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Discussion Starter · #1 ·
Hey guys,

I've been driving my 1995 Monte Carlo Z34 (3.4L DOHC) for awhile now, since gas sucks with my truck.

It's been leaking oil for awhile. I've done so much research on this car, it hurts my head. I'm sure if you've heard of this car, you've heard of its problems.

Anyway, I'm pretty sure that the o-ring on the oil drive pump is the culprit, (its a known problem with these engines) Does anyone have any estimates for a fix on this bad boy? I've read in upwards of $1000 in labor, all for a 97 cent part. In which case I say screw it. I'll be getting out of college in May.

I tried some Lucas oil stop-leak (a whole damn bottle) and had no luck.

Any info would be appreciated!
 

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Not sure if it's the same, but my 90 Regal with the 3.1 had a bad oil leak also. Turns out, it was an o-ring that went beneath a plug that is where the old distributor shaft went down. I had it replaced for a few hundred bucks about 6 years ago and haven't had a problem since.

Let me know what you find out. May be the same problem.
 

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Discussion Starter · #4 ·
Not sure if it's the same, but my 90 Regal with the 3.1 had a bad oil leak also. Turns out, it was an o-ring that went beneath a plug that is where the old distributor shaft went down. I had it replaced for a few hundred bucks about 6 years ago and haven't had a problem since.

Let me know what you find out. May be the same problem.
Im going to shoot in the dark and say its different. This 3.4L DOHC is quite the different monster. I've worked on 3.1's before.
 

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Im going to shoot in the dark and say its different. This 3.4L DOHC is quite the different monster. I've worked on 3.1's before.
The car now has 190,000 and that is the only repair to the engine. Tranny was rebuilt at 180,000 though.

Hope you can find an inexpensive repair for your car. Do you know if it's something you may be able to do?
 

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Discussion Starter · #7 ·
The car now has 190,000 and that is the only repair to the engine. Tranny was rebuilt at 180,000 though.

Hope you can find an inexpensive repair for your car. Do you know if it's something you may be able to do?
From what I've read. No, I can't do it. And I'm pretty skilled. Not certified, but I can do quite a bit, and I like to. I've replaced an engine, tranny, done many brakes. The list could go on.... (I'm not bragging by any means)

Maybe I will swing in at a dealer and see what they say, price range.

This monte has 181,xxx miles on it.

My truck just turned over 229,xxx this summer... so yeah lol.
 

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From what I've read. No, I can't do it. And I'm pretty skilled. Not certified, but I can do quite a bit, and I like to. I've replaced an engine, tranny, done many brakes. The list could go on.... (I'm not bragging by any means)

Maybe I will swing in at a dealer and see what they say, price range.

This monte has 181,xxx miles on it.

My truck just turned over 229,xxx this summer... so yeah lol.
Man, that's good mileage. I don't know why some people hate the 3.1 and 3.8 engines. I know some of any kind will have issues, but I don't know of anyone to have problems with either of them from any generation. Luck of the draw, I guess.

I enjoy doing as much of my own maintenance and repairs as well, but as vehicles evolve, I find my self doing less and less.
 

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Discussion Starter · #9 ·
Man, that's good mileage. I don't know why some people hate the 3.1 and 3.8 engines. I know some of any kind will have issues, but I don't know of anyone to have problems with either of them from any generation. Luck of the draw, I guess.

I enjoy doing as much of my own maintenance and repairs as well, but as vehicles evolve, I find my self doing less and less.
When it comes to the 3.8, I personally think thats the best. I think its one of the strongest engines I know of, other than the 350 (5.7L.) Its just an all around great engine. Gas mileage and performance. I prefer the 5.7 over the 3.8 :)
 

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Head has to come off to reseal oil drive correctly...

Lucas likelyy won't do anything but lighten your wallet...

that engine was GM's worse mistake...I'd take 12 HT4100's and 500 V8-6-4's over one of those...

You can get around if you can lift the drive up @ all...

degrease the area with brake cleaner...and IF you can lift up on the drive enough, get a GM distributor gasket #10108445, and slice it, meaning cut it so you can slip the gasket around the shaft, then with some Gorilla glue, glue the paper end back together, THEN get some RTV silicone, some GM grey Tri Bond, or anything that's hi temp & oil resistant...and apply the sealer to the gasket, top & bottom....I stiff object like a fireplace match would work....


Look here: http://www.midtekcars.com/engine_fix01.htm
 

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Discussion Starter · #11 ·
Head has to come off to reseal oil drive...

that engine was GM's worse mistake...I'd take 12 HT4100's and 500 V8-6-4's over one of those...

