Fix Top Side Distributer Plug Leak

[Fierobsessed]

All 1991 - 1997 3.4L Twin DOHC Engines will eventually develope this leak. The engine when manufactured came with a hole to mount a distributer. Well GM decided to just plug the oil with a dummy idler. It is located at the rear of the engine against the rear head. Simply put, on the back side, on the transmission side of the engine. Inside is an O-Ring that over time deteriorates and will leak or piss oil with any pressure that it is given. Sometimes it will piss oil onto the crossover pipe and cause a smoke to emerge from the louver or under the hood. There are many methods to fixing this problem. Some include pulling the rear head, others include cutting a notch in the head. Here's a suggestion that will take less time and cost less money/frustration in the end.

The Fix:

1. Disconnect the Negetive terminal from the battery.
2. Disconnect the Intake Air Temperature sensor connector and the Mass Air Flow sensor connector (if applicable).
3. Remove air box (or intake) including the tube running up to the plenum.
4. Remove the driver side cooling fan.
5. Remove the exhaust manifold cross-over pipes.
6. Clean the entire area with your favourite cleaner, carb/brake cleaner works wonders.
7. Remove the retaining clamp with a 13 mm wrench.
8. Pry up on the plug with a flat head screw driver, remove the old o-ring, clean all the oil out of the plug (the parts that you can see). Install a new o - ring (Can be purchased from a dealer or fel-pro.)
9. Slip the new o-ring onto the assembly. Add some RTV sealant.
10. Place the plug back into the block, using the proper finess.
11. Replace the retaining clamp securely tighting the bolt.
12. Reassemble in the opposite order, connecting the battery terminal last.

Done. It is a good idea to allow the sealant to have the proper amount of time before testing it. Failing to clean the areas and do a good job the first time will result in having to do it over.

[MONICAZ34]

funny I remember putting that together

[SappySE107]

Yeah, I am wondering how to do this. I want the original poster to be the author so that any questions can be sent to them. Well id rather see replies but it seems people email/pm Brad over the DOHC stuff cause his name is on it but I wrote most of it.

[MONICAZ34]

Its all good Its never bad

[ericjen]

Not to sound like I know it all , especially since this is my first post, but having just replaced this O-ring , it will not work as you have laid it out . At least not on a 1995 VIN X in a Cutlass Convertible. Not wanting to pull the head, I tried easing it out past the ear that is less than 1/4 inch above it , but couldn't. I also have a problem notching the head , as that is the gasket surface for the lower intake manifold. Perhaps GM put different heads on this motor when installed on other division cars ?

[jimdog]

I have this oil leaking dumb dist. in my 1992 3.4 euro and I read your fix instructions. You are able to slide the o-ring over the bumb plug ?? Plus How long did it take you to do the entire job??

[ericjen]

jimdog, it's been a while since I did this repair so actual time escapes me. I do know that you will need a new gasket for the air plenum and heads, if you only want to use the rear one OK, but laws of physics (solids will not pass through each other) require removal of the head. The only other way would be to stretch the O-ring over the cap of the idler(not recommended) or to split the O-ring(definitely NOT recommended). Not knowing the condition of the motor that I bought and needing to replace the cam belt and pulleys also I did all of these jobs at once which further hampers the time estimate. I am trying to remember all of this from over a year ago, If you want I could copy the pages out of the factory manual I have on this procedure for you.

[jmars55]

Can any one tell me the size of the o-ring? Looks like I'm going to have to replace mine also. Started to leak a considerable amount of oil all over the Tranny bell housing and crossover pipe causing some smoke.

[tommyz34]

im leaking a qt a week of oil from there and it smokes too so im definetly planning to replace it soon any ideas i have a 95 monte carlo z34 with 3.4 has 108,000 on it

[Crazy K]

There is a specific O-ring for this job. Go to your dealer and get the BROWN ring. they will know what you need. ask for a "OIL DRIVE O-RING" there or any reputable parts shop.

next.. GET A PAPER GASKET. One for a 1980 anything chevy v6 will work, but you can make your own. WHY? You should DOUBLE GASKET this seal. I do on all the 60V6s I've ever touched.

You cannot reach O-ring on the drive gear due to clearance on this motor (91-95 for sure) You must make the clearance.

CLEARANCING HEAD: I do not like hacking the head completely, so instead I removing maybe 1/4 inch of material with a hacksaw blade from the area right above the seal. This leaves the bolt from the lower intake functional, but thins the tab of metal hanging below it. You will need to remove a little of the very lowest portion of the bolt's hole.

CLEARANCING OIL GEAR:Next, I recess the "freeze-plug" type cover in the center of the drive-gear by tapping it down from above with a couple linked 3/8" extensions, turning it (or moving the extension) so the plug moves uniformly. Using the hacksaw blade again, I notch into the top of the drive-gear level with the top of the recessed cap. Cut about 1/4 of the radius, and a quick tap with a screwdriver will pop the cut section off. hack the edges clean, and even sand to de-bur so you don't damage the new o-ring.

The gear should lift high enough to have the bottom of the O-ring at or above the level of the block. Cut or break the old ring out. Grease or oil the new ring and the drive-gear cap (I prefer dielectric grease) and slip it over the cap, stretching it over and sliding it down until in position.(note that I used two pieces of wire to pull, see pics) Degrease the area and get the paper gasket. Cut the paper gasket and rub it with a RTV sealant. wrap it around the oil drive, make sure it is straight and slam that oil-drive gear home and bolt it down.

p.s. link to images of what I did:

http://s28.photobucket.com/albums/c214/Crazy_Ken/LQ1%20oil%20drive%20fix/