Coolant???? Going where????

Hey guys, me again. As some of you know, my g/f bought a 2002 Grand Prix SE over the summer. When it came home I checked everything as usual and found brown sledge in the radiator and it was very low. So i flushed it and filled it and replaced the cap. The thing still is losing an above average amount of coolant, and the odd thing is, the resiviore stays full, or at the full mark, but the level in the radiator seems to get lower and lower every time. There is no air left over in the system from when I bled it, and no evidence of leaks on the driveway or into the crankcase. Her low coolant light came on the other day, so now its getting me worried as a car "in theory" should never loose that much coolant between august and now. We have even quite frequently been filling it assuming the air in the radiator has just worked itself out of the system (or so I've been telling her to not get her worried).

My next step was going to be to borrow a pressure tester and pressureize the system to 20psi and find the leak. However no one around here has the coolant pressure tester except for Checkers about two towns over, and every time I have called, they said "its out already".

To verify the problem isnt a cracked head/block or blown head gaslet, I was going to do a compression test on each cylinder and watch the numbers to see if they drop, and listen for air escaping the radiator cap. However if the problem is a cracked head, it may not leak unless warm.

Any ideas how i should go about this? How likely is it for a grand prix to crack a head or block? What do you guy's think I should expect? Btw, 2002 GP se 3100 V6 with 69,xxx miles to date.

Thank you for the valuable insight. If nothing else, I will thouroughly check it out, and get back to all of you soon.

First of all 20 psi is to much test pressure stay at 15-16 psi, second if you suspect a head or head gasket they make test kits to check for exhaust gasses in the coolant. Make sure there is no gunk in the hose from the coolant jar to the rad, test the cap also, it may not be sealing and air is pulled into the system instead of coolant, hence the jar doesn't drop, just the radiator. This sludge can be very difficult to flush without using a strong solvent first. It is possible that this stuff is blocking some passages and as the coolant finally works it way around it the level drops. A compression test is almost useless to find a bad head or gasket, maybe a leak down test, then you could hear air escaping in the engine.

damn, i suppose your right. I just want to figue it out. I dont have a leakdown tester, or a decent compression tester to hook up to the air. I think im going to start with a pressure test of the radiator and try to find where it is going. I almost suspect combustion gasses coming it, because the level in the overflow goes up when warm, and drops when cold, but somewoh it doesnt seem to fill the whole radiator. I really dont know. The cap was also replaced. If i pull the sparkplugs out, will there be any telltale signs? Like completly white or something? thanks

Well if coolant is getting into the cylinders there will be signs on the plug or plugs, but without the right equipment and technique here ,you are guessing at best and this type of problem requires thorough analysis before doing anything.

Any ideas how i should go about this? How likely is it for a grand prix to crack a head or block? What do you guy's think I should expect? Btw, 2002 GP se 3100 V6 with 69,xxx miles to date.


Cracked block or cylinder heads possible but unlikely. Sounds more like the classic lower intake manifold gaskets to me. GM revised the gaskets and established new LIM bolt torqueing applicable to the 3100 SFI Vin "J". See below.



Engine Oil or Coolant Leak (Install New Intake
Manifold Gasket) # 03-06-01-010B - (10/24/2003)


Engine Oil or Coolant Leak (Install New Intake Manifold Gasket)

2000-2003 Buick Century

2002-2003 Buick Rendezvous

1996 Chevrolet Lumina APV

1997-2003 Chevrolet Venture

1999-2001 Chevrolet Lumina

1999-2003 Chevrolet Malibu, Monte Carlo

2000-2003 Chevrolet Impala

1996-2003 Oldsmobile Silhouette

1999 Oldsmobile Cutlass

1999-2003 Oldsmobile Alero

1996-1999 Pontiac Trans Sport

1999-2003 Pontiac Grand Am, Montana

2000-2003 Pontiac Grand Prix

2001-2003 Pontiac Aztek

with 3.1L or 3.4L V-6 Engine (VINs J, E - RPOs LG8, LA1)

Condition

Some owners may comment on an apparent oil or coolant leak. Additionally, the comments may range from spots on the driveway to having to add fluids.

Cause

Intake manifold may be leaking allowing coolant, oil or both to leak from the engine.

Correction

Install a new design intake manifold gasket. The material used in the gasket has been changed in order to improve the sealing qualities of the gasket. When replacing the gasket, the intake manifold bolts must also be replaced and torqued to a revised specification. The new bolts will come with a pre-applied threadlocker on them.

Notice

An oil leak may result if the vertical bolts are not tightened before the diagonal bolts.


Diagonal bolts may require a crows foot to tighten.

Tighten

1. Tighten the vertical lower intake manifold bolts (1) to 7 N.m (62 lb in).

2. Tighten the diagonal lower intake manifold bolts (2) to 7 N.m (62 lb in).

3. Tighten the vertical lower intake manifold bolts (1) to 13 N.m (115 lb in).

4. Tighten the diagonal lower intake manifold bolts (2) to 25 N.m (18 lb ft).

thanks everyone for the great info. I have not yet been able to aquire a cooling system pressure tester, so I havn't done anything. Soon hopefully will make progress on this one. I'll keep the updates coming.

