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Intake gaskets or Head gaskets


elumina

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The other day girlfriend and I took a trip in her 99 lumina 3.8L about two hours from home.

No problem on the way there. coolant light came on when we got there. Hasn't come on in two months I replaced the water-pump and thought that was the end of the coolant problem. Before that the coolant light would come on every three weeks or so. I just thought it was the water pump.

 

Anyways we went to leave and come home from our little trip, we weren't even a couple of miles down the road and the coolant light came back on and the temp gauge was at about 220 it usually is around 120.

I pulled over and poured about a gallon and a half of antifreeze into the recovery tank and it sucked it right down. that seemed to help. But we got a little further and the needle kept creeping up and up so I stopped at a gas station and topped it off with another gallon of antifreeze and later on some more. The car was stumbling and running roughly. I think that the gaskets were letting coolant into the cylinders. Eventually we did make it home running hotter than normal temp going up and down the whole time.

 

I'm thinking its just the Upper and Lower Intake Gaskets?

I'm now in the process of replacing the UIG and LIG and I'm wondering if anyone thinks that it could also be the head gaskets as well. No radiator fluid in the oil.

 

When I popped off the upper intake it looked like crap all wet and carbon deposits all over.

If anyone could give me any advice or suggestions or ask some further questions.

 

Also sort of worried about driving with it like that for a long distace.

Thanks for any help

 

E

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its not very common for a 3800 to blow head gaskets. that being said, when I changed the lim gaskets on a 96 regal as a "while i'm at it" replacement during a plenum replacement, they were pretty bad. car had only 110k miles.

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going through that much coolant you should either see:

 

1 - lots of white smoke coming from the exhaust.

2 - super milky oil

3 - a noticeable leak

 

did the upper intake look melted around the EGR stovepipe?

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Not sure didn't think to check the plugs until I was posting. I had to leave for work before I got the Lower Manifold off. My cheapo Star bit wasn't working so I stopped on my way to work and bought a set of Craftsman.

 

What is good and what is bad as far as the plugs are concerned?

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When I stopped at the gas station when I topped of the radiator and it was running horribly for a few seconds it did seem to have lots of white smoke. But I don't know if it was the coolant problem or because of the weather raining and cold.

 

Not sure if the actual intake was melted I did notice alot of crude around the seals for the egr and the collant bypass to the TB.

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Disconnect heater core feed and reroute it back into the engine block where the heater core feeds back into the system. Then run the car by adding coolant and getting the air trapped in the system out. If it no longer overheats, then your heater core was bound up with shit causing an airlock.

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Is it possible to for a head gasket to be blown without coolant in the oil.

 

Yes via burning, it would equal white exhaust.

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Not sure didn't think to check the plugs until I was posting. I had to leave for work before I got the Lower Manifold off. My cheapo Star bit wasn't working so I stopped on my way to work and bought a set of Craftsman.

 

What is good and what is bad as far as the plugs are concerned?

 

IIRC, if the plugs are whitish or brown colored, then the motor is burning coolant.

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Yes there was coolant on top of the Lower Intake Manifold when I pulled off the plenum. Is it supposed to be there because there was alot of it.

I didn't think it was supposed to be that way but I wasn't sure forgot to ask about that one.

 

I will check the plugs tomorrow and check back here as well.

I'm not quite sure where exactly the RTV sealant goes on the LIM. I have to stop at the parts store as well on my way home and get some loctite forgot it earlier.

 

Thanks guys for all the help

 

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Yeah, definitely replace the upper manifold or you'll keep having this problem. At work, I always request the Doorman upper intake kit from O'reilly. Had good luck with it at work and home. Comes with revised manifold and all the gaskets and o-rings.

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Yeah, definitely replace the upper manifold or you'll keep having this problem. At work, I always request the Doorman upper intake kit from O'reilly. Had good luck with it at work and home. Comes with revised manifold and all the gaskets and o-rings.

