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leaking oil internally; well, except what's coming out of the exhaust
Topic Started: Jan 31 2012, 12:49 AM (2,177 Views)
killerofangels
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My beloved G10 is losing oil. I lose about a quart after an hour's drive. Other than that, the engine runs fine. I've recently replaced a few gaskets to address an external oil leak. I replaced (in this order):

the cylinder head gasket
cam cover gasket
exhaust header gasket
intake manifold gasket
oil pan gasket
oil pump gasket (crank seal on pump side)
...and then I realized it just needed a cam seal on the timing side to stop the leak.

Now that I've thrown $100 in gaskets to fix a $3 seal problem, my engine is losing oil out of the exhaust. I don't understand how that would be possible unless it's leaking past the piston rings, right? Doesn't the oil on 4-strokes reside below the piston? If you don't already know, I normally work on 2-strokes where it's perfectly normal to blow thick clouds of oily smoke out of the exhaust.

Everything went together fine when I rebuilt it but I do have some concerns. I originally messed up the timing and tried to crank the engine (unsuccessfully). Could that have damaged the valves from crashing into the piston or something? I cleaned the piston tops with some scotchbrite and blew the carbon crap off with an air hose. Could the scrubbing motion have damaged the piston rings? Lastly, the oil coming out of the exhaust looks kinda watery. There was no scientific test involved in that - just me rubbing it with my fingers so I could be wrong.

Here is a picture of all the oil that came out after a two minute engine warm up.
Posted Image

Any advice is appreciated as my GF will be really pissed if I spend days in the garage without knowing what the problem is beforehand. :smackface
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crankcase


Check the compression. Tha't a lot of oil to loose.
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iBLKBRY
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Valve seals. Oil lost through the valve seals occurs during engine decelleration. Rev the engine and you will notice blue smoke as the engine spools down. If oil is going thorugh the exhaust, you will have alot of blue smoke, especially for the quantity you indicate.
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idmetro
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No worries about cranking the engine with the timing incorrectly set, these are NON-Interference engines so there was no contact and thus no damage.

You mention a number of things but not whether you have replaced the pcv valve and cleaned out the Y pipe?

A compression test as mentioned above http://geometroforum.com/topic/2574993/1/ is the best barometer of overal engine health. In the course of your "rebuild" what did you do?
Edited by idmetro, Jan 31 2012, 09:29 AM.
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killerofangels
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Quote:
 
You mention a number of things but not whether you have replaced the pcv valve and cleaned out the Y pipe?


Yes, I did replace my old, melted PCV with a new one. The pipe had some light brown oily mess in it that was cleaned out with compressed air. Aside from that, the only thing I did was media blast the cylinder head. I made sure the valves were closed and I cleaned it very well afterwards. Still, I wonder if the blast media worked it's way under the valves somehow.

Quote:
 
Valve seals. Oil lost through the valve seals occurs during engine deceleration. Rev the engine and you will notice blue smoke as the engine spools down. If oil is going through the exhaust, you will have a lot of blue smoke, especially for the quantity you indicate.


Wow! There was a sh*tload of blueish smoke coming from the exhaust. I got some on acceleration but much more on deceleration. Turned a little blackish when decelerating. What exactly do I do to clean the valve seals? I'm guessing the cylinder head has to come off for that, right? I'll still do a compression check first but I probably won't have time to work on this until the weekend.
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bogs
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Duct tape heals all wounds

killerofangels
Jan 31 2012, 12:49 AM
Any advice is appreciated as my GF will be really pissed if I spend days in the garage without knowing what the problem is beforehand. :smackface
My advice? Tell her that is what all men do, just like not reading the instruction manual or asking for directions. It worked for my whole life ;)
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Shinrin
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There's a check valve in the block itself that restricts oil passage. It's possible it fell out or was blown out when you airsprayed the engine.
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Coche Blanco
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Mileage? When you had the head off, did you do rings?
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iBLKBRY
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killerofangels
Jan 31 2012, 10:30 AM
Quote:
 
You mention a number of things but not whether you have replaced the pcv valve and cleaned out the Y pipe?


Yes, I did replace my old, melted PCV with a new one. The pipe had some light brown oily mess in it that was cleaned out with compressed air. Aside from that, the only thing I did was media blast the cylinder head. I made sure the valves were closed and I cleaned it very well afterwards. Still, I wonder if the blast media worked it's way under the valves somehow.

