New Development in 944 Water Pump Situation

[ColoradoSteve]

Thanks everyone for your help. Just for kicks, I thought I would put the hoses back on, fill with water, and see what happened. No thermostat and the car does not overheat now! That means the water pump is working, right?Is it possible that the old thermostat was just working part time or what? What would happen if I just run the car without a thermostat? I realize that would affect the time that it takes to get up to operating temp but I'm not running the AC or the heater so ??
Steve

[bobp53916]

Sounds like your water pump works just fine, and, I have had thermostats intermittently in the past. I would also be concerned about the coolant flow being to fast and not allowing it to cool properly, the thermostat also serves as a partial restriction for that purpose. I was told this by the engine shop that use to build the engines for my race car. They suggested punching out the center of the thermostat instead of removing it completely. Just thought I would throw that in there for you...

Bob

[onZedge]

The thermostats job is to maintain engine temperature by regulating coolant flow. The water pump flow is based only on engine RPM. Higher RPM = higher flow. Without a thermostat and at higher RPM's, you might reduce the residence time of the coolant in the radiator so it not sufficiently cooled. This can lead to overheating on the highway. At lower RPM's, you might over cool the coolant causing the DME II temp sensor to richen the A/F ratio.

Of course things like vehicle speed, humidity, temperature, cooling system condition and state of engine tune will certainly affect the possible results you might experience.

[nynor]

without the thermostat, the system will not work properly. the system relies on the thermostat to create a flow rate that will allow the coolant time to both absorb heat from the engine and then release it at the radiator. this can cause the coolant and block to heat soak.

[mfloren]

I removed my thermostat recently and my overheating issues quickly disolved.

Im planning on putting a new one in soon.

so yes. I know where you are coming from.

[DMRK]

Steve,
You should be able to pick up a thermostat at NAPA for around $10.

[ColoradoSteve]

Thanks,everyone for the advice. I replaced the thermostat and got a new radiator cap, that's all it needed, amazing! The temp does fluctuate a bit between the half mark and 3/4 but I guess that's normal. I also pulled the cover off the timing belt housing and inspected; the belts look good, no visible wear, so hopefully I'll be running for a while with no problems. The next project is getting the air conditioning working!
Steve