1998 GMC Truck Repair Question
Mileage: 105,000 miles.
Coolant leak
Asked by CologuyAnswer
Would help to know where puddle is located under truck. Front, back, P-side, Drivers side ? Have you checked ALL the hoses that run coolant? Is the water pump making a strange sound of late? Do you have a cream colored foam on the underside of your oil cap ? Have you checked to see if the overflow tank is cracked, or the attaching hose leaking ?
Ford Man in Michigan
I've check all the hoses an cannot find any visible leaks. As far as the puddle goes it's basically right under front, middle of engine, 6 inches behind the fan, Right under the waterpump but don't see a leak. It's cold out now (0 to -10) so yes something screams when I start the truck but I kinda think that's from the alternator (Have had to replace them on other GM products).Maybe it is the water pump making the noise.
My guess is the pump is where your leak is coming from ! It will only leak with a hot motor, or while running. With the temps in your area...
to test the pump....grab the fan shaft & wiggle it (while motor is warm).....if there is any movement, your pump is shot. Another trick to proving the leak is coming from the weep hole on the pump....after you park it for the night (day?).....place a dry rag under pump to catch coolant ( REMEMBER to remove rag before restarting motor! ), leave sit for several hours so that motor cools to the point of being cold. If the rag is wet, the pump is leaking. Before making this last test, make sure the motor got to running temp, & it has a full load of coolant !
Ford Man in Michigan
Just stopped at a local mechanic and he thinks it is the intake manifold gasket just wondering if that makes sense. He look at it very quickly with a flashlight and mirror and didn't think it was the water pump.
Could be..........but if that is the case...you should have cream colored foam on the inside of your oil cap, or inside the valve cover. With the puddle you mention...that points to the pump ! Do the rag test I spoke of....a sure fire way to prove, or disprove if it's the pump.
Ford Man in Michigan