How to fix and replace an intake manifold gasket on a GM 3400 Liter engine. These engines were put in a lot of various GM cars and suv’s of the late 90’s and…
How to fix and replace an intake manifold gasket on a GM 3400 Liter engine. These engines were put in a lot of various GM cars and suv’s of the late 90’s and…
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1. Tighten the vertical lower intake manifold bolts (1) to 7N·m (62 lb in).
2. Tighten the diagonal lower intake manifold bolts (2) to 7N·m(62 lb in).
3. Tighten the vertical lower intake manifold bolts (1) to 13N·m(115 lb in).
4. Tighten the diagonal lower intake manifold bolts (2) to 25N·m(18 lb ft).
But I just tightened them up by hand being careful not to over torque them again on both the upper and lower. The upper, just enough to snug them up.
VT247
Did you torque the intake screws
it’s not debatable, Dex-cool has been around for a long time and is pretty much the same thing many imports have used for years.any engine that has aluminum heads mounted to a cast-iron engine block is prone to head gasket failure. Whoever told you it was a kind of cool that you run was sadly mistaken. I have been an ASE certified Master technician for more than 25 years. I’m not pulling this out of my ass. Stop believing it’s the coolant. It’s just a fact that aluminum expands/contracts more.
Well, that’s debatable. Thought that the pink Dex cool is more acidic. GM head gaskets of that era weren’t designed to handle the new type of coolant. Either way, the head gasket GM put in the 3400’s weren’t of good quality. Always replaced my head gaskets with the severe duty Fel Pro gaskets and haven’t had a problem with one since.
VT247
Head gaskets dont fail because of Dex-cool. Thats ridiculous.They fail due to the aluminum head against a cast iron block. The chemical reactions and the different temp expansion and contraction between the to is what causes most head gasket failure, NOT THE TYPE OF COOLANT.
I’d highly recommend doing the head gaskets on it while your in there. They go bad about the same time the intake manifold does. Not fun having to tear into it all over again. Got a video up on doing that fix too.
VT247
got to do this on my Impala, quotes $550 by a good mechanic, deciding if I want to spend a weekend busting knuckles to save $200. Nice vid btw
Yeah, I like the yellow stuff best. For the “wet” lower manifold gaskets, on my 2003 Malibu 3.1 and other makes, models & yrs., there was a class action settlement where GM got off easy and victims got a raw deal.
The yellow is even better, but flushing was a pain in my 2003 Malibu 3.1. Staying withe the red Dex-cool would have been fine with my new metal gasket.
I switched to the green antifreeze. Done 2 head gasket jobs on these Azteks. It’s a long process to do, but can be done in a couple days.
VT247
One more thing, the best way to avoid this is, remember the coolant flush that had to be done around 60,000 miles? Have it done at 60,000 miles. If the service writer says it does not need to be done, tell him bullshit and either they do it or tell them they will be paying for the intake job that’s coming up at 90,000 to 100,000 miles!!!
I used to work at a GM service center and I do not care what anyone says. This should be a recall item!!!! This repair should not be happening on any vehicle. It happens because THIS DEXCOOL COOLANT TURNS INTO A GEL After 90000 miles and blocks up the intake. It is ridiculous!!! This should be recall item!!! The bad part is once its done, you never have to do it again!!!
Actually thats cheap. I used to see these priced at a minimum $1000.00 TO $1500.00. Take that $800!!!!!
If you are planning on keeping the car for any length of time, have them go ahead and do the head gaskets. It’s not that much more work and they will eventually fail because of the Dex-Cool antifreeze. $800 sounds right to do the head gasket AND intake gasket. Check Craigslist in your area, there are mechanics that can do the job at a very reasonable rate.
VT247
I need to have this done on my chevy monte carlo . they want to charge me 800 bucks wit the parts is that about the right price ….?? this video has helped me to understand what its all about. thanks ……..
Cool, glad it’s back together and running good now.
VT247
yeah same thing is happening every time i turn it on.(chemicals burning off). And the smoke was coming from exhaust pipe. Welded it and no more smoke. Thank you for your fast responses and tutorial videos. It helped me ALOT with rebuild.
