Hi guys, havent been on here in a long time, life is busy and I'm getting old well anyways, my wife's 02 Regal has been eating antifreeze (quart per week) so it was time to take the plenum and intake manifold off. I just pulled the plenum and discovered a fair amount of oil sitting on top of the intake manifold. Is that normal? It sure does not seem right. I hope the LIM gaskets are the culprit for the antifreeze problem, I have none in the crankcase so I'm hoping its not head gaskets. How do you tell if the plenum is warped?

How much is a fair amount? Sounds like the the UIM failed around the EGR.

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-Car Guy Carl
"Penelope" - 2003 SLE - 247k Miles
"Sydney" - 2000 Honda S2000 - 98k miles

well, thats hard to describe but, maybe a shot glass down in one pocket where a intake bolt is, and it is near the front where the PVC is

little concerned about this, the Lower intake gasket had two bad areas where the coolant ports are, but do not see why it would be eating coolant. My neighbor who is a pretty good mechanic thought it strange too. Well back together now

I think nos4blood70 may have a good point. The plenum around the EGR valve may have failed. I think it would be a good idea to investigate thourghly before reassembly. - BC

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In Memory of Brad - 1/21/1977 .. 10/23/2013 ...... Aaron - 1977 .. 2017 .....
2017 Hyundai Santa Fe Sport ..... 1992 Bonneville SSE 1SB 170 HP L27 4T60E retired/sold to MattStrike ..... 2005 Bonneville SE 1SC 205 HP L36 4T65E - retired/salvage yard ..... PBCF user 2321

I did not see anything peculiar Its all back together now. What should I have looked for? If it still eats coolant I'll have to pull it off and look closer. Thanks guys

What you described in the LIM is actually normal. In any case, if the UIM has never been replaced it might be time to do so. The three holes by where the throttle body attaches serve as the throttle body coolant loop and the spot where the EGR gasses come back into the intake. The hot EGR gasses eventually make the little pipe hot enough to deteriorate the plastic UIM which lets the coolant from the throttle body coolant loop leak in. I just blocked the loop by JB welding a pair of dimes in the LIM.

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-Car Guy Carl
"Penelope" - 2003 SLE - 247k Miles
"Sydney" - 2000 Honda S2000 - 98k miles

would it be clearly noticeable? If it would, mine looked fine.......I think

that car should have a SC anyways

Every car should have had the blower! Hahahaha

It wouldn't be clearly noticeable but you'd be losing coolant.

_________________
-Car Guy Carl
"Penelope" - 2003 SLE - 247k Miles
"Sydney" - 2000 Honda S2000 - 98k miles

Back to the oil problem, where exactly was the oil? You say on top of the LIM, was it under the plastic plenum or on top by the intake gaskets / intake manifold bolts? If it was by the bolts then the issue there is leaking valve cover gaskets, very common problem.

As for your coolant leak most likely was your intake gaskets or the UIM, very very small chance it is your head gaskets so I wouldn't even worry about that.

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Ryan

2003 Bonneville SSEi - The Black Mirror SOLD!
2002 Bonneville SE - The Mutt Complete 2004 SLE interior, drivetrain, and body harness swap, ECC swap, HUD swap, black GXP wheels, GXP headlights and tinted tails - SOLD
2003 BMW 540i M Sport, 2001 BMW X5 4.4i, 2010 GMC Acadia, 2017 Grand Design Imagine 3150BH
1982 Cutlass Supreme - The fun one

The oil was under the plenum, if you are standing in front of the car, the oil was in the upper left corner of the manifold down in that pocket where the bolt is. Well, I might be pulling the plenum off soon, rats

Forgot to say thanks for the help all

when you weld in the dimes, what does that change as far as the way the engine runs?

It doesn't change anything. The throttle body doesn't get coolant flowing through it.

_________________
-Car Guy Carl
"Penelope" - 2003 SLE - 247k Miles
"Sydney" - 2000 Honda S2000 - 98k miles

And that doesn't matter?

It's supposed to prevent the TB from icing over... LOL Okay GM.

Mine have been blocked for just over 2 years, never had issues with it even on the coldest of days. The Grand Prix guys do it too. I got the idea from a certain wise old 3800 guru named Billboost.

You can also drill and tap the coolant ports if you feel like spending more than 20 cents. Hahaha!

_________________
-Car Guy Carl
"Penelope" - 2003 SLE - 247k Miles
"Sydney" - 2000 Honda S2000 - 98k miles

That's what the youngest son did for me. - BC

_________________
In Memory of Brad - 1/21/1977 .. 10/23/2013 ...... Aaron - 1977 .. 2017 .....
2017 Hyundai Santa Fe Sport ..... 1992 Bonneville SSE 1SB 170 HP L27 4T60E retired/sold to MattStrike ..... 2005 Bonneville SE 1SC 205 HP L36 4T65E - retired/salvage yard ..... PBCF user 2321

The UIM can look fine in that area, but any pinholes or anything can lose a lot of coolant. Did you replace the UIM, or just inspect it and re-install the old one? Even the plastic being soft is enough for it to leak. A sharp pick or nail should be used to see if you can poke through the EGR pass-through area.

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Bye Bye:

RIP sandrock

I replaced the UIM gasket, I bought the whole kit from Rockauto a few years ago when we bought the car, figured it would need changed sometime. Well it's not eating coolant and the temp gauge stays steady, which it wasn't before. Hope I make it for a while or it will need changing when its minus 20 this winter