Pontiac Grand Prix Gt problem

[unluckyty]

1998 GT, what would cause a cylinder to fill up with coolant?

Son was driving car when started to run ruff, and then stall, check engine light flickered. Wife said she started car, and white smoke from exhaust, shut it of right away. I get home from work, look into problem, car will not turn over, like hydro locked. Codes were #6 misfire, and maf sensor. Pull plugs, and coolant flowed from #1 cylinder like a faucet, till it emptied out. No sign of coolant in oil.

Blown head gasket, I thought, looks great, intact no problem.
Cracked cylinder wall or head, I don't see any obvious, bore looks good, unless when it gets hot it will appear?

Any ideals on what might of caused this?
Any help appreciated.

Thanks Greg

[Mopar318]

3.4? Most likely its the lower intake gasket.

I had to change the intake gasket on our chevy venture the cyliners were filling with coolant and it was over heating, I went ahead and changed the head gaskets too. GM put that stupid --- coolant in that ate at the gaskets.

[black86glhs]

Upper Plenum and lower intake gaskets will be what you want to change. I am assuming this is a 3.8. The lower intake gaskets are just like the 3.1 and 3.4 V6, except they last a lot longer. They tend to leak on the ends near the intake ports.
Like said above, if it is a 3.1 or 3.4, lower intake gaskets.
Greg, where in Ohio are you? Akron here.

[Mopar318]

Upper Plenum and lower intake gaskets will be what you want to change. I am assuming this is a 3.8. The lower intake gaskets are just like the 3.1 and 3.4 V6, except they last a lot longer. They tend to leak on the ends near the intake ports.
Like said above, if it is a 3.1 or 3.4, lower intake gaskets.
Greg, where in Ohio are you? Akron here.

If I remember right you have to change the upper anyways...to even get to the lower intake. Its been a while though.

[raccoon]

isnt there a class action law suit over this?

[Mopar318]

isnt there a class action law suit over this?

There was a long time ago, but im pretty sure its too late by now.

[black86glhs]

If I remember right you have to change the upper anyways...to even get to the lower intake. Its been a while though.
Sometimes yes. I do just so there are no issues. This is on the 3.1 & 3.4 V6s.
The 3.8 is different.

[TurboSedan]

it might not be the intake gaskets. apparently the L36 has a problem with the upper intake manifold design (plastic) leaking coolant. something to do with the EGR passage? i forget. i believe Dorman makes a replacement UIM that has an air gap between the EGR stovepipe and the plastic. you might be able to replace the L36 plastic UIM with an aluminum one from the newer L26 NA 3800.

-------------------------
Joshua Mitchell
'91 Dodge SPiRiT R/T
'87 Shelby CSX #667
'98 Buick Regal GS

[unluckyty]

Thanks for the quick response, and ideals on cause.
Car had been using a little coolant but not over heating. There was a considerable amount of water between the upper and lower intakes, I could not confirm it was coolant, just nasty brown fluid. The intake gaskets looked ruff in spots, but nothing obvious or blown out. If I remember right, the upper intake gasket was replaced by dealership at around 60,000 miles when we purchased it used.

Mopar318,
It is a 3.8 with 170,000.
Yes I had to remove the upper intake to get to two hidden bolts.

Black86glhs, South of Mansfield, usually go to D42

raccoon, dexcool class action suite went to 7 yrs/150,00 miles

TurboSedan, plastic intake egr problem, car did throw an erg code, but always cleared. Ill take a closer look.

Thanks again, Greg

[black86glhs]

it might not be the intake gaskets. apparently the L36 has a problem with the upper intake manifold design (plastic) leaking coolant. something to do with the EGR passage? i forget. i believe Dorman makes a replacement UIM that has an air gap between the EGR stovepipe and the plastic. you might be able to replace the L36 plastic UIM with an aluminum one from the newer L26 NA 3800.

