1999 pontiac grand am losing coolant

[notamechanic27]

hi fellas and ladies merry christmas ihave a question on ona problem im having with my car. i have a 1999 pontiac grandam se with the 3.4 v6 my low coolant light has been coming on and i have been losing water out of the resevoir isee no visible leak the temp gets up .i have changed the thermostat radiator hoses and antifreeze. the motor starts to shake as if pressure has built up the water then starts to come out of the overflow my question is could it possibly be the water pump. when i first bught the car the dealership had put green antifreeze in the resevoir and i didnt notice until a few days later ive had the radiator rodded out and the system flushed any help would be greatly appreciated. the car has a103000 m onit and the oil and water is not mixing and it is not smoking
i also bled the system

[Hoags]

It could be the water pump, one way to check is to get the car up to temp, before it starts to puke out the over flow, feel the upper and lower rad hoses. If one is hotter than the other then there is some sort of circulation problem. I had the same thing happen on a 77 Olds Cutlass, it was acting the same as your car and it did turn out to be the pump. I put in a remanufactured pump and just my luck it was bad also, not even 50miles on it and the impeller quit spinning on the shaft.

If it is not the water pump then there is some other type of blockage.

Good luck I hope you track down the problem.

Oh yea, welcome to the forum.

[notamechanic27]

thanks for the help i bled the system for about an hour so far it hasnt started backflowing out of the overflow. how hard is it to change the water pump it doesnt look that bad but it looks as if i might have to remove the power steering pump

[xeroinfinity]

Hey notamechanic27 you dont need to remove the power steering pump to get the water pump off. Just hav to remove the belt. Its a really easy job.

About the blockage, you would know because you heater wont work well also if the WP isnt working it would over heat real fast. GA's are known to puke out the overflow. The trick is DONT overfill it, when I hav overfilled my resivour it seems to evacuate the extra and then some. If you had Dex and the green mixed, you might hav some gel leftovers in the cooling syst not letting it cuirculate. Just my

[frugalmcdougal]

You have a intake manafold gasket leak. Very expensive to have a mechanic remove and replace. Moroso auto products make a chemical called CERAMIC SEAL that will usually fis probelm for $15. Can be found at most NAPA and auto parts stores. Be sure to get right product as they make two different ones. One if you want to drain and flush entire system and another for just adding to existing antifreeze.

I suggest you try the one you just add to existing coolant, we have had a 100% sucess rate when using this one.

Just a couple os suggestions that differ from the instructions on the bottle. Add chemical to upper hose that goes into radiator. Adding to resevoir does not let enough of chemical get into engine. Make sure engine has cooled. Remove clamp and pour into hose. You will probably have to drain radiator down a little to make room for new chemical to system. Drain valve is at bottom of radiator. May be easier to siphon coolant level down using small hose from top of radiator where you have just removed hose. (this is where I would do it).

After adding moroso product put hose back on (no need to add coolent if you have just drained a quart or so of coolant). Drive car as usuall for a day and then follow instructions on can for drainage. This will work very well and is the secret-fix used by many new car dealer service department's on their own cars. Cost to replace gasket often over $500. Good luck. Rick

[frugalmcdougal]

To check for intake gasket leak, just look at top of engine where engine and transmission come together. If there is any standing antifreeze you have an intake leak.

[zirb]

Don't put that sealer in unless you have to. Its plugs everything up. Get a Haynes manual and change the intake gaskets. It just sounds like a hard job. Read the book a couple times, go back through this A.F. site and look for intake gaskets. You got alot of good people here who are willing to help out.If I can do it anybody can. Hell I got trouble changing oil my lawnmower. (the blade keeps moving so damn fast to get at the drain plug)
Good luck

[Bob312]

I'm new on here but I moderate 2 other auto and equipment forums and have worked on cars and turf equipment for a total of almost 40 years. One thing I can't agree with is a "quick fix".
Sealants may work well on a fairly new vehicle in a used car lot to get it sold and out the door,but if you own a car with 50 or more K,even with the radiator rodded out,you still got a heater core that may be OEM or at least have quite a few miles on it. The passages in the core are much smaller then in the rad,and if they are partially plugged already,soon after using a sealant,you're going to have a very cold passenger compartment.
Considering how some cores are packed in pretty tight,with half or more of the dash needing to be removed to replace one,you'l find yourself in more trouble then if you had just gone ahead and fixed the leak properly in the first place.

[frugalmcdougal]

Originally Posted by Bob312

I'm new on here but I moderate 2 other auto and equipment forums and have worked on cars and turf equipment for a total of almost 40 years. One thing I can't agree with is a "quick fix".
Sealants may work well on a fairly new vehicle in a used car lot to get it sold and out the door,but if you own a car with 50 or more K,even with the radiator rodded out,you still got a heater core that may be OEM or at least have quite a few miles on it. The passages in the core are much smaller then in the rad,and if they are partially plugged already,soon after using a sealant,you're going to have a very cold passenger compartment.
Considering how some cores are packed in pretty tight,with half or more of the dash needing to be removed to replace one,you'l find yourself in more trouble then if you had just gone ahead and fixed the leak properly in the first place.

We have a car dealership and have had mechanics do this process on over ten gm cars. We have never had a problem. One vehicle has put 20k on it since the sealent was flushed. Moroso is the only chemical that will work. They are a large company and really know what they are doing with this stuff. I know a very large Chevrolet dealership in Flordia that swears by this stuff. The instructions tell you about turning the heat to the off position and clamping the hoses going to the heater core with vice grips so no problems will be involved with the core. Hope this helps.

[Northcat]

I had the same issue with my wife's 00 GA GT 3.4

It somehow lost the coolant. We refilled the coolant...it lost it again. We could find anywhere it was leaking out and it wasn't making oil so I just refilled it again. It again lost the coolant, so I got mad about it, flushed the system, ran straight water in it for a hours, probably 50 miles or so, came home and flushed it again. Refilled it with the normal Green coolant instead of Dex-Cool.

Haven't had the problem since.

I don't know what the problem was, I don't know where the coolant was going but it wasn't going on the floor of the garage or the crank case and it wasn't inside the car...but in any case, since I flushed and refilled with green, I've had no more problems with it.

[Mikey_86326]

I have a 1997 pontiac grand am, and I am losing cooliant. It is not leaking anywhere visable by a hose or anything. It is leaking underneath the car and is getting my floorboard on the back seat wet.

[xeroinfinity]

Welcome to AF Mikey_86326 .

Please do not bring up threads older then 3 months.
As stated in the COMMUNITY GUIDELINES.
It is ok to post a link to an old thread that may pertain to your specific situation.
Start a new thread .

Thankx


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