'74 FJ40 Weird Water Pump Leak ?

[Spike Strip]

4/74 FJ40.

Help with a coolant leak problem, please:

Installed a new OE Toyota water pump, all hoses, radiator, heater valve, two years ago... Less than a 1000 miles.

I'm chasing a strange coolant leak that I can't duplicate. Pressure tested at 13 psi. No leak. No loss of pressure. I 've run to operating temp. No leaks with engine running or stopped...

Not going out the tail pipe. Don't see coolant in the oil.

But I will occasionally overnight, find a dried puddle of coolant under the front of the motor and found this (see pix) from the weep hole? But it's always dry when I check it. (I've checked the weep hole with engine cold and pressured to 13 psi, and at operating temp).

I can't find evidence of coolant loss anywhere else.

I guess new pump could be bad? If yes, why the intermittent leaking? Bad seal?

 

[John Smith]

If the weep hole is weeping your water pump bearing and or seal is going. In my experience they don't self mend and fail spectacularly on me soon after they start weeping. Was the pump NOS or a rebuild? Are you running your belts super tight? 1000 miles is a terribly short lifespan for a water pump.

 

[Spike Strip]

Pump was New in the box, purchased from American Toyota. I think I got one of the last ones available... Belt is adjusted properly, and new HD Gates.

 

[GA Architect]

I feel you pain.

I bought a supposedly new '77 OEM water pump from a guy here on MUD, and after 100 miles or so on my new/rebuilt 2F engine and all new Toyota parts for accessories.....THIS:

That leak made a mess of my engine bay. Now my OEM water pump wasn't from a Toyota dealer, so I blame myself, I bought a PIG-IN-A-POKE. (a.k.a. - a piece of $hit!) I can only surmise that the inner seals dried out or wasn't rebuilt correctly?

Needless to say, I quickly replaced this unit!

 

[Spike Strip]

Yeah, maybe from poor storage or something... And I was happy I was able find an OE Toyota.

I guess the hidden purpose of this thread may be to talk myself out of denial .

But if the seal were bad, it should leak under pressure?

Q:

Wonder if it's possible to leak from the backing plate and 'wick' up the bottom of the pump to the weep hole?