Oil Pump Drive Seal Leaking

[Robby1870]

Dont use JB weld, cuz if it sticks its never coming off, and who knows, you may need it to come off someday. A lot of RTV works wonders

[DOHCRagtopguy]

Here's how I fiixed the wife's 3.4: Notched the top of the shaft about 1/4". Turned it around until the notch was under the head so it would come up about 1/2" or so. This was enough room to put an old smallblock chevy distributor gasket on. Sliced gasket one side then snaked it on. Naturally, all surfaces were cleaned spotless using Brakleen. Smeared the shit out of gasket and surfaces using hi-temp RTV silicone sealer prior to installing. Turn the shaft while doing to ensure maximum coverage. Then tighten it all up, don't run it for 24 hours to allow for curing.

 

Oil Pump drive is leak free. Unfortunately, it now appears that I have an oil leak around the oil cooler area. I'll let youse know when I fix that one too.

 

Good luck, it's not that bad. Just be patient and somewhat meticulous.

[Slade901]

I did that same thing on my 3.1L engine oil pump drive.

 

I got a cork gasket and made my own gasket. I measured the outside and inside circumference of the oil pump drive. I then cut the gasket to match the outside circumference of the oil pump drive and then cut the inside to matchin the inside circumference of the oil pump drive.

 

Next, I have to cut the gasket so I can put it around the oil pump drive shaft. Instead of just cutting straight, I cut diagonal on the gasket so that the incision will be overlapping each other and then it will seal more when the oil pump drive is tightened.

 

I did that and no more leaks.

 

http://members.fortunecity.com/slade901/automobile/Oil_Pump_Drive_Gasket.gif

[ZXXXIV]

Hey DOHCRagtopguy I had a leak around the oil cooler area. It turned out to be the oil sensor leaking.Just my .02

[quaddriver]

Heh heh, I told you I'd be flamed.

 

rather than do the cut and paste, ubb quote crap ad nauseum Im just gonna answer all stuff at once.

 

First off, I have personally owned 660 motors of varying displacements in A, J, L, N, S, T, W, X bodies. that pretty much covers the gamut.

 

I own a shop and work on same, and due to the ubitiquosness of the motor, its probably not a brag that I have torn down to the bearings more 660 motors than everyone reading this COMBINED. As I often semi-joke, of all the parts I maintain in stock (I maintain little stock) 660 motor gasket sets are the most popular. Suffice to say, I might have a wee bit of insight into what lasts, what does not, what is good, what is not. Of course, at any time you are free to not believe me - which is good - always do investigation. find me *one* (1) automotive pro who considers the 660DOHC motor even a GOOD design, let alone an outstanding one (your words, not mine). In the first year of introduction it was panned by the journalists. Soon followed by the techs, and by a year later, the owners were far less than enamored. How many here got one brand new by 1993 and are original owners? Im betting far less than 5% of the board.

 

The 11 or 12 points I listed, yes, were not all attributable to the 34DOHC, of course this was given away by my use of the phrase '660 programme'. All displacments of the 660 have been used in the W body, making this series of posts at least in the ballpark. Of course the original post is not fully answered because as you can guess, there IS no fix for that posters problem. Period. Anyone who has made the fix has yet to cover the 30-40-50(etc) K miles to see if it really held.

 

so confining my raggin to the 3.4DOHC ONLY lets reevaluate:

 

1) the placement of the alternator made an item requiring frequent servicing, inconvenient to service. The problem in a nutshell, is that the I.F. alt uses too small of a nose bearing. The stress of the serp system causes this to fail, MOST OFTEN before 60K miles. The repair is north of $600. The repair is also out of the reach of the average joe including most hobbyists. Most alt rebuilders use the newer wider bearing, so a second failure due to this is unlikely, but the damage is still done. point of reference, my mother purchased a brand new 93 GTP in 1993 against my advice. The alt went at appx 70K as predicted. the bill was over $650 as predicted.

 

2) The add on of the cam drives on the front end have moved the accessories, or the mounts, or the access bolts to inconvenient locations. The PS pump and hoses frequently fail. Tell me, how easy is it to use the requisite puller on the PS pump to remove it with the cam stuff in the way? How easy is it to remove the hoses?

 

3) the size of the top end of the motor has made it impossible to remove the exhaust manifolds with the motor assembled. The rear exhaust manifold is prone to cracking near the passenger side strut tower. A small inexpensive fix is once again, an all day job.

