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Intermittent and annoying coolant leak

This is a 2000 Dodge Caravan with the 3.3 engine, just turned 100KM. On the passenger side of the car, where the serpentine belt and water pump are, there is a little bit of coolant leak once or twice a weak. It gets the splash guard wet and drips on the floor the size of a quarter. The water pump and the hoses seem to be dry. It seems like it might be from the timing chain cover and tracking down.

Question is what else do I look for? I think before I tightened some nuts and it “went away” for a while. Is this a must fix? I have found the UV dye, how do I get my hands on a UV light source (? $$).


With an inspection mirror if necessary, carefully inspect the weep hole on the underside of the water pump.

If it’s the source of the leak, then, yes, it’s a must fix.

Have inspected it without a mirror and daily for a week and it is dry. Actually the water pump is probably newer too. We bought the van with 60KM on it in 2006.

I should think you can try a pressure test. Basically, you attach a specially designed air pump to the radiator input, pump it up, and hopefully, the air pressure forces coolant out the leak in the cooling system.

My impression is that basic home mechanic pressure testers are cheap and safe. You won’t create new leaks. I could be wrong as I only remember doing this once – about 20 years ago. Maybe there is some reason that pressure testing is a bad idea on modern cars.

I would think that most mechanics have a pressure tester stashed away in one of those tool boxes and will track down your leak for you without charging you too much.

I am going to try and borrow a pressure tester from Autozone tomorrow. Apparently I have to pressurize it to 3 psi over the radiator cap rating. Now my problem is that the coolant leak only shows up after the engine cools down overnight. It might be because of evaporation when the engine is running hot, but even when I look and listen after I turn it off I don’t hear any hissing or see any vapors. This is a small leak and I don’t like the idea of tearing down the timing chain area. The minute someone gets in there, they will add a new T chain to the bill ($200), and then if this doesn’t fix it we will move to the intake gasket and then the head gasket.