New Member and New GTP owner needs help

[BulletGTP]

Ok, I just bought a 1994 3.4 GTP for about 800.00 and its in really nice shape and freaking fast. (Funny story how I got it) however there is a few problems I cannot seem to locate and need some real help. I was a user of another GTP froum and they are very unhelpful so I was told to try here by their Admin. So here goes,

 

 

1st, I have leaking intake gaskets making the car run real high idle at cold start then back to normal when it warms up but it runs like it is cammed at idle. I dont have any codes. Do I need to replace the top and bottem intake gaskets???

 

 

2nd, I have a massive oil leak from under and behind the intake, there is oil all over everything, i am losing about 1 quart a day and it stinks like hell. I was told this is the O Ring gone bad, Is this an easy job or do I really have to take the head off? I was told I can do it by just taking the intake off. What is the truth?

 

Please help, I did a search but it onlycame back with a 3.1 oil leak.

 

 

Bullet

[White93z34]

welecome to the board, you may as well fix both problems at once, take off the plenum and lower intake change the gaskets, and replace the oil pump dirve O ring, since its located under the lower intake

 

i'm not 100% sure on how to repair the O ring myself but i'll let the other guys chime in on how thats done.

[R Dubya]

Although I have never worked on a 3.4 myself, I have read many threads and lots of them pertained to this subject. The proper way to fix that distributor o-ring is to remove the rear head, the head stops the pump drive from coming all the way out. What you can do is blast it with some engine cleaner or brake cleaner, get all the oil off, then gobb the shit out of it with some RTV black and that should at least temporarily fix the leak. To do it properly, the black o-ring must be replaced with a soft brownish colored o-ring available at the dealer, for around $3. Too bad it would take 8 hrs to fix it. Good luck, and maybe someone else has some more useful info.

[95 3-4]

Having just removed a 3.4 today and looking at that massive nasty oil leak I can confirm the rear head must be removed to pull oil pump drive plug out.

 

The whole motor was a good laugh when he had it out and had a good view of it, thing looks like the exxon valdeez, it leaks oil everywhere even looks like the headgaskets are leaking oil in addition to the front main. What a mickey mouse place for the alt on the 3.4

 

Engine still runs fine 4t60e puked tho 108k, 3.8-4t60 going in

[Aaron]

You actually do not have to remove the head. It will help a lot, but it isn't neccesary. The part of the head that covers the plug is just a piece that was casted on to it, it has no real purpose. So you can cut off this tab, and you will be able to remove the cap. It will still be a pain, but IMO its easier than removing the ehad. Just be careful about cutting it, you don't want to cut too deep into it. But the aluminum on the heads/intkae cuts real easy, so a hack saw will work just fine.

[95 3-4]

Yea I guess you could grind it away, point taken

 

A quart a day has got to suck, i guess a quart every 2 weeks is pretty good

[HokemBokem]

A quart a day has got to suck, i guess a quart every 2 weeks is pretty good

 

My friends brothers 84' Mercadez leaks about the same. His driveway is almost completly black from the oil leak.

[BulletGTP]

Forget taking the head off. I called GM Dealer and they wanted 870.00 dollars. I'll do it the easy way myself...

[EurosportZ34]

welkom!

 

damn that must be one nice GTP....i'm love 3.4 GTP's

 

also welcome to the 3.4 oil leak, they are notorious for leaking oil

 

defaintely fix it yourself or have someone you know do it, like BulletGTP said, shops will charge up the a$$ to fix it.

[z34_nut]

i never liked the idea of grinding that casting off, but i guess if you want to, you can.

 

personally i would go through all that effort of taking the head off, mostly to see the internals of the motor and how it looks.

[dbtk2]

i never liked the idea of grinding that casting off, but i guess if you want to, you can.

 

personally i would go through all that effort of taking the head off, mostly to see the internals of the motor and how it looks.

 

I wouldn't, basically because I would want to save myself the large amount of work it requires, that and because it would cost a decent bit of money for new headgaskets & headbolts. Why spend the money when it isn't necessary. Not only that, but why replace a gasket that is working perfectly well therefore giving you the risk of having the new gasket fail you and have to do the work again. If it ain't broke don't fix it.

 

Just my opinion though.

 

Shawn

[93CutlassSupreme]

A quart a day has got to suck, i guess a quart every 2 weeks is pretty good

 

My friends brothers 84' Mercadez leaks about the same. His driveway is almost completly black from the oil leak.

 

Mercadez?

