Ladies and Gentlemen,
Got a 2000 silverado,137,000 on the clock,with numerous problems, lets start with the worst. Truck runs like a top after replacing intake gaskets due to "the leak" along with plugs, wires, etc. Engine will start running hot after about 15 minutes, especially if I'm heavy on the foot due to traffic. Oil pressure starts dropping as engine temp increases. Has new thermostat, backflushed radiator, does lose a little water still, light comes on about once a month. Guessing head gasket, just don't want to pull it all apart and have it do the same thing if it's an easier solution. Not guage as it erupts when cap is loosened. Turning off a/c helps me get home. Any help is greatly appreciated. Guessing not fan clutch cause stays hot, to hotter, on long highway runs.

All The Best, Kelly  

hey guy heres a few things to ck, take off the oil filler cap and see if is a tan milky-oily color if not do the same to the radiator cap, but not when hot, remove cap slowly and see if the milky-oily is there, also check the oil dip stick and see if any of the milky substance is there also, most likely if there is not any of milky substance at any of thees areas. most likely it is not a head or head gasket cracked or blown. now did you put a new o ring rear heater hose connection to the engine they have a bad problem of leaking. also if it has the plastic cooling fan we had problems with fan clutches not working well and causing truck to over heat.

thanks
Lee  

Thanks Lee,
Absolutely no milky color at all inside the oil filler cap and the oil on the dipstick looks clean as a whistle. No access to the radiator, but the water in the overflow is clear green. I know this truck could use a new fan clutch, but thought at highway speeds it would cool back down even if the clutch was bad. I will try the new fan clutch and see if that makes a difference. Any other ideas please shoot them my way. Someone mentioned in another post that a faulty temp sending unit could make engine overheat. Is this possible or just appear on guage to overheat.

Thanks much,

Kelly  

It would appear on the gauge to be overheating. What temp. does it come up to? Oil pressure always drops with heat. With the mileage your engine has, the bearing clearances are growing and the pump gears are wearing, which would lower your oil pressure. Ten lbs. per 1000 rpm. is perfectly acceptable. If you have a blown head gasket, cracked head, thats drawing coolant into the cylinder(s) and being combusted and exausted, it will go un-noticed because the extreme temp. of the cat. converter burns most traces of coolant odor and residule anti-freeze before it exits the tailpipe. This same condition would also pressurize the rad. and holding tank, and push coolant out the over-flow.  

I also wanted to say, if you suspect a blown head gasket, borrow a rad. pressure tester. Pull all the spark plugs, pressurize the system and listen for air or gurgleing. You will find out for shure.  

If you think the head gasket is going bad, what could be happening, gas from the combustion chamber/process could be bleeding into the cooling system, causing it to be over pressurized and not cool as effectively as it should.

The other thing, really basic, make sure your thermostat isn't sticking or not opening all the way. Replace the thermostat, go to a cooler one, and see if the truck runs cooler.  

This truck runs normally at about 200 according to guage, after 20 min's or so 210 for about 5min then starts climbing up to 240/250. It runs great, but I guess it could run great with a leaky H.G. The thermostat is brand new when I changed the intake gaskets to get rid of that leak, but sometimes brand new is the problem so I'll try another one. It's a great airport truck, the airports only 15 min away.