Reader Question: Hello,
I am in need of some help. I have a 1999 Oldsmobile Intrigue with 100,000 miles. I took it to the shop to have the water pump changed and the radiator flushed, when I got it back it began to overheat.
Since that time, the shop has changed the thermostat, installed two different water pumps, changed the radiator cap, radiator hoses, and some kind of sensor. The weird part of it overheating is that if you put it in neutral and rev the engine to 3500 RPM, the temperature immediately comes down.
The mechanic at the shop said that he has never seen anything like it in his 25 yrs of working on cars. He also thinks that it is either a head gasket leak or a clogged radiator. I have been renting a car for almost two weeks and can no longer afford to replace needless parts, or guess at the problem.
Has anyone ever heard of a problem like this, or offer any insight into what the problem is? Any kind of help would be VERY helpful.
Thanks in advance,
Have you read my article about engine overheating?
I ALWAYS start-off with a cooling system pressure test, this will locate an external or INTERNAL coolant leak and rule out the possibility of a head gasket issue, which I do not think you have.
Second thing to do is, use one of those laser heat guns, and try to find the hot spot, starting at the radiator move downwards to the lower radiator hose then to the engine block and thermostat. You want to do this with the engine HOT of course.
I bet you are going to find a major temperature difference either from the top and bottom of the center part of the radiator or at the engine block. You can use your hand if you do not have access to a digital heat gun.
If you did not have this problem prior to the water pump and flush, I would triple check to make sure you don’t have an air pocket in the cooling system that still needs to be bled out. Or, check to make sure the radiator is circulating like it should; your flush could have loosened up some crud that has now restricted the flow of coolant in the radiator.
Also, make sure the cooling fans are coming on, as they should. Those electric cooling fans are vital at idle and at low speeds, if they are not coming on…find out why.
Lastly, could this be a temperature gauge problem and not really an overheating problem? If the engine is not boiling over or acting like it is overheating this might be a problem with the temperature sending unit or the dash gauge. A digital heat gun would confirm that.