Better check the oil for water if you have a 3.1. Also check the oil filler cap for water condinsation. 3.1's are bad about blowing the intake manifold gasket and dumping the enite contents of the radiator into the block. When that happens it is a tow home or to the mechanic. Best to fix it ASAP.

One other tale tale sign is noisy lifters.

I learned the hard way.

Mike

Today i acquired a coolant pressure tester, pumped it up to 16lbs, and found the leak. Its coming out of the Intake Gasket on the back head. Looks like the car is getting an intake gasked job sometime soon.

My next question is someone on the forums not long ago mentioned that there is a felpro replacement that is metel, and this person also knew a part number. If anyone knows the correct part number for this felpro metel replacement intake gasket for a 3100sfi in a 2002 pontiac grand prix, that would be great. Thanks!!!!!

If anyone knows the correct part number for this felpro metel replacement intake gasket for a 3100sfi in a 2002 pontiac grand prix, that would be great. Thanks!!!!!

Fel-Pro MS98003t

Good luck and let us know how it turns out.

thanks buddy, I;ll have my girl take pictures along the way and I'll post a few. She is isnt going to beileve that her car has to be ripped down that far, but I know she's relieved we found the leak and that its a relatively easy fix.

hey, someone else mentioned that the heater hose off of the lower intake has a quick connect fitting that should get changed. Or am i thinking of a different motor. how do i go about this? Any other precautions I should take? I plan on also putting a new thermostat in it whil im there.

I just went through this; I was going to try to reuse this, but when I went to put it back together, I realized that all the o-rings that are part of it were junk, so I just went and bought the entire nipple. Amazingly, the stocker didn't break while removing it.

Ok, here is the update. On December 31's, my friend and I tore the grand prix down. Started at 10am and was all done bleeding the system at about 7pm. Was sort of a big job, but not being up at school, the tools i needed were not readily available. I also somehow chose to do it on the snowiest day of the year. Snowed a good 6 inches that day. I am so relieved to have this job done though. Below are a few pictures, and in the second one you all can see the distributor dummy shaft some people have been asking about recently.

http://img444.imageshack.us/img444/1843/1ln3.jpg
This is where it us leaking. Once the plastic gasket was off, I found out that it had split along one side of the rubber and plastic and all the way down, coolant followed the crack, and where it hit the RTV silicon valley gasket, half went into the crankcase, and half leaked externally.

http://img388.imageshack.us/img388/3719/2ps4.jpg
Here is a picture with the lower intake manifold off. For those of you that have not done this before, all the push rods had to come out also, and all have to be kept in the exact same order for wear reasons and also because the intakes and exhausts are different lengths. I wiped down all the pushrods, and cleaned all gasket surfaces up to a near mirror finish.

http://img165.imageshack.us/img165/9329/3mg6.jpg
Here is where it all starts going back together. We used the metel felpro replacement as mentioned above. Thats pretty much it with this picture.

http://img65.imageshack.us/img65/2236/4uf8.jpg
And here it is all back together. We had no bolts or brackets left over, and went relatively as expected. When everything was all back together, While bleeding the system, I snapped off the little bleeder just above the waterpump. Luckily it was as I was closing it, so its not leaking, so if anyone has any ideas as to how I'm going to find one of these short of a junkyard, that would be awesome.

Also on a drive the next day, I was being relatively hard on the car to just make sure nothing was going to happen, and to get the temp up. It ran perfectly untill I took it on the freeway. On the on ramp it started missfiring. Rythmic misfires, only under harder accelleration. Once up to cruising speed it was fine. Also when the tranny is in overdrive and the car has to climb a slight slope, it will sometimes miss. So, assuming a vacuum leak, I picked up some carb cleaner, and started dousing the injector ports listening for idle increases. Nothing was found. I was just about ready to call it quits for the day when it was idling in my driveway, and out of nowhere it misfires, and I heard a SNAP. Same snap you hear when a plug wire archs to ground. Feeling relieved, I grabbed a spray bottle of water, and doused all ignition components, but it didnt help. Remembering back to 9th grade chemestry with Mr. Kinsly (Ben Stein in the flesh), and how a salt water solution could conduct electricty very well. I put some salt in the water, and sprayed the ignition components again. As it was running, I heard SNAP, and again, SNAP SNAP. So i continued to spray, and watched for the spark. I found it was the plug boot for plug number 4 was allowing the spark to arch right through. After i found this, I realized it made perfect sence. Under accelleration, the pressures inside the combustion chamber are higher, so it requires more spark voltage to jump the gap, so rather than do this, it would arch straight throught the boot causing the missfire. For a temporary fix, i pulled the plug out and regapped it (even though it is a platinum plug), the platinum tips were long gone anyways. This seemed to fix the problem, and as soon as Natalie can afford it, We'll put some new plugs and wires in it.

Thats my project, but all in all, a job well done..... So far. The radiator isnt loosing coolant, and the oil looks good. Again, thanks all for the help God Bless!!!!

Any questions comments or suggestions, please post them......