oil leak top rear 2006 vvt n*

[CRawdon]

Hi all, this is my first post on this, or any forum for that matter.

I am the proud owner of a 2006 sts , and I am experiencing some serious oil issues. my car has about 100,000 miles on it now, it has never used a drop of oil in the past(have owned it since it had 40,000 on it) even with 12000 mile oil changes (Royal Purple and k&n filter) and I have developed a substantial oil leak. the big kicker is its not even close to consistent. Some times after not adding anything for a month, the dipstick will be almost right on, other times it goes off the dipstick in a matter of a couple days.

As far as I can tell the leak is coming from the top rear of the engine ,seems to be pressurized oil. I put it up on a lift and the leak would speed up when the engine was revved, and nearly stop at idle. on the lift and on the ground I couldn't see where the leak originated .I expected it to be an oil pressure sending unit, but after searching this site I found that it is located above the oil filter/adapter, which kinda rules that out. so I guess the question is does anyone know of any pressurized oil that would on the top rear of the engine. I apologize for being so long winded, but I figure its better to give all the most accurate info i can straight off, so thank you in advance for any knowledge that can be bestowed upon me.

[Cadillac Jim]

The cam and valve gear are pressure-oiled. The high pressure lines are in the front of the engine in the head gasket. A leak would be in the cam cover. Check the cam cover bolts and see if they are all tightened up the same. Don't overtighten them.

[airmike]

Cadillac Jim, is this a typo or am I not understanding?

"The high pressure lines are in the front of the engine in the head gasket."

I am always wanting to learn, so I am asking?

[Cadillac Jim]

The 1997 FSM in the section "Lubrication System" on pae 6-168 ends with these two paragraphs:

Oil for the camshafts and valve mechanisms enters each cylinder head through passages in the upper crankcase below the front camshaft bearing. Oil then enters the camshaft through a drilled passage and travels through the hollow camshafts for delivery to the remainder of the cam bearings. The same cylinder head passage that supplies the camshafts also intersects a longitudinal gallery for each group of valve lifters (intake and exhaust).

Oil returns to the sump either through the cam chain area or by way of cast oil drain back passages on the outside walls of the cylinder heads, upper and lower crankcases and oil pan. The lubrication system also includes a baffle, attached by the main bearings bolts, and channels oil thrown from the crankshaft back into the oil sump [an oil scraper!].

The 1997 FSM, pages 6-26 and 6-27, show the Left Bank Deck Face and the Right Bank Deck face. They show an oil gallery going through the head gasket on the inboard side on the front of the engine, right behind the space for the cam chain. You also can see it on page 6-18, Left Side of Engine Block, and page 6-21, Right Side of Engine Block.

So a main oil gallery goes up through the head gasket and feeds the front cam bearing. The cams have an oil gallery going right through them that feeds the rest of the cam bearings. The gallery coming up through the head also feeds two oil galleries, one for the intake lifters and one for the exhaust lifters. If you look into a lifter bore, you will see the oil gallery intersecting the lifter bore.

[airmike]

Cadillac Jim, I can't imagine what was going through my mind when I read that before! I had it in my head the statement was through the valve cover gasket and that was what was confusing me. WOW to many hours at work I think. Now that would be something to see. I even reread it several times before posting that ridiculous question.

[Cadillac Jim]

I'm sorry my post was confusing. Most of the time lately I answer questions in a hurry but usually I try to proof-read my posts before I leave the computer - but not always. I did say "head gaskets" but I can see someone who has not disassembled the top end of a Northstar reading it as "cam cover gasket" instead.

I think that the leak may be from oil pooling a bit at the edge of the cam cover, which is normal. But a loose cam cover bolt or two and a leak in the cam cover gasket is... not normal. I'm thinking that someone messing with the coil pack or ignition module might have inadvertently loosened a bolt or two and forgotten to re-tighten.

[airmike]

Honestly I don't think that post was confusing, I just went stupid for a bit there. Its not like I haven't disassembled a northstar either. Oh well I bet I can do something like that again sooner or later.

CRawdon, have you figured anything out yet?