| jessie baker |
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Reply with quote | #1 |
dear sir i have a 1982 gmc 3500 truck with a 454 in it on a recent trip the water pump failed and it overheated badly. it was running smooth when i shut it off and i allowed it to cool over time. i bought a new not reman water pump from a parts store and installed it the next day checked all fluids no water in the oil or oil in the water removed the thermostat started it up it ran fine but by the time i drove it 50 miles the temp guage registered 3/4 of the way hot steadily climbing. when i checked the coolant level it was totally full.so i went to an associate of the parts store totally confused and asked this guy who said he knew a lot about big blocks and he said i could have gotten a reverse flow water pump by mistake i was wondering if that would cause the steady increase in temp.i also installed a new fan clutch with the water pump witch i hate fan clutchs. any way i want to install just a sraight old fashioned fan he also said it could be a head or head gasket witch i cant believe as no oil in the water or water in the oil please help if possible any suggestion would be greatly appreciated.thanks jessie |
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| Howard |
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Reply with quote | #2 |
Jesse,
There are no "reverse flow" water pumps. Later models with serpentine belts typically drive the pump off the backside of the belt, causing the pump to spin counter clockwise. The water is still pulled from the radiator and pushed through the engine. If you install a pump designed for counter clockwise rotation (serpentine belts) with v-belts, the performance of the pump surprisingly will loose only about 10% flow at higher RPMs....none at low speed and idle.
The LT1 small blocks were reverse flow engines. The only reverse flow domestic engines I am aware of. These water pumps will not fit other engines.
Coolant level is a tough one. The engine usually needs to go through a heat cycle to purge all of the air.....but must be stone cold when you check the level. The closed loop cooling systems take care of this on their own. You just add coolant to the overflow tank after it cycles a few times. If your closed loop system isn't operable....fix it.
Of course if it ran cool with the old clutch fan and hot with the new one...that could be the problem.
A blown head gasket causes the engine to overheat ONLY through loss of coolant. The coolant can be leaking into the oil...spraying out between the head and the block....of blowing out the overflow due to compression leaking into the cooling system. If none of these are happening, you still can't be assured that your head gasket is not blown....but you can be assured that your overheating is NOT caused by a blown head gasket.
Chances are your system is just not full of coolant.
Howard Stewart
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