Head gasket or Intake gasket?

[bogart219]

Hey guys,
Quick question. This might have been addressed before but I can't find it. I got a 94 GPse with the 3.1 . Engine losing coolant, no sign of a visible leak that I can see. The oil cap got that "muddy" look around it. Puffs of white smoke out the tail pipe on occasion. I used my Stant testor and pressure tested the coolant system and the pressure was slowly going down.
The car still runs pretty good. My question is most everyone points to the intake manifold gaskets as the problem as it is common on these engines. How do you know when the Head gasket is leaking? Wouldn't a bad head gasket produce the same symptons? How do know its one and not the other?
or both? Trying to understand all this better.
Thanks!

[GTP Dad]

Check the oil to see if it is clear or muddy. If it looks like mud or chocolate milk then it is an intake manifold gasket. There is a possiblility that the coolant is also getting into an intake port on occasion that is why you are getting the puff of smoke. I would bet that you have a bad intake gasket. If you do a compression check it should give you a good indication of whether or not the head gaskets are bad. If you find one is bad change both. You already have the engine torn down so why waste time and money pulling it apart again to fix the other side. If the head gaskets are bad you must also use new head bolts as they are torque to yield and cannot be used.

One word of caution, if the oil is muddy or brown in color don't drive it, you will ruin the bearings.

[bogart219]

Originally Posted by GTP Dad

Check the oil to see if it is clear or muddy. If it looks like mud or chocolate milk then it is an intake manifold gasket. There is a possiblility that the coolant is also getting into an intake port on occasion that is why you are getting the puff of smoke. I would bet that you have a bad intake gasket. If you do a compression check it should give you a good indication of whether or not the head gaskets are bad. If you find one is bad change both. You already have the engine torn down so why waste time and money pulling it apart again to fix the other side. If the head gaskets are bad you must also use new head bolts as they are torque to yield and cannot be used.

One word of caution, if the oil is muddy or brown in color don't drive it, you will ruin the bearings.

Hey GTP,
Thanks for the response. I would say the oil is a dark brown color, just below the full mark on the dip stick. My kid drives this car. He came to pick me up at the garage I go to, (had work done on my company truck). When he got there he told me the temp gage was up to 260 degress. I had my mechanic pull it in and look at it. He said the radiator was real low on coolant.
He did say that by looking at the oil cap it looked like it was gunked up a little and that my intake gasket was probably going to need replaced. His placed charged about $800 to do it. Thats why I decided to try and do it my self.
So your saying doing a compression test is the only way to verify that the head gasket is leaking? You know when I put my stant testor on it and pumped it up to about 15 lbs, It droped down to about 7 or 8 lbs in about 10 mintues. I couldn't see any leaks or hear any hissing. So would this pressure be leaking out the bad gasket, whether it was the intake or the head gasket?
Also, when you say the head bolts are torque to yield , what does this mean exactly? Thanks for sharing your knowledge, trying to learn!!

[richtazz]

Torque to yield means the bolts are "stretched" during final torque, and cannot be used. If you re-use the old bolts, they will either lose their tension after a while, or snap during re-assembly. If teh car still runs ok, then i'd bet it's just a intake gasket. Fel-Pro has come out with an improved design steel/rubber intake gasket kit, part # MS98003T, that includes the valve cover gaskets. The only other parts you'll need is an EGR mount gasket (can't remember part number, sorry) and the oil-pump drive seal and gasket (o-ring 70800 and gasket 70194). I've done quite a few of these intake jobs, and have it down to about 4 hours. If you have decent mechanical skills, make it a weekend project. I'd say it'll take you about 8 hours the first time.

edit, the MS98003T fits 99-up 3100 VIN-J, the correct part number is MS98004T for the 93-99 VIN-M engines. Sorry for the screw up.

[johnb232323]

98' grande prix gtp. It has a oil leak in the front of engine right about the pipes. I am assuming that this is the intake manifold. I would say I am losing no more than .25qt per 4000 miles. I figured this wasnt much of a concern, should it be? Thanks

[bogart219]

Johnb,
Don't mean to be a prick or anything but you really should start your own thread with a unrelated problem and not highjack another thread. You'll get a better response that way.

