Thread: 3400 ohv lower intake manifold gasket questions

I am currently gathering parts for a lower intake job on a 04 impala 3.4

I made a trip to a Chevy dealership to get an ac delco lower intake gasket kit, part number 89017559. Apparently, there is an updated, "aluminum", gasket now instead of the plastic design. The problem is, just by looking at the gasket through the packaging, it looks like it's plastic and NOT aluminum; but from a little internet exploring, gm only has 1 gasket for that motor, it sure doesn't look aluminum though (comparing it side by side to the fel-pro design). Also, the gm gasket does NOT come with any rtv, and its a 1 piece gasket (no rubber strips for the sides). So, does this gasket not need any rtv? Maybe its only the 3.8's that have the separate rubber strips?

All that being said, it makes me wonder if I should have just gotten the fel-pro gasket kit from oreilly that comes with pretty much everything and close to the same price as the gm gasket. Except this engine already had the lower intake replaced with the fel-pro kit and is leaking again (~20,000 miles later).

AC Delco gasket:
More Information for ACDELCO 89017559

Fel-Pro gasket:
More Information for FEL-PRO MS98003T



This guy looks interesting too for $90. Comes with everything, including manifold bolts, and valve cover nut grommets for which together are like an extra $30 alone. Although, I have never heard of the brand.
More Information for VICTOR REINZ MIS16259WB

Well thats good to know. I'm still curiouse as to why it is leaking again. Only one way to find out I guess.

The gasket design/brand is still bugging me though. I dont even think ac delco makes the improved aluminum design for this motor. The fel-pro design looks a hell of a lot more like aluminum compared to the gm one.

I'm curiouse if I should replace the manifold bolts as well. Who knows, maybe they slowly backed out from the first LIM job.

I don't think you need to replace your lim bolts, when I did my head gasket "for the 2nd time" I noticed the replacement fel pro plastic llim gasket looked like it was close to failing, around the runners its like a 2 piece design with the inner piece being very flimsy and it disconnected from the rest of the gasket. I didn't look for or find an aluminum replacement. Went with another fel pro kit and 1500 miles in so far so good.

Originally Posted by dsmuts

Did you use loctite on the mainfold bolts? My wifes 01 ga gt had it done at a shop before we were married lasted about 6 months before it leaked again. I changed it myself and it was fine when we sold it last month with 187K miles on it. My lim job lasted 2 years and was still fine.



Also there is no gasket that runs between the 2 heads just gasket maker.

I'm not sure about the loctite as I had another mechanic do the service while I was still on the clock.

Called gm, apparently the only design they make is plastic. So, I'm taking that one back and getting the fel-pro kit, which looks like a much better design anyway.

As far as the manifold bolts go, are those washers (for the upper intake I would assume) necessary? I've only seen one company (VICTOR REINZ through rock auto) that supplies 4 washers with the manifold kit. I would much rather get the stuff from oreilly than deal with shipping though.

For the price difference between brands, the washers alone are $3 for a set 4, haha screw that.

Has anyone ever bought replacement car parts through amazon? Its like $30 cheaper than oreilly for this job, and about $10 cheaper than rock auto after shipping.

Also, do any of you replace the valve cover grommets since your already doing the valve covers (for this awesome 3.4 anyway) ?

This is a very common problem for all 3.1, 3.4 and a little less common but 3.8's.The upgraded set is still going to leak...eventually.but you should get somewhere bettewn 50,000 and 100'000 out of them before it goes again.Make sure all the surfaces are clean! i.e. free of oil and any debris. allow that bead of rtv(1/4 bead on both sides of valley) to set slightly before installing the lower intake back on as this is the most comment failure after replacement.as long as you torque it properly and in the correct sequence you should be good.A few things to look out for when doing this job...when you disconnet the fuel line from the rail be sure to replace the orange o-ring around the feed line as it does tend to leak if you dont and you will be quite angry if you have to take the upperintake back off after your all done to fix that.it is a special o-ring(fuel resistant) and comes with some of those intake gasket kits.if not DOORMAN HELP has them.also look at you timing chain gasket.is it leaking? these can also leak coolant and are much eaiser to do with all the manifold stuff out of the way.but in order to get it off you have to take the oil pan off.its probaly leaking oil to so this will take car of 90% of the places your engine leaks.A WORK OF WARNING!!! when you do the intake gaskets do not start engine untill you change oil! chances are coolant is in the oil pan from the intake.OH and these are known to knock after job is done if its been leaking awhile. why is a good question! but i dont know that one.they just do.also...if you havent done the head gaskets or thermostat yet i would go ahead and get that done while your in there(if you plan on keeping the car=) no point in doing all that work just to have to tear it all apart again when the head gasket blows! Good luck with that if you have any more questions about thuis job feel free to ask

I can understand the money situation. there just things i recomend to save time in the future.im not sure if these are your o-rings though. its hard telling over the computer.ever the original one is orange as was the one i replaced it with. i had to disconect the line at the fuel rail only because the bolt on the drivers side of engine that holds the fuel lines down wouldnt come out.as for the permatex ive always used the rtv black but to each thier own as long as its oil resistant.I think those plastic quick disconnect lines your talking about are to your heater core.Thats fun replacing

Originally Posted by dsmuts

don't pull the lines off the fuel rail and you don't need to replace the o rings then. Orielly's would have copper rtv just ask them where it's at. Also make sure you change the thermostat or you'll regret it if you ever do need to change it.

I was wondering about that too. I don't remember if the thermostat housing has to come off or not on the 3400

On my grandma's gp it knocked for about 15 min after i changed her intake gasket and the cam had scoring marks on it

Did the motor stop knocking after 15 minutes or did it blow after 15 minutes of knocking? Considering you had it torn apart enough to look at the cam.

Originally Posted by pontiacgtp24

I can understand the money situation. there just things i recomend to save time in the future.im not sure if these are your o-rings though. its hard telling over the computer.ever the original one is orange as was the one i replaced it with. i had to disconect the line at the fuel rail only because the bolt on the drivers side of engine that holds the fuel lines down wouldnt come out.as for the permatex ive always used the rtv black but to each thier own as long as its oil resistant.I think those plastic quick disconnect lines your talking about are to your heater core.Thats fun replacing

The fix to this was to put some rtv around the area of the fitting and plug it back into the engine, no replacing of lines haha. Just weird that this line has leaked on 2 different jobs that I've seen, and yet the line was never touched in the entire service.