After a 2 year hiatus from my Camaro (retired from active duty military and subsequent move kept me busy) I started back. I rebuilt the engine and kept the same specs as my sig (lost oil pressure and wanted to check the inside of the motor, bearings, crank etc..) Everything was fine so I machined the crank, new bearings etc.... Long story short, replaced heads with TFS's that were cut down from the factory. While putting the intake back on, bolt holes didn't line up, go figure. I had the machine shop cut it down until the holes lined up. I installed new gaskets, torqued it down WITHOUT rtv and check the clearance on the front and rear sealing surfaces. There was plenty of space (don't remember the exact gap but it was no where near bottoming out). I reinstalled with RTV and made sure it pushed out all around the manifold/block. After finishing the engine, had a RMS leak. Replaced it, stopped leaking. Still had small leak ONLY when driven which appeared to be VC gaskets. Sealed those, stop leaking......HOWEVER, it now leaks at idle. I've traced it down to the drivers side, rear above the oil filter. I ran the intake manifold as best I could and could not see or feel oil. The oil press sender is dry, I can see and feel that. With the engine running and wiped down, I see oil start to puddle up where the head and block meet on drivers side, rear, bottom. I can't see too well with a mirror but the back of the block/head/manifold are dry. I am lead to believe the leak is small and located at the rear manifold where it meets the drivers head but before I tear into it, here are my questions:

Has anyone heard of/seen an oil leak at the head gasket - guessing where the oil drains back to block from the head?

Is it common for a manifold to leak oil from a cold start, never above 1000 rpm after about 3-5 mins from initial start?

Total miles on engine from refresh - approx 75 miles

Taking all ideas! Thanks guys.

 

Have you checked the auxiliary oil pressure port (located just above the oil filter)?

aux_oil_port

 

Yes, bone dry. The leak is coming from above that area. Somewhere on the same plane (or higher) as where the head/block come together.

 

Can't see how gravity return oil would somehow get past the head gaskets.

Have you checked the oil pressure sensor connection on top/back of the block?

 

That was the first thing I checked. I can see it clearly with a mirror and it is dry. The only place I can't see clearly is the in front of the oil press sender where the manifold and block meet.

I am trying to post a pic from Shoe's site. Is it an infringement to draw on his pic and then post it? Don't want to step on anyone's toes but he has better pics than I do.

 

You have permission to use a pic from my site to illustrate what you mean.

I have seen an oil leak between the head and block at the back before. It was caused by improperly torqued head bolts on a new build.

 

Thanks Shoe. I'll try to figure out how to post it.

https://www.camaroz28.com/forums/mem...ensor-6130.jpg

Can anyone see this pic? I placed a red arrow on the back of the drivers head to show where I see oil puddling up.

 

That's exactly where I saw what I described in the previous post.

 

I'm pretty certain I have this very same leak issue although the head has never been off before - 120K miles on the engine. Is checking/re-torquing the head bolts a solution that might work, or does the head need to come off and a replacement head gasket installed?

 

You might want to get your head checked and resurfaced now that some miles are on it.(to be on the safe side) only thing that would cause a leak there would be like shoebox said improper torque or some type of noticeable crack in the block? What I do on the aluminum heads is I torque the heads to spec once and re torque them again in the same pattern. You will be amazed at how much play is in the bolts once the head finally seats to the block. Also yes a block typically has more oil psi from a cold start.

This is the back driver side of the head. It would have to be coming from one of the back oil journals.

 

I guess it is worth a try, since the alternative is to remove the head and replace the gasket. Before I saw this with my own eyes, it would not have thought it possible. Oil must seep down the corner head bolt that is puddled with oil (since it is in the back) and travel between the head and block. This oil is not under pressure.

 

I notice the oil dripping off the bellhousing cover and ending up on the auto-trans pan. Tried to trace it and the furthest I could get was in the same area back the back of the head. It was not the oil pressure sender.

Coincidentally, that very same area of the head had a broken exhaust manifold bolt(last one towards driver) recently although I don't see how that would have anything to do with the oil leak.

I guess I will try the re-torquing as I really don't want to go the full monty of removing the head as I'll have to do both and everything else involved doing a top end job, it's just not something I want to do with this vehicle right now.

Thanks.

 

Shoe - I wasn't thinking about the bolt being the culprit. I tq'd the heads myself, done it several times on LT1s. I am certain I followed the correct sequence and tq levels (3 stages) but I suppose it's possible I missed something. I was thinking the oil was draining down the back of the head and escaping thru the head gasket but I can't see how. Fred also thought this to be a far reach since it was gravity drain and not under pressure. Good thought to try and tq the back head bolt and see if the leak changes. I checked the rear manifold bolt and it was tight. Come to think of it, I gooped up the head bolts pretty good with the ARP sealant. After pulling heads in the past, the head gaskets had sealant where the head bolts go. I'll get a better look at the manifold/block when I pull the VC. I'll post as I go. Weather isn't all that sunny in sunny florida right now

 

Op

finding the "source" of the leak can be frustrating. I chased one thinking it was pan gasket and after swapping the pan gasket it still leaked....got a oil dye kit/light from local auto part store...found the leak. turned out to be RMS adapter. huge PIA as it required dropping tranny & pan to remove the RMS plate to swap that gasket

my point is before you go pulling heads, may want to use some oil dye to pin point leak as oil will migrate towards a lower point.

?, when you used RTV front & rear of intake manifold, did you run the bead up 1/2"-3/4" up onto the head?...if not you should.

 

Good idea with the dye.

I did run RTV up all 4 corners (block/head). Like anything else, maybe I needed more in the back corner? I'm pulling the VC today which will hopefully let me see that area a little better.