leak in manifold

[jeff_j1701]

Hello,

I recently had a new catalytic converter replace in my '07 Vibe.

The mechanic thinks there is a hair-line crack in the manifold; he can hear it but he can't see it. He suspects its where the individual pipes come together though.

I'm wondering if it could be along weld joints. Is there any way to determine where the link may be?

If I can find it, would something like JB Weld or a similar steel putty work on it?

My mechanic suggested replacing the manifold ($280 for the manifold, $100 labour) but I don't really want to spend money right now since I just replaced the catalytic.

Thanks.

[joatmon]

Its fairly common to have the intake manifold gasket leak, its really uncommon to have a manifold crack, not sure if anyone here ever had one crack. However, a gsaket leak wouldn't necessarily sound like it was coming from the input side of the manifold, but there's not a lot of distance between the two, and I suck at sound isolation of problems.

I only found one thread about an intake manifold crack, viewtopic.php?t=29466 where sparrow's mechanic said the intake manifold was disintegrating, but it turned out to be nothing actually wrong with the car

Not sure how you'd test. I know some shops can check for vacuum leaks by pumping in some sort of fluorescent smoke, leaks show up with a UV light, but I've never done it or had it done.

Depending on where and how significant a crack is, a surface patch might work, but if its in a place engine vibration could somehow flew it, it might not hold.

Are you having any performance issues or perhaps a check engine light with a code that indicates a lean condition?

[jeff_j1701]

Check engine light on at time but mainly off. The gasket appears fine.

I never knew about UV light thing. I will look into it.

Thanks.

[jolt]

Just want clarification on which manifold you are talking about; the intake manifold or the exhaust manifold? Your first post sounded like you are talking about the exhaust manifold and joatmon post is about the intake manifold. What are the codes, if any?

[zbyers]

Dorman Exhaust Manifold 674939 is $150 or so on Rock Auto.

https://www.rockauto.com/en/catalog/pon ... ifold,5860

1ZZ Intake Manifold is about $220 on Rock Auto. It can be had cheaper on eBay for a used one.

https://www.rockauto.com/en/parts/dorma ... ifold,5536

https://www.ebay.com/p/672275180?iid=19 ... gIdhfD_BwE

I'd presume you were talking about the exhaust manifold? What led you to replace the cat to begin with? as Jolt asked, what CEL codes do you have?

[joatmon]

Just want clarification on which manifold you are talking about; the intake manifold or the exhaust manifold? Your first post sounded like you are talking about the exhaust manifold and joatmon post is about the intake manifold. What are the codes, if any?

You're right, I misinterpreted . Intake isn't welded so it must be exhaust. Please ignore my previous.

Thanks for catching that

[jeff_j1701]

Hi.. yes it is exhaust.

I take my vibe in for an inspection every 6 month at the dealer, and they told me i had a leak.

Went to another shop for a 2nd opinion, and they showed me the leak.

I lent my obd scanner to a friend, so i dont know the code right now.

I don't know if JB Weld or some other steel putty would be good to use on a manifold.

[joatmon]

JB weld has a extremeheat high temperature variant that says "Ideal for repair work on : exhaust manifolds, ...". Sounds like worth a try

[jolt]

I have never in my lifetime seen any type of of putty, JB Weld, epoxy, etc.. hold on a exhaust manifold. The temperature, expansion and contraction of the metal as it heats and cools will not allow these types of things to hold on the manifold. They all break loose. You need to replace the manifold.

If you due a search on this forum, you will find a post about replacing the tubed exhaust manifold with the aftermarket Dorman cast iron exhaust manifold. I believe they had some trouble with the new manifold sealing with their exhaust pipe. Anyways, exhaust will crack over time due to not having the mass to absorb the temperature changes, which produces the expansion and contraction of the metal. This is like bending a piece of metal back and forth until it snaps. Having a bad convertor can also put more stress on the exhaust manifold with increased temps at the manifold due to back pressure from the bad cat.

JB Weld is used on oil line fittings on race cars for a dry, leak free threaded connection. How you get the threaded fitting apart after being JB Welded is to heat the fitting. The JB Weld softens and the fittings come right apart with heat. If it gets over 600°F, JB Weld will not hold and your exhaust manifold sees temps above that.

[Natty Vibe]

I had an exhaust leak too and was able to detect the leak by hooking up a small shopvac to the tail pipe and spraying soapy water on the manifold with heat shield removed. I'm not sure if my leaks started at the welds but I remember bubbles on top of the exhaust manifold. I paid $160 for my oreilly dorman, I see the rock auto link above is $125 now.

You can always try JB weld and let us know if it works.

[Vulcan]

I have a similar leak, and found it by putting a vacuum on the tailpipe.

Seems to be right on the exhaust flange just down from the manifold, way up under in the center of the car (2006 AWD)
There are some sealing products that rate to 2500F, and I've seen plenty of videos where this does work, at least for a while.

I would have tried it already, but the back bolt and lower passenger side bolt on the heat shield are too corroded for me to remove. I've tried an Irwin extractor socket, which seems to grab, but as soon as I try a wrench even the Irwin just slips right off. After about an hour trying to get those last 2 off so I could access the flange, I had to give up.

I notice on the Toyota Matrix version, the back 2 bolts of the heat shield are much better placed.

Pretty frustrating stuff, time to hand it off to the Pros. Problem is there are other issues with the car I wanted professionally done, might not have the funds, may just have to drive it loud and/or illegally for a while.

[Vulcan]

The 2nd mechanic estimate proved total BS. I left the car with him for a few hours, and he said he was "still waiting to see if I can get parts". I asked what parts, and its just the spring bolts and donut gasket. I already knew that, and those aren't hard to find. (That whole section of pipe however is not easy to get)
He put the car back down, and said he'd call when he heard. Obviously, he never called me back, and doesn't want to do the job. I'd rather he just admitted it. Wasted half a day of my time.

So, I'll go back to the first place, first thing tomorrow (Monday) morning. 400 bucks doesn't seem that steep to me now, if it can be fixed right. The mechanic who looked at it has worked there over 20 years. The exhaust leak is causing a lot of corrosion, it destroyed the lower part of the heat shield - its got to be fixed before it does more damage.