New noise from olds 307 ticking/knocking/exhaust leak?

[69hurstolds]

99% sure if it's an exhaust leak, it's in 1 (or more) of 3 places. 1- donut gasket where the cross over pipe bolts to the passenger side exhaust manifold, 2- flat exhaust gasket on TOP of the EFE valve on the driver side (bottom of exhaust manifold). And 3- the exhaust manifold to head- they did not come with gaskets from the factory and if there's any warpage, it'll leak there. An exhaust gasket would need to be purchased and installed if that is the case which may alleviate that issue.

Donut is part #1 in the diagram below.
EFE gasket is part #4.
If the exhaust pipes are leaking due to holes, then you really need to get those replaced.
Even though this is a VIN 9 dual exhaust system, from the cat forward, it's got the same pipes. Don't be fooled by the moron who approved this drawing. The EFE valve components #2, 3,4,5, and 6 are on the driver side.

 

[Tz44]

99% sure if it's an exhaust leak, it's in 1 (or more) of 3 places. 1- donut gasket where the cross over pipe bolts to the passenger side exhaust manifold, 2- flat exhaust gasket on TOP of the EFE valve on the driver side (bottom of exhaust manifold). And 3- the exhaust manifold to head- they did not come with gaskets from the factory and if there's any warpage, it'll leak there. An exhaust gasket would need to be purchased and installed if that is the case which may alleviate that issue.

Donut is part #1 in the diagram below.
EFE gasket is part #4.
If the exhaust pipes are leaking due to holes, then you really need to get those replaced.
Even though this is a VIN 9 dual exhaust system, from the cat forward, it's got the same pipes. Don't be fooled by the moron who approved this drawing. The EFE valve components #2, 3,4,5, and 6 are on the driver side.

View attachment 121715

#1

 

[Tz44]

#4

Doesn’t look like either have ever been touched. As soon as the car cools off I’m gonna get under it and see if I can feel any leaks around those. Thanks for the help

 

[Tz44]

Small update. Got all my exhaust parts in and replaced the donut gasket on the passenger side. If I can get the bolts loose I’ll do the drivers side exhaust flange gasket today too. I don’t have access to a lift right now so I’m trying to sort out how I’m gonna get the intermediate pipe in place.

This is what was left of the old donut gasket I replaced

 

[Tz44]

Tried to narrow down the origin of the noise today and it does seem to be coming from the drivers side.
It’s difficult to pinpoint it under the hood with the squeaking I’m getting from one or more accessories (thought I’d fixed that last weekend but apparently not lol) and the open exhaust.

 

[69hurstolds]

The gasket between the exhaust manifold and the EFE valve is GM p/n 22526988. Discontinued. But Fel Pro 60771 should be available at just about any auto parts store for about 3 or 4 bucks. This is the alternate gasket.

The exhaust pipe that connects to the bottom of the EFE valve does so without a gasket. It's a bell shaped bottom to the EFE valve. Just be careful with those studs and soak the living heck out of them with PB Blaster or equivalent. You bust them studs off and you'll be crying like a little beech. Nuts are 9/16" socket size. Nut p/n is 9414034. If you need to replace the studs, they're p/n 1246990. Pricey too, if you can find them. They have a small "divider" as it were where one part screws into the exhaust manifold about 1/2" and then bottoms out. Then you have about 2 1/2" of stud sticking out the bottom. I've heard of people using a 3" all thread 3/8"-16 size and gnarling up the threads about 1/2" from one end and screwing that end into the exhaust manifold. Anyway, if you want GM ones, they look like this.

Bolts for the down pipe from the passenger side exh. manifold to the cat converter uses 2 bolts, GM p/n 9442012. They're 2 1/4" long 3/8-16 bolts.

You know there are two springs on the donut gasket flange with special stand off bolts used for that, right? It appears you don't have that on yours in your pic. Just noticed that. Not a huge deal, but things outside of factory stock makes me wonder if someone hadn't worked on that car before. It basically allows for expansion and contraction by having spring pressure keep it in place rather than grinking down on the bolts. May be why it cracked the donut. Maybe. Anyway...

In case you wanted to get back factory stock with the donut gasket mounting:
You need (2) springs, p/n 587575
as well as (2) bolts, p/n 411405

PM me. I may have a couple of these spring bolts and springs for a nominal fee, if you need them.

