: Small coolant leak

01-20-05, 02:00 AM
For the past few days, I have noticed a small puddle of coolant after my wife leaves with the car. I cannot see any steam nor smell any coolant when the car is hot. This may sound stupid, but I think the leak happens when the car is cold (after it is started) and then when it gets hot, it "seals itself". The puddle is under the left (driver's) side near the front of the motor. I can see what may be evidence of a leak near where the top radiator hose connects to the block. Not the hose itself, but the "bracket" it attaches to. Any suggestions? Should I try Bars Leak?

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01-20-05, 08:20 AM
i have a similiar problem on my 94 it seems to only leak when cold until the thermostat opens, and its leaks where the hoses connect to the water pump housing but only until it gets close to operating temp. i noticed a slight smell and can see cruddy residue on the connections and a little bit of coolant on the abs pump too, i have just been to lazy to go get the coolant supplement and remove the houses and clean the connections since the hoses dont feel bad. hope this may help ya the coolant very slowly goin down in the surge tank bothered he hell outta me till i found the leak!!!

if i were you thats where i would check first get an inspection mirror and look at all the hose connections and see if there is a significant amount of residue o fresh coolant on any doesnt take very long to do and might save ya a lot of cash, i know the lower radiator hose from cadillac is 40 bucks!!!

01-20-05, 02:07 PM
If the 96 has never had the coolant drained and refreshed then it is overdue for fresh coolant.....

In the mean time, get the coolant supplement or the BarsLeaks "golden seal" powder and install it into the system. It is perfect for the kind of seepage you are describing. Just remember to pop one of the radiator hoses off when it is cold to install the sealer into the hose, NOT into the pressurized surge tank. You do NOT want to put it into the surge tank as it will not get distributed correctly.

It would pay to take the time to inspect and diagnose the leak. If it is a water pump seal starting to go the supplement may stem the leak momentarily but it will not fix a water pump seal leak. If it is a hose with a hole in it or something the supplement/sealer may stop the leak but masking a potential and immenant catostrophic cooling system failure would be misleading.

Chances are the leak is happening all the time but the dripping coolant is just blown off when the car is moving and you then see the drip when it is parked. The cooling system will retain a residual pressure for 20 or 30 minutes after parking (or even longer) so chances are that is when it is leaking.

To make it easier to diagnose, rent/borrow/buy a cooling system pressure tester that installs at the pressure cap fitting and allows you to pump the system up to 15 PSI while it is cold. That way the leak will happen while under pressure and cold enough to probe around the engine to pinpoint the leak source.

The coolant supplement/sealer is an excellent product that works extremely well just don't let it mask a potential catostrophic impending failure by using it to stop the leak without insspecting the system carefully.

01-20-05, 05:45 PM
My money is on the water pump gasket. The same thing happened to me, when I bought my car with 50,000 miles on it. I changed the gasket (and thermostat, and housing), and it hasn't leaked a drop since. My puddle of coolant was appearing just inside of, and a little in front of, the left front tire. The gasket is super cheap, and it doesn't take long to change. Good luck


01-20-05, 09:04 PM
FWIW, I also have a small leak. Never a drop on the garage floor but when I pull in the garage I can smell coolant. If I move the intake duct out of the way and get my fingers under the lower edge of the water pump cover I will get some coolant on my finger tips. I have a new cover gasket sitting on my work bench waiting for spring. In my caes it is very, very slow seepage. You might try looking there.

01-22-05, 08:50 AM
DO NOT USE BARS LEAKS! The problem you describe is one of several common problems.

1- the water pump
2- the water pump cover gasket ( gm has come up with a new design)
3- coolant corrosion on the hose neck ( looks like battery acid oozing around the hose)
4- the worst..the water pump housing gaskets very hard to change

The cover gasket ( #2 ) is very well known to cause this "only leaks over night issue", the coolant corrosion is also known for this. The old design gasket is blue or red, the new gasket is black.

01-22-05, 01:56 PM
I have the exact same little leak....I just haven't been able to pin point it.....the coolant is getting leaked onto the crossmember just behind the radiator and drips from there. There is no evidence of coolant on the core support in front of the radiator, but behind it on the driver's side appears to be wet. I just can't get a good look at the area to tell for sure because it is such a tight area right there.:banghead: P.S. Mine is a '97 STS.

01-22-05, 02:10 PM
I would do a careful visual inspection to try and determine where the leak is actually coming from. I have had two radiator hoses, on different cars, start leaking from small "scratches" that must have been done by the parts house opening their delivery packages with a utility knife. They only leaked when the engine was operating above 2500 RPM or so.

Get a screwdriver and tighten all of the hose clamps that you can find.

Don't forget the two small silicone heater hoses, just to the right (toward the firewall) and below the throttle body. They are hard to see, but it is worth the effort to tighten the (4)clamps.

If you haven't changed your coolant yet, I would follow bbobynski's advice on that.


01-23-05, 03:53 PM
Some good points made here. :yup: For my experience, I coughed up a water pump @ 65K mi. I too had a small puddle on the garage floor overnight. It was very hard to see, laying under the car with a good, strong flashlight. The coolant runs down across several parts, causes build-up and disguises itself as a leak somewhere else.

Cooling system sealer such as Bar's leak is, in my opinion, only to be used in an emergency to get you to the next town. If it will plug a hole, it will also plug radiator tubes the first time air bubbles get in there and cause the additive to harden. Which they will if you are doing cooling system repairs. If there is a leak somewhere, something is wrong. Find it and fix it. Stopping up the hole temporarily will only buy you a little time. It will ultimately fail later on, and probably leave you walking! *lol*

01-23-05, 10:05 PM
If there is seepage from a porosity or an imperfection at the water crossover gaskets the coolant supplement will seal up the leak fine.

I agree that if the coolant supplement is used to cover up some impending serious problem that it could stem the leak and then when it fails catostrophically it is inconvenient. But...if the system is in good shape and there is a minor leak at a gasket surface or from a casting porosity or somthing like that the coolant supplement or the recommended BarsLeaks product works fine. The coolant supplement is WIDELY used by many manufacturers to seal such imperfections in cooling system. It is installed at the factory by many automakers so chances are it was already in your cooling system no matter what you drive.

The coolant supplement is clearly called out as a standard service item in the service manual for that Northstar......

01-23-05, 11:06 PM
The only cooling system additive that I am aware of is a chemical designed to balance the pH and reduce cavitation. We used it exclusively in diesel trucks during the eighties, and it was marketed under the name of Nal-Cool. Concentration of the additive was determined by the use of test strips that you dipped into the radiator tank. But at any rate, the use of a stop-leak type additive is clearly a matter of personal preference.

01-24-05, 01:23 PM
Below I have posted a picture of the tag specifying the supplemental cooling system tablets. The tag is located on the cowling over the radiator. My car is a 97 SLS.
I am a firm believer in a little bit of cooling system sealer in any auto or truck cooling system. BTW you older mechanics should remember that in the late 60s and early 70s Prestone antifreeze was sold with stop-leak as part of the solution, great idea IMHO.