Grand Prix 3.4 DOHC Problems!!

[flyingbyfast400]

Alright for all you motor heads out there, and for everyone eles with a Grand Prix GTP with the 3.4 DOHC motor in it, or in this case anyone with a 3.4 DOHC motor plzs help me out here.. About 20,000 miles ago I blew a set of intake gaskets.. It just made a mess every where.. Coolant all over the place and so on, and now today on my way home from school I think I just ate up onther set of them damn things... The car did the same thing it did when it blew the last set.. I've done all the work to this car my self.. But there shouldnt be a reason it just tore up this set to with only 20,000 miles on them... Inless there was some old gasket left from when they had been replace right? and as far as I know I did everything right.. If I did do anything wrong it would of blew apart alot sooner. I wrench on Over the road semi trucks so I have a pretty good anount ok skills when it comes to this type of work. What do you guys think? Whats the cause of my motor to blow intake gaskets? I'm at the point I'm just a little lost. The car has never been over heated.. or anything of that sort. Any help would be great as I'm taking it apart this weeked to see what more is wrong with it, and what might of caused this. Thanks for any help at all guys.. by the way this is a 1995 Grand Prix GTP with the 3.4 DOHC motor. Bone stock!!
Victor


http://www.imagestation.com/picture/sraid148/pc2a7d22be0c26b136c44f90ca17f96a6/f6222a87.jpg

[TRX250X]

I've heard of a lot of people having problems with this motor. My wife's Grand Am has the same one and no problems at 52,000 miles so far. We bought it used this past fall and got a 2 year warranty on it because I had a friend who about blew one of these up. I would do some checking around on chevy sites to see if you can find out more about them. I don't know any of the specific problems they had, but I do know that some model years seemed to be a problem.

[flyingbyfast400]

Ya, I've had alot of probelms with this motor.. Its crazy quick and fast.. and I love the flat out get up and go it has. It truly comes to life around 5500 rpms to 8,000 rpms. But what year is your wifes grand am. I think the motor your talking about in the grand am is a bit diff. then the 3.4 I have in my prix. My cousin has a Grand Am GT and it also has the 3.4 motor. I wanna say her car is a 2001? But the 3.4's in these cars are not the same as the 3.4's like mine. and so far she has not had any problems with hers yet. Seems to be holding up greeeat.. But I guess I'm just going to end up selling my car, and get a truck... So at least when the race season comes around I wont have to use my uncles truck every weeked... But I tore into my motor and alot more is wrong with it then what I had 1st thought... :ermm: o welll... for sale as is :devil: Sumone eles can have the beast that is high mantince (sp?) Well good luck to everyone with the 3.4's and if anyone comes into any problems get ahold of me and Ill help everyone out the best I can..
Victor

[K_Fulk]

My wifes Monte Carlo has a 3.4, the mechanic complaines everytime I bring it there. :ermm: i wished it had the 3.8 or the 3.1 instead. We definatley wont get any thing else with a 3.4

[DEAL]

Originally posted by K_Fulk
My wifes Monte Carlo has a 3.4, the mechanic complaines everytime I bring it there. :ermm: i wished it had the 3.8 or the 3.1 instead. We definatley wont get any thing else with a 3.4

I guess those motors are a pain in the *** to work on. I saw a manual on those motors and the timing belt is a big job to get in right.
They aren't bad motors otherwise .. they seem to work pretty well in those cars.

[K_Fulk]

We had the timing belt replaced 2 years ago. The first mechanic we took it to wouldnt do it.

The last thing that went wrong was the main power steering line went bad and the fluid leaked into the alternator and ruined that.

Power wise it isnt very impressive, a 3.1 does just as good of a job. But for any fwd GM car a 3.8 would be my motor of choice.

[flyingbyfast400]

lol... Its not the 1st time I have heard that K_Fluk.. lol They are very very hard motors to work on... and they are packed in so tight. To change plugs on the 3.4 quad cams.. You have to remove the whole upper intake and alot of onther crap. Its a joke. But there are alot of tricks that a person should know befor working on this type of motor. More or less ways to get to stuff that most people dont think off.. But yes For the most part your every Day mechanic will hate this motor.. Gotta love the 3.1's and the 3800's great motors last forever.. Stay away from the 3.4's there quick and fast but not worth it inless you like for it to nickle and dime you to death...

[flyingbyfast400]

I myslef like the 3.4 power.. Great get up and go for a V6 but I'm in the same boat.. I'm willing to do a timing belt but I dont want to. My Car needs one. But I dont wanna thouch it If i dont have to. I've been asking around and no one is willing to thouch it with a 5 foot poll... That and u have to have a tool from gm to hold the cams in place as u change the belts

[K_Fulk]

We ended up having to take it to the stealership. We should have just traded it in for a diffrent car. Its been nothing but problems. But its paid for.

Performance wise I think its slow. But some motors always run better then others.
I used to drive a 86 cutlas ciera with a 3.8 in high school, it would have shown that monte carlo up pretty easy. But then again that car went through 2 transmission in 110k miles.

