kindwarf Posted August 7, 2008 Share Posted August 7, 2008 Help ! Iwas driving along today when the engine started making a popping noise and a lack of power I took it to the garage and had a good look at it at first it sounded like a inlet manifold leak but on closer inspection the popping noise was coming from the air box, took the lid off and found that instead of sucking all the time there was a force of air coming from the engine into the air inlet could it be a inlet valve slightly jammed open, it starts ok and drives with slightly reduced power, no smoke from the exaust or anything, what is the gap between the valve and the pistons. Its a 95 300TDI auto I only had it a month and done 500 miles since purchased its done 119500 and according to the service history it had a head job and skimmed last year, by the way it didnt over heat or any thing, any comments would be appreciated. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted August 7, 2008 Share Posted August 7, 2008 I have seen a handful of 300 Tdi engines where the inlet valve on No 1 cylinder wears the seat down and gives much the effect you describe. I hope it isn't that but it might well be Quote Link to comment Share on other sites More sharing options...
Les Henson Posted August 7, 2008 Share Posted August 7, 2008 Possibly also the inlet/exhaust gasket has blown between an exhaust and inlet port. Otherwise - valve problem I would say. Les. Quote Link to comment Share on other sites More sharing options...
Richard Mills Posted August 10, 2008 Share Posted August 10, 2008 If there is a dodgy valve, a compression test will prove it. I have never done one on a diesel before, so I expect a reply from someone else will tell us how. Quote Link to comment Share on other sites More sharing options...
Guest DiscoTD4 Posted August 10, 2008 Share Posted August 10, 2008 Before you start major surgery it might be worth looking at other possible explanations as to the noise, what your experiencing regarding the positive air pressure may be normal. I had Citroen Berlingo van 1.9D that exhibited a similar phenomenon. The inlet ducting upstream of the air filter box has linear slots around the outside on one section and at idle you could feel a real blast of air pumping out through the slots. I presumed that the slots were there by design for this reason to allow the pulses of positive pressure to diffuse, as to why the phenomenon occurs I'm not sure. Possible explanation is that at particular revs a positive pulsing effect occurs due to slight valve overlap ? Good luck Quote Link to comment Share on other sites More sharing options...
kindwarf Posted August 11, 2008 Author Share Posted August 11, 2008 Found out what it was, the last tappet at the rear of the head instead of being 8 thou was about a quarter of an inch, the car drove ok and over 3 mile the tappet opened up to without exageation 1/4 of an inch the locking nut was tight never known of it before readjusted all the tappets runs lovely,and found out that the ERG has allready been blocked, saves me a job. Quote Link to comment Share on other sites More sharing options...
Guest DiscoTD4 Posted August 12, 2008 Share Posted August 12, 2008 good news ! might be worth keeping an eye on the clearances as it does seem strange that the gap was so big yet the lock nut was tight. I wonder if you have a sticking valve ? Cheers Quote Link to comment Share on other sites More sharing options...
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