Question about 1998 Oldsmobile Bravada
Ranger is overheating after head gaskets were changed. I have checked or replaced waterpump, belts, hoses, radiator, coolant, thermostat, ports in engine
If the cooling system has no bleeder valves to vent air, you may have to temporarily loosen a heater hose to get all the air out of the system...Also check to see if there is water in the oil...If there is water in the oil then it could have a head gasket problem....Excessive exhaust backpressure because of a clogged catalytic converter could also cause overheating..Also check belt tension and condition. A loose belt that slips may prevent the water pump from circulating coolant fast enough and/or the fan from turning fast for proper cooling...Another thing it could be is a faulty Water pump -- Any wobble in the pump shaft or seepage would call for replacement. In some instances, a pump can cause an engine to overheat if the impeller vanes are badly eroded due to corrosion or if the impeller has come loose from the shaft. The wrong pump may also cause an engine to overheat. Some engines with serpentine drive belts require a special water pump that turns in the opposite direction of those used on the same engine with ordinary V-belts... Also check the Fan -- With mechanical fans, most overheating problems are caused by a faulty fan clutch, though a missing fan shroud can reduce the fan's cooling effectiveness by as much as 50% (depending on the fan's distance from the radiator) which may be enough to cause the engine to overheat in hot weather or when working hard.
Posted on Apr 18, 2009
Still sounds like a bad radiator...new or from scrapyard? If you can't add coolant faster than a really slow dribble that's a big clue.
You can run the engine with the heater on high and the engine should not air-lock. I'd also remove the thermostat just to make sure it is not defective. Run the engine without it and see if it still overheats. Last, it is possible that your head gasket has failed, and engine compression is causing the overheat. I tend to think not only because the hose stays soft.
While it's running, also make sure that the lower hose is not "sucking in" if it is, replace it. On 4.0 engines you can also get the serpentine belt on wrong and it will drive the pump backwards. if you replaced the belt check that too.
Posted on Sep 28, 2009
Testimonial: "thank you for the help. "
Sometimes after changing the coolant, people (like me) decided to fill the radiator ... only to find the car overheated like a candle.
When you fill the car, DO NOT fill the radiator first. Pull the top hose off, and fill the engine (via the hose) with coolant. Once that's full, shove the hose on and then top off the radiator.
Solved the problem for me. Has never overheated since.
Posted on Dec 26, 2009
If you have white smoke from the tailpipe, coolant in the engine oil, engine oil in the cooling system, that indicates a head gasket failure. However, the most definitive way to test is to have a hydrocarbon test done on the cooling system (checks for exhaust gasses that obviously don't belong in there).
If the system comes up clean, you still can have either a leaking intake gasket, partially obstructed radiator (many times flush will go around obstructions not through them), a malfunctioning electric fan or fan relay, or even an obstruction in front of the a/c condenser or between the condenser and radiator (leaves, plastic bags etc) Don't forget though even if the cause is other than a gasket, if repeatedly or severely overheated the head gaskets can also fail. That is why complete testing is very important.
Posted on Jan 20, 2010
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