 

4) Unfortunately, the 3.4DOHC was based on the 87-93 gen2 block. This block, although improved from the first generation block, still moved quite a bit in the bore area. Regular 3.1s have a somewhat agravating problem with headbolts breaking between 2-4, 4-6, 1-3 or 3-5. Once one breaks the head gasket will quickly fail. The 3.4DOHC failed head gaskets at a worse rate than the 3.1 failed an intake - WITHOUT breaking the bolts. A 3.1 intake is 8hrs in and out, the 3.4 head is longer. time=money. PLUS, since the heads come off and are aluminum, and since aluminum warps more and easier than iron, you MUST have the head cut to hold proper seal. Well, a shop would or else they would be negligent, no telling what the backyard guys do.

 

5) as mentioned, the oil pump drive shaft is inaccessible without doing a $1200 (or more) head job on the car. But ALSO is the valley cover. It also leaks oil but into the new valley.

 

6) a regular 3.1 oil pump requires 1/2hp to turn 500rpm in 5-30 oil. the HP requirement goes up proportionally to the SQUARE of the RPM. The DOHC pump requires about twice the hp. The net result at 5000rpm is about 10hp. This is not trivial

 

7) nearly all the excess heat in oil (where temps are > coolant temps) come from bearing friction. A 3.1 has 4 mains, 6 rods and what 4 cams? A DOHC has 4 mains, 6 rods and 20 cams. It is very sensitive to oil used, dirt in the oil, and the alluminum cam carriers are gone forever if you dry start the motor. another maint nightmare

 

8) the heads were specially designed by GM to allow a 3.4L engine to produce a target of 275hp. Unfortunuately, GM could not come up with a tranny that would take that in a fwd application. So the engine was artificially detuned via injector size, cam timing and ECM programming. There is no aftermarket simply because it IS aftermarket. 3.1/3.4 pushrod motors use off the shelf items, incl the GTP. If those GMPP heads are used on the pushrod motors, to match the GMPP heads on the DOHC, HP climbs correspondingly. As I pointed out before, emissions legal 225hp 3.1s with no turbo are common using hand tools you can get at kmart

 

9) slight divergance...have you ever asked WHY GM FWDs with dogbone mounts have additional bracing from the radiator support to the strut tower? have you ever asked WHY improved versions of these parts are used on the high torque motors (3800 and super) and on the motor that rocks far more? Crawl underneath an look where the rad support attaches on a nonDOHC car vs a DOHC car. At least in late 92-on. GM did that for a reason.

 

10) because of the crummy cam belts and the throwaway tensioners, the belts must be done at 60K intervals. It is again out of the capabilities of most people and very time consuming.

 

I could go on, but Im tired. suffice to say, you can still call me full of shit. You can also call the 100's of 3.4DOHC specific TSBs bogus. fine. As I challenged you, find ONE SINGLE automotive professional who is enamored with that motor such that they will buy one. (oh they are enamored all right, 660 motors in general, but DOHC motors in the specific are known as 'cash cows' to a shop. Not real techical, does not require many exotic tools - consumes a lot of billable hours. Enables techs to pick up low mileage mint GTPs and the like for cheap and perform 3800 transplants.)

 

FWIW, when I used to visit my mother in AZ, I would borrow her GTP for runs 120 miles up to vegas. I could and did easily maintain 100mph+ on the sam kinneson hwy for most of the trip, and 90+ when over 7000ft. The hud was pretty cool at night and the leather seats and steering wheel controls were cool. Id say those runs put me in the class of someone who has driven one ONLY at speed for extended periods of time, not Jr High street racing, not commuting, not grocery getting. I can say from experience, her wide trac was faster, smoother, quieter and gets 4-5mpg better. GM made the right decision dumping that motor.

[PaPaPooh]

Heh heh, I told you I'd be flamed.

 

rather than do the cut and paste, ubb quote crap ad nauseum Im just gonna answer all stuff at once.

 

First off, I have personally owned 660 motors of varying displacements in A, J, L, N, S, T, W, X bodies. that pretty much covers the gamut.

 

I own a shop and work on same, and due to the ubitiquosness of the motor, its probably not a brag that I have torn down to the bearings more 660 motors than everyone reading this COMBINED. As I often semi-joke, of all the parts I maintain in stock (I maintain little stock) 660 motor gasket sets are the most popular. Suffice to say, I might have a wee bit of insight into what lasts, what does not, what is good, what is not. Of course, at any time you are free to not believe me - which is good - always do investigation. find me *one* (1) automotive pro who considers the 660DOHC motor even a GOOD design, let alone an outstanding one (your words, not mine). In the first year of introduction it was panned by the journalists. Soon followed by the techs, and by a year later, the owners were far less than enamored. How many here got one brand new by 1993 and are original owners? Im betting far less than 5% of the board.

