Thread: td5 strange sound after head gasket replacement

check the ECU earths, earthing points and the crank angle sensor.

if youve got a bad earth to the engine from the multi earth point to the ECU or the connection on the crank angle sensor is dicey the vibrations can put it in a constant make/break situation which will give you that noise set until it warms up or settles itself.

I've never seen it in a TD5 but I have in a transit. in that case it turned out to be the earth shield wire in the plug on the angle sensor, we found it by accident. (the pin came out when we pulled the plug to inspect the nose of the sensor for filings)

Let's add more strangeness to this... Figured out how to simulate the problem - drive about 7km or 10 minutes. Coolant temperature should be up to about 90 degrees Celcius for it to work. Let it rest for 15 minutes, switch it on. Clack clackity clack

Then, switch on the aircon, and it goes away... I checked the MAF airflow when I started it from cold - it was about 56 (kg/hour?). After the drive and restart it was sitting at 52kg/hour. I think when you switch the aircon on it puts some load on the engine and then the "knock" goes away.

It goes away (or softer) after a few minutes (< 5 minutes) as well.

I did check the aircon pulley, and there is nothing sinister knocking in there.

I'm no mechanic and I haven't listened to you clip as I have no sound at work.

You mentioned at the start that it is an erratic rattle, if you search for Harmonic Balancer threads you find they describe it as a Marble Rattle (Think of a marble in a steel cylinder). You also mentioned that the HB was replaced with a second hand unit?? When my HB started to play up I had that erratic rattle. Just up the revs a little and it would be gone.

Have a look at what your tentioner and HB is doing, is it jumping or is it stable. To confirm my suspicions I ran mine without the belt (just for a couple of minutes) and she was as quiet as a mouse, belt back on and so was the rattle. It was the bearing inside that was cactus.

Any way I hope you get it sorted.

Cheers, Jurgens.

FYI

TD5 injector codes make only minute adjustments to opening and closing times.. We're talking m/sec here.

Even without coding a vehicle the vehicle should run ok.

The injector codes are 'trim' timings for the ECU and based on injectors in as new condition. Whilst this setting is optimum, its not the be all and end all.

Originally Posted by Tombie

FYI

TD5 injector codes make only minute adjustments to opening and closing times.. We're talking m/sec here.

Even without coding a vehicle the vehicle should run ok.

The injector codes are 'trim' timings for the ECU and based on injectors in as new condition. Whilst this setting is optimum, its not the be all and end all.

Yeah, I thought so too - had read that somewhere. But I did want to at least check it out.

Originally Posted by Steve Td5 130

Hi Bud

I would start by checking the adjustment on the rockers and the hydraulic lifters ( lash adjusters )

Cheers

Steve

Checked them at the indy who did the work. They're all set at 3/4 turns out. We did it again to make double sure.

Originally Posted by Blknight.aus

check the ECU earths, earthing points and the crank angle sensor.

if youve got a bad earth to the engine from the multi earth point to the ECU or the connection on the crank angle sensor is dicey the vibrations can put it in a constant make/break situation which will give you that noise set until it warms up or settles itself.

I've never seen it in a TD5 but I have in a transit. in that case it turned out to be the earth shield wire in the plug on the angle sensor, we found it by accident. (the pin came out when we pulled the plug to inspect the nose of the sensor for filings)

This sounds like a worthwhile idea... Wonder if I should have been able to pick up anything in hawkeye?

Originally Posted by phuma

Let's add more strangeness to this... Figured out how to simulate the problem - drive about 7km or 10 minutes. Coolant temperature should be up to about 90 degrees Celcius for it to work. Let it rest for 15 minutes, switch it on. Clack clackity clack

Then, switch on the aircon, and it goes away... I checked the MAF airflow when I started it from cold - it was about 56 (kg/hour?). After the drive and restart it was sitting at 52kg/hour. I think when you switch the aircon on it puts some load on the engine and then the "knock" goes away.

It goes away (or softer) after a few minutes (< 5 minutes) as well.

I did check the aircon pulley, and there is nothing sinister knocking in there.

How serious can this problem be if it hides when the aircon is switched on? It can't really be mechanical can it?

Had a diesel injection specialist listen to it yesterday, and he reckons it will go away after a while due to the head being recently reconditioned. I don't exactly understand the reasons - there was talk about new valves etc. In any case he did not think it was terminal, and that it would resolve itself as things wear in?