 

Definitely get the upper intake manifold, as that's probably the source of your problem to begin with. Might as well replace the LIM gaskets too while you're at it. I'd get all my parts from rockauto.com. If you're buying that much stuff, might as well go all out with new spark plugs, wires, injector o-rings, and so forth. Here's the list of parts I purchased when I did this job preventatively (to make sure she didn't have the problem you have now):

 

spark plug wires

spark plugs

Dorman Intake manifold (kit, which comes with all gaskets)

Fel-Pro fuel injector o-rings

Fel-Pro LIM gaskets

serpentine belt (if necessary)

5 quarts oil + filter (I would recommend a Fram ToughGuard)

Thermostat seal

Thermostat gasket

Heater line elbow (right next to the idler pulley)

Heater line elbow o-ring

 

For reference, here's what the LIM gaskets looked like on the car I worked on:

 

http://www.w-body.com/forum/index.php?topic=71766.0

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You definately need to replace the LIM gaskets with the new upper plenum...

 

Of course the other route is to not do them, and good luck when you hydrolock the engine...

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You definately need to replace the LIM gaskets with the new upper plenum...

 

Of course the other route is to not do them, and good luck when you hydrolock the engine...

 

lol no kidding.

 

Do NOT forget to replace that coolant elbow. Its the elbow that goes into the LIM and runs to the heater core behind the firewall. It **will** crack and leak coolant all over the place, guaranteed.

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UPDATE:

Been working at it all day. I was planning on doing the just the upper and lower gaskets but after reading numerous stories and getting more information on the junk original design. Went ahead and got the Intake as well just to be safe. I'm also replacing injector o-rings, plugs, wires, water heater elbows one was broken.

 

I had most of the engine apart yesterday afternoon. But this morning when I pulled the lower intake and got a good look at the LIM gaskets I realize what the problem was. It was pretty bad to say the least. I'll see if I can post some picks. Although the pretty much looked like the ones that xtremerevolution had a link to in his post. Just plain ugly.

 

Spent most of the morning cleaning everything and getting organized. Then went up to O'reilly and bought a Dorman Intake and it came with injector O-rings, and a few other gaskets installed had to put the PCV valve in never seen one like that before.

 

FYI bolt the Throttle body to the manifold before you put on the engine. When I tore down the engine I left the TB support bracket in place to avoid taking the exaust crossover pipe off, saved a lot of extra work. But with the support still attached to the LIM I couldn't bolt up the Throttle body to the UIM so I had to take the UIM back off and then bolt up the TB.

 

And that stupid header elbow was busted off inside of the LIM had a heck of a time getting it out.

 

Got the LIM and UIM back on and tightened up. Going to finish the rest up tomorrow tomorrow. Still need to put on the fuel rail, install new o-rings on injectors, plugs and wires, new radiator hoses, heater elbows and a few others. Seems like so much being replaced but it needed it.

 

Just have to remember to change the oil a couple of times to make sure all of the coolant is out of the motor.

Also going to flush the Radiator when I get a chance.

 

 

 

 

 

 

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Nice dude. Sounds like you're doing exactly what I did. This should ensure that the engine lasts a good long time. I'm hoping you used the felpro gaskets for the LIM.

 

Are you going to port the LIM? While its off, if you have the tools, its definitely worth it. There are a lot of gains to be made from porting an L36 LIM, as they're very horribly machined from factory. Its up to you though.

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The elbow is called a heater bypass elbow or something like that. It connects from the Idler pulley bracket to the LIM.

When I went to the parts store to get it it was in the aisle with the parts that break regularly. The guy up front says "Yeah we sell one of those a week at least."

 

You would think that GM would design something to last a little longer.

 

Yeah, I figured I would just go ahead and do it all since I was at it to help the car last as long as it can. It has almost 200000k on it thats alot for being a 99' probably been needing this for a while. Not really thinking about porting although maybe in the future if the car last long enough. Just trying to get it back together as quick as possible as it is it'll be three days down and thats too long.

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