3.1 intake gaskets - PY Online Forums

lugnutx2 · #1 04-08-2018, 10:17 AM

Oil leak just started, anti freeze leak probably not far behind, so replacing intake gaskets on my 1999 3.1. Should I expect the intake to be warped and need machining? Machine shop says have it planed, but I haven't read of this being a usual issue. Any input appreciated.

1969GiPper · #2 04-08-2018, 10:43 AM

Quote:

Originally Posted by lugnutx2

Oil leak just started, anti freeze leak probably not far behind, so replacing intake gaskets on my 1999 3.1. Should I expect the intake to be warped and need machining? Machine shop says have it planed, but I haven't read of this being a usual issue. Any input appreciated.

Manifold should not be warped so machining not necessary. I suggest you buy the gasket kit GM sells. It comes with the correct gaskets and all the bolts which already have the correct thread locker applied to their threads. Tighten the bolts to the correct torque. Do not overtighten them. If you don’t want to buy the kit from GM, then you need to throughly clean the threads on your old bolts and apply the correct threadlocker to them.

One more very important thing. When reinstalling the push rods and rockers do NOT use an impact gun or air ratchet to tighten the nuts on the rocker stud. Only use a torque wrench. Over tightening the nut CAN cause the pressed in stud to loosen in the head. You won’t even know it until sometime later when you start hearing a ticking type sound. You’ll trace the sound to a loose rocker. You’ll replace the stud and then later on another stud will come loose. And you’ll keep doing this until all the overtightened (loosened) studs have been replaced. The difference between tightening to the correct torque and overtightening to start loosening the stud isn’t much. Trust me many dealer technicians have found this out the hard way.

lugnutx2 · #3 04-08-2018, 04:20 PM

I thought the machine shop was trying to sell a service. I planned on using a fel pro gasket and fel pro bolt kit, but I'll also check on a GM price, thanks for the tip. I'm guessing the new GM kit isn't like the one that originally came on the car?

TedRamAirII · #4 04-08-2018, 08:59 PM

Dont worry about the intake manifold. Do yourself a favor and dont take the rocker studs off at all. There is a tool to push the rocker and release the pushrod, Note the order of the pushrods, 2 different lengths. The lifters can stay pumped up after you put the pushrods back in, so let them set for a while and bleed down, otherwise they can keep the valves open. Or take the lifters out and bleed them down manually. http://www.lislecorp.com/divisions/p...n=1&category=6

lugnutx2 · #5 04-09-2018, 08:07 AM

I ordered the gaskets thru Summit last night, wasn't sure which bolt set to use either ES2226 or ES2225, so just going to clean and re use the originals. Thanks for the link, I'll get that tool this week.

1969GiPper · #6 04-09-2018, 09:37 AM

Quote:

Originally Posted by 1969GiPper

Manifold should not be warped so machining not necessary. I suggest you buy the gasket kit GM sells. It comes with the correct gaskets and all the bolts which already have the correct thread locker applied to their threads. Tighten the bolts to the correct torque. Do not overtighten them. If you don’t want to buy the kit from GM, then you need to throughly clean the threads on your old bolts and apply the correct threadlocker to them.

One more very important thing. When reinstalling the push rods and rockers do NOT use an impact gun or air ratchet to tighten the nuts on the rocker stud. Only use a torque wrench. Over tightening the nut CAN cause the pressed in stud to loosen in the head. You won’t even know it until sometime later when you start hearing a ticking type sound. You’ll trace the sound to a loose rocker. You’ll replace the stud and then later on another stud will come loose. And you’ll keep doing this until all the overtightened (loosened) studs have been replaced. The difference between tightening to the correct torque and overtightening to start loosening the stud isn’t much. Trust me many dealer technicians have found this out the hard way.

Need to correct myself as I got my engines mixed-up. The rocker stud is NOT pressed in the head, it’s threaded in. When you overtighten the rocker nut with an air tool you start to pull the stud threads out of the aluminum head. The damaged threads in the head can be repaired using a insert. And yes there is a tool that eliminates the need to loosen the rocker arm nuts. Definitely worth having if you work on these engines regularly. The one I have is made by Lisle.

1969GiPper · #7 04-09-2018, 09:42 AM

Quote:

Originally Posted by lugnutx2

I ordered the gaskets thru Summit last night, wasn't sure which bolt set to use either ES2226 or ES2225, so just going to clean and re use the originals. Thanks for the link, I'll get that tool this week.

Just make sure you put threadlocker on the bolts or you’ll be doing the job again some day.

lugnutx2 · #8 04-09-2018, 10:56 PM

Quote:

Originally Posted by 1969GiPper

Just make sure you put threadlocker on the bolts or you’ll be doing the job again some day.

Red or blue? I ordered the Lisle push rod remover today, probably the best $18 I spent on this repair. I read somewheres that the rocker studs were pressed in?

1969GiPper · #9 04-10-2018, 09:21 AM

Quote:

Originally Posted by lugnutx2

Red or blue? I ordered the Lisle push rod remover today, probably the best $18 I spent on this repair. I read somewheres that the rocker studs were pressed in?

I believe GM wants the red (high/permanent strength) used. Problem using that is if you ever have to take it apart again good luck. The blue (medium strength) should be good enough. Also make sure you tighten the bolts in the right sequence.

lugnutx2 · #10 05-19-2018, 10:07 PM

Started the job yesterday, finished tonight, worked a little both days.I bought the tool to slip the push rods out, worked great! Fel pro gasket kit, new GM bolts, bypass hoses, thermostat, flush radiator, Gates radiator hoses, fresh oil change. I knew going in it was a big job, mainly because I had no experience with this style of engine and had to remove: coil packs, Power steering pump, alternator, air cleaner housing, washer fluid tank, valve covers and EGR valve and deal with alot of electrical, cooling and vacuum lines. I'm actually looking forward to installing all new gaskets in my old square body that has a 454. Thanks for the tips!