Thread: noisey tappets 300tdi

More than likely buggered valve stem caps.

They are a small, hardened cap that sits on top of the stem under the rocker pad.
They have a limited life and are treated as a service item, often failing and either disappearing or leaving just a ring of cap around the top of the stem.

What Rick said. 3 out of 8 were worn through completely when I pulled the head off mine at ~260k km. No idea if they had been replaced previously.

backing the stem caps, I replace them at 50K intervals

IF he has been adjusting them at 0.2mm (0.008') and the noise is still evident, the lash caps may not be the problem, especially if you haven't lost performance. The vacuum pump can get very noisy if one of the valves breaks off its seat inside, the lift pump can get noisy tooo if worn, and the other unusual but possible issue that can sound tappety is mistimed camtiming, did the noise appear suddenly or after some other work being done? like a timing belt replacement? It has been my experience with these engines that rocker shaft wear is minimal even at 500,000km, (as long as oil supply hasn't been interrupted) the same for camshafts.Other possibilities are the rocker shaft studs stripped and pulling out of the head, worn tappet slides/ guide pins OR bent pushrods- Even a slight bend in them will cause erratic valve clearances as they rotate.

JC

Originally Posted by justinc

IF he has been adjusting them at 0.2mm (0.008') and the noise is still evident, the lash caps may not be the problem, especially if you haven't lost performance. The vacuum pump can get very noisy if one of the valves breaks off its seat inside, the lift pump can get noisy tooo if worn, and the other unusual but possible issue that can sound tappety is mistimed camtiming, did the noise appear suddenly or after some other work being done? like a timing belt replacement? It has been my experience with these engines that rocker shaft wear is minimal even at 500,000km, (as long as oil supply hasn't been interrupted) the same for camshafts.Other possibilities are the rocker shaft studs stripped and pulling out of the head, worn tappet slides/ guide pins OR bent pushrods- Even a slight bend in them will cause erratic valve clearances as they rotate.

JC

Thanks JC, I have just done my timing belt and it feels like it's not making much boost down low and sounds tappety and I've checked the tappets 3 times thinking that I had done something wrong there.

I think I will pull the timing case off again and triple check everything is where it is meant to be.

I didn't think of cam timing but that makes sense.

Cheers Casper.

By the way, I have never had one of those caps wear out, I changed them when I did the head gasket as they were in the VRS kit I got so I have a spare set that have no signs of wear sitting on my shelf in the shed.

Originally Posted by Casper

Thanks JC, I have just done my timing belt and it feels like it's not making much boost down low and sounds tappety and I've checked the tappets 3 times thinking that I had done something wrong there.

I think I will pull the timing case off again and triple check everything is where it is meant to be.

I didn't think of cam timing but that makes sense.

Cheers Casper.

By the way, I have never had one of those caps wear out, I changed them when I did the head gasket as they were in the VRS kit I got so I have a spare set that have no signs of wear sitting on my shelf in the shed.

Yes i didn't want to alarm old mate in the original post too much but I have seen one a tooth out on the cam (Advanced) and the noise was actually the pistons tapping the valves. Didn't hurt them though, set the timing right for them and they were on their way That was 12 months ago.

JC

I thought recently that I had noisy tappets, turned out to be the vacuum pump on the way out. Now the pump has shaat itself the engine is super quiet

Cheers

do all 300tdi's have lash caps? the haynes book says "as specified" or something, and Im 90% there weren't any on the old head.

Cheers,
Jeff