I have a 89 s10 blazer just finished rear main and out put shaft seal. Put fluids back in. Had a tranny pan leak and pretty sure I remedied it. Then noticed a drip up front. Thought it might be the coolant hose going into water pump so I loosened and repositioned the clamp and tightened it up. But still have a drip. Grab a shop towel and dried everything up in the area and it looks like coolant might be coming from water pump. Anybody have any insight on how to be sure? I am a d.i.y.er and already pretty much tapped out so I want to be sure that's what's wrong. Thank u

 

One option is to do the following: With the engine hot and thus the cooling system pressurized, you shut it down, dry everything off, and then place paper towels blow suspected areas to see where the water accumulates. This will help you find origin of the leak. You might find that there is a pin-hole in a hose or there is a bad gasket for the water pump. But you also might find that the water is coming directly from the front seal or the relief hole in the pump. It might take a couple tries to home-in on the leak.

 

There's usually a little weep hole on the bottom of the water pump snout (the one that Christine mentioned). That's where it's supposed to leak if the seal goes bad. It can be hard to see, so it may help to stick your phone down there and take some pictures. If you can beg/borrow/steal a cooling system pressure tester (I think places like AutoZone might loan them), pump it up when it's cold and again when it's hot. Sometimes leaks only show up in a certain temperature range.

 

Thank you guys for the input. I did end up putting a shop towel above where the lower hose comes in from the radiator to the pump. And found that the drip stopped with the towel in place for a lil while and then the steady drip started again. That was with the block cold. I am going to try and call auto zone and see about borrowing a pressure tester. I also drove the truck around a bit got the juices flowing and still had a drip with the truck running but not with it turned off and hot. Not sure if it's because the coolant lvl was low but I did add some water and top it off. It's wierd if y'all caught that, cold and truck off there is a drip, hot and truck running there is a drip but no drip when hot.. any other ideas or input is appreciated and I am calling parts stores to see about borrowing a pressure tester for radiator

 

So, I did not have this happen to me but I read about it here; A forum member reported that their leak was due to a pin-hole in a hose that when the system was hot would leak a fine stream of coolant that would immediately evaporate. But when the system was pressurized when cold the leak was very evident and none of the liquid would evaporate.

What are the ages of your hoses? It sounds like the pump is original. Perhaps there this pitting on the hose fitting on the pump that is allowing leaks? From what you describe, coolant is definitely leaking but apparently when things are hot, the leak goes away (or is much smaller). Perhaps there is something swelling when it gets hot that plugs the leak?

It'll be interesting to hear back about your results of using the pressure tester when your engine is cold.

Good Luck!