Diagnosis By Noise?

[onesea]

found this lurking somewhere on the internet, is it correct?

 

 

SOURCES OF ENGINE NOISE

1) MISFIRING or BACKFIRING.

POSSIBLE CAUSES.

- Fuel in tank has wrong octane/cetane number, or is wrong type of fuel.

- Ignition system faulty.

- Engine temperature too high.

- Carbon deposits in the combustion chamber start to glow and cause misfiring.

- Timing incorrect, which causes misfiring in the intake/ exhaust system.

REQUIRED ACTION

- Determine which type of fuel was last put in the tank.

- Check the ignition system

- Check the engine cooling system

- Remove the carbon deposits by using fuel additives and driving the vehicle carefully

- Check the timing

2) VALVE TRAIN FAULTY.

POSSIBLE CAUSES.

- Valve clearance too large due to faulty bucket tappets or incorrect adjustment of valve clearance.

- Valve timing incorrectly adjusted valves and pistons are touching.

- Timing belt broken or damaged.

REQUIRED ACTION

- Adjust valve clearance if possible and

renew faulty bucket tappets – check cam

condition.

- Check the valve timing and adjust if necessary.

- Check timing belt and check pistons and

valves for damage – renew any faulty parts.

3) FAULTY ENGINE COMPONENTS.

POSSIBLE CAUSES.

- Pistons.

- Piston rings.

- Cylinder head gasket.

- Big-end and/or main bearing journals.

REQUIRED ACTION.

- Disassemble the engine and check

components.

4) ANCILLARY COMPONENTS

POSSIBLE CAUSES

- Engine components or ancillary components loose or broken.

REQUIRED ACTION.

- Check that all components are secure, tighten/ adjust as required. Renew if broken.

[Ian Frog]

As with almost anything like this on the net it`s not wrong per se but it is over simplistic.

It takes a lot of experience to start diagnosing faults by sound alone and I for one would be looking for a lot of other factors before plumping for a cause and getting the spanners out.

Sorry if that`s not much help.

Cheers

Ian

[Mississippi Bullfrog]

When exploring engine noises I find a mechanic's stethoscope takes a lot of guesswork out of the process. 

 

Considering how cheap they are it's amazing how few people have one. 

[JRH]

28 minutes ago, Mississippi Bullfrog said:

When exploring engine noises I find a mechanic's stethoscope takes a lot of guesswork out of the process. 

 

Considering how cheap they are it's amazing how few people have one. 

Mine doubles up as a screwdriver. 

[Fiddlesticks]

My wife goes nuts if I stick a cotton bud in my ear, I'm not risking it with a screwdriver!

[V650]

1 hour ago, Mississippi Bullfrog said:

When exploring engine noises I find a mechanic's stethoscope takes a lot of guesswork out of the process. 

 

Considering how cheap they are it's amazing how few people have one. 

Can be very handy when you are deaf as a post like I am

[Tiggie]

4 hours ago, Mississippi Bullfrog said:

When exploring engine noises I find a mechanic's stethoscope takes a lot of guesswork out of the process. 

 

Considering how cheap they are it's amazing how few people have one. 

 

I wonder if I could use my Wife's Midwifery Pinard?

 

 

[Ronnie]

5 hours ago, Fiddlesticks said:

My wife goes nuts if I stick a cotton bud in my ear, I'm not risking it with a screwdriver!

Just use the handle end, not the pointy bit !

[Stu]

On 11/01/2023 at 16:59, JRH said:

Mine doubles up as a screwdriver. 

 

Same! 

 

A trick my dad taught me early on 

[Mississippi Bullfrog]

I've often used a screwdriver, but a proper stethoscope is cheap, much easier to use, safer and if you get the type with a probe very very accurate.