-------------------------
Joshua Mitchell
'91 Dodge SPiRiT R/T
'87 Shelby CSX #667
'98 Buick Regal GS
Yes Josh is correct. That is why I stated you want to do both the lower gaskets and the upper plenum. Believe me, at 170K miles, you need to do the lower gaskets!
I am out of it now, but I was a GM master tech. I have done all of this to my 98 Intrigue, including head gaskets.(my fault, don't ask why:banghead:) Don't forget to put the seal back in the PCV housing when doing the work. I chased this for 2 weeks on mine. I would get this sqeaking noise after about 30 seconds after starting. The idle was a little high and it would burn oil. Yes, my fault again.:banghead:
On second thought, maybe I shouldn't be the one to give advice.....lol:confused:

[unluckyty]

Upon further inspection, the lower gasket looks to be the problem. Very brittle, and some slightly blown areas.

Thanks again, Greg

[turbovanman]

I would still replace the intake, there not that expensive, :nod:

[black86glhs]

I'm good!!!!!:thumb:
<reaches around and pats myself on the back> :rolleyes:

Just kidding. Glad you found it. If they are brittle, they are bad.

[unluckyty]

Replaced upper/lower intake gaskets, plus head gasket on 1,3,5 side (because #1 was full of coolant, initially thought head gasket. Changed oil/filter, new plugs.

Started car ran ruff, still white smoke, I though was residual from first failure, started to clear. Car could barely get me back home, low on power, an only code was #6 misfire.
Replaced plug wires, ran smoother, but shortly ran very ruff, the eventually would not start.
Fresh oil now has coolant mixed with it. (did not before)

Did compression test:cold
#1 190 #2 182
#3 150 #4 175
#5 179 #6 155

So I have two low cylinders, opposite sides of block, plus the coolant in oil.

Any new thoughts, I really thought the lower intake gasket was the problem.

Thanks, Greg

[unluckyty]

Low cylinder pressure increases with oil added to them.

Greg

[88_pacifica]

rings are probably bad from the "washdown" of the coolant/gas mix when it was still running. They aren't THAT bad. You could 'get by' on it, but it will be far from "clean/efficient." :(

[black86glhs]

I'll bet the intake gaskets slipped out of place while installing the lower intake.

[TurboSedan]

time for an SS M90 kit from ZZP :)

seriously though, hopefully the coolant in the oil is just a mishap from the lower intake gasket job. either that or the plenum is really bad. as for the low compression, i don't know...it does have 170k, but i wouldn't have thought the rings would be a problem. could the contaminated oil itself cause low compression readings?

let us know what you find.

----------------------------
Joshua Mitchell
'91 Dodge SPiRiT R/T
'87 Shelby CSX #667
'98 Buick Regal GS

[unluckyty]

Ok, this is driving me nuts now. #2 intake was full of coolant:(

The gasket is a rigid plastic type, with seals around each port. Doesn't look like it is able to move and still get bolts in. Took it down to the lower intake, everything looks ok, just tightened the bolts more, than last, book calls fo 132"pounds.

Put it back together, changed oil, start it up smoking bad, and barely running.

Smarter now, I just pop the fuel rail and look at the intake ports: #1 is now full of coolant.

Has to be a problem with the gasket, because of the random intake problems.

Greg

[unluckyty]

time for an SS M90 kit from ZZP :)

No kit fo this ride, it is my son's, and I was hoping it would last through high school.

Greg

[black86glhs]

Did you put a new upper plenum on it? Also, look at the lower manifold coolant passage openings. If they are badly pitted, you need to fill them in with JB Weld and sand them down back to the level of the manifold. I think this or the upper plenum is where your problem is.

[unluckyty]

Found the problem, I not the best shade tree mechanic, but there is no way I can screw up those gaskets.

Problem is the plenum, where the egr tube passes through, melted the plastic, allowing the coolant passage to enter the egr plenum area.


Thanks again for the help, Greg

[black86glhs]

Cool, new plenum and your all good.