Thread: Lower intake manifold gasket

I've attached a pic of the pitting. I tried to get a close up but it didn't turn out too well... but you can clearly see it. It's like this the entire length and on both sides - and generally worse around the coolant ports.

Update: I finally got around to getting the car back together.

I decided to get a new intake manifold. Changed all the A/C parts I mentioned a few posts up, put the intake on. Went to put the fuel rail on and noticed an injector that was missing the ring that keep the lower seal on... on inspection I found another one with the ring cracked. So I had to wait a week for the two replacement injectors, as I couldn't find a part to repair the old ones...

Pressure tested the fuel rail first before assembling everything else... all good. No fuel leaks. Put the rest of the car back together and I noticed it runs better now. When I had it all apart, I replaced all hoses and vacuum lines.

The issue with my temperature gauge is gone now (although I think there's still air in the system.) I put a small hole in the thermostat so some coolant (or air) could get by when the thermostat closed. When the car warmed up, no smoke out of the exhaust, so that's good. So the temperature gauge no longer goes to 220, then suddenly fall to 160, then climb to 220, etc. Temp gauge went up to 190 ish, then fell a little when it opened (down to 160-170.) This will probably get better when I get all the air out.

The weird thing I have now is the low coolant light comes on and off. Not blinking fast. Comes on for maybe 10 seconds, then goes off again. Now, as I had the entire cooling system apart (including the hoses to the heater core) I'm sure there's air all over the place. The first few times it did this I shut the car off (it started doing it around 150-160f) and checked the radiator and it was indeed down. So I kept adding fluid a little bit at a time and let it burp down. Do you think air in the system can cause that?

I did check under the car and see no leaks (except for under the thermostat housing when I cracked the bleed screw a couple of times.

I can't stress enough that the car sounds different now. When it's idling it's a lot more smooth.

Maybe I'll try warming the car up a few times over the next few days and see if I can get the air out somehow.

Originally Posted by danf

1997 L67, Supercharged. I don't have a plastic plenum.

Funny, my 1998 L67 sure did. Don't believe me? I may still have a picture of the bearings somewhere....

Just an update.

I've driven the car for almost a month now. The temperature is rock solid now, it doesn't drift up to 230f and back down again, it stays fairly steady unless I'm at a stoplight. It obviously is pressurizing properly now, and I don't see any leaks. Who knows if it was the old LIM gaskets, or any of those old hoses and seals I found along the way. I kind of suspect it was a combination of all those old seals and hoses!

A/C works great too. Of course I replaced the obviously leaking thing (the compressor was leaking like mad.) Time will tell if that was the only thing though. Just in time for over 100 degree weather!

if you have lots of time on your hands, go for it, replace the lim gaskets. Just my 2 cents, I've had oil puddles of oil around or below my uim for 10s of 1000s of miles. It could be on account of a constant leakage from the rocker arm covers (yes and I've gotten perhaps my 30th recall notice last week). Not really sure. 180k on my grand prix. I actually have decent, I suppose, Felpro lim gaskets, head gaskets, plastic and later aluminum uims and a host of other parts I may never actually install. Who knows. Right now I do need to replace my a/c clutch bearing. O/w car is pretty darn good. I have to admit though compared to other Gm cars I've owned, this car has needed a decent amount of upkeep. Water pump, alternator, starter, coolant elbows twice, uppper and lower radiator hoses, 2 radiators, 4 wheel bearings, brake lines (all, including those cylindrical things that name of which escapes me). o2 sensor (need another one). Tires, struts all around. That may be everything. The GMs I used to own were largely, but not entirely, maintenance free all the way up to around 200k.

Originally Posted by skogkatt999

if you have lots of time on your hands, go for it, replace the lim gaskets. Just my 2 cents, I've had oil puddles of oil around or below my uim for 10s of 1000s of miles. It could be on account of a constant leakage from the rocker arm covers (yes and I've gotten perhaps my 30th recall notice last week). Not really sure. 180k on my grand prix. I actually have decent, I suppose, Felpro lim gaskets, head gaskets, plastic and later aluminum uims and a host of other parts I may never actually install. Who knows. Right now I do need to replace my a/c clutch bearing. O/w car is pretty darn good. I have to admit though compared to other Gm cars I've owned, this car has needed a decent amount of upkeep. Water pump, alternator, starter, coolant elbows twice, uppper and lower radiator hoses, 2 radiators, 4 wheel bearings, brake lines (all, including those cylindrical things that name of which escapes me). o2 sensor (need another one). Tires, struts all around. That may be everything. The GMs I used to own were largely, but not entirely, maintenance free all the way up to around 200k.

having my '03 uppers and lowers done now.