Spicer

I'm working on my friends '90 pickup w/ a 3vze, there's a coolant leak towards the back of the block that I've narrowed down to probably being either the coolant bypass pipe that runs across the top of the block under the intake manifold (toyota part #16268-65011) or a head gasket. I've got the intake manifold off to expose the bypass pipe, but I can't figure out a way to take it off / put a new one on without removing the heads. I've turned and twisted it all over the place but it just seems to be stuck on something any way I go. I'd really like to avoid doing the whole headgasket job if I can, so it would be great to be able to take this out and look it over for leaks. Anyone know a trick to get it out and put a new one in?

Obviously I could get the old one out by bending or breaking it, but that wouldn't really do me any good since I'd still have to get a new one back in in it's place.

Here's a picture of what I'm talking about. It's the tube down the middle of the motor there.

voiddweller

Looks like that large bracket that it runs through towards the back might be stuck, you can't pry it out?

Get all the nuts off?

fnrunner

I know this is an old thread but any chance you remember what it took to get this by-pass hose out?
I've got an 89 @208k mi with a similar issue....thought it was the water pump until the new aisin pump appeared to leak immediately after it was replaced. WTF! Under closer inspection I have coolant puddling under the intake in the "valley" of the engine.
I'm going to try & blow air through this hose after taking the water pump off again & see if it's clogged or maybe it will blow coolant into the valley if it has a hole.
2 years ago I had to replace the upside down U bypass hose @ the back of the intake...and have cleaned out the rad a couple times in the last 60k miles/16 yrs I've owned it.
This has to be related....
Why the F did Toyota put all of these steel coolant lines everywhere on this engine?! Especially under the intake!!

Any shortcuts? Can the intake be removed as a unit? I haven't dug into my 3.0 this far or the FSM...but have had the upper intake off more than once for the other hose & earlier for a pvc mod.

Any thing I should replace while I'm in that far?
Knock sensor seems to be a common issue? Knock on wood mines never had an issue yet, unless I just jinxed myself...

This sucks!LOL
Thanks for any help!

amamike91

There is a nut/ stud and bolt/ tube support on the back side of the pipe assembly with one bolt in the middle of the V then the 2 bolts that are in the flange. you don't have to pull the heads to get it out.

amamike91

The intake does have to come off. Best to replace the knock sensor and pigtail while you are in the there.

fnrunner

Thanks for the insight amamike....looks like I'd better get some intake gaskets on order.... :/

fnrunner

Here's a crazy thought to replacing that knock sensor....
could it really detect a knock on the outside of the head & all the way across the block from cyl 1-3-5???

scope103

This has come up a few times on this forum, and some posters do claim that it made the code 52 go away. Me, I just don't believe it. Why would Toyota bury the knock sensor in a sensible (but inaccessible) place, when they could just hang it outside the engine? But hey, if it's on the internet, it must be right, right?

I like how in the video he removed the plenum (upper intake manifold) "and noticed where the knock sensor was." x-ray vision? (The knock sensor is under the lower intake manifold.) So I'm guessing he "noticed" where the harness to the knock sensor went under the edge of the lower intake manifold.