Quote:
 
Valve seals. Oil lost through the valve seals occurs during engine deceleration. Rev the engine and you will notice blue smoke as the engine spools down. If oil is going through the exhaust, you will have a lot of blue smoke, especially for the quantity you indicate.


Wow! There was a sh*tload of blueish smoke coming from the exhaust. I got some on acceleration but much more on deceleration. Turned a little blackish when decelerating. What exactly do I do to clean the valve seals? I'm guessing the cylinder head has to come off for that, right? I'll still do a compression check first but I probably won't have time to work on this until the weekend.
Pull head, change valve seals. Most likely there was residual media in there that damaged the seals. Doesn't take much.
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TimmyD
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A Metro Driver

bogs
Jan 31 2012, 10:56 AM
killerofangels
Jan 31 2012, 12:49 AM
Any advice is appreciated as my GF will be really pissed if I spend days in the garage without knowing what the problem is beforehand. :smackface
My advice? Tell her that is what all men do, just like not reading the instruction manual or asking for directions. It worked for my whole life ;)
X10 on this one - except I go out with the Haynes manual. Ya look up what is the problem & it will tell ya what to check first, second, third, ect; plus your own know-how of the car. Same as if'fin I'm working on the OLs car-need to figure it out before I can fix it.

no offense KOA, but a comment like that usually would put one's man card at risk...
:whistle
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killerofangels
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Back again. Dismantled engine for 3rd time this month and still leaking oil! :banghead

I did a compression check. 130, 115, and 110 psi for cylinders 1, 2, and 3, respectively. I know they're supposed to be even but anything over 100 sounds like compression is still good to me so it shouldn't be leaking past the pistons.

Upon dismantling the engine, I noticed only cylinder 1 was burnt while cylinders 2 and 3 were still shiny. I had thoroughly cleaned the piston crowns when the engine was last apart only a few hours of runtime earlier. So, cylinder 1 was the focus of my attention. I removed the old valve seals and installed the new ones. First set was hard to seat so I gently tapped it with a small hammer and socket extension. I completely smashed the little spring on the top. 2nd set of seals I just pushed down with my finger until they wouldn't go any more. I didn't get a popping sound or anything that would confirm they're seated but they seemed pretty snug. Started my engine and still leaking oil out the exhaust. Thinking that maybe the seals weren't completely seated, I tore down the engine again and put on a 3rd new set of valve seals as hard as I could press them in with my fingers. Still no indication of if they're seated. Still have an oil leak.

I know that it could also possibly be cylinder 2 or 3 but I was out of new valve seals and getting the valve retaining semi-circle thingies back in was a bitch and a half. And wouldn't the burnt, oily piston indicate that it's the one with the oil leak?

I know I shouldn't really re-use gaskets but I did with the cylinder head gasket since it's new as of the first teardown. Seems like it's still in good shape. Could that possibly be the cause or maybe the head became warped when I reassembled it? I would really like to know what's the proper procedure for torquing the cylinder head bolts as it doesn't say in my service manual.

I guess it's off to the auto parts store for a new round of valve seals (for every cylinder this time) but I wanted you guys' thoughts before I go for teardown #4.

EDIT - Just reread the "how to compression test" thread and it looks like I did the test wrong. I will redo test in the morning and see if I get different numbers.
Edited by killerofangels, Feb 28 2012, 02:19 AM.
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clarkdw


Engine needs new rings. 155psi is the lowest acceptable compression according to FSM.

Are you doing comp test according to http://geometroforum.com/topic/2574993/1/ using wide open throttle?
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Coche Blanco
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Compression has nothing to do with oil consumption.
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snowfish
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killerofangels
Feb 28 2012, 02:00 AM
I would really like to know what's the proper procedure for torquing the cylinder head bolts as it doesn't say in my service manual.
Bring them up so spec slowly, a little at a time, starting in the middle, like this...............

Posted Image

Take about a half dozen steps to bring them to spec.

This is a generic image, but should give you the idea. Principal is the same for cars, boats, snowmobiles, etc.
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Coche Blanco
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I always do:
5 1 3 7
6 4 2 8

EDIT:
Posted Image
(credit to rcmemeleleme for the picture)
Edited by Coche Blanco, Feb 28 2012, 11:47 AM.
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