to flush or not to flush.......

[Parrothead]

A question........I took my 92 coupe to a lube shop yesterday for the first oil change since I bought her 2 months ago. The vette has 40,780 miles on her and because I have been at sea most of the time hadn't got around to doing this until now. Anyway when they pull the drain plug the oil coming out was black and looked very old. I don't know what synthetic looks like having never had it before but didn't think it looked right . Well the service people recomended a engine flush. I wasn't sure about the ramifications of this so I just had them change the filter and fill it back up. Is there any problems with flushing a LT-1? I figured I would ask and see before risking damage to my engine.......thanks for the help!


finzs up

[jmccloud]

My dad worked in the oil refining/testing business for decades. His advice was that oil (even synthetic) normally turns black due to heat, 'wear' and partly due to 'blowby' (combustion gas getting passed the rings even in tiny amounts). This is normal.
So, he said change oil often and keep 'other stuff' out of the oil. 'Other stuff' like most popular oil additives and especially water (which turns the oil into a milk shake). Dad's recommendation was to use single weight or minimal weight range (never 10-40w for example) and change 'normal' oil at 3,000 miles and synthetic at 6,000 or less.
I've had several cars with 200,000+ miles that didn't 'burn' oil. This was due to frequent changes and keeping 'other stuff' out of the oil.
I'm not sure what's in the flush. Would the flush damage seals? I limit flushing to occasionally pouring 1/2 or 1 quart through during the oil change to help move the sludge in the pan out the drain.
Always drain oil hot and change the filter at least as often as the oil. The LT-1 calls for Mobil 1 synthetic.
Hope this windy reply helps

[JonM]

My suggestion...just continue changing the oil regurarly. If the previous owner didn't do this and you do have sludge built up in the heads, you don't want to start loosening it up. The reason is you don't know what is in the sludge (metal filings) and loosening it could cause more damage to bearing and other parts.

[oldace84]

Please don't use anytype of engine flush. Will screw everything up, especially main bearings.
Been there done that.
Just keep changing the oil.
tony