Hi, I have a heat problem whit the engine temperature in my Z28 LT1 from 1997.
The temperature is to high at idling speed, its going up to the red field 240-250 F., and the oil pressure is falling, but if I give a little throttle the temp will fall to about 200-220. When I am driving the temp is around 190-200.
The fan is running ok at idling speed, and I have changed the cooling (TX3) sensor and changed thermostat to a 160* , in stet of the 180, but it has not solved the problem.
The airdam is also ok, but I have a West Wings frontspoiler and a larger airdam, it work before, sow it shut be ok.
I think that that the problem may be the waterpump or what do you think?

 

What is your idle speed? My 6 speed idles at ~1000rpm.
Do you have an underdrive pully set on this?
You know changing the thermostat and air dam wont effect the temp's. at idle. Before you change the pump make sure the rest of the cooling system is OK, rad. clean and new anti-freeze, rad fins ok, that sort of thing.

 

My idle speed is 900-1000 rpm. It have to come up to 1500 before the temp is falling a bit. What is underdrive pully set? (sorry, I am from Denmark )
I have already used rad. clean twice, because there where not radiator heat in the cabine, and its a little bit better now.

 

What's your voltage reading at idle? When you increase rpm you're also increasing the generator voltage causing the fan speed to increase.
I'm sure it's not a water but an air problem. The fan motors could also be old and are drawing high current and running slow.

 

Thanks
My voltage is 14 at idle. I will tjek the fans speed.
But why kan the temp not go down to 160, when driving?
Should the wind/air when driving not be Enough to cool down the engine, whit out the fan?

 

These are after market pulley's (add ons) that are smaller in diameter so that your accessories run slower. Doesn't sound like you have them, so I wouldn't worry about this.

 

When driving down the road at speed, your engine temps. should drop to the thermostat setting. i.e., If you have a 160* stat it should drop to 160*. The thermostat is used to control the minimum temp. of the engine, the cooling system is used to control the maximum temp. So at slow speeds or stopped at idle the thermostat will be wide open and you will get max. flow through the rad. So if your pump is not working at full capacity, or your rad. is glogged, outside(full of dirt and leaves, etc.) or inside(corrosion or crud blocking the tubes) or both fans not running your engine will over heat. You also need to check at what temps. the fans are turning on.