Automotive help needed

[HayZee518]

This is home related but not home construction. I am about to embark on something I haven't done in years. This is replace the intake manifold gasket on my 3.4 liter GM engine. The last work I did on ANY engine was way back in the 70's on a Buick. My engine experienced maybe four occurences of overheating, twice to red lined and no more. It is now sitting in the driveway waiting for the car doctor. Can anybody give me some tips that I should know about? I know after reading a bunch of stuff that GM has new bolts for the intake manifold. I know the new gasket needs to be beefed up so as not to leak again. I know dexcool is not the coolant of choice but some recommend against using the green coolant. This engine has about 146,000 miles on it. I read about the O ring on the fuel rail. Now to go finding a torque wrench with in-lb rating and crow foot metric tools.

[mrcaptainbob]

Advil. And most likely you already have the shop manual for it. Both my sons are Michigan certified mechanics. I'll pose this issue to them on Tuesday eve and report back with any suggestions.

[HayZee518]

Actually Bob I haven't amanual yet. I been looking at a lot of stuff off the internet from guys that have done the repair. Some say this some say that some even offer things you should have purchased from the parts dealer that you didn't etc. I have a few friends that are willing to loan me their spare car for errands but I don't want to overstay their welcome and where I live is really out in the sticks. My nearest town in any direction is 30 miles.

[HayZee518]

I wouldn't wish this job on ANYONE! It's a real pain in the butt! The alternator is waaayyy in back on the left side facing the engine. the front pivot is there BUT they don't tell you about the two bolts underneath and in back. They're about an inch and a half from the firewall. A 13mm ratchet just about fits. Now I see why the GM techs get the big bucks! The intake manifold bolts have a 10mm hex head and look almost like a 1/4-20 bolt. I used a 1/4 inch ratchet to crack free the bolts and they came off by the fingers the rest of the way. Torqueing specs say tighten to 62 in-lbs. That's not much! Now to clean it up and wait for MONEY!!!

[mrcaptainbob]

Hi, Hayzee. Spoke with my older son today and his cautions are:
*Lots of patience.
*Take lots of pictures. The wiring harness especially needs to be put back EXACTLY as it was. (His emphasis.)
*Loosen bolts in criss cross fashion.
*New intake bolts are not req'd unless corroded. Usually new bolts are for the heads.
*Take a very close look around the head gasket areas as best as you can and look for the tell tale corrosion of small antifreeze leaks. Over heating could cause a head gasket leak as well as an intake one.
*Check spark plugs for being either very clean (indicates steam from anti freeze) or chalky white (also indicator of burning anti freeze).
*Check oil for coolant in it
*Check coolant (bottle and rest of system) for oil in it. Will manifest itself as a brownish, muddy goo.
*At this point consider replacing the t'stat as well as the water pump.
*The job is a PITA. (Son's words).
Sent you a PM.

[HayZee518]

here's some pix I took of what I found after tearing it down.

[WVslottech]

Originally Posted by HayZee518

here's some pix I took of what I found after tearing it down.

Why are you pulling the gasket?? You should have checked the thermostat first...maybe make sure the radiator isn't plugged and flowing normal.....the problem is still going to be there if you go to all the trouble of changing the gasket, and find that a 90 cent thermostat is stuck!!

[HayZee518]

Don't ya think I thought of that first? I changed the water pump and thermostat and the temp still went red lined. I burped the system after adding the anti freeze. THAT's why I pulled the intake manifold. All car forums say that the intake gasket with the dexcool coolant fail after about 89-140,000 miles. The 3.4 liter engine has been around since 1996 and is on Pontiac, Olds, Chevy - anything GM makes.

[WVslottech]

I realize you probably already know this ...but i'll tell you anyway.I have worked on alot of 3.4 liters.I have also found that alot of the problems lie in the heads,because they warp from bad gaskets from the factory similar to the dodge neon.If you have redlined the temperature I would not recommend putting it back together unless you have the cylinder heads flowed and pressure tested,because if you over heated it or went into the red with it you have warped or cracked the heads.You are right though they did come in 90's gm's.I am not trying to be a goof but I did the same thing you are doing 3 times before I junked my 97 grand am.I found that the problem wasn't anything more than a plugged radiator.If you do find that the heads are warped take them and have them milled to get them back to true.Also make sure you get the right thickness gaskets to accomodate the couple thousanths you will remove from the heads.

[HayZee518]

OK, now I'm really confused. when the engine was running and the temp went sky high, I shut down the engine, waited a few ten minutes and the temp dropped. The engine continued to run very smooth as if nothing happened. If the heads were cracked or warped, wouldn't it have run rough or backfired or any miriad of noises? I managed to get it home and during this time period the temp got to the 3/4 mark and didn't red line. When I got home I cracked open the right bleeder and hot steam and "some" fluid came out. I shut it off and waited a few. By this time all the coolant was in the plastic recovery tank. I cracked the radiator cap and all of the coolant got sucked back into the radiator. I used a garden hose and back flushed the radiator and had water coming out the other end. So judging from this, is the radiator still blocked if I get back flow through it?