Hot Runnin'

[achtungE30]

So I'm about to undertake my cooling system overhaul. Right now the car's issue is it runs too hot while idling or stop and go. It will go beyond the 3/4 mark before red which is when, hopefully, I'm at speed or shutting the motor down to cool.

Now, after I changed all my coolant/vacuum hoses, I lost a bit of coolant, so I topped off with distilled water and bled the system. I noticed now even while the engine is at operating temp and I turn the heater on for the first time, it still takes a bit to warm or get remotely hot. My water temp gauge will fluctuate from 1/4 to above 3/4, at speed, hover around 1/2 till i come to a stop or have to go uphill where it will slowly rise and get hotter.

I'm thinking its a combination of a faulty thermostat or possibly the water pump needs replacement or I need a new fan clutch or all 3. What do you all think?

[johna]

Maybe it wasn't bled completely. I think the bleeding process doesn't work so well. I prefer to bleed by running the engine wihtout the radiator cap. Make sure the heater is on and engine is at normal operating temperature (1/2 on gauge). Run the engine for several minutes and rev the engine regularly. Some suggest parking up hill makes it easier too.

[Alpine003]

Fan Clutch - Test with rolled up newspaper
Thermostat - soak in boiling water
Water Pump - A bit harder but you can do a visual on the impellars once it's taken out.

If you're having heat issues, I would say to make sure your system is bled correctly first and filled up. Also for the fact that you have fluctuations on the gauge sounds like this.

[individualist]

Might also want to check the hoses going into your heater core. The bottom one feeds the core and the top exits the core. Let car warm to operating temp, turn heater on. Bottom hose should be a bit hotter than the top. If top is luke warm or cold, you probably have a failed temperature control valve between the head and the firewall. This can also cause your heater core to trap air in the system, making it very difficult to bleed the air out.

[Febi Guibo]

+1 to individualist;

hot engine + no heat; worth a check...