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Discussion Starter #1 (Edited)
I need some help regarding the timing chain. Until the oil reaches the nominal temperature there is a rattling noise that can be heard from the engine. It currently runs on motul 300V power 5w40...had the same issue with castrol 5w30 except it would warm up quicker. It starts from 1500rpm then if you go above 2k it gets quieter and reappears when you lift the foot off the gas pedal. It sounds like the chain of a bicycle when rotating the pedals backwards . When the engine gets hot the sound is hard to detect. I***8217;ve already replaced the chain tensioner but nothing changed. I suppose this engine needs a timing chain replacement. Also I was wondering, it doesn't seem to be enough space in front to work at the chain, is it necessary to remove the front bumper, radiators and the metal elements body between the radiators and the engine?

The car is a 2008 e86 3.0si, 100k miles
Thanks
 

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With only 100k on the car, I don't think its your timing chain. That noise could also be a dry or worn pulley bearing on one of the ancillary components. For a quick test, try running the car with the serpentine belt removed and see if the noise is still there.
 

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Discussion Starter #3
Thank you.
I***8217;ll check with the mechanic next week. The car has 100k mileage but I also did 100miles on a race track. I***8217;ve heard that they may need replacement between 100-200k km depending on driving style and maintenance. I bought the car at 150k km and the previous owner changed the oil at bmw recommended intervals which is not that good (2y/25k km)
 

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I hear you but 100 miles on a racetrack should make no difference to the timing chain. Don't let him sell you a timing chain job before you try my suggestion.
 

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Discussion Starter #5
Thanks,
I didn***8217;t check that alternator belt because it didn***8217;t seem to be related to the noise.
The car is now at the mechanic for the timing chain replacement and while they were preparing to assemble the components they found a missing oil pump sprocket securing plastic element that is now probably in the oil pan (they couldn***8217;t find it yet) that could***8217;ve been the cause of the rattle.
The oil pump chain they say it doesn***8217;t need replacement. Is it better to replace it anyway considering the mileage 100k mi ?
 

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Based on that info I wouldn't replace it. Sounds like you really dodged a bullet that with the missing retainer the sprocket didn't fall off. That would be have been catastrophic.
 

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Discussion Starter #7
I got the car from the mechanic a few days ago. He has replaced the chain, guides and sprokets, seals and also the oil pan gasket and bolts, and the valve cover gasket.
I can still hear that chain running at before it warms up but it***8217;s a bit quieter. Before I could hear it even with the engine warmed up. Anyway the old chain doesn***8217;t look that bad. The rails/guides were as new. The chain has some lateral play between the pins and link plates like between 1 and 2mm for each link, but the in the longitudinal it has no play and not sure if it is stretched in that direction. The noise possibly came from side to side motion
 

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Discussion Starter #8 (Edited)
After less than 100miles there is a new problem, the low coolant lamp switched on. There is a bit of coolant spill below the coolant tubes in the right side where is the coolant filling cap. I did a bleeding program and there seems to be some air bubbles in the circuit. After stopping the engine the lamp turns off but reappears within a few minutes. I've check the oil filling cap and it has a a bit of creamy coat on it. I think there is a chance the head-gasket is blown and air bubbles get into the coolant which causes bubbles and extra pressure in the circuit and also coolant gets into the oil circuit and contaminates it. There is also a white smoke coming from the exhaust but not always visible, however it behaved like that is since I bought the car 3y ago. I also did an emission inspection after the timing chain replacement and they didn't report anything abnormal. The chain noise could be related to some oil pressure less than nominal because of the leak.

I***8217;ve checked the oil again by draining all of it and it looks ok. The coolant also looks good. There is no sign of pressure in the cooling tubes at idle. I***8217;ll top up the coolant again and see what happens and do a hydrocarbon test on it. One problem could also be the cap valve.
 

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Do you have the N52 engine with the electric water pump? It would be worth testing the cooling system to see if it holds pressure. Those plastic expansion tanks are also known to develop hairline cracks over time.
 

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Discussion Starter #10
Do you have the N52 engine with the electric water pump? It would be worth testing the cooling system to see if it holds pressure. Those plastic expansion tanks are also known to develop hairline cracks over time.
Yes, it***8217;s the n52 with the electrical pump. I can activate it without starting up the engine. The system seems to hold pressure. When I open the filling cap there is still air coming out even after like 12hours.
 

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Discussion Starter #11
Regarding the old timing chain condition the chain had a degree of stretching I can***8217;t estimate how bad it was anyway but the plastic rails were a bit brittle. A confirmation of the plastic condition was the little plastic chain holder that failed which was found in the oil pan. The degradation is caused by high temperatures over time I think. So the replacement was necessary.
 

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Discussion Starter #12
My Disa units are overdue and because they can fail anytime unless they actually already did, I disconnected the large unit and incidentally the rattling noise I thought was coming from the chain is gone. I pulled the cable off from the secondary unit. So the idea is they are parked in an open position and with the cable off it will stay open which lets the air flow by easily without causing stress on the flaps joints. I didn***8217;t get any eml so far.
 
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