I have a coolant leak on the driver side right above the head gasket from what I can see from underneath, so I know its not a head gasket problem at all. I was looking at threads and pictures online and it seems like the lower intake gaskets have a coolant passage on the front and the rear which allow coolant to run through the lower intake from side to side of the cylinder heads. It appears the leak is coming from the driver back head right by the top of the lower intake manifold. Can anyone verify that this is true? I didn't any info on any rebuild threads about cooling flow

 

sure its not dripping from the throttle body coolant hose? I had that prob one time on a past 3.0 i had and it was a hard leak to trace. Dunnno alot about the 3.0 intake manifolds... didn't know they had coolant passages on the rear i thought they where toward the middle but eh dunno...

 

Nah, I just replaced that hose not too long ago, I don't even have mine running through the throttle body anymore, and as far as all the heater hoses and center by pass hose and the junction on the rear of the engine with the sensors, they are all dry.

 

I guess I should mention also, it ONLY leaks, over night after the truck has been sitting for hours at a time, once its warmed up for the day it leaks nothing and is bone dry. The leak amount is a small puddle underneath with no noticeable loss to the radiator at a time. When I look under the truck up next to the trans I can see the back of the coolant by pass hose underneath the intake, and to the left of the I can see the bottom of the lower intake with some pink build up but like I said that area where I see pink to the head gasket is about 2 inches, that why I'm ruling head gaskets out

 

it could be leaking from the thing that bolts to the back of the lower intake manifold, or one of the small hoses coming off of that

 

nah that junction is more on the passenger side and dry, along with all the hoses for the heat and rear heat etc. I def see pink build up underneath the lower intake next to the by pass tube

 

yes... as far as Ii can remember... there are coolant passages in the mani. I do remember a rubber gasket around a hole that looked like it had coolant residue in it.

 

 

thats the hole I was talking about... I'm pretty sure it is a coolant passage, but it been a while since I had any of mine apart.

 

Thanks team, I figured I'll re-do the idler pulley while I'm there, hopefully be able to clamp the belt to the gears to just remove the manifold real easily with out disturbing the timing

 

dont bother... I'd just pull the belt. easy enough to put back, just dont move the cams.

U gonna need play in that belt to get the idler out anyway.

 

doesn't the idler just lay in between the cam gears?

 

ya, sort of... but the t belt rides on the under side, so ya... u might be able to get it out, but how u gonna get it back in.... I know others have said they done it... but I personally think its best to do it right the first time... that way you dont cause more problems trying to force it back together. my $.02

 

yeah, I suppose your right, I wont know until I get ready to do it, the leak isn't bad enough where the truck isn't drivable, I work for Toyota, I have just never personally dug into one of these motors that deep

 

I would just go "by the book" the fsm that is... trying to take short cuts usually dont end well. U dont have to disturb the timing to pull the belt, just make sure it @ tdc before hand, just in case.