My 4runner has been sitting in the garage and when inspecting the engine bay I noticed my fan shroud looked wet and dirty. It's usually always wiped clean. I peeked around and noticed it was wet around the lip all the way around the upper metal lip of the radiator. the coolant was definitely low, no signs of overheating even when i topped off and drove it to find the leak.

After driving it part of the day, it lost coolant, but I couldnt tell from where. no obvious drips/leaks. at ~148k it needs a new radiator and I plan to replace anyways but have read that the water pump could possibly leaking. Not really sure how to inspect that. Where else should I be looking? Is it possible that the radiator cap is bad?

from what i've seen, wetness around the upper rim of the radiator and it looked like the fluid was sprayed(atomized in a sense) and sprayed on the outside of the fan shroud. coolant level in the overflow drops. No milkshake in tranny or radiator fluid.

Currently at school so I cant take pics or check to see if my waterpump was ever replaced.

Thanks Gents.

Sounds like the radiator has a leak at the seam. It happens.

To check the water pump, locate the lowest large pulley on the front of the engine and shine your flashlight underneath it. If it's wet, that would be cause for concern.

Just keep the overflow tank level correct until you get a chance to replace the radiator.

If it's not a very obvious leak, it sounds like it could be an old coolant hose. Often times, the leaks aren't obvious until the engine is hot and the coolant gets pressurized.

Have you adjusted/moved the hoses recently? On old hoses, if you don't seat the clamps back in exactly the same position on the hose, they'll leak because the indents on the hose have hardened and so the clamp doesn't apply equal force on the nozzle.

The following hoses could all be culprits: upper radiator hose, lower radiator hose, oil cooler line hose (to water pump), oil cooler hose to engine block (this is a very small U shaped hose and difficult to locate)

Thanks guys.

I bought the truck in December and have no taken off the hoses. They look brand new. I will check the water pump today after class and order a radiator/thermo/gasket/cap for preventative maintenance.

I keep wanting to throw money at the suspension before I lift it but SOMETHING ELSE always pops its head up. Haha.