 

The 11 or 12 points I listed, yes, were not all attributable to the 34DOHC, of course this was given away by my use of the phrase '660 programme'. All displacments of the 660 have been used in the W body, making this series of posts at least in the ballpark. Of course the original post is not fully answered because as you can guess, there IS no fix for that posters problem. Period. Anyone who has made the fix has yet to cover the 30-40-50(etc) K miles to see if it really held.

 

so confining my raggin to the 3.4DOHC ONLY lets reevaluate:

 

1) the placement of the alternator made an item requiring frequent servicing, inconvenient to service. The problem in a nutshell, is that the I.F. alt uses too small of a nose bearing. The stress of the serp system causes this to fail, MOST OFTEN before 60K miles. The repair is north of $600. The repair is also out of the reach of the average joe including most hobbyists. Most alt rebuilders use the newer wider bearing, so a second failure due to this is unlikely, but the damage is still done. point of reference, my mother purchased a brand new 93 GTP in 1993 against my advice. The alt went at appx 70K as predicted. the bill was over $650 as predicted.

 

2) The add on of the cam drives on the front end have moved the accessories, or the mounts, or the access bolts to inconvenient locations. The PS pump and hoses frequently fail. Tell me, how easy is it to use the requisite puller on the PS pump to remove it with the cam stuff in the way? How easy is it to remove the hoses?

 

3) the size of the top end of the motor has made it impossible to remove the exhaust manifolds with the motor assembled. The rear exhaust manifold is prone to cracking near the passenger side strut tower. A small inexpensive fix is once again, an all day job.

 

4) Unfortunately, the 3.4DOHC was based on the 87-93 gen2 block. This block, although improved from the first generation block, still moved quite a bit in the bore area. Regular 3.1s have a somewhat agravating problem with headbolts breaking between 2-4, 4-6, 1-3 or 3-5. Once one breaks the head gasket will quickly fail. The 3.4DOHC failed head gaskets at a worse rate than the 3.1 failed an intake - WITHOUT breaking the bolts. A 3.1 intake is 8hrs in and out, the 3.4 head is longer. time=money. PLUS, since the heads come off and are aluminum, and since aluminum warps more and easier than iron, you MUST have the head cut to hold proper seal. Well, a shop would or else they would be negligent, no telling what the backyard guys do.

 

5) as mentioned, the oil pump drive shaft is inaccessible without doing a $1200 (or more) head job on the car. But ALSO is the valley cover. It also leaks oil but into the new valley.

 

6) a regular 3.1 oil pump requires 1/2hp to turn 500rpm in 5-30 oil. the HP requirement goes up proportionally to the SQUARE of the RPM. The DOHC pump requires about twice the hp. The net result at 5000rpm is about 10hp. This is not trivial

 

7) nearly all the excess heat in oil (where temps are > coolant temps) come from bearing friction. A 3.1 has 4 mains, 6 rods and what 4 cams? A DOHC has 4 mains, 6 rods and 20 cams. It is very sensitive to oil used, dirt in the oil, and the alluminum cam carriers are gone forever if you dry start the motor. another maint nightmare

 

8) the heads were specially designed by GM to allow a 3.4L engine to produce a target of 275hp. Unfortunuately, GM could not come up with a tranny that would take that in a fwd application. So the engine was artificially detuned via injector size, cam timing and ECM programming. There is no aftermarket simply because it IS aftermarket. 3.1/3.4 pushrod motors use off the shelf items, incl the GTP. If those GMPP heads are used on the pushrod motors, to match the GMPP heads on the DOHC, HP climbs correspondingly. As I pointed out before, emissions legal 225hp 3.1s with no turbo are common using hand tools you can get at kmart

 

9) slight divergance...have you ever asked WHY GM FWDs with dogbone mounts have additional bracing from the radiator support to the strut tower? have you ever asked WHY improved versions of these parts are used on the high torque motors (3800 and super) and on the motor that rocks far more? Crawl underneath an look where the rad support attaches on a nonDOHC car vs a DOHC car. At least in late 92-on. GM did that for a reason.

 

10) because of the crummy cam belts and the throwaway tensioners, the belts must be done at 60K intervals. It is again out of the capabilities of most people and very time consuming.

