Exhaust Issues, Help!

[zephyrus17]

Following my Mazdaspeed Mount failure, I decided to go back to the default mounts. However, there's some terrible noise and it sounds like a tractor. And there's also smoke. I'm not sure if this smoke was from the exhaust wrap I removed or from the engine. I torque everything according to Mr Haynes, so I'm not sure what's going on. I have a video for you guys, if it helps.

[NitroDann]

hard to tell from video if its internal or cracked exhaust manifold.

Dann

[zephyrus17]

By 'internal' do you mean smoke coming from the gap between the block and the exhaust?

[NitroDann]

usually if you have an exhaust leak there wont be smoke, exhaust is usually clear.

Smoke is often from greasy hands on hot parts.

The sound I would guess is an exhaust leak, either from a dodgy gasket or lack of correct tightening or the exhaust manifold has a crack in it.

My reference to internal was saying that from the video its impossible to say if its an exhaust leak, or dropped valve, or cracked piston or etc etc etc.

Dann

[zephyrus17]

usually if you have an exhaust leak there wont be smoke, exhaust is usually clear.

Smoke is often from greasy hands on hot parts.

The sound I would guess is an exhaust leak, either from a dodgy gasket or lack of correct tightening or the exhaust manifold has a crack in it.

My reference to internal was saying that from the video its impossible to say if its an exhaust leak, or dropped valve, or cracked piston or etc etc etc.

Dann

I think the tightening can be ruled out since I tightened everything twice to the correct torque. A crack shouldn't happen.. I've been careful with it... hmm

Let's hope it's the leftover exhaust wrap 'dust' or just crap from my gloves..

[NitroDann]

The smoke will not be exhaust related, it will be heat related. Hot exhaust that has greasy fingerprints on it, however the exhaust manifold is probably cracked or the gasket is FUBAR.

Take a metre of garden hose and use it to locate the leak.

Stock NA manifolds crack often just with age.

Dann

[zephyrus17]

Take a metre of garden hose and use it to locate the leak.

Wet it as it's running?

[NitroDann]

No, use it to listen in close to the engine without burning your ear.



Boy am I glad you asked before you tried.

use it like a stethoscope to locate the leak, if its from the gasket you need to check it is clean and undamaged or get a new one, if its from the manifold you will need a new one of those.

Dann

[zephyrus17]

All right.. I'll give it a check! Thanks. If it's the manifold's cracked. Fancy I could get a manifold from you?

[zephyrus17]

I took it out for a spin, and noticed that at acceleration it sounds very much like a diesel tractor. What does that lead to?

[Apu]

I cranked my (standard Dell) speakers up and it sounds really tappetty and that stood out over any exhaust noise. It sounds like when a mechanic dropped a washer into one of the cylinders of my dad's car.

I haven't heard many cracked manifolds but they always sounded more like a big exhaust (if you know what I mean) and the exhaust smell as pretty clear, as opposed to just smoke).

[93_Clubman]

Agree it does sound similar to HLA noise, but it seems to be missing the high frequency range noise also associated with HLAs. Given the recent exhaust work, worth rechecking what had been done there first for a leak.

[zephyrus17]

I know what you mean. Initially I thought it was just something wrong with the belts or something was caught in it. But when taking it for a drive, it didn't make a sound under constant velocity or lift off, but only under acceleration. So I've pinned the issue with the exhaust. It can't be anything in the cylinders because I never open the spark plugs and stuffed the exhaust ports up when the header was off. There was no smell, and the smoke is now almost all gone.