New and some questions.. oil leaks

[crash93ssei]

Hi everyone!

Ryan here from Michigan checkin in.
I own two 3.4 DOHC engines; '92 Grand Prix SE, and a '95 Monte Carlo Z34. I also own three S/C 3800 engines; '93 Bonneville SSEi, '93 SSEi parts car, and '03 Bonneville SSEi.
Yeah, I gues you can say that I like cars I am fairly knowledgeable about the 3800 and it's great reliability being a member of bonnevilleclub, and I am anxious to learn much about the 3.4's that I have also. Have no fear though, I am not going to ask about a L67 swap into either car

What I am going to ask though is a question I am sure you get all the time.... oil leak on the 3.4 DOHC.


So, I have the oil leak pretty bad on both cars, and I am basically wondering if anyone can point me to a good writeup and some pics of what I will be looking for when I do the repairs on both cars this spring / summer. I am not %100 sure that it is the O ring, but from what I have seen with searching around here, I think it is. Also, the spark plug holes on the rear head of the GP were filled with oil when I pulled the plugs, not sure what that is all about, but I am sure it isn't good.

Both cars have over 180,000 miles on them, and the timing belt on the GP was replaced within the last two years. The Monte's belt I don't know, but it looks to be in good shape, no fraying or cracking.

Thanks for taking the time to read my long winded post.

[Schurkey]

IF (big IF) the dreaded oil pump drive O-ring is the source of your oil leak, you have a few choices:

1. Sell the car

2. Pull the upper and lower intake, pull the timing belt and the rear head, pull the oil pump drive and replace the stupid O-ring. Might as well valve job the head, then you might as well valve job the OTHER head, and as long as you have the engine that far apart, might as well ring 'n' bearing it. Then you might as well overhaul the transmission...and the suspension...and the brakes...

3. Pull the manifold, lift the oil pump drive the 1/8" or so that it'll move before hitting the rear head, CAREFULLY split and install a Chevy distributor gasket under the flange for the oil pump drive. Goop it nicely before installation with Permatex gasket sealer or your choice of schlubba paying particular attention to where you've cut the gasket so as to wrap it around the oil pump drive. Some folks prefer RTV. Verify that you've closed up the split in the gasket; and that the split is sealed appropriately with goo. Torque the hold-down bolt and pray that it seals. I line up the split in the gasket so that the hold-down doesn't cover it; I wanted to SEE that the split was still closed up as I tightened the hold-down.

I just did this about three weeks ago. What a pain in the tuckus. For what it's worth, I used the hard-setting Permatex sealer; the next day I began an 1800 mile trip. Last weekend, I drove home. About 3900 miles altogether; and it's not leaking from the oil pump drive.

If I ever install an oil pump drive from scratch, I'm gonna use a genuine Viton O-ring; and I'm gonna install a non-split Chevy distributor gasket "just in case".

[crash93ssei]

Thanks for the reply

Why do you say IF? Is there more places that I could be losing a quart of oil every other week from

I actually do plan on selling one of the DOHC cars, but I refuse to sell them leaking oil, and in bad shape in any way. I am looking to build a reputation for my cars, whether I keep them or sell them, of being good solid reliable VERY nice looking cars. I work with a guy that buys and sells cars and everyone knows not to buy from him because he rigs the crap out of them just to sell them. I don't want that reputation, and right now, a good reputation is worth more to me then the money. If I want to ever sell a car, I want people to want to buy a car from me, rather then shy away from it.

Also, I am a car guy, so I actually enjoy doing the work and love the progress and end result of a job well done.

That being said, I WILL be fixing the leaks on both cars before I even think of selling.

[Schurkey]

Why do you say IF? Is there more places that I could be losing a quart of oil every other week from

Front main seal, rear main seal, engine oil cooler, and the oil pressure sending unit are four that come to mind.

That said, if the leak is dripping off the rear of the engine/front of the trans--and the top of the engine block is oily--you know what the problem is.

[pocket-rocket]

I've had oil start coming from the cam carrier to head gasket, but that one was obvious because it was on the front head and exposed. I've fixed 3 of these little pains in the backside. 2 on my 2 cars, and 1 on someones van that I tore down to a bare block because they didn't realize the intake gaskets let go until it read 2 gallons over on the dip stick... Anyways, in all 3 cases, I used the Chevy dist. gasket, and RTV. The 91 has been this way since.... wow, 2003? It still has yet to leak a drop. But on another note, I had the heads off, and bought a new o ring from the local hardware store, I did not get a Viton one from GM, and I used it along with the dist. gasket and what seemed like 1/4 tube of black RTV.

