Author Topic: Leakdown test inconclusive, heres a recap... (Read 3356 times)

JoeDellio · « **on:** July 09, 2009, 09:55:17 PM »

Comp test a month ago yielded 180,230,230,230 psi

Burning half gallon of coolant in 10 miles, not leaking it.

Leakdown test (Yes I did it right, TDC comp stroke on corresponding cylinder) = about 10 % loss in cylinders 1,3,4 cylinder #2 15% loss. But keep in mind the comp test showed #1 to be roughly a 50psi difference, yet the leak down shows its good.

All I hear is a faint hiss when I remove the oil cap, which is normal.

While watching my coolant it never bubbled or raised with any of the tests.

WTF? I am seriously getting irritated as a MOFO. Ill I can think to do is tear the bitch apart and look for the gremlin.

UPDATE:

From what I know the car doesnt leak visually. I have let it idle for 40 minutes in my garage watching the ground, and shining a flash light through the intake manifold looking all over the block for leaks and nothing.
Nothing steams, but I can smell coolant, and I am 100% sure its not the heater core.
No coolant in oil/no oil in cooant, both look excellent.
Car puffs out light white/gray/grey smoke at idle , and plumes it out above 5500 RPMS.
Car consisently looses on an average of 1/2 a gallon of coolant after about 10 miles.

FUNNY THING: Car drives GREAT, except for CEL of 1226 (KS #2),1222(running too rich or lean), and ocassional 1221 (Front O2)
Plugs are black (from running rich) but not wet with coolant, nor is anything super clean from burning steam in combustion.

I am going to check cylinder #1 for an internal leak.

Im guessing only way to check the head for cracks is to just pull it off and take it to a machine shop?
Do they test it complete, or do they tear it down? Because Ill tear it down myself so I know its put back right.

WHERE IS MY COOLANT GOING? :confused:

DesktopDave · « **Reply #1 on:** July 09, 2009, 09:58:31 PM »

I heard that the junction of the overflow tank & radiator is a likely place for a leak. You don't smell it in side the car? If it's leaking there it'll hide beneath the carpet...but you'd definitely smell it.

http://www.realoem.com/bmw/showparts.do?model=CA53&mospid=47490&btnr=17_0089&hg=17&fg=05

I think #3 & #14 seals look likely to me. You'd still be able to see it, I'm confused too. I never worked on an e36...

JoeDellio · « **Reply #2 on:** July 09, 2009, 10:44:17 PM »

Quote from: DesktopDave;75040

I heard that the junction of the overflow tank & radiator is a likely place for a leak. You don't smell it in side the car? If it's leaking there it'll hide beneath the carpet...but you'd definitely smell it.

http://www.realoem.com/bmw/showparts.do?model=CA53&mospid=47490&btnr=17_0089&hg=17&fg=05

I think #3 & #14 seals look likely to me. You'd still be able to see it, I'm confused too. I never worked on an e36...

No smell in car, checked heater core for a leak, my carpet is dry as a dinosaur bone, and my interior smells like leather. I smell it under the hood and see it in my exhaust, now more than ever.

Definitely not leaking. Radiator and overflow resevoir are both brand new - less than 4K on them. I literally let it idle today for 40 minutes in my garage (letting her warm up for LDT) with a flashlight trying to find leaks under the hood, on the block and under the car. None found. Then when it cooled down enough to check it my coolant resevoir was all the way down to where it was almost sucking air.

Thanks for always chiming in Dave, I have never been so stumped diagnosing a vehicle like this. If I would have has this car when I was 16 and had this problem I honestly probably never would have picked up turning wrenches as a hobby, because this is by no means fun at all. Ive never had a turbo car with a problem half this confusing. It looks like my weekend warrior DSM thats been getting ragged on everytime its driven for the past 3 years is gonna be the new DD, and thats scary.

quinn11m20 · « **Reply #3 on:** July 09, 2009, 11:36:09 PM »

Hey... Your still having problems? WTF. How is the color of your oil? I know stupid question. OK. Has this been suggested. Remove your sparks plugs one by one and while doing this have some one crank the engine.This will give you more proof of which cylinder is pushing coolant .. If you think that is happening. I know again. Sounds stupid. But, Murphy's law states "if its stupid and works, It ain't stupid". Or try this, fill up your coolant, crank the motor, let idle. Let the engine come to normal operating temperature.
I am gonna say that you have already tried this. I have been following this thread but not too closely. I hope I have suggested some other forms of resolution for you. Good Luck.

