That is truly weird considering your input and out temps before. I really wonder if you just had an air pocket that wouldn't come out before. That's what it sounds like to me, we once had a vette that the dealer released 3 times and 3 times it overheated with the customer (embarrassing that it left without being verified 3 times and our dealer was one of the best but when the wrong people get assigned to the car then only so much can be done). Anyway it was trapped air in the upper crossover pipes. Do a vacuum fill and done no more issues, sometimes it really is the simplest thing.

Yeap, it was an air pocket. Sometimes they can be a challenge to get out.

Question: is there a way to test the high and low speed cooling fan function on our cars? If you didnt see the video already i did test them with a direct 12 volt from the battery which im assuming would run them at their high setting, but cant seem to find an answer anywhere on how to test the low speed setting.

According to page EC-486 of FSM, "Cooling fan motor receives cooling fan motor operating voltage from cooling fan control module. The revolution speed of cooling fan motor is controlled by duty cycle of the voltage." Ie, it turns the power on and off real fast. An oscilloscope would work to check output.

So what you're saying is im SOL lol

You should be able to rent/borrow an o'scope.

Some multimeters will work and would be easier to use/interpret. https://duckduckgo.com/html?q=multim...uty%20cycle%22

What im wanting to test is the fan motors themselves though, the control module i know is good as it is s brand new unit, the motors on the fans is what im unsure of. I've seen guys test the fan speeds with the higher priced scan tools, but just wasnt sure if there was a way to test the motors at their different speeds without that

I'm amazed at how complicated this is getting to try and resolve! Interesting though. :eek:

Update: finally had another over 80 degree day and tried out the ac once more.....engine started overheating again. Went ahead and have ordered a brand new water pump and will update once i find the time to install it

Sounds like you have a blown head gasket. This is the only thing that I know will cause this type of issue except for an electric fan issue where the fans will not kick up to high speed.

Radiator pressure test passes, block test passes and no pressure left in system when car is run hard and left to cool down overnight, all of which would have indicated a blown head gasket. Only thing left to provide a definitive answer on that would be a compression test which i will most likely do after swapping out the water pump, but i have my doubts that the head gasket has anything to do with it as i have been talking to several other mechanics including those at corner 3 garage and with all the information I've given them they doubt it's the head gasket as well and have come to one of two conclusions....either the water jackets around the cylinders are clogged or the water pump impellers have corroded away. Being that their is no record of the coolant system ever being flushed or serviced and with all the troubleshooting that I've done along with the mechanics it leaves me with the only component i havent addressed in the system, which is the water pump. I know it's hard for some to believe that our water pumps could fail due to how they are constructed, but with how acidic coolant can become after so many years of not being changed you kinda have to entertain the possibility of that acidity eating away at the impeller on the pump. I will update this thread when i get the time to change out the pump and will let everyone know the results along with pics if i can get them.

When you swap out water pumps. I would like to see pictures of the impeller. Be best if you can show both new and old. :tup:

May have finally gotten the water pump to give up the ghost and caught it in the act. Started car from cold start today with no load on engine and low and behold i can hear the faint sound of.....squeak, squeak, squeak, squeak. Bend down in the engine bay to try and locate it and nearest i can tell it's coming from where the water pump sits. Definitely not belt squeak or pulleys as i have already dealt with that in the past and know what it sounds like so i think we have a winner here.

That could be the bearings going bad now.

On the water pump?