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Old 12-01-2007, 07:03 PM   #1
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Default Oil leak from head gasket?

I need a sanity check here. Has anybody ever seen a case where oil was leaking from the head gasket area and yet compression was perfect in all 4 cylinders? (195-210 all 'round)

The story:

Last weekend I lifted the hood and saw a bit of oil on the top of the valve cover. Checked the dipstick and the oil was about 1/2 quart low. So I pulled the valve cover and replaced the gasket and the CAS O-ring (both of which were less than three years old) and installed a 323GTX PCV valve with a new grommet.

In all, the oil had lightly covered the top of the valve cover from the #4 plug back, along with the ignition coils, the CAS, and the left side of the block. A few drops were on the ground. There was no oil inside the plug wells, nor on the underside of the hood or the firewall. I removed the cover from the CAS to verify that there was no oil inside it, and it was clean. The heater hoses are dry, though there is a bit of oil on the water neck.

While reassembling everything yesterday, I happened to look at my turbo oil feed line. It is covered by a foil / fiberglass sleeve, and that sleeve had soaked up some oil as well- more at the bottom than the top, so it may have been wicking action that drew it up the full length, or it may have been that gravity pulled it all down. I really don't know. To be safe, this morning I built and installed a new feed line with new fittings. There was no oil on the top of the turbo, so it wasn't leaking from there, but amazingly there was a tiny bit of oil on the surface of the downpipe, right where it bolts to the turbo.

I cannot for the life of me figure out how oil got onto all the places that it did, without getting on the places where it didn't. I'm going to have to de-grease and rinse down the engine so I can observe it for a few days before I can determine whether I've fixed the problem or not.
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Old 12-01-2007, 07:08 PM   #2
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iirc there is an oil galley in the corner of #4 on the driver side, if it leaks out the edge and the piston side is not compromised I could see it.
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Old 12-01-2007, 07:57 PM   #3
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It's happened to me when my head bolts stretched on install. I was leaking oil between 3 &4 and coolant between 2&3. Compression was fine, but I was burning oil over 4K rpm and high load.
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Old 12-01-2007, 09:36 PM   #4
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the same thing happened to me before.
check your head bolts.
i changed mine and haven't had any problems since.
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Old 12-01-2007, 10:24 PM   #5
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Take a really good look at your oil feed fitting. I had a similar issue when I first installed my turbo. Mystery oil in a number of places, turbs out the fitting that goes into the block hard cracked and I thought that that the oil was coming from the head gasket.

Another area to look at is the dipstick tube, there is only an oring that seals it.
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Old 12-01-2007, 10:25 PM   #6
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go to ARP studs and never look back... you won't regret it.
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Old 12-02-2007, 12:43 AM   #7
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Hmmm. Sounds like Adam and Jamie would call this theory plausible then.

I guess I'll pull the valve cover back off and re-torque the head bolts for now. I cleaned up the area around the head gasket so if the oil comes back in that spot hopefully I'll notice it quickly.
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Originally Posted by jayc72 View Post
Take a really good look at your oil feed fitting.
Good advice. I replaced the entire oil feed line this morning, and re-torqued the banjo fitting on the block. And the dipstick o-ring is fine. In fact, it's only a few months old (the handle broke off the last one) and as I said- no oil on the dipstick tube itself.
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Old 12-02-2007, 12:27 PM   #8
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Quote:
Originally Posted by Joe Perez View Post
I guess I'll pull the valve cover back off and re-torque the head bolts for now. I cleaned up the area around the head gasket so if the oil comes back in that spot hopefully I'll notice it quickly.

careful about re-torqueing them. if they are stretching than that will probably make matters worse.
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Old 12-02-2007, 01:27 PM   #9
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Ok, after driving the car yesterday, I pulled the cover back off this morning, and there was oil on the 2-3 ignition coil again. I'm pretty sure it coming from either the valve cover gasket or the CAS seal.

