I have a 2002 Pontiac grand prix. Gt 3800 it's leaking antifreeze on top of the motor. Could u tell me what it would be coming from?

Asked by Apr 02, 2015 at 04:20 PM about the 2002 Pontiac Grand Prix GT

Question type: Car Customization

19 Answers


You must fill it, burp it, then leakdown test. Coolant can leak above? puddle? But it can also be flung there by a belt. Or it can be condensate after a steam. You can use the tester at the parts store to provide controlled pressure when it is cool enough to get at.


Hose connections can leak any where. the clamp? the hose itself? Follow the trace evidence if it shows up after sitting to cool. When it's full but cold, you can squeeze the upper rad. hose with both hands to make it act up.


It's the upper and lower intake manifold gaskets. They're notorious for failure on these cars (3.8L V6). HTH. -Jim

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sure, provided they fail the tests, then you would look for the updated parts to be available and use GMS rather than RTV following the service bulletin, but this girl may need to run the test and understand. we cannot know. Thanks for the help

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Oh, a car like that , of that age and expected mileage could very well be up for a water pump and timing chain before the trans starts slipping too. I hope it gets taken to a tech who can help plan its future.

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These gaskets usually fail between 90,000 and 120,000 miles. Some hold out longer, but not many. You are correct, it needs to be tested. But coolant on top of the engine, is a sure sign of intake gasket failure. HTH. -Jim


Agree with Js. This sounds like leaking intake gaskets and/or the plastic heater hose elbows about to fail which is also very common. The heater hose elbows will leave you stranded if they do fail so you should have them replaced with after market metal ones right away even if they are not failing now. It is just a matter of time until they do so this should be considered preventative maintenance on an older car. (I speak from experience, having learned the hard way a few weeks ago.) A visual inspection should be sufficient to determine if the intake gaskets are leaking. If they are, they are most likely not leaking a great deal... yet. Don't let a repair shop talk you into an expensive repair. First treat your cooling system with Bar's Leak. It is available at any auto parts store and is engineered for exactly this sort of problem and does not hurt your cooling system in any way. It works extremely well and may well solve the problem for the remaining life of your car. I used it on my '03 three years ago and have been driving it ever since. About once a year I have to top up the cooling system, so its not 100% cured, but its enough to keep it driveable and out of the shop. Good luck with your car.

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I am glad this munron has luck with Bars leak.................But any product containing solids and petroleum distillates is a stop gap for a car you are going to sell, and then run and hide. No tech uses bars leak unless he has no time or money or want-to. The solids can completely block passages in radiators and heaters. The petrol based additives can swell the rubber to stop leaks you have already invested goods time and money in, sure, it works for stubborn cumbersome asinine design problem systems. Be wary, try doing it right. it will cost less and you wont have to flush the oily stuff out. Personal experience of watching customers go thru it, and then another family member brings the same car in chasing hard to find problems with the same system. At the end, They are out all that money and mad at one another and the tech. Then someone asks... why didn't they just put the hoses, clamps, and pipe fittings on in the first place??? Out of the mouths of babes ! Let your tech advise before using stop leak, let him do it, let him use the one he believes in. Or fix it right.

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Of course techs don't use it. They make their living repairing the problem. They might use it for exactly the reasons you say they would. No time, or money to do the repair properly. Or perhaps the car is not worth spending the money on, like say an '02 GP might not be. There's a good chance Ashley is not in a position to fix her car properly. Bars Leak will at least keep her on the road. The product itself has been around for years, is proven to work and is approved by GM. It does not plug up or damage the cooling system. The particles break down and are far smaller than the largest particle allowed by GM in a cooling system. Of course if she has the money and the car is worth it it should be fixed properly, but I'm guessing that's not the case.


The black pieces of matter in the kind I have seen are the problem. they are hard and as large as gravel. The petroleum is the other, if it helps? it is with the antifreeze removed, most of the solid matter still in the bottle, and then flushed back out after a little swelling of the rubber at a hose connection where a good clamp still does not seal it. to each his own, but if my little girl writes in, send her to get a free leakdown test and go from there.


I have a roomate who has spent his last money for the month on mechanic in a can without telling me and we just had to replace his engine, then of course his radiator, then comes his heater. he spends hours trying to fill it and does not listen to technicians, but his money is good. his updated gaskets for the real fix were a phone call away. He continues to struggle with it. It seems he has now clogged his new radiator. This is why. and GM approving products can mean a few different things if you think about it. it is a stop gap for a car you plan to hide from.


Yes its a stopgap, but that's been the point right from the start. Sometimes a stopgap is all you need. And sometimes its all you can afford and sometimes its all the project warrants. You don't say what products you are talking about, but they are not Bars Leak. Bars leak is a proven brand that does a certain job without doing any damage. That is why I recommend it by name because there are probably other products out there, some of which work and some of which may not. When people come here looking for advice they need specifics so they don't make a problem worse instead of better.

