jetrainor

I had very similar issues....two things righted it...put a new thermostat in even though the other one was fairly new and replaced the inner seal at the same time...made sure there were no airlockis in the system....and added waterwetter agent to the system....this has dropped the temp guage from middle betwee the white lines to just above the lower white line and right now in the Okanagan im driving in 100F temperatures.

Bill Ball

Right. Was it plastic or metal impeller?

Tampa 928s

It maybe hard to reach but an old trick is to start the car cold let it warm up a LITTLE and feel the center core. If you feel cold spots that part could be blocked.

potsiewebber

an update. i removed the radiator and it looks ok. no caked up gunk that can be seen. i will be installing another used radiator tommorrow.

Ispeed

I had a similar problem, running well but hotter than I wanted.
Dave C and I changed a bunch of things, but I believe the Bosch +4 plugs were to blame for running hotter than oem plugs.
New t-stat, water pump, checked my MAS (it was perfect though), and the radiator is less than 2 years old. Anyways, temp is great now.

Walt L

I have similar intermittent overheating problems but I hate the idea of replacing parts *****-nilly until it is fixed.

potsiewebber

I agree about replacing parts until its fixed. I ve had this other radiator in storage so its really only my time involved and no money. Ive tried to reason out the problem taking into consideration all of the suggestions that were offered to me in this thread. I came down to the radiator not cooling sufficiently or a pressure leak in the system. since i had this other radiator i thought i would try that first. like i said previously i have a new water pump, thermostat and coolant so...

potsiewebber

I also have regular bosch plugs.

H2

It doesn't take a lot to cause a 928 to overheat but when everything is right, there's no problem. The difficulty is figuring out "what's not quite right" from the myriad possibilities. Is there a part in the oil cooling path that is a relatively frequent problem?

Also, my S4 AC condenser sits in front of the radiator and has to contribute to reduced flow because of the tight cooling fins, heat, etc. I've wondered if it would help much to put yet another cooling fan in FRONT of the AC condenser, to help the two fans behind the radiator. Has anyone done this, or is it just one more thing in front of the radiator that might inhibit air flow in normal driving?

H2

Bill Ball

H2: That's not a bad thought. It strikes me that even at high speed, the airflow through the small, low grill opening may not be enough for what I am doing. Hoiwever, I should check what Tim & Cheryl have done. As mentioned before, I would like to get rid of the oil cooler inside the radiator.

I do know that when stationary and doing AC charging, I have to add an external fan. The factory fans are running full bore, but they are not dragging enough air across the radiator and condenser. But I think that is common to many cars.

Murph's SC kit guys add a front fan (although they have changed the rear fans to somewhat smaller ones due to the SC obstruction). I may try that too.

potsiewebber

I replaced thre radiator with a full aluminum race radiator that i got a good deal on. I tested the thermostat and pressurized the over flow tank to show no leaks. This is what is happening. When i run the car, the fans work, the thermostat works but when the car gets hot enough, the coolant blows out ot the port on the overflow tank every time. anyone know what could be causing this????

dr bob

A kit from a better parts store may help you find combustion gasses in teh coolant. If you find them it means a head or head gasket problem.

JP Rodkey

You just described classic air pocket(s) finding it's way to the reservoir.

potsiewebber

sO I GUESS THE QUESTION IS, how do i get all of the air out of the system? What is the name of the kit at the autoparts store to test for the gasses?

potsiewebber

Could it be something as simple as a bad coolant resevoir cap not working correctly?
Thanks,
James1