This may have come up before but I am a little perplexed with what could be going on here.
I have a 1990 BMW E30 (318i) with an M40 engine. I service the car myself completely since I have owned it and have always used the onboard service indicator to determine when the service is due.
On the most recent oil change I noticed the valve gear to be unusually noisy (The car has done 146K). I have been using fully synthetic oil in the past and have only changed brand to a Halfords own brand fully synthetic oil on this last change. The viscosities are the same (and protection factors A3/B3 etc) as my previous oil.
When I start the engine, it is quiet and smooth and idles smoothly but after driving for about 30 seconds the valve gear gets noisy (Like a tappet / cam lifter not adjusted correctly) yet there is no degredation of performance from the engine. When I am sitting at lights for instance there is this tappety noise for a short time and then it goes away to leave the normal engine noise.
Am I right in thinking that this is an oil starvation problem rather than a tappet problem - If the tappets are worn wouldn't it be noisy all the time? After a long run on the motorway the engine runs relatively quietly, except when I am waiting at lights or travelling slowly in low gears. I have taken the rocker cover off and briefly turned the engine over to see if the oil is correctly lubricating the cam and there is a spray from the oil pipe onto each cam eccentric indicating that there isn't a oil blockage.
The question remains, should I put the car into a workshop for further investigation, or should I return to my original oil at the next change? The engine does not burn any oil and doesn't appear to be low on power, the fuel economy has not changed either.
Thanks for any advice
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Some wear on cam and lifters I would think - not unusual for them to sound a bit 'cammy' at that sort of mileage.
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Low oil pressure at idling?
Oil pressure should not be an issue at motorway speed as the engine will be at 2-3000rpm so oil pressure will be fine.
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Yesterday evening it sounded a lot worse, it was rattling / ticking all the way to tescos and back. This morning however it was behaving itself. It was ticking around the 2000rpm mark but was quiet below and above that.
I have heard you can get an oil additive that flushes out tappets, Has anybody tried this? Is there any other ways of cleaning out the oilways to the tappets? I am thinking of flushing out the oil with an engine flush and replacing it with the more expensive brand that I have always used in the past.
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Some dealerships use 'Forte' engine flush. Not cheap at about £10 a can. You add it to the oil and it idle the engine for a while to remove deposits (its basically a strong detergent).
I used some about 10 years ago to quieten noise hydraulic tappets on a Rover 827 - it seemed to work.
Beware though, that if your engine is 'dirty' it will stir up a lot of the debris and residue, possibly leading to blocked oilways or pick-up screen.
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Ive got the problem first thing in the morning when I start my Rs2000. It goes away after 5 mins driving.
2 x Engine flush and 2 x oil changes did not seem to fix it.
Ive taken the oil filler cap off when its been idling and there is loads of oil flying about so mine cant be oil starvation either.
Might have to live with it I guess....
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I have the same engine in my 1988 318i and have the same problem particularly when the engine is cold. The noise usually goes away after a few miles.
I've done some research and apparently it is due to the oilways in the hydraulic tappets becoming restricted due to normal products of combustion over a long period of time and mileage. The restricted oilway prevents the tappet from fully pumping up and therefore you get the noise from the cams hitting the cam followers until the oil thins enough for the tappets to work correctly. It seems to be a routine proble with M40 engines with 100k+ miles. I've tried Wynne's hydraulic tappet treatment, engine flush and various grades of oil but there is no significant improvement. My local BMW mechanic advises that the only effective solution is to replace the tappets. These are about £100 a set from Euro car parts.
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I agree with IKM's diagnosis. I went through the same experience.
However, since this occurred after changing to a cheaper oil, I would flush with Forte and put the original make of oil back in to see what happens. I think that hydraulic tappets are very 'sensitive' to the oil used and although the lubricants appear to have similar properties eg. grade, they do not always work the same. Let us know how you get on.
There are other factors which can cause the problem such as wear of the HLA's (tappets) and oil aeration but these require fairly expensive remedies so you might decide to live with the noise.
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Well, The car went in for its MOT last week and failed on a few minor things, Suspension bushes and a ball joint. I also took the car to an engine specialist in Southampton who has been reported to know all about BMW's. He has said that it is a regular thing with these engines and agrees with the comments other people have made on this forum.
Euro car parts (set of 8 Tappets) = £56 + VAT
Fitting = £40
More expensive than an oil change but it now sounding very noisy. I feel this month is going to be expensive.
Thanks for the advice everyone.
Mike
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