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I believe the Bar's Leak product that's approved by GM, for these engines, is the tablets only. Not the liquid. The tablets are very similar to the AC Delco tablets you can buy at the dealer. They were originally designed for the Northstar Engines and have been approved for other GM engines as well (the Delco tablets). But here's the catch they are designed to be added to the cooling system as part of routine maintenance. I don't know how well they'll work if the gasket has already failed. I added the Delco tablets to the 3.8 in an '02 Impala that I sold to a coworker back in 2009. He's still driving the car every day with no ill effects. I flushed out the cooling system and replaced the (then) leaking radiator. I crushed up the tablets and added them to the new radiator along with fresh coolant. He's driven the car nearly 70,000 miles since and has had no issues with the cooling system. However, on the other hand, my '00 Grand Prix GT with the 3.8 still has issues with the cooling system from a liquid stop leak product being added to it back in 2010. The intake gaskets had failed and the product was added to do exactly what is being discussed here. The gaskets were replaced but I plan to do a chemical cleaning of the cooling system, and replace the heater core. It's clogged from the stop leak product. The car also heats up especially in the summer. I've flushed the cooling system with plain water which has helped but the root of the problem is, I'm sure, the liquid stop leak product. Once I can get it all out the issues should be solved. HTH. -Jim


Yes, specifically bars leak. because the solids are clumped at the bottom of the bottle as it sits on the shelf, after shaking for 1/2 hour this guy with a 302 came over wanting my advice/ rejected my advice, and used it. a few days later he calls 6 miles away, overheated. needs water pump, thermostat. fills it and comes over. brings pump and 'stat. we get it apart ? It has some electrolytic corrosion on its 'stat housing. We ended all his repairs with head gaskets and clean his old school radiator of the stop leak chunks. He sells the thing, at a profit, then refuses to pay me saying I cracked his block. To me, that's who uses that garbage. A young girl would be better directed to the right test, the trusted shop, and the causal part replaced, the first day. she puts it on step dad's credit card. Bob's your uncle.


The guy with the rad, heater, and new engine, then another new rad? He has a newer jap car. he specifically chose bars leak the first time. that kept him from getting his system full and diagnosing a head gasket, lead to numerous additional new parts replaced because they are non serviceable items, best to use new only. He ignores tech advice and spends twice the hours fooling with it. always has another story about one of the latest stop leaks. he gave up on bars leak and started trying the more expensive ones on payday, then calls me after the money was spent..............Telling a young girl she needs to save money by ignoring learned and tested advice is going to bite somebody, just sayin.


Stop leak, when used by a technician can allow that tech to get away from a problem car where the guy goes on the cheap. but the decision, the brand and the circumstances are controlled by the more experienced person. It's discussed, and the customer even refuses good used parts. His circumstances or his stubbornness takes him where he's headed. Or the design of his car's system means cost of repair exceeds value of vehicle. Then keep an eye on it is signed for by the customer, and responsibility is his own. that ends all BFS stories and no little girls are involved. They always want to know. Why didn't someone tell me, I could have parked it and rode with friends, or had my stud boyfriend do it? But you hear this after the fact. The best advice always ends up agreeing with what your dealer would say. HMMM that's odd, I thought they were painted as the evil people.


So, agreeing with jim about the gasket parts update, the correct sealer, and the TSB procedure, Then inspecting the favorite future fixes and planning a calendar for the car's maintenance is the smart money, for a young girl. she can sell it, park it and wait, call her daddy, whatever. But all she recieved was step by step correct advice. Her daddy or mommy or trusted technician can help her decide. That's where I'm at.......... Her call to the dealer may say GM owns that company, sure, but they would ask to inspect, test, visual, and advise. That's how it was when I worked for GM.


GM may not actually own that product, but use it under controlled conditions and follow directions to the letter. They dont use it on 12 year old,second hand, overheating cars that lack warranty work and service bulletin implementation having been done. They try it during testing of their product while they torture it, and it is only months old. They signed off on it for many reasons and it probably contains a disclaimer. Ask your parts man, do I get a free rad. if this poop blocks it ? will you pay the labor ? Will GM ? on my 12 year old product they closed the dealership for? NO, but you can have a coupon to buy some A/C delco wrenches ! OH, BABY. I suggest the GM dealer whenever this stuff starts to go sideways, because my experience there was the best of the best people, doing their darndest, and getting the thing right at the lowest cost. Most of the crew was Ford guys from across the street. (coughing in hand)


I offer the benefit of that experience to you FOC, and hope all your GM cars win on race day. And can get you to the job after you drop off the trailer. If not? maybe your grass is greener across your street.

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