Valve cover or rear main?

9

92Pony

New member
I changed the oil in my son's '98 3.4l auto a week and a half ago - no drama. Yesterday morning, I noticed a small puddle (would all fit on a dollar bill) in the garage where he parks his truck. :suspicious: When he got home, I immediately crawled under to take a look. Filter and drain plug were clean, but oil was dripping off of a cross member after coming off of the bottom edge of the tranny bellhousing (where it mates to the motor).

I immediately thought rms and headed inside to see what the forums said I was up against. I was not thrilled to read the general con$en$u$.

Hoping against hope, I went back out an hour or so later to try and see the valve covers and see if the leak could be from one or both of them. It was really hard to see the back of the heads (to see if oil was running down from there). The pass-side looked to be a little wet with oil on the rear, but it was tough to see definitively.

My question(s); Which would be more likely to let go rather suddenly? RMS or VCG? Also, once the truck was shut off and cooled, the leak seemed to stop or at least slow greatly. Would that point to one or the other?


Thanks! (everybody please say it's definitely VCG! :cowboy: )
 
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Wait until the motor cools and stick your hand back behind the heads, and crawl underneath and stick your hand on the top/sides of the bell housing. If a valve cover leak is causing the puddle, you'll come away wet with oil. If not, time to rent a tranny jack.
 
^^ do this...

You can also take a torque wrench and check all your valve cover bolts to make sure they're to spec. The gasket over time wears down and creates just enough gap that some oil can seep through. Especially now days since most people use synthetic oil. It's thinner at non-op temps and get through smaller cracks until warm.
 
Just a follow-up;

I checked the back side of the heads, and while they were 'damp', they didn't appear to be the source of such a substantial leak. I stopped in a local independent shop and he gave me a verbal ballpark quote of $500 to do the rear main, but wanted to see it to verify.

Welp, turns out it was the rear main. Once into it, he said that he saw the oil pan leaking as well. Since he was already halfway to it, said the labor would be about 1/2 to go ahead and do the pan as well, so we got that taken care-of at the same time.

End result, $700 and a new rear main, sealed oil pan, and a new PCV valve (which was sticking).
 
92Pony said:
I checked the back side of the heads, and while they were 'damp', they didn't appear to be the source of such a substantial leak. I stopped in a local independent shop and he gave me a verbal ballpark quote of $500 to do the rear main, but wanted to see it to verify.

Welp, turns out it was the rear main. Once into it, he said that he saw the oil pan leaking as well. Since he was already halfway to it, said the labor would be about 1/2 to go ahead and do the pan as well, so we got that taken care-of at the same time.

End result, $700 and a new rear main, sealed oil pan, and a new PCV valve (which was sticking).
Click to expand...

Thats not terrible. I would do the Valve cover, cam plugs (half moons, front and rear of head) spark plug tube seals as well soon and you should be good to go for a while on leaking oil.
 
GHARP57 said:
Thats not terrible. I would do the Valve cover, cam plugs (half moons, front and rear of head) spark plug tube seals as well soon and you should be good to go for a while on leaking oil.
Click to expand...

Are cam plugs and cam seals two different things?
 
GHARP57 said:
cam seals are VERY different from cam plugs. Cam seals go on the camshafts behind the cam gears. the cam plugs are the half moons
Click to expand...

Cam plugs are circular rubberized plugs that kinda look like freeze plugs, which are on the back of each head. Half moons are the half circle aluminum pieces that recess into the front and back of each head and are sealed with FIPG or similar sealant.
 
Cam housing plug:

1118865010.jpg


Half moons (also called semi-circular plug):

w01331637277oes.jpg
 
I took of my skid plates off to examine an oil leak this weekend. Kind of similar to your situation, except it's even less oil than you are talking.

It's rather odd... I have noticed fresh looking oil (changed oil less than 1000 miles ago) leaking around wiring harness that runs along oil pan where it bolts together. However, I also have oil dripping from the bell housing, but this oil looks much older? Can anyone make any sense of that?
 
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sport05 said:
I took of my skid plates off to examine an oil leak this weekend. Kind of similar to your situation, except it's even less oil than you are talking.

It's rather odd... I have noticed fresh looking oil (changed oil less than 1000 miles ago) leaking around wiring harness that runs along oil pan where it bolts together. However, I also have oil dripping from the bell housing, but this oil looks much older? Can anyone make any sense of that?
Click to expand...

The white wiring harness in the front? If so, maybe a crankshaft seal. Could also be the VC gaskets leaking down the front. One thing about the VC gaskets is when they leak they go EVERYWHERE. As far as the bell housing goes that's probably the VC or associated, things fixed in the repair (cam plugs, half moons) I guess the theme is fix the VC gaskets, clean everything up good then you'll see right where the next leak is (if there is one)
 
Yea I'm hoping it's just an VC issue. Just went and put my hand on the back side of tranny bell case and coated in oil.
 
GHARP57 said:
cam seals are VERY different from cam plugs. Cam seals go on the camshafts behind the cam gears. the cam plugs are the half moons
Click to expand...

JRZEE2000TR4LTD said:
Cam plugs are circular rubberized plugs that kinda look like freeze plugs, which are on the back of each head. Half moons are the half circle aluminum pieces that recess into the front and back of each head and are sealed with FIPG or similar sealant.
Click to expand...

Ok, consider me educated. I've never noticed a full circle plug/seal/thing on my 22RE or 3RZ motors, just the half-moons (rubber and aluminum, respectively), is this a V6 thing?
 
GHARP57 said:
Thats not terrible. I would do the Valve cover, cam plugs (half moons, front and rear of head) spark plug tube seals as well soon and you should be good to go for a while on leaking oil.
Click to expand...

Yeah, I figure while it may be a pain in the butt, the valve cover work is something I can do - it's not wrestling a 300lb tranny around while on my back. For now, I'm going to recover (financially) from this repair, and address the VCs (and relateds) in the not-too-distant future.
 
JRZEE2000TR4LTD said:
Cam plugs are circular rubberized plugs that kinda look like freeze plugs, which are on the back of each head. Half moons are the half circle aluminum pieces that recess into the front and back of each head and are sealed with FIPG or similar sealant.
Click to expand...

Wtf are the point of these? Cam plugs somewhat make sense from an engineering standpoint... But the half moons? Seems like a designed hole in the damn head. Why?

Sent from my LGMS428 using Tapatalk
 
amalik said:
Wtf are the point of these? Cam plugs somewhat make sense from an engineering standpoint... But the half moons? Seems like a designed hole in the damn head. Why?

Sent from my LGMS428 using Tapatalk
Click to expand...

I think it's from the machining process.
 
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