Need help with possible intake/exhaust manifold leak...

[85BrownCruiser]

I tried searching but came up with nothing.
A couple of months ago i had my cruiser (new to me), 1985 FJ60 2F, serviced for what i thought was a vacuum/exhaust leak. Had a bad "pfft pffft pfft" sound under acceleration. Mechanic pulled intake/exhaust manifold (was warped and leaking), had surfaces planed, and re-installed with new gaskets. Along with this i also had the radiator re-cored and serviced. So, life was good, cruiser running cool and quiet! Fast forward, and i have not been driving the cruiser that much recently, and the "Pfft pfft pfft" noise is coming back, especially under acceleration. when the truck is warm, it quiets considerably, leading me to believe that their is either A: another gasket leak (ive read about EGR and J-tube) B: the same gasket blown again or C: the bolts need re-torqueing.
I really want to avoid bringing it in to him for something that could be simple (he's 50 miles away and $), and i'm a decent mechanic, but i need your expertise. I've read about the spraying the carb cleaner, listen for change in idle trick. that sounds good. and the proper sequence to re-torque the bolts.
My question, HOW IN THE HE!! do you guys get to it? do i need to remove the air cleaner assembly and the carb? Is there some sort of shield there? from underneath? keep in mind i'll be working with a $85 set of craftsman tools

any advice is GREATLY appreciated!

 

[2mbb]

You might need to spend a little more $ on some extensions and univesals. There is a heat shield that sits under the carb., but you can get to most if not all of the manifold bolts by using a proper lenght extension (6", maybe), the last bolt is also difficult, but you can get it with a swivel joint. It's not a bad thing to spend money on more tools, especially if it expands your capabilities...

It's not a bad idea to re-torque the manifold bolts. However, if you can gear the sound with the hood up, you can use a length of tubing as a stethascope. Put one end near your ear, and hunt around with the other end to locate where the noise is coming from.

Good Luck.

 

[D'Animal]

Make sure you EGR system is in check and the smog items as well.

Some components are only used on acceleration and deceleration.


X 2 on retorqing.

You do not have to remove the carb. A thin wall 17mm socket and extension is all you would use.

 

[soggy60]

OK, here goes....

pfft, pfft . . .if you can hear that, more likely an exhaust leak.

Get a length of rubber hose ( 2 foot or so); one end to ear, other end tape to footruler, garden sticke...so you can probe around and not burn or cut hand....

Start engine....

Probe around jount where ex manifold & downpipe bolt together...the joint and 'just below' where the downpipe flange is pressfitted to the down pipe.... (that's where mine leaks,,,,for now)

Probe around where ex manifold mates to block (top side)

Get under truck

Probe around where ex manifold mates to block (bottom side)

Probe around where EGR "J" tube joins # 6 exhaust at manifold.
( a very common area for the put-put-put . . .I removed & used block off plate when I desmogged)

The 'spray carb cleaner' is used to find Intake Manifold leaks....

Have fun

Pete

Oh, in 2mbb's pic, I've found it almost impossible to get to the two nuts ( 1 , 2 ) without removing the small heat sheld bolts (12 mm head) a few inches "left right" { in the above pic} of carb, and gentley bowing up the heat shield plate . . .maybe I need to get a real thin wall 17mm socket

 

[D'Animal]

The Air Rail may have developed a crack at one of the "nipples". Very common to have them crack at the main tube when removing and reinstalling, kinda hard to find.

 

[85BrownCruiser]

Wow thanks all! I'm just going to have to dive in there this weekend. I have a couple of extensions, i can invest in some more and some thin walled sockts, but i can only "see" one of the bolts, on the left hand side. maybe it's more of a look at the diagram and "feel" thing. I'm gonna try and get that heat shield off and get to the bolts if it makes it easier.
I'll also try the hose/tube trick to see if i can diagnose the problem.
I'm thinking the exhaust leak sounds louder towards the back, so it could be that J-tube.
you guys are great on here, can't thank you enough
This site rocks

 

[2mbb]

Bolts 1 through 6 are 17mm. Bolts 7 and 8 are smaller--14mm IIRC. The bolts are there, you'll find them.

 

[D'Animal]

They do not HAVE to be thin wall, they just cannot be the thick wall designed for impact guns.

 

[hank14]

I replaced my intake and exhaust manifold gasket about 3 months ago. I used the Fel Pro gasket as others recommend.

I also replaced the J-tube with the sor.com stainless one and a new Toyota gasket.

I did not separate the intake and exhaust to replace those gaskets. I probably should have, but was afraid of messing up the plate between them.

I had the assembly checked for level by a machine shop. Everything was OK.

I also did not pull apart the swivel ends of the exhaust manifold to replace the "wave gaskets." Now I wish I did, because I think it's leaking there and from the exhaust manifold to exhaust down pipe mounting location.

Looks like I'll be doing this again sometime. At least the loud tft tft tft sound from the J-tube is gone.

You can use the vacuum tubing from the A/C idle up solenoid to introduce some Seafoam into the intake, and see where your exhaust leak is coming from.

 

[Butt Ugly Chuck]

To get at the nuts that secure the EGR tube flange, I've found it best to get some LONG extensions and a deep 12mm socket and access them from under the rig. That's the particular surface that gave me my "pfft pfft pfft" battle. I eventually broke down and bought SOR's stainless version that has a much thicker flange less prone to warping than the stock version. Problem solved for me (knock on wood).

Butt

 

[hank14]

To get at the nuts that secure the EGR tube flange, I've found it best to get some LONG extensions and a deep 12mm socket and access them from under the rig. That's the particular surface that gave me my "pfft pfft pfft" battle. I eventually broke down and bought SOR's stainless version that has a much thicker flange less prone to warping than the stock version. Problem solved for me (knock on wood).Butt

Roger that. If yours is making the tft tft tft sound, bet on the J tube until proven otherwise. Mine had the J tube replaced with a Toyota factory one twice, and 3 or 4 new gaskets, before the SOR stainless one was installed. Night and day difference in design.

 

[85BrownCruiser]

Problem FOUND! man i love this site...

and thanks to EVERYONE and their suggestions. I fabbed up a old vacuum hose, indeed found the noise coming from the J-tube. I bought a 3/8" wobbler and some extensions to add to my tools. With that i re-torqued the manifold bolts (all were pretty snug). I then got underneath and the bolts on the j-tube flange were both pretty loose. Tightened both up, drove around, and it was 95% quieter. once the engine was hot i got underneath and tightened a little more, eliminated some more noise.
I still think that flange is warped and i'm sure the gasket is toast, but it's such a relief to find the culprit.
i'm gonna order that stainless version from SOR to try and fix the problem once and for all.
Thanks again to EVERYONE for all the advice and diagrams and words of encouragement.

 

[hank14]

Good job. It will start leaking again....very soon, until you get the stainless J-tube. Be sure and get a new Toyota OEM gasket or a Remflex one (search here).

One other thing to do to check your intake manifold is use a vacuum gauge and measure vacuum at various ports on the intake. Should be 17-19. If it's low, there may be a leaky intake/exhaust gasket.