Thread: td5 strange sound after head gasket replacement

Info in the later part of this....

www.discovery2.co.uk / TD5 Engine - Injector Seal Replacement

Sounds like injectors to me too... As said before, the injectors are coded.. If they have been mixed and matched, you will need to lift the rocker cover and make a note of the letters atop the injectors before taking it to someone and having it plugged in. They'll then put the injector codes into the ECU in the right order.... Also make a note of the colour of the plastic that the letters/numbers are on. They should all be the same. Mine used to have an intermittent tap that came at higher revs, dipping the clutch and idling the engine used to get rid of it... Sometimes I wouldn't hear it for a month or more.. Your sound clip does not sound too bad to me... Didn't note where you are from, but as it gets colder, Td5's make fuel adjustments when initially starting off... Anything below 10 or 12 deg and it wud rattle, and advance injection so it had a real diesel cackle for the first few min of a journey...

Originally Posted by Sitec

Sounds like injectors to me too... As said before, the injectors are coded.. If they have been mixed and matched, you will need to lift the rocker cover and make a note of the letters atop the injectors before taking it to someone and having it plugged in. They'll then put the injector codes into the ECU in the right order.... Also make a note of the colour of the plastic that the letters/numbers are on. They should all be the same. Mine used to have an intermittent tap that came at higher revs, dipping the clutch and idling the engine used to get rid of it... Sometimes I wouldn't hear it for a month or more.. Your sound clip does not sound too bad to me... Didn't note where you are from, but as it gets colder, Td5's make fuel adjustments when initially starting off... Anything below 10 or 12 deg and it wud rattle, and advance injection so it had a real diesel cackle for the first few min of a journey...

I am in Cape Town South Africa - not too cold here. It does it regularly on a hot restart though, so it can't be the cold?

Originally Posted by phuma

I am in Cape Town South Africa - not too cold here. It does it regularly on a hot restart though, so it can't be the cold?

Ah! Fantastic place Cape Town. No, prob not the cold!! Worthy making the call to see if the injectors were refitted in the correct order tho.. and then go from there..

Originally Posted by Sitec

Ah! Fantastic place Cape Town. No, prob not the cold!! Worthy making the call to see if the injectors were refitted in the correct order tho.. and then go from there..

I'll see if I can get this checked out.

When you have the rocker cover off have a look down into the timing chain area for signs of chain slap.
My thoughts...
When hot the oil will be thinner.
The chain tensioner is an oil feed adjuster with an internal spring as back up.
My 2 obvious questions...
How long does the oil light stay on when started hot?
Is the right oil being used?

Originally Posted by alien

When you have the rocker cover off have a look down into the timing chain area for signs of chain slap.
My thoughts...
When hot the oil will be thinner.
The chain tensioner is an oil feed adjuster with an internal spring as back up.
My 2 obvious questions...
How long does the oil light stay on when started hot?
Is the right oil being used?

I'm going to buy a mechanic's stethoscope now, and will listen around to see if I can pinpoint the area. Oil light goes off quite quickly - and I've got a second electronic gauge running off a VDO pressure sender to watch oil pressure.

I spent some time with the hawkeye looking at injector balances. When it's idling quietly all the balances are between -3 and +3. When it's clacking / rattling all the balances are worse - they appear to go to around 8. It does not look like a specific injector that is "out".

I also ran it with / without the MAF plugged in and it made no difference to the noise. Last night I wanted to check again after a long drive - waited 10 minutes, started it up. And then it was quiet again - no noise. The problem is quite intermittent.