Intake sucking coolant

Ok, I've got problems and no hits off of other threads I've posted to so........... here I'll repost in hopes of response.......................

First, thank you all for the information, second, sadly, I have a Buick L36 engine contained in a 1998 Lumina LTZ vin K. I also feel that my local dealers shop borders on criminal. So much for feelings.

This info will help tremendously in my current project of rehabilitating this car ( my wife's daily driver ) which has not been driven, except into the garage for the past 3+ weeks.......things are getting a little tense around here.

It has 72,000 on it, she had called me from her office, said her low coolant light had come on. I went down & added a quart of H2O to the overflow, started & warmed it. Every thing OK. Left for 3 day trip, get call 2nd night at motel, light came back on & she took it to dealer and was given the following assessment :

leaks aren't bad - need to be fixed
2 minor leaks
waterpump could go anytime
lower intake gasket just starting to leak
level sensor bad = $210
waterpump = $300
lower intake = warp = $1000 not warped = $650

When I picked up the car I figured I would pay for the diagnosis ( bad news ), but, there was no charge or paper work. Obviously the dealer is covering GM's lack of responsibility for poorly engineered components and protecting their interests.

Let's see , car value = $3000 - $1600 m/l if fixed at dealer = park it & I'll fix it.

From what I've read on this subject, here & elsewhere, it seems that I shouldn't have to pull the lower intake manifold at all, but only repair or replace the upper intake manifold, which brings me to the following questions on the options of repair. ( before I rip it apart )

GM# 24508923 lower intake = $224 +/-
GM# 12537197 lower intake gasket = $24 +/-
Fel Pro# MS 95809-1 = $40 +/-

Utilize the GM redesigned ( May 2004 ) upper intake manifold and gasket kits ;

GM# 89017272 upper intake manifold kit includes: upper intake manifold & throttle body mounting studs = $104 +/- ( this supercedes GM# 17113136 = $
GM# 89017554 upper intake gasket kit includes: upper to lower intake manifold gasket, throttle body gasket and PCV draft tube = $28 +/-
GM# 89017274 PCV kit includes: PCV valve, PCV valve cover, O-ring seals and PCV spring = $15 +/-

or

Dorman / OE solutions upper intake manifold # 615-180 = $130 +/-
Fel Pro # MS95812 plenum gasket set = $38 +/-

or

The repair in the above thread. Got any more of the repair kits left? What gaskets did you use for assembly after th EGR tube repair?

This site lists a repair kit, but no retail sales, anyone know where to buy this kit retail? http://www.fmsiinc.com/manifold/default.htm

Thanks again,
Rick R.

I had a similar problem. Before I found this forum I assumed it was a bad head gasket. I stopped tearing down the engine when I removed the lower intake manifold and noticed evidence that the gasket had failed thus allowing coolant into the oil.

Yours sounds as though the intake is forcing the engine to burn a scientifically unverified mixture of fuel, air and anti-freeze.

good luck!

Hi guys:

I have the same problem.
I already blew an engine on a Buick Century.
Had it replaced with a Lumina 3.1 Engine.

Now you fill it up with coolant to the rim. 45 minutes later it starts to overheat. to the point of vapor bubbling into the overflow tank.

Went through 3 different mechanics.

Did several things to the engine without curing the problem.

1. Hot wired the electric fans, full speed, all the time.

2. Changed the water pump.

3. Replaced Radiator side tank that blew because of the excesive pressure.

4 Replaced Upper water hose that blew because of the excessive pressure.

5. Replaced the O-Ring of the Low Coolant sensor on the Radiator, that blew out because of the excessive pressure.

6. Replaced the water hose of the heater.

7. Next alternative was replacing the engine. The car is a Taxi and cannot be out of service very long.

But because of this Forum, I will go tomorrow to the mechanic to replace the intake manifold gaskets.

Thanks a lot

I will post results tomorrow.

yep, intake was my first thought there. Or maybe even head gasket.

Buick Century, your motor sounds like its toasted, if your pay to have it tore down to the intake manifold you may as well have them pull the heads and check the cylinders, sounds like head gaskets or the cylinder sleeves are done.

I started tearing down the Buick L36 3800 series II 3.8L V6. The first thing I noticed was that I could see the orange gasket material between the throttlebody & upper intake (plenum) on the left side of the engine (front). The flange on the plenum is warped & after I got them off,(I had to take them off together because one bolt is hidden behind a bracket off the lower intake manifold & the exhaust pipe) I could see the dirt on the face of the gasket = no seal here, this could be why it runs into the wall at 4100 RPM. No codes in the computer, so , I figured it was sucking air & leaned out so much it choked.

I was prepared to see the plenum all eaten away around the EGR tube, but this wasn't the case. Really can't see for sure where the coolant was leaking at .... though the flange was warped enough to let air past, the coolant passage from the plenum to the throttlebody seal directly under it didn't look like it was leaking (pehaps it does under pressure).

The other area that looked suspect was the bottom side of the upper(plenum) to lower intake gasket near the EGR tube, it looked indented, like it had perhaps melted & pulled away from the lower manifold.

The whole upper manifold (plenum) looks warped to all getout. I pulled the lower manifold to make sure its sealed up. The inside of the upper manifold looks like alligator skin, oily with coolant washing over it to create the visual effect, so I think it is just the plenum & gasket that is leaking, lots of gunk in the lower intake runners & head ports.

LOTS of cleaning to do, & try to get parts tommorrow................ later

Ok, so I fixed the intakes, now I have bubbles in the coolant overflow bottle, just have the engine filled with water. The engine still hits a wall at 4100 rpm. Now that I have practice on the intakes, it should take no time at all to pull the heads & change the gaskets, or is there some other measure i should take before pulling the heads???

oh, man, that sucks. You went as far as the intakes, and didnt go a little more to do the head just incase? Dang, sorry to hear you have to rip it all back apart. Good luck.

The 4100 wall, if this is in neutral that is the pcm fuel cut to save engine damage, normal.