LScowboyLS

there is your answer!

I would abandon this water pump idea and fix the actual problem, likely the sensor in the radiator or possibly a fan relay

if cooling fans are not coming on during an overheating situation, then the water pump is exonerated, and something tells me you may not want to open this timing belt/water pump can of worms

also a water pump impeller issue would be worse at high speed, not better

LScowboyLS

here is what my shopping list would be at the dealership:

● water temp fan switch p/n 89428-33010 (I think that number is correct)
● new o-ring for switch above
● thermostat p/n 90916-A3003
● gasket for thermostat
● 2 gallons of Toyota red coolant

make sure to negotiate at least a 20% discount and preferably 25%

and get 2 gallons of distilled water from the store to mix with the coolant

that Toyota water switch is a little pricey, so you might want to test yours by unplugging your current one with car idling and fans should start right up, but I guess that would involve two trips

also, if funds are tight, you could try autozone on this part, as precise temp is not as critical as say the engine coolant temp sensor

Crybicki

I owe a huge thankyou to LSCowboy for all his advice and help on this crazy fix. I got all the way down to the fan assembly, see previous post, and couldn't get that part off. Luckily, Cowboy and I talked and he helped me realize that it wasn't my water pump that was bad...



It ended up being a combination between my water temperature switch (the switch that is on the bottom driver side of the radiator) and not having the correct RED coolant in my car.



So I got all that stuff out of my car, spread it all over my driveway, then turned around and put it all right back together.

BUT this wasn't a total waste because I did get to clean a whole lot of dirty nasty stuff around the engine compartment and it is much cleaner down there now thanks to a whole lot of degreaser. So, it all worked out in the end and my car is currently running great! NO overheating!

Thankyou again Cowboy!

Legender

And another satisfied customer... Great job LScowboy... and glad your car is back on the road Crybicki..

pcolex

FWIW I went through all the diagnostic steps on my overheat, and it was indeed the water pump. The impeller had broken away from the shaft so no coolant was flowing. Also FWIW this was not the original water pump.

1UZFEric

I second that pcolex; also a 93 SC400 w/ ~157k. I suspect the water pump isn't original, as there was lots of RTV on it, car was running green coolant, timing belt was NAPA and I had a DTC code 13 that I didn't know about until after I'd owned the car a while and realized the CEL bulb had been smashed to hide the DTC13 (f%#& whoever did that, precisely why I trust NO ONE but myself with my car maintenance)

I have an AISIN pump kit on the way, but going back to the water pump not being original- I DID notice the "Toyota" pumps I've seen for sale online, as well as the one in the shop manual, seem to have channels on the backside of the pump body and are supposed to be used with FIPG (aka RTV). However, the AISIN pump, from pictures, does not seem to have the grooves and instead comes with a gasket. Are there other aftermarket pumps out there that have the groove/FIPG setup? I'm just curious as to whether the pump in my car may have been original or if it's aftermarket...

Regardless, it's getting all OEM going back, down to the red Toyota coolant : )