Rattle on start up with my E30
 

The other day I started my car to get ready for work and it made a clattering sound on start up. The sound went away after a second or two. Does it only when it's "cold".

Pulled the valve cover off today and didn't see anything unusual. Timing chain was tight. Ramps looked good as did the tensioner.

Got any other ideas to look at.

I had a Ford van with the 300ci six in it years ago. When it got between 200K & 250K miles on it, it would rattle on start up. It would go away like yours in a couple of seconds. I thought it was slop in the rod bearings from wear. I solved it by going to a multi weight oil with a lower range. If I remember correctly, I used something like 20WXX and changed to 15WXX or 10WXX and the rattle went away. I figured the clearances between the bearings & the crank were getting pressured up faster with the lower weight.

Hydraulic valve tappets drained overnight, needed a second or two to fill up and extend? I have same "issue" with my 200kmile Audi, no worries really...

Pretty sure that no E30 had hydraulic tappets. That said, it could be a weak tensioner that is not completely holding pressure when sitting overnight. This may not be detectable from grabbing the chain with your hand as described.

I am going with your timing chain tensioner being worn
swap in a new part and change the oil to a heavier weight.

http://www.google.com/aclk?sa=l&ai=CA0RNItabU5H2IMm5yQHiioDoDcKIjaAFgtbK v1SFvcikswEIBBABKAVQpZXdwvr_____AWDJnrSM0KTkD6ABlr-t_wPIAQeqBCZP0LBA9obpp2MMokeNH03RFMEq8wLhMm_PDSUXh 0kRfFO08sUy5sAFBaAGJoAH0sBSkAcD4BL2hefx18O0yw8&sig =AOD64_0RTY3xvvGjw8tVWCfpcTeEIsCdBQ&ctype=5&rct=j& q=&ved=0CCUQww8&adurl=http://www.turnermotorsport.com/p-180-e30-m3-timing-chain-tensioner.aspx%3Futm_source%3Dgoog_product%26utm_m edium%3Dfeed%26utm_campaign%3D11311307782

If this is a M42 4 cylinder, it does indeed have hydraulic lifters and they do stick over time. I'd consider running a little BG EPR or Seafoam in the oil just prior to an oil change. I'd run a heavier weight oil too.

Well E30 318is with M42 engine certainly does SmileWavy But yes, it can be the tensioner as well...

Thanks for the tips guys. It does have the M42 engine with 178k on the clock.

It's funny how it just started one day after owning it three years.

So you have 318is! One of my favourite cars, I've literary spent days driving 318is on the track. M42 with more than 150k on the clock is more or less guaranteed to have valve clatter when cold. It's a wonder yours it lasted so long :)

Oil pump usually doesn't supply as much pressure on idle as it did new, tappets will have more clearance and there might be a piece of dirt that blocked the one-way valve preventing tappet to bleed out the oil. But it's all cosmetic really....it will probably run 100k more even if it clatters on startup.

Mine clattered all the time on idle when hot. Try to change the oil to thicker, if it doesn't help you can always buy a set of valve lifters off the Ebay. (but check chain tensioners and plastic chain rails first, if they are never changed they are pretty much worn down at 178k as well).

I've been using 5w-20 synthetic. What weight would you guys recommend?

It's funny but after I typed that, I had a thought that maybe the last 318 twin cam motors had hyd tappets? Wasn't sure though, thanks for clarifying. :)

As for oil, unless those motors have different requirements than the earlier engines, I would run 20w50 dino oil, (not synthetic), in a hot climate. The oil you are running has the consistency of water. :cool:

Id run 20-50 as well.

I've been running 5W-50 synthetic for last 5 years. Mostly track, never winter driving. Once I had to use semi-synthetic and was greeted by clack-clack whenever below 2000 RPM once I slowed down on the track.

Well, I swapped over to Castrol 20W-50 yesterday and it started much quieter than before. I'll see how it goes over the next few days before I declare victory.