Oil Leak Diagnosis.

[LeeMajors]

2000 LTD, 157k mi. Purchased a month or so ago.

Noticed some oil burning smell from time to time, nothing major, just in passing. No puddles under engine in driveway, nothing noticeable on skid plate (except directly below oil filter that appears to be from sloppy oil changes, which I cleaned).

Engine appears a little grimey below valve covers, but hard to tell if its new leaking or not. Haven't had a chance to degrease yet.

Anyways, went underneath to check it out--noticed some oil on the front of the transmission pan, front of the bell-housing between it and the oil pan, and some newer looking oil in a single drip coming down the oil pan.

I'm worried that it could be rear main seal or oil pan, but it seems to be coming from above. It's just very hard to see.

Noticed some on the steering components as well. My oil level is spot-on full just as when I changed it 1000mi ago.

Is this something I should be overly concerned about? I think it is probably the passenger side valve cover leaking down. It's hard to see up on the block to tell where it's leaking from exactly, but it seems to be from above the oil pan and bell-housing.

Thoughts? Any better diagnostic way to tell?

Should I change VC gaskets immediately, or is it ok to wait a bit since it isn't affecting my oil levels?

 

[LittleCaesar]

Probably both areas are leaking from what you are describing.

The VC replacement is not hard, just time consuming. Plenty of DIYs on replacing them. Do this first.

The rear main is much more of a PITA. If it is still leaking after changing the VC gaskets, and if you don't have a lift and a tranny jack plus a high mechanical acumen, then you may want to leave it up to a mechanic with such access. Drop by Lex Tech on Savannah Hwy and ask them how much they charge.

What oil are you using at the moment?

 

[LeeMajors]

Probably both areas are leaking from what you are describing.

The VC replacement is not hard, just time consuming. Plenty of DIYs on replacing them. Do this first.

The rear main is much more of a PITA. If it is still leaking after changing the VC gaskets, and if you don't have a lift and a tranny jack plus a high mechanical acumen, then you may want to leave it up to a mechanic with such access. Drop by Lex Tech on Savannah Hwy and ask them how much they charge.

What oil are you using at the moment?

5w-30 dino.

I'm not positive the rear main seal is involved--it seems mostly like oil is blowing back onto the front of the bellhousing between it and the oil pan. When

I tried to take some pics to be more descriptive, but I couldn't get a very good one with the lighting.

When I shine my flashlight up above it appears that the oil trail begins from above--the block looks shiny above the oil pan below the exhaust manifold.

I didn't see any new oil on the driver's side.

I'm thinking of doing a degreasing, then tightening the valve cover bolts hand-tight with a socket extension, then watching to see if I can get a better location.

It doesn't seem to be leaking like a faucet yet, which is encouraging.

 

[LittleCaesar]

After I posted I thought to tell ya just to tighten the valve cover bolts and see if it stops. If you are lucky, then that is good. Just a little more than finger tight. But given the sheer age of the gaskets it just may be time to change them.

 

[LeeMajors]

I hope it's not the rear main seal. I don't have the resources to fix it myself, and I would prefer not to spend that much money having it done professionally.

I've seen a lot of folks talk about leaking out of the rear 90s of the valve covers because people don't properly seal with FIPG--I'm hoping that may be the case.

Some other threads about rear main seal leaks suggest that you generally wouldn't see any oil above the oil pan and on the block if it was isolated.

Hopefully it isn't both though. Damn.

 

[gamefreakgc]

:worthless:

But being serious, if you give us a picture we can help pinpoint it for ya. We've all had oil leaks before.

 

[LeeMajors]

:worthless:

But being serious, if you give us a picture we can help pinpoint it for ya. We've all had oil leaks before.

I tried to grab some today but lighting was difficult. Should be sunny tomorrow so I'll give it another shot.

 

[LeeMajors]

Pics:

Ok, here we go.

Valve covers: Passenger then driver. Both don't seem to have leaks around the edges, just old grime below. Bolts were tighter than hand-tight, didn't seem loose at all:

This is behind the passenger side valve cover--it appears to be leaking toward the firewall and down the backside of the block. This is kind of why I think the leak is valve cover related:

This is between the bell-housing and oil pan. Light oil on the lower side of bellhousing, but it seems to be coming from further above.:

Driver's side, just above oil pan. Seems to be pretty far forward for a rear main seal leak, right?

 

[mattman]

It almost seems like the previous owner may have done the valve cover gaskets already. If they hadn't been done with that age I would suspect some loose bolts and the little rubber washers to be toast - mine sure were.

I did my valve covers and have a similar leak. I did the half moons but not the cam seal plugs. Try using a mirror to look at the valve covers right in front of the firewall.

 

[JRZEE2000TR4LTD]

Sure looks like the VC gaskets are leaking, or a component related to the VC gaskets (camshaft plugs, halfmoons). Looks like it was cleaned up on top, probably to sell it. Clean it up real good before the repair with some engine degreaser. Follow the write-ups on here. Don't take any shortcuts. Use OEM parts. Watch out for the brittle wire harness loom on the passenger side. After a successful repair, you can get a better idea if you have a rear main seal (which I doubt) which is an infinitely more difficult repair. Good luck!

 

[jreask]

This is definitely the cam plugs leaking. Some don't replace them or seal them when they do the gaskets. I recommend removing them and putting a thin bead of RTV around the plug and then re install. I had the same problem. It was the Cam plugs leaking. I don't know what purpose the plugs serve, but I do know that they leak and can drip pretty much oil. It seems like a lot by looking at your motor, but not enough to change the dipstick reading.

 

[LeeMajors]

Thanks for the help guys. I'll probably go through and do it sometime in the next month or so.

 

[LeeMajors]

Ok--going to get this done tomorrow. Decided not to do the spark plug tube seals bc they clearly are not leaking.

I am, however, doing the camshaft housing plugs. In the fsm, it only shows FIPG on the small grey edges of the bracket but many write ups suggest running a bead around the plug itself. Since I think this is the source of my leak, this seems like a good idea.

Can that actually screw anything up, or would it be harmless to further seal it?

 

[LittleCaesar]

Don't bother. Using less is more IMHO, just torque the cap correctly.

How hard will you be kicking yourself if those tube seals start leaking, though I have never heard of them doing so.

 

[LeeMajors]

Don't bother. Using less is more IMHO, just torque the cap correctly.

How hard will you be kicking yourself if those tube seals start leaking, though I have never heard of them doing so.

I will be soundly kicking my own ass.

 

[LeeMajors]

So, did just the passenger side today. Been battling the flu. Didn't pull the semicircular plugs--it appears they had been done very recently, and were soundly sealed with grey RTV. I did trim down the grooves the gasket had made in the overflow, until it was nice and smooth. The gasket was new (blue felpro), but with a mirror I saw the obvious leak from the base of the camshaft housing plug.

So I pulled it, replaced it, using a thin bead of FIPG on the seal itself and in all the specified places. Seems to have done the trick. I'll degrease and recheck later this week, but overall a success. I'll be doing the driver's side then too.

Anyhow, not too shabby after 158k mi on dino oil, no? No sludge at all, but a solid varnish.