Water pump dying? - Toyota Nation Forum : Toyota Car and Truck Forums

stormhawk · 11-25-2011, 12:23 PM

I have a 1990 GTS with a transplanted 1996 S5HE 2.2 motor. This summer I started getting overheating issues and I believe my water pump is dying.
Here's the symptoms; car will run nice and cool on the freeway doing 70 with the tach turning at 3.5k. As soon as I get off the freeway and RPMs drop the coolant temp will spike almost into the red. Accelerating from the stop will drop the temp but it will hover near the high end of the middle till I get back on the freeway or RPM's go back up. It does the same thing when climbing hills or when the engine is under load. It did it bad this summer when it was hot out and I was running the AC. Bad enough that it boiled over a couple times. The radiator is brand new and just based on the symptoms I'm thinking water pump.
Am I right on this or is there something else I can check? The thought of tearing apart the motor to replace the pump isn't something I look forward to.
Thanks.

***MR2Jedi*** · 11-25-2011, 07:46 PM

From what you stated, I would suspect radiator fan(s) before water pump.
Check to see that the fan(s) are running at idle after car has been running awhile.

stormhawk · 11-27-2011, 06:40 PM

The fan is running fine, also replaced the thermo this afternoon. Any other ideas?

***MR2Jedi*** · 11-27-2011, 07:32 PM

Thermostat woulda been my next suggestion.
Strange.
You said you have a new radiator. Have you confirmed that the heater core was bled properly?

stormhawk · 11-27-2011, 09:06 PM

Heater core has been bypassed (it was bypassed when I bought the car, not sure why). The car only has a single fan, would a dual fan setup be more practical? Scratching my head on this one too.

RobMilkshakes · 11-27-2011, 09:59 PM

A single fan should be sufficient. With the symptoms and temp change being consistent I wouldn't really suspect air in the system. Honestly, with a good thermostat,the water pump is the only other thing I would suspect.

***MR2Jedi*** · 11-28-2011, 12:06 AM

Quote:

Originally Posted by stormhawk

Heater core has been bypassed (it was bypassed when I bought the car, not sure why). The car only has a single fan, would a dual fan setup be more practical? Scratching my head on this one too.

Only if it originally had 2.

Quote:

Originally Posted by RobMilkshakes

A single fan should be sufficient. With the symptoms and temp change being consistent I wouldn't really suspect air in the system. Honestly, with a good thermostat,the water pump is the only other thing I would suspect.

With all thats been said, I agree.

engine1CD · 12-04-2011, 07:00 AM

Warm up engine and check-compare temperature of rubber hose from head to radiator top placed and hose from radiator to engine block bottom placed, on warm engine there should be a little difference in temperatures of both hoses few degrees, checked with hand on hose. If same occur after, engine is warm up, probably there is a problem with sensor for inlet temperature of water, located on head near inlet pipe. Give different info to ECU of your vehicle.