Hi, my name is Phil and I am new to this forum, and this was my experiance with overheating.
Two years ago the water pump let go in my 99 concourse.I didn't have time to deal with it so I brought it to a local GM dealer. After they replaced the pump they called and said that the car had other problems and that it was overheating. I told them that the car was running fine when I brought it in and has never had an overheating problem.They told me that they tried everything they could and that I would have to take it to a Cadillac dealer to have the head gaskets replaced.
I went and picked up the car and on the way home it did begin to run hot but I noticed that it ran fine for about 5 miles and suddenly the temp started rising fast.I turned on the the heater as high as it would go to try and help cool the engine and immeadiatly realized there was no heat! So this told me that there was no coolant in the heater core and there must be a blockage or an air pocket and that I probly had a circulation problem
When I got home The temp was just below hot on the guage. I let itCOOL DOWNand looked in the reservoir and it was full, but when I started checking I felt the upper radiator and it felt empty. I removed the hose and it was DRY!
To this day I don't know why this happened, but I ended up pouring coolant into the upperhose ( I added another gallon ) and pouring coolant into the res. until it came out the goose neck.I reattached the hose and have been running the car ever since with no problems! The temp stays in the middle of the guage, the heat works fine (And we use it a lot up here in the Adirondacks ) and the A/C works normal.
So I think this is somethiong that should be checked on all Northstars BEFORE doing any head work and I hope this may save some major headaches for some people.
PS If anyone has any explanation or has heard of this I would be interested to here from you.

 

OOPS, I ment to say that I felt the upper radiator HOSE and it felt empty.

 

Phil,

i think twice before using those guys again.
they didnt refill the system properly. i do hope
you reported this to GM and to the dealer mgt.

with a pump replacement a complete coolant refill is in order, a
new serpentine belt is in order, and a coolant supplement (if applicable)
is in order.

any car, any engine, low by a GALLON of coolant will run hot or overheat.
any car. at a gallon low, the water pump may also cavitate creating other
overheating issues that you dont want. most modern cars have a low coolant
sensor, yours didnt kick out a code? if so, i be interested on why.

no one should ever go for a headgasket replacement w/o testing it.
the testing is CHEAP, the teardown is VERY EXPENSIVE !

if you look in our FAQ section you will see several method of testing the integrity
of the heads / headgaskets BEFORE you approach an engine teardown.

you are correct of course, 1st TEST, then decide.

NEVER, NEVER, NEVER take a mechanic's opinion to replace headgaskets.

only after a proper test has been done and the results provided to the customer.




.

 

Stealth,
No my low coolant level did not turn on because the resivour was full ( I beleive the sensor is in the res.), It did turn on when the pump started leaking and that was my first indication that threre was something wrong.So the resivour being full no more coolant could be added BUT the top radiator hose didn't have any coolant in it and I don't what caused this problem.