Top end engine noise on 2.5 10v petrol

Hi

Started with a funny sound, only on start up last week. Sounded like a bike chain running over a crackcase. Anyway, I traced it to the top end of the engine, valves presumably. Are these hydraulic tappets on the B5252 engine? I presume so because the noise disappeared after a couple of minutes / couple of good revs. Iknow that the handbook advises you can get this noise after a long run, for example, but this was only on start up.

Anyway, I thought that an oil change might do it. The only place I could find open yesterday was Halfords. They didn't list the oil filter !!!! but the advisor at the couter assured me that it was the same as the 20v engine et.al. and this seems to be confirmed by looking on the Europarts site, but it was a bit shorter (about 20mm), hence all the checking before I fitted it.

I also went the full hog and had their own fully synthetic oil, where as I usually use Esso Ultra (semi-synth)as it was on offer.

The only problem now, is it is worse than ever, with the tappet noise being almost constant when the engine is running near idle speeds. It disappears with a good few revs and remains silent then until there is a prolonged period of near idle speed running, when the noise returns. This has only occured since the oil/filter change.

I am not seeing any oil pressure warnings, and the engine had been A1 up to now (120K mls) with FSH.

Any ideas gratefully received folks.

Cheers

Ade

[warthog]

Ade,

seems that some of the 850's can make more tappet noise at some times than others. As the engines get older it's possibly more likely to happen due to slight wear in the hydraulic tappets. The change to fully synthetic may have not helped as this is usually of a lower viscosity and therefore will be more likley to leak out of the tappets past their internal valves.

You don't say what grade of oil you are using, but on a 2.5 10V at 120k miles I would need some convincing that the cost of fully synthetic oil was justified. One of the main benifits of fully synthetic is that it maintains a continuous oil film and lubricity at higher temperatures and pressures than a mineral multigrade or semi synthetic. Unless you're continuously using the engine at full power/high revs would not a semi synthetic oil changes at regular intervals not be a better and more economic proposition?

The synthetic/semi synthetic oil debate has been discussed for years and I'm sure there will be a variety of view points expressed here for you to ponder!

Hi

Thanks for your reply.

I did think about the synthetic bit (after????) but at the time it just appeared to be the best value (being bh Monday and all) at £14.99 for 5l fully synthetic 4w/40 (a half price offer supposedly) - I just don't trust cheap oil.

I was more worried about the filter, wondering if it should have a n/r valve or something and this one supplied by Halfords hadn't got one - I don't know this for sure, just guessing at answers really.

If it continues I think I will try another (better!) filter and a slightly thicker grade oil.

Thanks again for the info

Ade

[imac]

Maybe your lifters, which is usually caused by lack of oil getting to the top end of the engine.

There is a good fix for this, I'll just get the instructions rather than type them out. (It's a biggish job though)


Will update thread when I have the instructions...

Great, thanks....

Not bothered about the work, love getting stuck in (as long as the sun stays out!!!)

Ade

nb If it's any easier you can email them to me, just let me know, you can email me from my homepage

Sorry to bother everyone again, but did you find the instructions for your cure - it's getting mighty annoying now (but no louder, thankfully)

Ade

And furhter to this, I took the plunge and went and got another oil filter (from a local Import specialist in Sheffield) and some more (thicker grade) oil.

The noise is still present and seems to go at different engine speeds, so I think I may have to fit some new lifters.

Looking, it doesn't seem to bad, requiring only the top half of the cylinder head removing - has anyone ever undertaken this task and can offer any advice?

[sholtby]

You will need some special tools or make them yourself from some old spark plugs as detailed in the Haynes manual to compress the 2 cylinder head sections. Failure to compress the head sections before removing the head bolts or when trying to reassemble the head will cause the bolts to strip the soft aluminum threads in the head.

Simon

Thanks for that info - looks like I will have to invest in a Haynes manual as well (and I thought I was getting to old to get me hands dirty, but try telling the rest of the family that - lol)

[sholtby]

A Haynes manual is a must!

Simon