coolant leak

xheadnut · Post by **xheadnut** » Tue Oct 13, 2009 11:15 am

Put new 4lb. cap on radiator, old one had no rubber. Now the pressure seems to build up it pushes out the overfill,and now I have a leak somewhere around the fuel pump and I can't see it, and suggestions. Put new water pump on last Fall and the leak does'nt seem to come from it. Marshall

Post by **wesk** » Tue Oct 13, 2009 12:19 pm

Borrow a coolant system pressure test set and you will find it easy to pinpoint your leaks. Otherwise you have to deal with the engine running and the fan turning blowing the evidence all over the place.

Leaks around the water pump are usually:
1-from the gasket at the block
2-From a worn or shrunk shaft seal in the pump
3-from one of the threaded ports on the pump.
4-from the bypass hose or it's fittings
5-from the front edge of the head gasket.

The overflow can be just a too high coolant level, a cap overpressurizing the system, or flow blockage usually in the radiator core. Stuck thermostats can also cause that.

The usual reason you had a cap without a seal is because the PO didn't want to have the leaks show up.

xheadnut · Post by **xheadnut** » Tue Oct 13, 2009 11:45 pm

Put in new thermostat at the time of replacing the water pump. Everything around the pump looks dry it seems to be lower,somewhere around the fuel pump, can see everything around pump area. I was getting ready to leave for Ladysmith with it to hunt and it just started,there was no problem before.
Marshall

oreo3156 · Post by **oreo3156** » Wed Oct 14, 2009 6:09 am

did you put the thermostat in upside down? I've seen it happen

Post by **wesk** » Wed Oct 14, 2009 9:16 am

New thermostats should be tested with a pot of water and a thermometer before you put them in. Now that it's already in there the simple test is when it's cold start it with the cap off and watch the coolant movement through the cap hole. There will be a slight flow or movement because of the bypass hose on the head/pump but as the thermostat opens there will be a much faster flow. If you see a lot of bubbles which increase in quantity as you rev the engine up then you have a head gasket compression leak to fix. A compression leak will also cause the overflow issue.

If the leak seems to be from the fuel pump area then it may likely be the front exhaust manifold stud threads were not properly sealed.

If you are hunting up here at Ladysmith there's still no snow cover and the trees are only halfway dead for the winter.

xheadnut · Post by **xheadnut** » Wed Oct 14, 2009 10:32 am

Thanks Wes, will check it out when I get back, just strange that it just now happened and not during the summer when driving it. Was hoping to say Hi and see your toys as I come thru Holcombe tomorrow,but the son wants to scout early.