4.0 leaking coolant waterpump

This is a good read, applies to 2nd Gen Tacos:

http://www.rav4world.com/tsb/2011/T-SB-0117-11.pdf

 

From the Toyota TSB listed above:

NOTE
The seal and mating rings are lubricated by the surrounding coolant; a small amount of coolant
leakage is normal.
Temporary Leaks
If debris becomes trapped between the mating ring and seal ring a small gap is formed. This allows
coolant to bypass the mechanical seal, flow into the fluid catch pocket, and drain out of the weep
hole. This condition is temporary and will no longer be present once the debris is crushed or works
its way out of the seal. Water pump replacement is not necessary.


Mine has been leaking/weeping forever. I have never seen it wet, never had a puddle and reservoir has never been empty. Get yourself a gallon on Toyota antifreeze (and a gallon of distilled water) next time you pick up filters and you're good to go for a long time....probably.

 

I've just found the same issue most are seeing on the bad wp / seal. I've always had a slight coolant smell after a drive but it'll be small wiffs. Finally took the skid plate off and saw weeping/crusts formed around the pulleys and front of the block. Never any puddles or even drips in my garage. Funny thing is I haven't lost coolant, overflow reservoir remains at the same level, even after long drives . In a few weeks i'll be driving quite a ways to tow back a jet ski.... not sure i should risk this but not sure if i'll have the time to replace the WP. I may have to bite the bullet and take the job on instead of risking being stranded hours away from home.

 

I totally understand the uneasy feeling. Just take a gallon of that fine toyota coolant with you. That gallon will last you till you sell it and you can give a half gallon to the new owner. The TSB says some leakage is normal. It's not blind faith on my part. I just think that the odds of catastrophic failure is 0%. Another reason to raise the hood and check fluids during fillups. I personally don't mind adding 6-8 oz of coolant every couple months. I think this seal arrangement is a trade off between a LONG life and coolant lubricated seal vs a shorter-life absolute seal that cannot "flush" itself. Best of luck either way!

 

Thanks for the reply BCephus ,

I went ahead and replaced the pump with an Aisin pump, it leaks even more now, LOL .. just my luck. i started it up and theres a fairly steady drip coming down the block. I haven't driven it yet, just bled the system and let it idle for some time. One of the areas that was leaking actually stopped, but I think now the leak has sprung from another location. I'm going to try to drive around town tomorrow and see how it does, Im hoping the new metal gasket needs to expand and wear in and maybe try to tighten a few bolts that I can get to... this sucks. Prior to the pump swap, there was quite a bit of crusting down the front of the motor, though there were no drip marks or overheating. I wire brushed the mating surface and cleaned it off as best I could with a razor blade to get the old gasket material on there, dont think I did a good enough job so it may be another 2-3 hour job tomorrow... argh.

 

Man that stinks. I was putting a winch in my ARB bumper late last night and gave my seep/leak the eyeball. Every time I get nervous about it I go back and read the tsb...and end up not pulling it. Thats a lot of bolts and seating surface to remove, clean, torque etc. I hope you get it today. Best of luck!

 

Just found this thread...and been reading it.

My truck has been loosing fluid since the first year when I bought it new. It'd been leaking at the radiator cap. I've had 3 caps in 7 years.

I drive to my Toyota dealer and they top off my overflow tank for free.

But now that I'm 62k, gotta keep an eye on this. I'm sure I'll have to change the pump soon. UGH

 

Update ! So after some driving and putting on a few hundred miles after the pump swap, seems like the seeping and smell has stopped . For sure after the swap there were many active leaks present, but it looks like after a few heat cycles and some distance the gasket has finally sealed itself and system worked out any debris. I don't smell any coolant after driving and don't see any leaks or dribbles anymore. One thing I noticed, when I pulled the pump, all of the bolts were very loose, didnt take much to break them, they didnt really need to be broken or loosened. When I did put them back I tightened them a bit snugly , probably more than specified torque but i didn't lock tight them this time thinking there may be a separate issue. Hopefully it holds, goodluck to anyone who tries the replacement, fairly straight forward install and takes a bit of time but worth it!

 

Nice. Glad you fixed it!

 

I know you posted this 4 or so years ago, but you don't happen to still have that thing sitting around do you? Just came back from getting my engine check light/transmission dealt with and was told my pump is leaking as well. I know it's a long shot but if you do please let me know.

 

Has ANYONE read the TSB posted by Medusa 1066? Just because you have residue doesn't mean the seal has failed. I am still on my original wp, and still have more than 3/4 of my original jug of premix Toyota antifreeze. It has been "self cleaning" for a long time...like 55,000. I have 115k on it now. Clean the residue and see if it comes back in a short period of time or if it rinses the trash out and stops. Mine has shown indication before, and reseals after flushing the trash. They knew what they were doing when it was designed. Its not meant to be an absolute seal until replacement is needed. Here's the TSB again: T-SB-0117-11. It might save y'all some work.