 

I could go on, but Im tired. suffice to say, you can still call me full of shit. You can also call the 100's of 3.4DOHC specific TSBs bogus. fine. As I challenged you, find ONE SINGLE automotive professional who is enamored with that motor such that they will buy one. (oh they are enamored all right, 660 motors in general, but DOHC motors in the specific are known as 'cash cows' to a shop. Not real techical, does not require many exotic tools - consumes a lot of billable hours. Enables techs to pick up low mileage mint GTPs and the like for cheap and perform 3800 transplants.)

 

FWIW, when I used to visit my mother in AZ, I would borrow her GTP for runs 120 miles up to vegas. I could and did easily maintain 100mph+ on the sam kinneson hwy for most of the trip, and 90+ when over 7000ft. The hud was pretty cool at night and the leather seats and steering wheel controls were cool. Id say those runs put me in the class of someone who has driven one ONLY at speed for extended periods of time, not Jr High street racing, not commuting, not grocery getting. I can say from experience, her wide trac was faster, smoother, quieter and gets 4-5mpg better. GM made the right decision dumping that motor.

 

haha own a shop?

 

you know my famous saying all cars rule as long as i make money off them

 

i would say you need to let it be

 

you of all people (just because you own a shop) should not say that one engine is better than the other. you make money off them breaking right?

 

i feel that this has gone enuff and a mod needs to lock this debate because

1) there is a shop owner looking like an ass

 

2) this hass been covered many times

 

3) im sick of seeing the debate over whats better than the other

 

4) im a trans guy and i feel there are taransmissions better than others but i don't get into a debate about it because it is a waste of time to argue about other peoples opinions

 

5) who cares if he likes them and he doesn't because he is a "mechanic"

 

so lets stop this right here and right now it has got out of hand

 

i also understand that there can be some good things about what could go wrong with the 3.4 DOHC or any other engine for that matter!!

i just don't think it should be exposed in this way! it should be done on a volentary basis and not in the way of flames!!!

 

have a nice day!!

[joey b]

the pulleys cause the alts to go out? And you own a shop . No, the voltage regulator is more prone to failure, just like is the case on 90% of alt failures. That is caused by heat, not pulleys. You don't even need to buy a new alt. You can simply weld in a new voltage regulator and they cost about 12 bucks.

In addition to that, you keep talking about 660's. That includes the 3.1 which shares many of the same faults of the 3.4, including the car breaking in 2 . Of course the 3.4 is larger the cams are OVERHEAD and there are 4 of them! It also allows to adjust the cam timing, which if GM would have done it, it would have a strong powerband of 4K RPMs. I love the sound of my 3.4 and I also love the extended strong powerband, instead of the 2K that I had with the 3.1.

[93GTP]

What really makes me laugh about his posts is how he treats the entire 660 programme as a failure.

 

WTF, that can't be further from the truth, the 60*V6's outnumber all other engines used by GM in passenger cars in the 1990's timeframe. It has been a real workhorse for GM, and as much as this "mechanic" dogs it, it has been a great success.

 

My mothers Grand Prix with a 3100 now has over 300,000km with only a head gasket replacememnt at 220,000. And what do you know, the car hasn't "cracked in half" yet. If these engines were so crappy, then I don't understand why so many cab companies would use them as cabs, where reliability, and the price of maintenance are key. It's because the 3.1 holds up forever with minimal repairs.

 

The whole basis for your argument for it being a bad design is pretty much the alternator position. Well like I said before, there was no where else to put it in a DOHC engine bay, which is why many japanese cars use the exact same positioning for it. Yes it is an expensive repair, but that's just the way it is, and it hardly a downfall of the actual motor, stop confusing the motor itself with the car. The only bad design feature of the 3.4 is the distributor drive, and there are many easier fixes than a $1200 complete tear-down. And like I said, this could have been easily corrected by GM by using higher quality o-rings or a gasket.

 

You also keep saying that the engine is not very accessible, well duh, its a DOHC V6, it's the name of the game, it's god damn big! Just because it isn't easy to access some things that fail (like PS hoses), once again doesnt mean the engine itself is badly designed, there wasn't much choice in the matter. Of course mechanics will say the "engine" is badly designed, because they dont give a shit about all the good sides of the engine, like the DOHC design and the fact that some actual technology was put into it. If it were up to mechanics, engines would be very simple, with no advancement in technology. No concepts like fuel injection and DOHC, everything would just be a carburated chevy V8. Well guess what, times change.

