eversoslight knock

[Pillarian]

Anyone notice a slight knocking at startup? My 94 has a slight knocking at startup in upper part of engine for a brief second, then it goes away. The noise hasn't changed and only occurs when the engine has been sitting for more than 4 hours. Recent 60K maintenance showed absolutely no wear on valvetrain. Engine runs normally other than this noise. Question: is this the oil running out of the valvetrain over night and not a serious concern? Or is this a sign of something major coming? The oil has no metal in it and stays fairly clear between oil change intervals of 3K. A thread search didn't help me much.

thanks folks.

 

[Toolman]

Sounds perfectly normal. You might try some of that Castrol 'START UP' engine oil. It may help. But if it is just that very light tapping sound for that split second on startup then you are more than likely just fine, especially considering everything else you said.

 

[yamahaSHO]

I had that on one of my cars until I changed out the rod bearings... It really is nothing to be worried about, but it annoyed the crap out of me.

 

[jbeano]

Same with me. I changed the rod bearings as well and the slight startup knock went away.

 

[Pillarian]

sounds like cheaper insurance and a great opportunity to rid myself of an annoyance - I don't really want to spin a fod bearing anytime soon......

Napa has them for 85 clams locally - no muss; no fuss.

 

[bradman]

Don't count on this to fix your start up knock. I changed my rod bearings at 120K and the old ones were not badly worn. Still knocks at startup just the same as it did before the bearing change.

BTW - Rod bearings can be had for much cheaper than that:
http://search.ebay.com/taurus-sho-rod-bearings_W0QQfkrZ1QQfromZR8

 

[DHMag]

Don't count on this to fix your start up knock. I changed my rod bearings at 120K and the old ones were not badly worn. Still knocks at startup just the same as it did before the bearing change.

BTW - Rod bearings can be had for much cheaper than that:
http://search.ebay.com/taurus-sho-rod-bearings_W0QQfkrZ1QQfromZR8

a knock at cold startup occurs for 2 reasons coinciding with each other. first, if the engine has not been driven, all the oil drains to the pan. this leaves the entire lubrication system dry. secondly, the gap between the crank and the rod bearings. a .001" gap wont produce an audible knock, but .0015-.002" will.

9 times out of 10, cold startup knock is associated with worn rod bearings. in my experience, it has been the case 99% of the time. the other 1% is valvetrain clatter.