[flyingbyfast400]

I've put a tranny in my grand prix already... I have also done belts, timing belt is due, plugs,wires,fule pump,tires,struts,egr,ecm, and a list of many more things... like I said it will nickle and dime you to death.. but nothing beats a 3800 S\C motor...

[Scott-300ex]

ok, well its stock so you didn't put a smaller pulley on the blower to get more boost, so it shouldn't be blowing it out with the boost


what you should do, is clean off the intake and head surface with a die grinder, not a cutting wheel, but with the scotch brite pads, cause those do work wonders cleaning off gaskets, i did it when i put a new clutch in my dads quad and i used the scotch brite pad on the anle air grinder and it made it perfect and shiny, so do that to get the old stuff off and get any rough spots off where fluid could be leaking, just don't get any dust into the head and clean the intake before you put that on


also, you should put silicone on the intake and on the head that way, it will give and it will COMPLETELY!!!!!!! seal off everything.


Do this and i bet nothing will ever happen again.

[MIA450R]

Dang, never thought I'd see GP talk here. Come over to www.clubgp.com and ask some of the pre-97 nuts what to try. (MIA450R a.k.a. MIAGTP)

Oh and the older 3.4 DOHC is/was a quick car...but it's no where near as reliable, and wont beat Mustang GTs, Maxima/InfinityG35s and WRXs like a modded '99 S/C 3800 can. Awesome car to mod as much and fast as you want to take it. My GTP is modded more than my quad right now...thats a first. Giddy up.


'99 GTP - DHPv1|3.4|WizCAI|160°|Delco932s|RT DP~UBdel~FFCat|Borla|NL SBs|SLP STBs|KYB|12"Binders|245~45~18"EVO5s|Alpine~RF~MB Quart|V1

[K_Fulk]

Originally posted by flyingbyfast400
I myslef like the 3.4 power.. Great get up and go for a V6

Is your supercharged , my 3.4 isn't.

[oldschool]

YOU HAVE TO REPLACE THE HEAD BOLTS WHEN YOU PULL THEM, THEY ARE ONE TIME USE STRESS BOLTS!!!!

[A4StrokeGuy]

maybe its the 125mph u were doing when it happened:o u need to call nate and have him look at it, since his GTX is in storage he's bored

[flyingbyfast400]

MIA450R your prix is sick looking.. very very nice car. Keep up the good work.. whats all done with your car?
My 3.4 is not s\c... none of the 3.4's are
Like I said I;m not going to worry about fixing it. I'm looking at trucks right now, and I'm going to be starting college in Aug so I need sumthing for the drive from Mich to Ohio and back again many times over. I'm just selling my car how it is. best offer takes it. and yes It was that 125mph or so that did it.. oops o well **** happens..... what can ya do right?
MIA450R You should see my buddies GTX ... Its sick... Ill see what I can come up with for pics. Its crazy nice and from what I'm told crazy fast. I havnt had the chance to ride in it yet. But I hope once all this snow is gone I can go for a ride in it. Its nice to see sum people on here talking about Grand Prixs and also the 3.4's If it wasnt for me racing and needing a truck to haul my quad . I know I would have onther grand prix gtp.. I love them. about one of my all time Fav. cars
Victor

[MIA450R]

Right on...thanks man. Ok get me talking......

Yeah post a pic of his GTX. I nearly ordered my GTP as a GTX way back in 1999 (Pontiac sends it to SLP to have it "converted"). But for the additional cost, all you really get is the ram air hood and GTX badging, mind you, the Grand Prix is SLICK looking with that scooped hood. I would love to get one someday, if only for looks (the ram air effect raises IAT levels since air flows over hot engine--hot air and a S/C dont mix...KNOCK RETARD=timing/power loss).

Instead I put my money into the bolt-on power-makers: 3.4" pulley (soon to be 3.25" with 1.9 rockers & headers), DHP PCM (the wizards of 3800 ECM/PCMs), WizAir cold-air induction, free flow cat, ubend deleted & 3" downpipe added (stock, both are huge restrictions in airflow), and a Borla exhaust (similar to V8 Mustang exhaust note, aside from S/C whine :devious: ), and some other odds and ends performance-wise. I am assuming I am around 275hp, and just over 300ft/lb tq right now.

Handling-wise, the beefier sway bars front and rear, strut tower braces and steamroller 245/45-18Z's all equate to wonderful slight oversteer (stock is understeer with pig-squealing tires), and amazing high speed turning/stability. It's FWD, and I can break the back end loose and control it in a powerslide/turn.

As is, thusfar I've had my GTP at 144mph for a top speed. It will go higher....someday. :devious: With a faulty MAF sensor and with massive wheel spin off the line at New England Dragway, it hit 14.58 in the 1/4mi, at around 96mph...not how a modded GTP should perform. However, after replacing the MAF, the car made a huge jump in power (can you say WHOLLY torque steer now) and is running 'properly'. It just did a 0-60 in around 6.2 seconds (stock size winter tires on--much slip), and I am certain it is well into the 13's in the 1/4mi now, considering the cars I've raced and beaten. (G35 coupe does 1/4mi in mid 13's...and that car has jack for off-line torque) The car easily breaks the tires loose if you lightly mash the go-fast pedal at 20-40mph.....not bad for an automatic.