[bogart219]

Rich,
Thanks for the info. I will use those numbers you gave me.

[bogart219]

Hey rich,
Is there a difference between the Fel-pro gasket sets #ms98003t and #ms98004t (besides the one digit). Will either one work? thanks.

[johnb232323]

Not a prick at all, new to the forum and I had no intentions on hijacking your thread or offending you. I thought if something related to a problem you were having it was better to post a question under that condition other than creating another thread.

[bogart219]

John, No problem. Hope you can get some help for your problem on this board.
There are a lot of smart people here who are very helpful in sharing their knowlege. There aren't too many things more stressful than when you have limited funds and car problems. Just thinking about having to take my car to the garage and be at their mercy gives me a lot of stress. It could be this or it could be that. You know how that goes. Good luck!

[richtazz]

Bogart, the MS98003t is for the 3100 VIN-J motors(and the 3.4 vin-E), and the MS98004t is for Vin-M motors. The MS98004t is the correct application for your year, i oopsed the part number above, sorry.

[BNaylor]

Brian, here is the general procedure on a compression test and so others can reference it. Hard to tell based on your symptoms but I'm leaning towards LIM gaskets but you never know so it doesn't hurt to run the compression test as suggested just to be sure. With limited funds this may be cheaper, especially if the sniffer test will cost $75 and hopefully helps you make the right decision.

A 3.1L in good shape will show around 125 - 145 psi but you should have nothing less than 100 psi at each cylinder. Good luck!

Engine Compression Test
A compression pressure test of the engine cylinders determines the condition of the rings, the valves, and the head gasket.

Important: Remove the Powertrain Control Module (PCM) and the ignition fuses from the I/P fuse block.

Disable the ignition.
Disable the fuel systems.
Remove the spark plugs from all the cylinders.
Remove the air duct from the throttle body.
Block the throttle plate in the open position.
Measure the engine compression, using the following procedure:
6.1.Firmly install the compression gauge to the spark plug hole.6.2.Have an assistant crank the engine through at least 4 compression strokes in the testing cylinder.6.3.Record the readings on the gauge at each stroke.6.4.Disconnect the gauge.6.5.Repeat the compression test for each cylinder.
Record the compression readings from ail of the cylinders. The lowest reading should not be less than 70 percent of the highest reading.

No cylinder reading should be less than 689 kPa (100 psi)
The following list contains examples of the possible measurements:

When the compression measurement is normal, the compression builds up quickly and evenly to the specified compression on each cylinder.
When the compression is low on the first stroke and tends to build up on the following strokes, but does not reach the normal compression, the piston rings may be the cause.
If the compression improves considerably with the addition of three squirts of oil, the piston rings may be the cause.
When the compression is low on the first stroke and does not build up in the following strokes. the valves may be the cause.
The addition of oil does not affect the compression, the valves may be the cause
When the compression is low on two adjacent cylinders, or coolant is present in the crankcase, the head gasket may be the cause.
Remove the block from the throttle plate.
Install the air duct to the throttle body.
Install the spark plugs.
Install the Powertrain Control Module (PCM) fuse
Install the ignition fuse to the I/P fuse block

[supremesniper]

the exact problem that i have was the car losing power like mine was? also running the car in this condition will it ruin the rings as well as the bearings?

[GTP Dad]

Water in the oil will indeed ruin the bearings and the rings. Water has no lubricating properties and when the oil gets very contaminated there is no lubrication and therefore the engine will fail. The same thing applies if there is fuel in the oil as well. This can be caused by a sticking fuel injector that introduces too much fuel into the cylinders and it gets by the rings and into the oil. Not as common today is it was with the older mechanical fuel pumps but it can happen.

[bogart219]

Thanks guys for all the help and info. Will let you know how I made out in about a week. Thanks again!!