M40 metallic tick

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parakeats
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Post Sun Jan 18, 2015 1:23 pm

1990 318i m40 97k miles regularly serviced, service less than 500 miles ago with 10w40 castol magnatech semi-synth

Recently I've had an intermittent loud metallic tick coming from the engine first on startup and then comes and goes while warming up, it stops at around 1/4th on the temperature gauge, I'm assuming it's the lifters and hydraulic tappets? It sounds like it's just one of them in case that information is important?

I took the rocker off to have a look today and I found the below. The cover itself has the brown gunk in it but looking at the camshaft, it seems clean with no gunk on it at all, or down into the engine? I also had a feel of the cam and found that very few were smooth and a lot had scores on them. Is this the traditional m40 top end problems?

I have checked the spray bar (without taking it off) and it seemed clean and unblocked - I've read this can cause the ticking noise?

The car also has a problem where it drinks all the water you put into it, until it gets to the bottom of the radiator where it sits at a constant level, which is odd? I'm going to have a go at bleeding the cooling today and if it all disappears again, investigate the headgasket. - the car feels more responsive and drives better than it ever did since owning it, but it could be a small leak causing my water to disappear and cause the brown oil gunk?

Sorry if the pictures are bad, camera didn't like the rare sunny day! and I apologise if I haven't explained it very well either
:roll:

Oh, and can anyone tell me what the plug in the last photo is for? It's below the air intake tubes and not plugged in (never has been)

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Grrrmachine
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Post Sun Jan 18, 2015 1:41 pm

Plug is for the carbon cannister:

http://www.e30zone.net/e30zonewiki/inde ... n_Canister

And that rocker cover tells the complete opposite story of "regularly serviced". That's horrendous gunkification! Unfortunately it seems to have lead to a textbook case of noisy tappets. Read more here:

http://www.e30zone.net/e30zonewiki/inde ... sy_Tappets

Looks like it's time for a 16v swap :D
parakeats
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Post Sun Jan 18, 2015 2:34 pm

I'm not going to worry about that plug then! :P

also, didn't realise the pictures would be that big so apologies anyone on phones ;D

Well according to my original service history book, it's had a service every 6k miles throughout it's life, I've only had it the past 6k and serviced it myself. I guess I'll clean it all off and then see if it comes back :P

Just been for a drive and the loud tap (happens more when cold) didn't happen at all, I guess it's come and go depending on if it's gunked up or not?

I was thinking that, or even better, a 2.5/8? :mad:
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Brianmoooore
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Post Sun Jan 18, 2015 7:32 pm

97k miles in 25 years is less than 4k miles per year. Short runs, and never fully getting hot is a good way of getting gunge like that under the rocker cover.
I had a 318i I used as a daily driver a few years back that behaved like yours, and I gave it a fill of oil intended for diesel engines that I ran in it for a few months. This oil contains more detergents that most, to deal with all the contaminants produced by the filthy things, and when I changed it again for a 'normal' oil there was a noticeable improvement.
The knock from an under inflated tappet doesn't sound good, but doesn't do any significant harm, or have much effect on performance, so I wouldn't worry too much, if you can live with the noise, and the occasional "sounds like your big end's gone, mate" comment.
parakeats
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Post Mon Jan 19, 2015 10:07 am

I've read that short journeys has that effect, dads 56 plate 911 gets condensation badly because it only gets used to go to the shops and back, such a waste... ;)

Think I'm going to clean it out and fit a new rocket gasket, clean the spray bar and clean the breathers and see what happens, if it comes back I'll investigate further if not then happy days :)
parakeats
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Post Mon Jan 19, 2015 1:27 pm

little update

Bled the system (snapping the old bleeding screw in the process, had to take a trip to BMW who luckily had one in stock...) no air in it and my coolant was only about 0.4l low after about 2k miles and is still bright green from the anti-freeze + isn't over pressurising, so ruling out headgasket failure for now :)