 

Oh and about the PS pump, what in the hell are you talking about? You say the pulley is hard to pull on it? Well, for one, the pump is easy as pie to remove, so next time pull it off if you need to. And the reason the PS lines are a bitch to replace (I replaced my high pressure line which is notorious for being a "bitch") Is more so because of the size of the 4T60E transmission. It's fucking huge and gets in the way of accessing the fittings on the rack. If a smaller, and better transmission was used, this job wouldnt have been that bad. And I imagine it's already easy on 5 speed cars, bcause that tranny is reasonably sized.

 

"Regular 3.1s have a somewhat agravating problem with headbolts breaking between 2-4, 4-6, 1-3 or 3-5"

 

Man I really don't know where you get these problems, this is not a common problem with 3.1's. Hell, all the 3.1 owners on here can vouch for that.

 

"5) as mentioned, the oil pump drive shaft is inaccessible without doing a $1200 (or more) head job on the car. But ALSO is the valley cover. It also leaks oil but into the new valley."

 

The distribution cover is also not known for leaking, only the distributor drive o ring.

 

Oh, and the stuff about the rear manifolds being prone to cracking is a load of bologna.

 

I don't know man, for a mechanic that has done so much work on 660 engines, I expected better.

[Brian P]

Let that be a lesson! I know Ill get flamed but the DOHC 3.4 was an engineering nightmare/disaster - the designer should be shot or worse. The thing is, with the age of the cars now, simple jobs like this, or an alternator, or cam belts etc are causing the cars to be scrapped - not worth the repair (just hauled off a 92? 93? GP in mint condition otherwise)

 

For the record, under no circumstances should the 660 block have been adapted to DOHC - chevy should have taken a page from the olds 3.5DOHC, or just borrowed the damn engine. What they did is frighteningly akin to making a diesel out of a gas 350....to borrow a line "everyone was so busy seeing if they COULD do it, no one bothered to ask if they SHOULD...."

 

quite frankly, the number of valves and the methods of actuation have little to do with specific engine output - a pushrod 3.4 (a bored 3.1 which is a stroked 2.8) with off the shelf heads and cam from GM will make more power than the DOHC, at a lower RPM, have far less noise and rotational inertia and be servicable.....

 

I realize there is appeal to having a 'one-off' model, but stuff like this is always gonna be in the way

 

rant over

 

Arguably the best post on this whole board

[Robby1870]

Let that be a lesson! I know Ill get flamed but the DOHC 3.4 was an engineering nightmare/disaster - the designer should be shot or worse. The thing is, with the age of the cars now, simple jobs like this, or an alternator, or cam belts etc are causing the cars to be scrapped - not worth the repair (just hauled off a 92? 93? GP in mint condition otherwise)

 

For the record, under no circumstances should the 660 block have been adapted to DOHC - chevy should have taken a page from the olds 3.5DOHC, or just borrowed the damn engine. What they did is frighteningly akin to making a diesel out of a gas 350....to borrow a line "everyone was so busy seeing if they COULD do it, no one bothered to ask if they SHOULD...."

 

quite frankly, the number of valves and the methods of actuation have little to do with specific engine output - a pushrod 3.4 (a bored 3.1 which is a stroked 2.8) with off the shelf heads and cam from GM will make more power than the DOHC, at a lower RPM, have far less noise and rotational inertia and be servicable.....

 

I realize there is appeal to having a 'one-off' model, but stuff like this is always gonna be in the way

 

rant over

 

Arguably the best post on this whole board

 

Yeah, I second that!

[Heza]

does the 3100 Vin M have that stupid distributor oil seal thingy too? because before i left for Iraq, i noticed oil disappearing and there's an oil mess underneath the throttle body on the tranny housing (i think) that i had never seen before.

[cutlassdude96]

yes they do

[Heza]

yes they do

 

damn it...that solves that problem. hopefully im certain enough that that is the problem because that would make me happy to not lose anymore oil. ironically...it all started when i got recalled from leave to deploy and drove 10 hours at an average of 90 mph. oops..

[jimbud22]

If anyone remembers what this thread was about, a guy needed help with his car and half of you guys want him to junk his car. Try fixing your o-ring oil leak by cleaning the area good with gumout, take the oil pump drive cover off and lift the oil pump drive up as far as it will come and work a rubber o-ring the same size thats in the butt end of a D cell Maglite flash light and then work a lot of red hi-temp silocone in and a round the oil pump drive. Put the cover back on, install the manofold and start it up. Change the oil and chances are you fixed your oil leak with out pulling the rear head. I did this and it's been fine for over a year.

[Brian P]

That's good enough for a conclusion!