TD42 loud tap HELP!!

[forkcy]

Hey guys

A few months ago a bought a nissan patorl gq with a n/a TD42 (330,000km). When I was testing the car it seemed great then I bought the car a week later it had a bit of a diesel rattle. Another week came an went and it got a hole lot worse so I booked it in to Sydney diesel centre to have it cheeked over. Turned out to be one of the injectors couldn’t hold any pressure and was leaking almost continuously. After getting all injectors changed, the value clearances set, and a compression test (all cylinders tested between 420 –400psi) all seemed great. About a week later I had been driving it for about an 1 hour when I pulled up to a set of lights and there was a loud tap at idle. As soon as I revved it it would stop and wouldn’t come back. I think it happen about 3 times that day. Now when I start it up cold the same tap is there (mostly at idle but you can hear it bit when driving) until it warms up a bit then it seems to go away until it gets hotter. So I took it back to the mechanic and as it’s a car it decided not to make the sound at all. The mechanic suggested it may not be a noise from the motor but from the clutch but I really doubt that he also said to try out a lifter cleaner which is now in but doesn’t seem to make much difference. Fuel consumption seems good and it does use oil. Any help would be greatly appreciated.

Luke

[MyGQ]

even though u have replaced ya injectors, lets start with them just incase
Have the engine running, what you need to do is 1 at a time is crack the injector lines on the injectors to see if the noise goes away. Til will tell you if you have a dodgy injector

[garth]

have had the same prob, tap from front of engine, goes away when hot.....turned out to be loose belts of all things. Good way to check is to tip bottle of water on belts when running if its them it'll kill the noise.

good luck

[patrolla]

compression is down a bit. i've got an '88 gq td42 with 320,000km and compression is up around 500 on most cylinders.

[GutSquisher Media]

I wouldn't be surprised if it's your tappet bar.

They wear out along the bottom side causing the gap setting for the valves to vary. You cannot see if it is worn until you remove all the tappets and springs from the bar.

[forkcy]

hey guys

Thanks for your comments they are greatly appreceated i did try the water trick and that didn't fix it. I haven't tried cracking the injector lines yet. The sound that i have this time is very different from the first injector problem but i'll hopfully give it a try this weekend anyway. I was also told by a diesel mechanice to try a top end motor cleaner. Has anyone on here ever tried one before and was there any differance? It would make sence that it could be wear on the tappet bar as the mechanice said a few tappets were to tight and lossened them off. They probebly where fine in the first place and now there to losse.
Sorry i haven't replied i have had so little time and any free time was spent working on other cars.

Luke