Ahh...my other true love. Now I just have to fight like hell to keep the f*cking wife away from my 2 toys in this gawd forsaken divorse....... :ermm: :eek2: :eek: :rolleyes: :( :grr: :scary: :mad:

[flyingbyfast400]

You do know your grand prixs... Your list of parts on that car is pretty crazy.. :devil: If i can come across onther grand prix with the 3800 s\c and the price is right I would more then likely get it. When shoping around for Grand Prixs what is stuff I should look out for? as in wear and tear, whats knowin to go wrong with the 3800's s\c motors. Just pretty much what I'm asking is what should I look over befor getting buying onther prix if I do? What type of rims are on your car MIA450R? and Good luck with keeping your toys...
Vic:blah:

[CRE Performance]

If its blowing coolant out when they blow, then it can be a flatness problem on the head side or the intake side or just a case of crappy designed gaskets.

You need to take the intake off and check for straightness on both areas and make sure its within spec. Id say as thick as intake gaskets usually are you can get away with probably .003 warpage. Also, I dont know if you did or not, but make sure you use a known good torque wrench and torque them in the correct sequence, you might even add another 2 ft lbs to the end bolts after properly torquing. If your not using a torque wrench and in the proper sequence, disregard other info in this post cause that is definitely the problem.

Also, get a visual on several different brand of gaskets such as GM, Fel-pro and Detroit and see which one is the beefiest on the coolant passage, buy the ones that are.

[MIA450R]

Originally posted by flyingbyfast400
You do know your grand prixs... Your list of parts on that car is pretty crazy.. :devil: If i can come across onther grand prix with the 3800 s\c and the price is right I would more then likely get it. When shoping around for Grand Prixs what is stuff I should look out for? as in wear and tear, whats knowin to go wrong with the 3800's s\c motors. Just pretty much what I'm asking is what should I look over befor getting buying onther prix if I do? What type of rims are on your car MIA450R? and Good luck with keeping your toys...
Vic:blah:

Thanks man. But trust me, I'm only a mid-level GTP guy...some of the wizards at ClubGP have their S/C 3800's beating Z06 Vettes. 11 & 12 second 1/4mi. No lie. Serious mods can take you to and over 400WHP. My goal is approx 320HP.

3800 SeriesII motor is near bulletproof, BUT, on a 97-03 GTP:

- Check the condition of S/C oil. If jet black (and the worst smell you have EVER smelled), then check for play in the S/C by trying to rotate its pulley back and forth...should be almost none. A worn coupler or other S/C internals will make a pretty loud knock at idle. Coupler is easy to replace for $40. Impeller damage isnt.

- If the GTP ever had all the "typical" bolt on mods (or more) the #1 failure on a GTP (even stock) is the tranny and or the flexplate (cracks). If not maintained WELL--change fluid every 20k. Check the oil. Dark? Full of metal bits? If the car has 75k miles or more and doesnt already have a new tranny, it will need one soon. Once you change that fluid to new, its gonna slip. Mine went at 125k. My friend needed one at 30k. Go figure.

- Another point of failure with all the typical bolt on mods--if the owner had no clue if they were generating knock (timing-retard), then the pistons could have been "chunked". Meaning, repeated detonation could actually blow a piece of a piston off and either bang the hell out of the cylinder or blow out the exhaust valve, possibly damaging the valve seat. Bring a compression tester, unscrew each plug and test. Should be 130-150psi per cyl.

- Hubs and tie rods wear out quick on GTPs with aftermarket wheels and upgraded brakes. (more rotating mass) Had to replace mine before 100k. My wheels are 18x7 Mille Miglia Evo5's BTW. Very heavy, unfortunately.

- Fuel pump resistor goes on almost every GTP. Not a big deal to fix, but when it fails, car starts, runs in ECM "prime" mode, and when it switches to either open or closed loop, it stalls (within 10 seconds of starting). See if its been replaced. If so, it usually gets relocated to top of firewall.

- Belt tensioners wear out. (some tensioners/pulleys are plastic...some are metal) This can make S/C belt slip & lose boost. VERY BAD! Need boost.

- If a Cold Air Induction kit was installed with a cone K&N filter, and the previous owner over-oiled it, the oil wreaks HAVOK on the MAF (mass air flow sensor). This happened to me. The reduction in power due to a damaged or dirty MAF can be almost 40hp...huge. When it fails outright, you will think you accidentally filled your car up with diesel fuel. Not easy to check. Cleaning requires VERY VERY delicate touch. Check ClubGP.

Ok I have a headache. That will get you started. If I think of another important one, I'll post. Otherwise, look out for typical used car stuff.

Good luck. :devious:
mia