Last Lemming

When I'm at idle my car seems to creep to the 2/3 mark even once the fan kicks on. If I rev the car to 3k while at idle the temperature will drop, but below that is doesn't want to drop. And while I'm on the move the temp does drop, but it drops faster if the revs go over 3k. I've the WP, thermostat and radiator. And of course I have bled the system MANY times. I've verified I don't have a head gasket issue.

So something is amiss. I'm just sure which component is at fault. I will be going to a lower thermostat and fan switch to start to see if the thermostat is at fault. I live in louisiana so going lower can't hurt here. My hi and low fan works as well so that is out of the picture.

If the thermostat change doesn't help the I have to suspect the new water pump or new radiator. I've verified the belt is tight enough and that the WP pulley isn't slipping on its shaft.

I will then try a Linsey Racing radiator. If that doesn't work then there must be something up with the pump. Though I doubt it.

Any other suggestions or thoughts?

mytrplseven

When you bled the system, did you have the heater selected on? If not you won't move air bubble in the system when bleeding. Also was the engine up to at least operating temp so the thermostat was tripped before bleeding?

Fara

If you have the heater on in the car, does it seem to lower the temp?
I had similar issues and it was my thermostat only opening part way.

Of course, shortly after that, my head gasket failed and gave me similar symptoms.

Last Lemming

I did have the heater on max and it does lower the temp when on and fan is on max.

Last Lemming

Any other thoughts?

944Ross

Sounds like as you suspect, a partially plugged radiator. Have you cleaned the fins? And the condenser fins?

My car behaves just the opposite. For instance if I hold 4th at 40 - 45, it runs hotter than if I go to 5th, to the point the 1st fan will come on after a couple miles when it's warm out (90+).

CBR944

Could be the radiator cap if you haven't already replaced it. Mine was bad, which along with a small leak in the radiator, meant the system would overheat as it couldn't hold enough pressure. Possibly a cheap fix!

Last Lemming

If it's plugged it's plugged from the factory. It's a new radiator. It could be a manufacturering flaw. Though I have no idea how to test it.

Van

Have you verified the temperature with something like an infrared temp gun? Perhaps it's running well, but you have a ground/electrical issue, and when the engine revs (alternator spins faster) the gauge shows a different reading.

Last Lemming

I do have an infrared gun and I have used it to test. I can't really tell if the temp I'm reading at say the water neck off the engine block corresponds actual water temp.

As for the electrical issues: I've cleaned all my grounds and when I rev the engine the temp does not drop instantly as you would think would happen if the revs changed suddenly and it was an electrical issue. The temp gradually changes with prolonged raving of the engine.

Van

Is it a new water pump? Or a reman pump? I've seen reman pumps where the housing was damaged by the impeller prior to the "rebuild", so the clearance is off and the pump doesn't move the volume of water it should...

Last Lemming

It was a new Laso

thomasmryan

Are you using a 50/50 coolant mix? (Antifreeze won't carry the heat away like water)

Will the system hold pressure? If you don't have a tester, the upper hose should be firm for a while after you shut off the engine. Or after a cool down cycle, there is usually a vacuum released when you remove the radiator cap.

In this situation, it would be worth a shot to test your thermostat(s) on the stove.... just to be sure.

Do you have any exhaust leaks, vacuum leaks or anything that would cause a lean condition?

Van

To verify, you're not getting any air out when you'd "bled it MANY times"?

konakat

You could use the IR temp reader to scan the radiator and make sure it is fairly uniform in temperature. If an area is plugged, it should be cooler.