 

or, as they say down in Detroit, Macadez

[95 3-4]

With 100k on an alum. headed engine some of which came with crappy dexcool you aint doing no wrong putting new head gaskets and intake gaskets on them.....sadly its ton of work, hence the reason the cars are treated as bic lighters

[dbtk2]

With 100k on an alum. headed engine some of which came with crappy dexcool you aint doing no wrong putting new head gaskets and intake gaskets on them.....sadly its ton of work, hence the reason the cars are treated as bic lighters

 

Yeah, but honestly, if the head gasket isn't leaking, why put a new one in? I can't count the number of times I have heard of someone blowing a head gasket that they just installed it a couple hundred miles before. I've heard of new ones going out in these engines more than the originals. I see no reason to fix something that is working perfectly fine, there is always a possibility that you can make it worse.

 

My $.02 deposited.

 

Shawn

[95 3-4]

I feel the same way about the timing belt @ 108k, sadly the motor wont be going back in to put another mile on it

[JoroCorona]

Bent up some valves aparently, that sucks. I got lucky, all my valves survived my timing belt. And I've FINALLY pinpointed the reason why it runs so bad at cruising speed with tq lockup. My friend was testing the coils by grounding out the wires. DOH! Torched 2 of the 3 coils, So I'm just gonna replace them with a set off of a 3400.

 

While I prolly wouldn't want to remove the head to fix th O-Ring, I am DEFINATLY not cutting the head up. Yanking a head isn't that god awful, and the parts arent excessivly priced either. And while your at it, you can bring the heads to a machine shop and have the valves finished, and maybe deck the head alittle. Get alittle more out the motor ya know.

[95 3-4]

My 3.4 dohc runs fine except for the it has been removed cause the trans puked, lost everything but 1st gear.

 

series 1 3800 replacing it, doesnt leak any oil, has more power, and gets better gas mileage, doesnt need a timing belt, tensioner, idlers, and $100 worth of gaskets to seal up the oil leaks, not to mention easier coil pack access, more engine compartment room and an alternator that can be swapped in 8 minutes

[BulletGTP]

This was a big fu$%ing job.

 

Well the good news. I replaced the upper and lower intake gaskets, installed new Injectors, ect.. Tuned up everything. SLP cat back is on. C.A.I. is on as well and installed my custom burnt chip. The car runs like brand new, runs really fast now. Woo Hoo and sounds mean.

 

The bad news (knd of) the o ring isn't leaking oil at all.It was bone dry. I got me an bad oil leak some where else. God dammit.

 

Peace!!!!

[Aaron]

My 3.4 dohc runs fine except for the it has been removed cause the trans puked, lost everything but 1st gear.

 

series 1 3800 replacing it, doesnt leak any oil, has more power, and gets better gas mileage, doesnt need a timing belt, tensioner, idlers, and $100 worth of gaskets to seal up the oil leaks, not to mention easier coil pack access, more engine compartment room and an alternator that can be swapped in 8 minutes

 

Except it has the same, if not less, power, worse gas mileage, and has little performance capabilities compared to the Z34 motor. Who cares if the coils are hard to get to? If you are doing this swap in the first place, you aren't interested in performance. And there is no other reason you should go near the coils. And the DOHC does not have a habit of burning up coils like cars have of burning up 3800s. And they aren't even that bad...And none of my 3, plus the almost 100 DOHCs I've seen/driven have leaked oil.

[95 3-4]

My 3.4 never had any power, it had a 1 second delay before it reved when you floor it, never ever squeled tires, it did have some power up high 4k-6k. The only time it had really good power when it was ice cold in the winter, once it warmed up and all that alum expanded the power would really fall off

MyRegal 3.8 W was always faster than this 3.4 Gtp and got better gas mileage. Guilty as charged on the non performance issue. I rather have longevity and reliability first and foremost.

FWD cars are hardly a a performance platform that need a performance engine, most of the W's I see on the road are daily drivers, including the the high performance L67's driven by old people. I liken W cars to bic lighters.

I installed a 170 hp motor, the 3.4 was 225 "supposably" probably why the 3.8 got better mpg, and the coilpack/icm on both cars are original 180k on the 3.8 and 108 on the 3.4. And having the coil packs up top is obviously a better design as is the 3.8 itself, not next to an exhaust manifold and away from road grime/saltwater

If I had to have any 60 degree v6 it would be a gen 1 3.1, I would take a 3.8 over any 60*

 

Its obvious that there are some staunch 3.4 lovers here and thats all well and good but the LQ1 is no LT5, its more like the northstar which is also a pretty wack design and known oilburner at 100k, oh and the quad 4 ~known headgasket eater~........The difference between the the LT5 and the Northstar,3400 DOHC and the Quad 4 is that lotus designed the LT5 and mercury marine assembled it, the other engines were designed by Gm's finest in Warren, where they call it "engineering"

 

The flagship W cars have always had the 3.8 and thats a fact

As far as your 3.4's never leaking oil at the oil pump drive it seems that all the 3.4 cars you have seen defy the laws of gm assembly problems, kinda odd cause that seems to be one of the most brought up topics here.