If it’s cold outside it might be condensation coming out. Hate to say this, but hopefully it’s not the head gaskets as they are known to go bad too. Does the exhaust have any funny smell like it being sweet? A sweet smell would indicate burning antifreeze (i.e. head gasket). If it’s not coming from the exhaust, it’s probably just the chemicals (oil or antifreeze) being burnt off from you doing the intake manifold. My Aztek did the same thing after my fix. Burnt off fumes for a while.
VT247
yeah i found that sucker under all that pile of crap lol. Van wouldnt start with out that sucker. Have another question. When i was removing the exhaust pipe, the nuts wouldnt come off. So i cut it. it turns on and everything but after a while white smoke start coming out front in engine compartment. Is smoke coming from exhaust pipe since i havent welded it back together? i ve been told that the engine is no good if smoke comes out, burning too much oil. will welding it back together fix it?
All the plug ins for the coil pack have wires coming in. I believe the one your referring to is the crank trigger sensor. It does not come off the main wiring loom. It’s an individual wire plug in.
VT247
On the right side of coil there are 2 connection entries. there was 1 connection by itself coming out of the all wiring that fit on one entry; another one behind it. cant find anything that goes/fits there. is it just an extra entry. thanks
Hopefully you didn’t mix match the pushrods. They are different lengths. The bolts holding on the rocker arms should be fully seated. You might get by just taking off the valve covers and not have to remove the intake. The back valve cover is kind of a pain to get off there. Having to remove the alternator bracket and all. Let me know if you need any further assistance. : D
VT247
shit I just saw your post when I already had the whole thing together I tighted without and specific torque and now it doesnt wanna turn on you think it may be the problem do I have open the whole thing again or just the valve covers and adjust it to the proper torque from there
Torque the rocker arms down to 50 foot pounds.
VT247
how much do the pushing rods need to be tighted torque/lb or just an idea please respond ASAP Im working on this right now and dont have a clue thank you
It’s not that much more work to go ahead and do. I certainly recommend doing the head gasket as well since your already almost there. I have a video on how to do the head gasket fix on my channel for this 3400 engine. There is a part 1 disassemble. Part 2 it goes back together. : )
VT247
How much further do I have to go thru to replace the head gasket talking like how much time and parts to take out thanks great video by the way
You probably should replace the thermostat. I’d recommend drilling one two small holes through it. Will allow air to bleed out. If you tear the EGR gasket, then replace it. Didn’t have to replace mine. Don’t need new lower intake bolts. I just re used the old ones. Might consider replacing the head gaskets while your in there. I’m replacing mine on a Black Aztek right now. Got the tear down video online. Putting together the reassembly as it goes back in.
VT247
a few more things need to be clear before i start this weekend.
1. do I have to replace thermostat?
2. do I have to replace the EGR gasket
3, do I need to use new lower intake manifold bolts
thanks.
Should consider going ahead and replacing the head gaskets too. But to answer your question, just loosen up the rocker arms and set the push rods aside and the intake manifold gasket lifts out. Make sure you know which push rods go to which lifter, they are different lengths. Torque the rocker arms back to 50 pounds when your ready to re assemble.
VT247
this video is so informative. wondering if you have to take off the rock arms and push rods? thanks
The power steering pump wasn’t that hard. Trying to get a slightly bent EGR tube back on though was a royal pain though. The valve covers came off fairly easy too. More room than what it looks like to get to things in the back.
VT247
Your power steering pump would of slid out easier without taking out all that stuff, if you woulda just took your fuel rail/injectors off first…. lol maybe next time.
Haha definitely… there was no gunk at all inside my valve covers. I dont know how you got that power steering pump off before taking the fuel rail off(must be houdini)… lol your motor is set far back which prolly made it hard to get to the back valve cover haha nice vid though…
Took me about 7-8 hours. But I was in no hurry. I took everything off and cleaned it out best I could. Sounds like you got lucky with it leaking outside the engine instead of inside. : )
VT247