when replacing the new insulated piping to the newly insulated OS valve. A new "O" ring should also be obtained for reinstalling the dipstick tube. The old lines will easily break apart to remove them. They have been heat cycled and will be brittle. You should also get a new throttle body gasket. Reinstalling the new lines once the OS is in place is a bit of a trick. Practice the fit and how they line up to click into place before actual installation of the valve. A little vaseline will help matters. When you've pulled out the air box and MAF meter, be sure to check the intake hose for cracks and splits. It's a bitch to get the new one back in place, along with trying to tighten the clamps that hold it. It's a tight fit, that could be helped with a little persuasion from a heat gun. While the throttle body is off the car, it's a good time to clean it with the carb cleaner you have on hand to clean the dipstick tube. The cold weather version of the valve is wrapped in foam insulation. This is to give the condensate a chance to drain back down into the oil dipstick tube before it freezes. The new design dipstick tube has a larger "Y" connection to facilitate drainage, it's also another $150 or so. That's why I gave you the cleaning option. It took me about 5 or 6 hours including changing the oil to do this job. Then there was the matter of driving the car about 30 miles at high RPM to burn off the oil that was present in the exhaust. Insure that the thermostat is working properly and the engine is coming quickly up to temperatur. Cooler running engines will produce more condensate inside the engine that doesn't get to "burn" off. In our climate, it only burns off in the summer time. Check the car from time to time by simply looking at the bottom of the oil filler cap. Try to dry out any moisture trapped in this area with a good paper towel. The inside of the cap when working properly should not have the yellowish, milk-shake looking goo, that is the condensate moisture mixing with blow-by

JR

[Bimmer Nut Ed]

Cool JR, thanks for the info. I have the new insulated kit, bought it today, everything except the dipstick tube. Eh, for $150, I'll prolly just stick with the old one, and just clean it out as you suggest. Those other parts, the cold weather versions, only cost me $100. They are easily identified on realoem.com. Next chance I get to dig into this "new" project is Sunday. Next update will come then. Thank you everyone for all your feedback.