Russel Finehout

I've been fighting the cooling system on this van for almost three months. I'm going to preface this with the work I've done in chronological order.

Water pump, thermostat, upper and lower rad hoses, orings, temp sensor. After these fixes I was noticing I was getting bubbles in the coolant overflow tank and it smelled like exhaust. I changed the head gaskets along with every other gasket dealing with cooling or intake along the way. I finished it off by flushing the cooling system.

Now I have no more bubbles in the coolant over flow tank but I'm still seeing my temp gauge slowly float to 5/8th at highway speeds. Takes it about 10-15 minutes. The coolant gauge drops below half once I'm doing city driving.

Yea both the fans are working and the air damn is installed.

I'm think I sill might possibly have air trapped in the system or I didn't flush it well enough and still have debris in the system.
Any help would be awesome I'm fed up with this van

cj1

Verify actual ECT with scan tool. Is it above normal operating temp?

Russel Finehout

Do you think it may be the gauges?

cj1

Best to compare to ECT from scan tool or you could reinstall the old sensor maybe a difference between sensors.
Do you have a cooling fan controller also?

Russel Finehout

Okay on the first part, and I threw out the old sensor.
I do not have a fan controller, I can get one. What are you thinking?

cj1

Just trying to determine what sensor is turning on cooling fans. Appears then you have a single sensor/sender for ECT and dash gauge?

A 1/8th tick up from halfway on temp gauge when running under load isn't much. Not an overheating problem like you had before. Maybe leave will enough alone?

Russel Finehout

The cooling fans are running all the time. I live in Arizona and the venture had a seperate rely for the fans when the AC is running the fans are running, so the fans are always going. I noticed yesterday if I run the cabin heat on high when driving it stays at or below half.

And that is what I am thinking. This may just be the new norm for working under load. What do you think about putting a 180° stat in instead of the OEM 195° to help cool more?

cj1

I think you need to verify ECT. That will be the baseline for any action you need to take.

Regarding the fans always running with A/C on, this is not enough to sufficiently cool the engine when under load.
Fans running with a/c are normally running at half speed and when ECT exceeds a preset limit, maybe 220, the fans are set on high speed.
Very important to verify ECT and high speed fan operation.

If you change the stat to a lower temp then it may run too cool. If you can verify ECT then we will have something to work with.

Russel Finehout

The fans not kicking on high seems like a very good possibility to the issue. I'll research and see when they are supposed to kick on high or see if I can get them jumpered to turn on high to make sure they are working.

I be testing it in the next couple days and get back to you with what I find

Gregdd

I always thought the amount of air forced through the radiator at high speeds on the highway was much greater than the fan can supply. For that reason I do not think it is the fan's. Could it be the radiator itself is old and dirty inside or out? They can loose capacity to cool over time. Getting all the air out of this cooling system is a lot easier using Leslie's spill free funnel. It allows you to raise the level of the coolant above the top of engine so when you vent the ports all the air is forced out rapidly. You fill it correctly the first time and don't have to screw around with it again.