 

[69hurstolds]

If you're exhaust is off or way too loud, I'd try to button up the down pipe to the cat converter and on back so then you KNOW that part of the exhaust is fine, and then if you really HAD to, you could drive your car for a bit and it will help you quiet it down enough to pinpoint the exact leak point on the driver side. It may not be leaking around the EFE valve. It may be the exhaust manifold to head. Because if you just go jerking on stuff and those studs bust on you, that means removing the exhaust manifold most likely. And that can be a real PITA.

 

[Tz44]

The gasket between the exhaust manifold and the EFE valve is GM p/n 22526988. Discontinued. But Fel Pro 60771 should be available at just about any auto parts store for about 3 or 4 bucks. This is the alternate gasket.

The exhaust pipe that connects to the bottom of the EFE valve does so without a gasket. It's a bell shaped bottom to the EFE valve. Just be careful with those studs and soak the living heck out of them with PB Blaster or equivalent. You bust them studs off and you'll be crying like a little beech. Nuts are 9/16" socket size. Nut p/n is 9414034. If you need to replace the studs, they're p/n 1246990. Pricey too, if you can find them. They have a small "divider" as it were where one part screws into the exhaust manifold about 1/2" and then bottoms out. Then you have about 2 1/2" of stud sticking out the bottom. I've heard of people using a 3" all thread 3/8"-16 size and gnarling up the threads about 1/2" from one end and screwing that end into the exhaust manifold. Anyway, if you want GM ones, they look like this.

View attachment 122259

Bolts for the down pipe from the passenger side exh. manifold to the cat converter uses 2 bolts, GM p/n 9442012. They're 2 1/4" long 3/8-16 bolts.

You know there are two springs on the donut gasket flange with special stand off bolts used for that, right? It appears you don't have that on yours in your pic. Just noticed that. Not a huge deal, but things outside of factory stock makes me wonder if someone hadn't worked on that car before. It basically allows for expansion and contraction by having spring pressure keep it in place rather than grinking down on the bolts. May be why it cracked the donut. Maybe. Anyway...

In case you wanted to get back factory stock with the donut gasket mounting:
You need (2) springs, p/n 587575
as well as (2) bolts, p/n 411405

View attachment 122256

PM me. I may have a couple of these spring bolts and springs for a nominal fee, if you need them.

I’ve been soaking them with Pb blaster but still no luck. I’m not in a huge hurry right now though so I’ll just keep working on them. I think I can get an impact to them and that’ll be my next move. I have some springs and studs here but may need a couple of the bolts. Ill message you if I do once I get them out.
I had three spring bolts on the exhaust pipe right above the catalytic converter and that’s where the donut gasket I replaced was. I’ll have to order another for the crossover pipe in case it crumbles when I finally manage to get it off. I’m thinking I’ll be able to replace the flange gasket above the EFE and the other donut gasket at the same time.
Thanks for the part numbers too

 

[Tz44]

If you're exhaust is off or way too loud, I'd try to button up the down pipe to the cat converter and on back so then you KNOW that part of the exhaust is fine, and then if you really HAD to, you could drive your car for a bit and it will help you quiet it down enough to pinpoint the exact leak point on the driver side. It may not be leaking around the EFE valve. It may be the exhaust manifold to head. Because if you just go jerking on stuff and those studs bust on you, that means removing the exhaust manifold most likely. And that can be a real PITA.

If I narrow it down to the exhaust manifold I may just end up leaving it alone unless it ends up driving me crazy lol. I don’t see myself keeping this 307 in the car forever but want to make sure it’s in good running condition. But I do have to replace the TPS sensor soon and I’d like to replace the oil pan gasket. If I keep this motor in the car long enough to do the oil pan gasket I’ll look at adding exhaust manifold gaskets too. Might make it a little easier with the motor picked up.

 

[69hurstolds]

That exhaust diagram is totally whacked. I kept looking at it then just a few minutes ago, realized that something wasn't quite right.

I still don't get where there's an exhaust donut on the cross over pipe. I distinctly recall the crossover has flanged ends. There should not be a donut on the crossover. If there is, something doesn't seem right.

There should be 3 bolts/springs on the down pipe to the cat converter. THREE. The donut should be on top of the down pipe to the converter.

Here's what you should be seeing according to the 1987 Chassis service manual.