Buick 3.1L Coolant Leak at Intake

[turbojimmy]

Hi all,

I've been losing quite a bit of coolant on my 3.1L Century. I can smell it all the time and can sometimes see steam rolling out from under the hood.

I finally got around to looking at it yesterday and it looks like it's coming out between the intake and the head at the back of the engine but it's really difficult to tell.

So I did a search on the 'net and it seems as if this is a common problem on 3.8L, 3.4L, and 3.1L V6s. Can anyone familiar with these things help me verify this? Like where they typically leak, what the problem is, how can I fix it? The information out there is sketchy.

Thanks,
Jim

 

[The Radius Kid]

Pull the intake and reseal it with new gaskets.Those engines are notorious for that.

 

[Quick Turbo V6]

Yeah those are common. Replace the intake gasket and the dist./oil pump gear drive. o-ring. That o-ring gets hard and leaks oil.

HTH,
Scott

 

[The Radius Kid]

Originally posted by Quick Turbo V6
Yeah those are common. Replace the intake gasket and the dist./oil pump gear drive. o-ring. That o-ring gets hard and leaks oil.

HTH,
Scott

Good point,I forgot about that one.The o-ring should be part of the intake gasket kit.

 

[turbojimmy]

Thanks!

I wasn't sure if I needed to do anything special with the intake itself (like if they're warped or something).

It doesn't look like an awful job, just annoying because it seems to have been a well known problem for a long time.

Thanks again,
Jim

 

[topfuel]

Re: Thanks!

Originally posted by turbojimmy
I wasn't sure if I needed to do anything special with the intake itself (like if they're warped or something).

I heard the heat from the EGR valve is causing damage to the
plastic intake plenums and creating a coolant leak.
Not sure if this applies to your model, but it can't hurt to
check it out.

 

[steve hughes]

I wouldn't wait too long to fix it. They leak to the inside of the motor too. Antifreeze in the oil = new motor.

 

[jdodman]

I just went thru this with my daughters 3800 motor.

If your upper intake manifold is plastic, you have to replace the whole upper intake, as well as the gaskets, o-ring, etc...

I ordered it from GM Direct and it should be here this week.

The plastic intake warps with time, and as mentioned - leaks antifreeze into the motor. My daughters car has identical symptoms to yours.
The whole kit including the intake, gasket and o-ring , was $147.00 at GM Direct. I hesitate to give you the part number as you have a different engine.

I have not changed it yet, so I do not know if it is a large job or not.

 

[turbojimmy]

Originally posted by jdodman
I just went thru this with my daughters 3800 motor.

If your upper intake manifold is plastic, you have to replace the whole upper intake, as well as the gaskets, o-ring, etc...

I ordered it from GM Direct and it should be here this week.

The plastic intake warps with time, and as mentioned - leaks antifreeze into the motor. My daughters car has identical symptoms to yours.
The whole kit including the intake, gasket and o-ring , was $147.00 at GM Direct. I hesitate to give you the part number as you have a different engine.

I have not changed it yet, so I do not know if it is a large job or not.

Thanks for the info. My intake is aluminum so it sounds like it's a little different. I'll slap some gaskets on it and see what happens.

Jim