sprockmember

Hey guys,

I just noticed a coolant leak this morning when I moved my truck... as in, the motor wasn't running more than 3 minutes and there were already drops on the ground.

It was leaking from the front side of my oil pan on the passengers-side with a trail that appeared to lead under the timing belt cover.

I looked on top of the motor, in between the intake manifold and timing belt and noticed that there was coolant puddled here. (pics below)

Here's the area...


Here's a closer look at the area where the leak is...



Any guesses?

cjserio

It's hard to tell....if it's coming from down near the timing cover, it's probably the water pump. You can pull the top timing cover off and take a peak without too much drama.

TNRabbit

That is most likely one of the two hoses that pass thru the throttle body. They are about as big around as an index finger.

....water pump...? Really?!?

cjserio

His images don't really show any evidence of a leak source and he said the trail leads to underneath the timing cover. Next time you're up in CT, I'll buy you a beer. You should relax a bit.

Wrenchinjoe

lmao - that is hilarious!

+2 on the coolant hoses that connect to the throttle body. When they leak, the coolant collects on the lower intake manifold. Look closely at the hose coming off the front side of the TB and follow that to where it reconnects to a fitting on the lower intake... that is pretty close to where you think the leak is coming from.

The water pump is mounted below the lower intake manifold so any leak would have to run up hill to pool there, and also I think if the water pump were leaking it would likely stay within the timing cover and drain out through the drain hole in the lowest cover (the one that surrounds the crank pulley).

Let us know what you find - good luck.

sprockmember

Thanks guys... even though it doesn't seem to be leaking anymore... I'm going to tear into this thing pretty soon. It's a new 4runner and I have some "house-cleaning" projects to do on it anyway.

Just from examining it a bit closer, there is a coolant hose from the TB to the front of the intake manifold... the hose looks good from where I'm standing, we'll see when it gets ripped into. Thanks again dudes! -Nels

greencactus3

what is the point of the coolant through the tb?

TNRabbit

Warms up faster & there is a sensor there to tell the ECU that the engine is warm so it changes out of cold mode for fuel mix, etc.

greencactus3

good to know... explains why my truck is running rich since i bypassed that... I'll be rerunning the hose through that again soon

Tubbyfatty

https://www.yotatech.com/forums/f116...ak-3vz-194240/

greencactus3

this is a separate sensor from the ECT sensor at the back of the block?
not seeing anything about a sensor in the throttle body in the FSM...