Oil leak at 6th cylinder head gasket?

[SCDreamer]

So I've had an oil leak that been slowly getting worse over the course of the last 3 months or so. It's still only just started dripping at 3-4 drops per day, so I haven't been to concerned. I originally thought it was from the oil pan, then I noticed it was a little higher up so I was thinking upper oil pan rear arch. But then today looking up from under the passenger side I saw that it was dripping from the header/head gasket area around the 6th cylinder. The rest of block is totally dry it only looks like it's coming from around the 5th and 6th cylinders. I just changed the oil and its looking pretty clean, same with the coolant. Once in a while I'll get a long turn over during ignition on a cold engine, no noticeable with smoke on turn over, but I might start trying to pay more close attention.

Is this sounding like a blown head gasket to anyone else, or am I barking up the wrong tree? What would be the next steps for diagnosing the head gasket? Compression test, chemical analyzer, something else?
I just hit 152K miles, I've gone through replacing all fluids, PHH bypass, and a few other PMs, but the previous owner definitely neglected the vehicle for an extended period. Any other ideas? Thank you guys for your help!

 

[Tools R Us]

Rear part of the valve cover gasket?

 

[SCDreamer]

I just ran out to check. The rear part of the valve cover is definitely dirty and has oil on it, so it might be leaking. But it's not holding fresh oil like whats showing up directly under that sixth header. Possibly leaking down from the valve cover and just accumulating under the header? It's hard to say. Is it possible that oil is being sprayed from the HG and regurgitating back and upwards coating the valve cover?

 

[BILT4ME]

Odds are it is the valve cover gasket. They are known to develop leaks there due to temp from EGR and there is one bolt that is hard to get to and torque properly.

Also, my spark plug tube seals were leaking so much my #6 plug was immersed in oil.

It not your HG.

 

[SCDreamer]

Well I have been wanting to pull the valve cover and paint it, replace all the vacuum lines, clean the throttle body, and do all the other "while I'm there" stuff. I guess I've got a reason to now, and at least I'll have this ruled out if it does keep leaking.

 

[paladek]

As said before, just hope it is coming from the valve gasket....and by the look of it you are in luck....it looks like it's the valve cover gasket.....
it is quite easy to see if indeed is coming from there....put your hand around the lower part of the valve cover and see if you get any fresh oil on your hand.....if clean.....than.....bad news......HEAD GASKET !!!!!!
anyway.....at 152K you just stepped into the "zoooooonnnnnne" .....
good luck....

regards

 

[Oscar Witte]

Just degrease that whole area then see where it is seeping.

 

[flintknapper]

Most likely just the valve cover gasket. They get hard and brittle over time and besides 'shrinking', will develop cracks.

Unless the valve cover bolts are loose back there...DO NOT tighten them in an attempt to fix the problem, they are easily broken off and the valve cover has built in 'stops' that only allow the gasket to 'crush' so much.

Fairly easy to remove the Valve Cover and see if that is your problem. You'll want to replace your Spark Plug Tube seals as well.

 

[SCDreamer]

I just put all the gaskets on order so I'm gonna tackle it this weekend. I'll let you guys know the results. Thanks again for all your help!

 

[BILT4ME]

Don't forget the dizzy o-ring while you're in there. Also need a throttle body gasket and get the hoses that are under the TB.

 

[BILT4ME]

Oh yeah. Don't forget the PCV valve grommet.

 

[flintknapper]

Yes, PCV valve grommet for sure. Throttle Body Gasket is metal and in most cases reusable, but I replaced mine.

Good time to clean the throttle body.

IF your spark plugs are old....good time to change them. Be sure to look at your heater valve while you are at it. If it has become brittle, it will be easy to get to with the valve cover out of the way.

 

[SCDreamer]

Ok replaced the valve cover gasket, spark plug gaskets, pcv gasket, cleaned throttle body, replaced all pcv hoses and vacuum lines, and rebuilt starter.

Strong first start and drives really smooth. Since I've owned it I've been getting a deceleration whine anytime I let off the gas when I'm going over 40, but this seems to have fixed that. I assumed it was a driveline or viscous coupler issue but it seems like something I did this weekend might have smoothed it out.

Does anyone know the purpose of that hole that's above the main plenum intake? The whole thing was completely plugged with carbon fouling, hopefully cleaning this is what smoothed out the engine a bit.

Also got a check engine light after putting the whole thing back together. Code checker on order, any common codes get tripped after pulling valve cover?

Haven't driven enough to assess oil leakage but will report back with findings.

 

[sbrodacz]

It looks like the same spot mine was leaking at. It ended up being the valve cover gasket. A fairly inexpensive and easy fix.

 

[SCDreamer]

So after driving for a couple days I think I've definitively answered the question on the leak. It turns out there were two leaks, one from the valve cover which has already been fixed, and a second coming from the rear arch of the oil pan. I was finally able to see it this morning, immediately after I shut the engine off there were tiny little pin hole sized bubbles coming from this seal. For now I'm gonna clean it and pack a little bit of ultra black over that lip until the next oil change when I can pull the whole pan.

Still haven't fully addressed the deceleration whine and what might have temporarily alleviated it after working on it this weekend. Im guessing it's something to do with the throttle assembly or the TPS sensor/set screw. Anyone ever have something similar to this?