MY 95 wrx On Start up from cold the engine knocks like a goodun for approx 1-2 secs or so then goes away and is fine no knocking at any engine speed after that deffo not tappet noise to deep might be the start of the dreaded death knock... could also be piston slap but i think the noise goes away to quickly for that ... oil ok etc has any one else experienced this ??? as i listend to a 98 Turbo and diddnt sound like mine

cheers Mark

 

From your very good description, i think it is only one thing and has all the hallmarks of the dreaded B.E bearings. And IMHO is B.E knock. However, before you condem it, i would be inclined to strip and check the oil pressure releif valve as it could be sticking open on first start up, until it "feels" pressure to snap it shut. This sounds like a probable cause as i would expect the knock to continue and not stop after a couple of secs. i would also check oil pressure readings when hot and cold. Oil pressure should slowly get worse, especialy when hot as obviously clearances will get larger with B.E failure.

 

Tappet noise doesn't occur as such, you could have worn valve lifters which are hydraulic (using engine oil) on your car, its a common thing and they can take a bit to pump up when cold especially on a higher mileage older car. the noise is quite deep in tone.

bob

 

Leviathan, the relief valve will open on first start up - not close.

 

Thanks for your replys guys ..

Bob i think your explination is exactly what i am experiencing also it runs a little rough the same time as the noise occurs indicating the hydraulic lifters are not opening the valves enough untill filled with oil, never expeienced this type of noise with any other make of car relating to hydraulic lifters, dont suppose there is any adverse consiquenses that you know of from experience continuing running like this ? apart from annoying noise and a rough start

Mark

 

I notice from one of your posts you frequently thrash it when using non super unleaded?

Might not be a good idea. Maybe not related to this, but wouldn't want that nocking to get worse!

MB

 

DBM no i dont think so only used 95 in Italy last week when nothing else was availiable i first noticed this noise in april this year 5000 miles ago

Mark

 

Im sure mine makes that noise on start too.

MB

 

Mine makes a similar tapping noise, although goes on for a little while. All this paranoia about piston slap had me wondering but then I remembered that a couple of Golf GTi's I had did the same and they turned out to be worn valve lifters failing to pump up.