94 Caprice Classic overheating

I changed my radiator because of a leak. I noticed that the leak suddently came under great pressure and my temperature gauge was all the way hot. I insatlled the new one, burpped it and all after filling with antifrezze. My car is now overheating the same way. I went and changed the thermostat. Still over heating. When running at idle it was runs for about 20min then he temperature shoots straight to hot and the reservoir has boiling coolant in it. I'm thinking it is my water pump gone because i'm having the same problem even with a new radiator and thermostat. My water pump has and electric conection in the front. I read the voltage supply to it and it has 5 volts DC to it. Is it supposed to be 12 volts DC? What kind of water pump is that? Can anyone help! Thanks!!!

your vehicle does not have an electrical water pump as built by GM ...

if you have some aftermarket pump that is electircal I would find out how the power is supplied to it ...most likely it has a relay to apply 12volts to the pump...the relay contacts may be defective ...

this mod was used to attempt to get increased power ...as with most devices like this, it is not reliable...hopefully you did not blow the head gaskets , or ?????????

Does your water pump look like this?

http://www.wwdsltd.com/files/1994LT1Balancer.jpg

That is a stock arrangement. The electrical connector at the lower right is for the coolant temperature sensor. This type water pump is driven via a coupling to the upper camshaft gear through the front of the timing cover (the upper stub shaft in the photo):

http://www.wwdsltd.com/files/LT1TimingSet.jpg

Thanks j cat. I hope I did not blow a head gasket. Thanks Blue Bowtie. I did learn yesterday that that is a temp sensor. Yes, mine looks exactly like your picture looks. What do you guys think is happening? May I need a new sensor? What will be my symptoms if I do need one? Is what is happening to my car a common problem in theses cars?

Thanks j cat. I hope I did not blow a head gasket. Thanks Blue Bowtie. I did learn yesterday that that is a temp sensor. Yes, mine looks exactly like your picture looks. What do you guys think is happening? May I need a new sensor? What will be my symptoms if I do need one? Is what is happening to my car a common problem in theses cars?


since this is an as built vehicle , the water pump being OEM , the cause of the overheating is in need of finding the source of the problem ..using a pressure tester see if your coolant system holds pressure..any leaks will cause overheating.

when the coolant system was opened was the metal clean ? excessive corrosion black goop can plug up the engine coolant passages..collapsed radiator hoses when running ...then on the back of the engine is the steam pipe. this part has been known to fail causing overheating,,,hard to get to area..

make sure you use the correct thermostat, these are very different than the standard type ..

only use the proper coolant in your system ,,,do not mix different coolants...the fill cap will say what coolant to use ...only use what is listed with distilled water to keep the system clean and corrosion free..your vehicle will need 2.5gallons of coolant the total capacity is 4.5gallons..to drain the complete engine removal of both knock sensors will completely drain the engine, then you can blow out the heater core to get that cleaned out ..

now its just overheating when im sitting still

now its just overheating when im sitting still

do the testing as previously mentioned ..then post back what you found..make sure you have the correct thermostat..radiator is not plugged with black goop from mixing different coolants ..also !

I haven't did it yet. Will do. I will see you in a couple days....I left out that my overflow has a leak in it also. When I cut the car off after it starts to overheat my fluid in the overflow is BOILING!!

I haven't did it yet. Will do. I will see you in a couple days....I left out that my overflow has a leak in it also. When I cut the car off after it starts to overheat my fluid in the overflow is BOILING!!

the overflow tank is a pressure tank...if you have a leak there you will cause the coolant to boil...pressure reduces the coolants ability to boil ...this is why we all have coolant pressure caps...

step one you must have NO LEAKS !

I did not see anything mentioned about the electric cooling fans. Are they working properly? If not there is where the problem may be. The cracked overflow tank sounds suspicious. Make sure that there is coolant circulating.

the overflow tank is a pressure tank...if you have a leak there you will cause the coolant to boil...pressure reduces the coolants ability to boil ...this is why we all have coolant pressure caps...

step one you must have NO LEAKS !


That did the job!!! i replaced my leaking O/F tank. thanks all see you on the next problem which hopfully is a long time away.

the overflow tank is a pressure tank...if you have a leak there you will cause the coolant to boil...pressure reduces the coolants ability to boil ...this is why we all have coolant pressure caps...

step one you must have NO LEAKS !


That did the job!!! i replaced my leaking O/F tank. thanks all see you on the next problem which hopefully is a long time away.

the overflow tank is a pressure tank...if you have a leak there you will cause the coolant to boil...pressure reduces the coolants ability to boil ...this is why we all have coolant pressure caps...

step one you must have NO LEAKS !


That did the job!!! i replaced my leaking O/F tank. thanks all see you on the next problem which hopefully is a long time away.