Engine coolant
 

Had green coolant and switched to Prestone with COR-Guard, to be used with any coolant, any vehicle as they say. Less than 200 miles and the water pump leaks like a sieve after warm up. Supposedly no silicates. Have I been plain stupid all my life and it is just showing up more with the Toyota,:horse:. Do you think the Prestone done the pump in that quick or something else?

Took the upper and middle timing belt covers off to see better , filled the radiator full and started the engine. As the coolant got warm the leak showed up where the pump gasket seals to the engine block, not the shaft seal. Pump had been replaced by previous owner and a paper gasket was used. Am ordering an Aisin #WPT100 pump which includes a gasket, should I use the gasket or get FIPG from Toyota?

Use the gasket that comes with the AISIN water pump. It will likely be metal with a sealant bead on one side. Toyota switched from FIPG to a gasket on the 3.4L 5vz-fe water pumps.

...and it works great. I have 50k on my AISIN WP and I don't think I've added coolant even once.

Thanks for the replys! Any thoughts on the Prestone antifreeze that I used, called Prestone customer service and asked about silicates, they told me they have not used silicates for 10 years.

i'm going to guess it was coincidence

I also gotta say just one of those things!!

I'm going to say it was the paper gasket. Toyota never spec'd a paper gasket for the 4Runner. It was either FIPG in a groove or a fancy metal/rubber gasket. Now you know why...

I am with you on this.

The pump that is on it now says Toyota and Asin. It has a groove where I would say a FIPG material should be used. The groove was filled with some sort of liquid gasket and also a paper gasket was used. After looking the pump over after removal I see there are 2 weep holes and not just the one on the upper left (11 oclock) of the shaft housing that I was looking at for a leak. There is also another weep hole that is located lower right (5 oclock) and extended out a ways from the shaft housing so if it leaks the coolant is directed away from the timing belt. If it leaked there I could have mistakenly thought it was the gasket leaking. I put the pump in a pan of water and applied 30 psi of air to one weep hole while the other was plugged and had no air leakage from the impeller shaft area. But anyways the pump I ordered looks like it has a groove for a sealant and the remaining area really does not give much area for a paper gasket to seal up so probably looking at a FIPG material unless the gasket that comes with the pump has a sealant in the groove area.

water pump off ebay?
 

I just finished my timing belt/water pump/t-stat/belts maintenance this month and noticed the pump I got was the revised type (also Aisin) with NO grooves and the gasket was the rubber and guessin metallic-type.

What's the manufacture stamp on your pump? Mine still reflected '99 from the previous owner. The one I got off ebay had '14 on it. It's been a good couple weeks and I continue to cross my fingers that the coolant leak has finally stopped. I keep checking and it hasn't gone down. Really make sure the old gasket is carefully scraped off the surfaces as they said...

I went with Toyota coolant. But it seems to be a safe choice for most.
http://www.toyota-4runner.org/3rd-ge...olant-use.html

Tempting to try prestone.

I can not see a date on the old pump which had the groove. The new pump does not have the groove and came with a metal gasket with rubber sealant on both sides. It was dated 12-09-14 and manufactured in the U.S.A.. No leaks and am confident the gasket is a good design.