keflaman · « **Reply #4 on:** July 10, 2009, 02:16:14 AM »

If you're "burning" 1/2 gallon of coolant in ten miles, I would think your engine would be encountering hydrolock.:eek: Maybe not:confused:

Anyway, one or more of the combustion chambers should be squeeky clean and the sparkplugs will tell you if coolant is entering the cylinder.

If all the sparkplugs are the same color, and you're not spewing thick, white smoke from the tailpipe, I'd suggest you try pressurizing the coolant system and look for leaks while the engine is cold. One component suspect is the black plastic coolant pipe under the intake http://www.m42club.com/forums/showthread.php?t=7574. Many more details are included here: http://www.m42club.com/forums/showthread.php?t=2742. This pipe is kind of hard to see with everything in place, so it's easy to miss a leak there. Just grab a flashlight and look where the left hand motor mount attaches to the block. If there is coolant leaking it will pool in the areas of the block webbing. Even if there's no coolant pooled in that area, look for "waterline" marks on the block indicating a leak that has evaporated off the block while it was hot.

I wouldn't say your test results are inconclusive because they tell us this:

Compression Test - The cylinder wall of #1 may be scored below TDC, so the cylinder loses compression as the piston passes the damaged area during the compression stroke and pressurizes the crankcase. (This possibly explains why you are leaking oil out the cap;))

Leakdown Test - Indicates nothing wrong with the head, valves and rings @TDC.

Neither test indicates a warped/cracked head nor a blown head gasket.

You can verify a damaged cylinder wall with another leakdown test using low pressure . Install sparkplugs in the other cylinders (this helps to "brake" the engine after it passes TDC) and slowly turn the engine over by hand. If the cylinder is scored/damaged, the pressure will drop when you hit that area during the downstoke of the combustion cycle. Listen/feel for air coming out of the dipstick tube or oil cap.

JoeDellio · « **Reply #5 on:** July 10, 2009, 03:33:05 PM »

From what I know the car doesnt leak visually. I have let it idle for 40 minutes in my garage watching the ground, and shining a flash light through the intake manifold looking all over the block for leaks and nothing.
Nothing steams, but I can smell coolant, and I am 100% sure its not the heater core.
No coolant in oil/no oil in cooant, both look excellent.
Car puffs out light white/gray/grey smoke at idle , and plumes it out above 5500 RPMS.
Car consisently looses on an average of 1/2 a gallon of coolant after about 10 miles.

FUNNY THING: Car drives GREAT, except for CEL of 1226 (KS #2),1222(running too rich or lean), and ocassional 1221 (Front O2)
Plugs are black (from running rich) but not wet with coolant, nor is anything super clean from burning steam in combustion.

I am going to check cylinder #1 for an internal leak.

Im guessing only way to check the head for cracks is to just pull it off and take it to a machine shop?
Do they test it complete, or do they tear it down? Because Ill tear it down myself so I know its put back right.

nickmpower · « **Reply #6 on:** July 10, 2009, 04:25:21 PM »

you can buy a device that pressurizes the cooling system

keflaman · « **Reply #7 on:** July 10, 2009, 04:36:27 PM »

Quote from: nickmpower;75079

you can buy a device that pressurizes the cooling system

And I think that would be a better course of action before tearing the engine apart.

The smell of coolant may be because it is pooling somewhere not quite hot enough to boil off (causing steam), yet hot enough to evaporate fairly quickly.

JoeDellio · « **Reply #8 on:** July 13, 2009, 02:58:10 PM »

Ok, slap me silly and call me suzie. I delelted my TB heater awhile ago because it had a leak from where it comes out of the head. Sooo, there was a shit load of burnt coolant on the head there already.

It was still leaking from there, and like many of you said it was just burning off. I just overlooked it because I thought it was the old shit.

I found it by taking one of you guys advice of cranking the hell of out the engine cold.

Whew. But I still have low compression in cylinder #1 and a plague of problems.