[Schurkey]

I did not get a Viton one from GM

IS the GM O-ring made from Viton? Viton is known for resistance to high temperature, resistance to compression set, and resistance to many common automotive chemicals--so--as many of those O-rings go bad, I figured GM was making them from inferior material.

Viton was going to be my "secret weapon" in the fight against oil leaks...


Bummer.

[walterdude]

GM did upgrade the material that the O-Ring is made of.... Don't know what it's made of tho.... What you gotta look for is the newer style is BROWN in color,,, where as the older/inferior one is BLACK.... I might have a number,,, somewhere,,,, if I find it I'll post it.....
Hope this helps,
Tom

[pocket-rocket]

Homeslice above me said Viton, and I didn't know for sure, so I assumed (yes, I know what that does to us :P) that it was indeed Viton. The ones I have used were not brown, but normal black ones. But hey, I don't mind spending a day and a half tearing the heads off my car and putting them back on. But then again not everyone is as comfortable with that as I am.

[bve32k]

GM did upgrade the material that the O-Ring is made of.... Don't know what it's made of tho.... What you gotta look for is the newer style is BROWN in color,,, where as the older/inferior one is BLACK.... I might have a number,,, somewhere,,,, if I find it I'll post it.....
Hope this helps,
Tom

You just go to any GM dealership and ask for them. They all have them in stock and they are only like $2.

[RedZMonte]

Hi everyone!
I am not %100 sure that it is the O ring, but from what I have seen with searching around here, I think it is. Also, the spark plug holes on the rear head of the GP were filled with oil when I pulled the plugs, not sure what that is all about, but I am sure it isn't good.

mine was leaking from the O ring. Very common on GM V6/V8's. It was also leaking from the lower intake gasket from the oil valley if i remember correctly. you should be able to see that on the heads where the LIM bolts to the head.

The plug holes filled with oil is also common esp. if they have miles on them. The valve cover gaskets need replaced. The valve cover has O rings that go around the spark plug holes and when they get old and dry it drain into the spark plug holes. the front valve cover gasket is a snap (if you remove it you will see what i mean) the rear requires removing the upper intake manifold to replace, easy job just takes a few min to do.

[crash93ssei]

Thanks for the help guys, good to know about the O rings for the spark plug holes, I didn't think of that.

I will probably tear into them both and do the distributor gasket fix. Before I do though, is there any way to know 100% sure that the O ring is the source of the leak? There is oil all over the block, front and back.

[Schurkey]

is there any way to know 100% sure that the O ring is the source of the leak? There is oil all over the block, front and back.

No. Nothing is 100%.

Take the car to a car wash, blast the oil off with the high-pressure, soapy water. Run the engine and see where the oil comes back first. The leak will be close by.

[pocket-rocket]

The O ring in the valve covers isn't the typical O ring like it is on the dist plug. It's more of a rubber like valve cover gaskets anymore. In fact, if you do those, just buy the valve cover gaskets from Fel-Pro, as they come with those "O rings", and Fel-Pro makes good gaskets IMHO.

[RedZMonte]

Thanks for the help guys, good to know about the O rings for the spark plug holes, I didn't think of that.

I will probably tear into them both and do the distributor gasket fix. Before I do though, is there any way to know 100% sure that the O ring is the source of the leak? There is oil all over the block, front and back.

ALOT of degreaser and a pressure wash. Get the oil off the engine, heads, Block, top of trans. once all clean add some oil leak dye (from parts store) and use a UV light it should GLOW nice and bright. Best way to find leaks.

The Dist. O-Ring is a BITCH. but the valve covers and plug o rings are a snap.

S

[Juglenaut]

I didn't use a dist. gasket on my repair of the oil plug deal, I did use a rather stiff phat viton ring that would barely stretch over the end cap. notched the end cap top and slipped the pia to stretch ring over the end cap and retorqued it down never leaked again.

If the dist. plug ring is leaking pools of oil will be in the valley around the int. cover plate however other things can cause this pooling to, but ussally the end cap top is dry if it is leaking. More common is the dist plug issue. Also if it is leaking you may want to inspect other oil seals this somehow serves as a maintance flag.