I pulled the upper half of the CAS seal cap so I could give everything a proper scraping. I'm going to re-install it with a tiny smear of RTV on the mating surface of the cap and head, and liberally coat everything else (including the machined surface of the CAS body and the whole back half of the gasket) with black RTV upon re-assembly. I'll never be able to change the base timing again without pulling everything apart, but hey, that's what engine management is for.

While I was in there I re-checked the torque on the head bolts, first to 55 and then to 60. They were tight. A couple of them moved just a tiny little bit, but it's not like any of them were loose. So I'm pretty sure it ain't the head gasket.
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Old 12-02-2007, 11:10 PM   #10
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hmmm i've had a oil leak for a while that defiently seems like it comming out of the head where it meets the block. Right out inbetween. I have no clue if my headbolts are still torqued down or not. Would you'all recommend re torquing them down??
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Old 12-03-2007, 03:46 PM   #11
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Quote:
Originally Posted by rappadan View Post
hmmm i've had a oil leak for a while that defiently seems like it comming out of the head where it meets the block. Right out inbetween. I have no clue if my headbolts are still torqued down or not. Would you'all recommend re torquing them down??
I recommend ARP studs so this is never a concern
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Old 12-08-2007, 02:30 PM   #12
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... And the oil is back.

There's a small bit of it on the top of the valve cover, right where the intake-side bolt that holds the ignition coil on is located.

I am a sad panda.
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Old 12-08-2007, 05:06 PM   #13
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Blown head gasket - intake side. ARP studs.

BTW this is just 500 miles into the 2Ls life.

Last edited by slowmx5; 12-08-2007 at 05:19 PM.
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Old 12-08-2007, 06:04 PM   #14
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I just don't see how it could be getting from the head gasket up to the valve cover without also getting everywhere else.

It really seemed like it was coming from the valve cover gasket / CAS seal the last time. But there's so much RTV in there now it's gonna be a chore to get that sucker back off.
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Old 12-08-2007, 06:13 PM   #15
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Quote:
Originally Posted by Joe Perez View Post
I just don't see how it could be getting from the head gasket up to the valve cover without also getting everywhere else.

It really seemed like it was coming from the valve cover gasket / CAS seal the last time. But there's so much RTV in there now it's gonna be a chore to get that sucker back off.
No that one is hard to square - you can see how the oil has sprayed over the under side of my intake manifold though. If oil is present that high up I would still suspect the cam-cover gasket/CAS seal.
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Old 12-08-2007, 10:14 PM   #16
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Do you have the breather vented to the turbo intake and a good PVC valve?
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Old 12-09-2007, 12:36 AM   #17
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Quote:
Originally Posted by olderguy View Post
Do you have the breather vented to the turbo intake and a good PVC valve?
Breather (hotside) is currently VTA with a small filter on it. It's been like that for over a year.

When this problem first arose two weeks ago, I'd been running a stock PCV valve which was about two years old. Last week, when I replaced the valve cover seal and CAS seal, I installed a new 323GTX PCV valve purchased from the dealer.
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Old 12-09-2007, 12:49 AM   #18
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i have an oil leak on the front, driver side of the head...just a little tiny bit of oil.
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Old 12-09-2007, 10:23 AM   #19
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Just a shot in the dark: Did you make any additional connections at the oil pressure sensor or run oil lines to anything else that could be spraying?
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Old 12-09-2007, 11:03 AM   #20
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Quote:
Originally Posted by olderguy View Post
Just a shot in the dark: Did you make any additional connections at the oil pressure sensor or run oil lines to anything else that could be spraying?
Nope. The only two things I've touched on the oil system are:
1- Turbo oil feed taken from the "usual" 1.6 location on hotside of block near bellhousing (not leaking) and
2- Installed 1.8-style sandwich oil cooler (oil-water) at oil filter location.

I guess I should check the pressure sensor anyway.

From the location of the oil, it's almost like its coming from the intake-side bolt that holds the coilpack on. That's impossible of course, but it's the best I can do to describe the location of it.
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