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vic
12-24-1998, 03:07 AM
Hi, I have a '95 M3 and I noticed on very cold morningsI hear a sound that sounds like tappets or valve lash for about 30 seconds coming from the engine. I was wondering if anyone has ever experienced this? I was told by the BMW service mechanic that the oil I am using might be too thin(currently a 5w30 Castrol Synthetic) but this is what BMW also recommends in terms of viscosity at this particular dealership. Any suggestions would be welcome. The car only has 39,000 miles.

Rick Carlstrom
12-24-1998, 07:25 AM
Question what is "Very Cold"? For someone in FL it might mean 40 degrees. For someone in Barrow Alaska it might mean -40 degrees.<p>If anything you would want to go to a thinner oil not a thicker oil (0w-30w). One problem is if you live in a place Like Washington DC where one day it can be 70 and another 10. This makes oil selection tough.<p>Another solution is to keep your car in a garage where the temp never falls below about 45.<p>Every car I have owned (American, german and Japanese) has made valve lifter noise on mornings when it has been below freezing. Usually only for about 10 seconds. I would not worry too much just make sure you do not put any load on the engine until after it stops.<p>Rick<p>PS for those of you who do not understand the viscosity number for oil they are very easy to decode. A multiple viscosity oil like 10w-30 acts like a single weight 10w oil at freezing and a single weight 30w oil at boiling temps. The higher the actual number the thicker the oil. Therefore a 80w oil is much thicker than a 10w oil. Theoretically a 0w-30 oil will perform almost identically to a 10w-30 when the engine is fully warmed up. However at cold start the 0w-30 will flow much better.<p>The viscosity of oil can tested by putting it in a bath of either ice water or boiling water and letting it flow through a small tube. You then calculate the time necassary for a pre-determined amount of oil to flow through the tube. Its a really easy test you can rig yourself. I once tested some new Mobile 1 10w-30 and compared it to used mobile 1 after 3000 miles.

PHAT M3
12-24-1998, 02:05 PM
<i>: Hi, I have a '95 M3 and I noticed on very cold morningsI hear a sound that sounds like tappets or valve lash for about 30 seconds coming from the engine. I was wondering if anyone has ever experienced this? I was told by the BMW service mechanic that the oil I am using might be too thin(currently a 5w30 Castrol Synthetic) but this is what BMW also recommends in terms of viscosity at this particular dealership. Any suggestions would be welcome. The car only has 39,000 miles.<p></i><p>This is probably "normal". See the service bulliten section on Suzy Krafts page.<br>http://www.bmwmpower.com<br>Tim


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