You can get around if you can lift the drive up @ all...

degrease the area with brake cleaner...and IF you can lift up on the drive enough, get a GM distributor gasket #10108445, and slice it, meaning cut it so you can slip the gasket around the shaft, then with some Gorilla glue, glue the paper end back together, THEN get some RTV silicone, some GM grey Tri Bond, or anything that's hi temp & oil resistant...and apply the sealer to the gasket, top & bottom....I stiff object like a fireplace match would work....
F my life...........
 

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C/T


I edited my post, read the link I attached...good info there...

I know we've done it in the shop without taking the head off and informing the customer we can do this, but we won't guarantee it'll leak again!!!


As with all these 60* V6's we not only replace the Oring #10477565, b ut add the old dist gasket, #10108445...usually that 1-2 punch works...
 

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When it comes to the 3.8, I personally think thats the best. I think its one of the strongest engines I know of, other than the 350 (5.7L.) Its just an all around great engine. Gas mileage and performance. I prefer the 5.7 over the 3.8 :)
Agreed. My dad's 1989 truck has 207,000 on it and no maintenance at all to engine or tranny. The rear seal leaves like a sieve until it gets warm and the rings are worn, but other than that it runs fine. I told him he could replace the rear seal and he said it'd be best to just add a quart every 800-1,000 miles or so no more than he drives it, which is around 5,000 miles a year at the most. It actually only leaks on short trips when the engine hasn't really gotten warm, so it's no biggie. I kinda see his point in not replacing it, 'cause sure as he does something else will happen and it will start the whole "nickle and dimed" to death that vehicles that old have a tendency to do.

My 1983 Nissan pick-up (beat-around) could use a set of tires, but I'm gonna hold out as long as I can b/c a set of tires would be twice what the truck is worth! Know what I mean?
 

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Discussion Starter · #15 ·
Agreed. My dad's 1989 truck has 207,000 on it and no maintenance at all to engine or tranny. The rear seal leaves like a sieve until it gets warm and the rings are worn, but other than that it runs fine. I told him he could replace the rear seal and he said it'd be best to just add a quart every 800-1,000 miles or so no more than he drives it, which is around 5,000 miles a year at the most. It actually only leaks on short trips when the engine hasn't really gotten warm, so it's no biggie. I kinda see his point in not replacing it, 'cause sure as he does something else will happen and it will start the whole "nickle and dimed" to death that vehicles that old have a tendency to do.

My 1983 Nissan pick-up (beat-around) could use a set of tires, but I'm gonna hold out as long as I can b/c a set of tires would be twice what the truck is worth! Know what I mean?
yep. You should just go buy a GM truck instead of new tires ;) hahah. Oh I am a GM fan.
 

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yep. You should just go buy a GM truck instead of new tires ;) hahah. Oh I am a GM fan.
Oh, don't worry. I've still got 99 GMC ext cab z-71. Only have 77,000 on it and it looks and runs like new. Kinda think it looks better than the new ones, but that's just me. The Nissan is the one for errands or just piddling around. I had it since high school, but it is by no means a primary vehicle! More like a fun vehicle!
 

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I had to replace it on my 3100 which took a good afternoon. I'd imagine it would be a bit more difficult on a Twin Dual Cam.

To my knowledge the extra gasket is basically a Chevy 350 distributor gasket, readily available. I probably should have added that but I RTV'ed instead.

Sonoma's suggestion of splicing a gasket and picking up the distributor drive just enough to slip it in seems plausible but when I did it the big issue was getting a socket, wrench, anything on the single bolt that holds it in.
 

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I had to replace it on my 3100 which took a good afternoon. I'd imagine it would be a bit more difficult on a Twin Dual Cam.

To my knowledge the extra gasket is basically a Chevy 350 distributor gasket, readily available. I probably should have added that but I RTV'ed instead.

Sonoma's suggestion of splicing a gasket and picking up the distributor drive just enough to slip it in seems plausible but when I did it the big issue was getting a socket, wrench, anything on the single bolt that holds it in.
It is the SBC dist gasket, the smaller one though...

It's easy on the 3100 though...
 

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For a car with 180 k I would just try this.The oil drive o ring is what is leaking.It gets dry and brittle over time.The correct way to do it is pull the back head to get the oil drive out of the block.But now you are talking a new timing belt etc..Has the belt ever been done?I doubt it lasted 180 K miles.If the belt is older meaning you do not know when it was done last just bite the bullet and do it the correct way.You can try and cut a small block chevy distributor gasket under the oil drive.Some people have had good luck.You can also try to work a new oil drive o ring over the top of the oil drive.It is kinda tight and you can only get the oil drive up a little after removing the hold down.It is worth a shot if you are on a budget.
 

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i have the same car i found out that on the 3.4 dohc, there is a dist. plate that has rtv to seal it. that is a common leak, in order to fix that you have to remove the upper & lower intake. the other common leak is the rear valve cover gasket, let me know if this helps you out
 
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