GM dexcool or piston slap anyone

 

Flame on

[sonyman87]

in not reading all the above posts

 

my suggestion since its a 94dohc.. your SOL on changing the actual 0-ring, its not possible without removing the rear head more work then you want and what its worth. What you can do is after taking off your upper and lower intakes is remove the valey plate/ scrap away the paper gasket High temp RTV it back on. The 0 ring cap will not come up very much at all b/c of clearance issue. You can clean around it as much as possible remove the hold down clamp clean under the cap the best you can and RTV under it the best you can all the way around spinning helps.

 

assemble and flollow your RTV instructions. If you do a good job it will not leak. some people have over a years worth of driving like that and its still holding. Intake gaskets do both! It helps to put a little RTV on the Paper gasket on both sides to ensure a good seal and also help it from breaking.

[Aaron]

My 3.4 never had any power, it had a 1 second delay before it reved when you floor it, never ever squeled tires, it did have some power up high 4k-6k. The only time it had really good power when it was ice cold in the winter, once it warmed up and all that alum expanded the power would really fall off

MyRegal 3.8 W was always faster than this 3.4 Gtp and got better gas mileage. Guilty as charged on the non performance issue. I rather have longevity and reliability first and foremost.

FWD cars are hardly a a performance platform that need a performance engine, most of the W's I see on the road are daily drivers, including the the high performance L67's driven by old people. I liken W cars to bic lighters.

I installed a 170 hp motor, the 3.4 was 225 "supposably" probably why the 3.8 got better mpg, and the coilpack/icm on both cars are original 180k on the 3.8 and 108 on the 3.4. And having the coil packs up top is obviously a better design as is the 3.8 itself, not next to an exhaust manifold and away from road grime/saltwater

If I had to have any 60 degree v6 it would be a gen 1 3.1, I would take a 3.8 over any 60*

 

Its obvious that there are some staunch 3.4 lovers here and thats all well and good but the LQ1 is no LT5, its more like the northstar which is also a pretty wack design and known oilburner at 100k, oh and the quad 4 ~known headgasket eater~........The difference between the the LT5 and the Northstar,3400 DOHC and the Quad 4 is that lotus designed the LT5 and mercury marine assembled it, the other engines were designed by Gm's finest in Warren, where they call it "engineering"

 

The flagship W cars have always had the 3.8 and thats a fact

As far as your 3.4's never leaking oil at the oil pump drive it seems that all the 3.4 cars you have seen defy the laws of gm assembly problems, kinda odd cause that seems to be one of the most brought up topics here.

GM dexcool or piston slap anyone

 

Flame on

 

Power aside of course, the LT5 was one of the worse engines ever put in a GM car. Did you know that within the first 2 months, 78% of LT5 equipped Corvettes came back? My dad sold 6, I have the paperwork on all 6. They range in price from $58k to $65k. EVERY SINGLE ONE came back within the first 2 weeks of being sold. But it was a highly technical engine, that made awesome power for its day.

 

Your 3.4 was 200hp btw. And how your 175hp 5500rpm screamer beat it defies all laws of common sense I guess...Or it means that you are not educated enough to maintain it, in which case I see a Honda SOHC being best for your future...

 

I have 1/4mi times showing a .18 difference after the outside air temperature dropped nearly 20*F. So maybe my heads are bolted down tighter

 

Of my current 3 DOHC 3.4Ls, none have any road grime anywhere near the ignition. And the manifolds do not heat the ignition up at all. I can and have touched mine while the motor is running. Remember, hot air rises, and when you have air moving in when your vehicle is moving, or your fans are on, that is cool air directly on the ignition.

 

I don't want to get into another pushrod vs DOHC war. We know which is better for racing, and better for going to church. We all know the 3800 has its issues(fire), as do the 660s. But becuz you didn't take care of it, or didn't buy one that has been taken care of, it isn't a representative of them all.

[95 3-4]

Great point on another POS dohc 32v engine then. They are still worth a ton of money and cost a ton to maintain, you gotta pay to play, boy it was fast for its day. But like you said no need for a pushrod war cuz the z06 16v pushrod motor smokes the piss out of it

 

I for one am very glad to see Gm kicking azz with their Ls series of pushrods motors in all different types of motor vehicles from 6.0 pickups to 6.0 vettes

[Aaron]

I wouldn't say smoked the piss out of it, but the Z06 was quicker. The fastest times I've seen was a 12.4 for teh Z06(Motor Trend). But MT has also had a Z06 run as slow as a 12.7. The fastest time for a ZR1 was a 12.5 by Car and Driver, and C&D's Z06 ran a 12.5 as well.

[95 3-4]

Yea hookup issues suck, both nice cars