Cadillac & LaSalle Club Discussion Forum

Cadillac & LaSalle Club Forums => General Discussion => Topic started by: Richardonly on February 04, 2012, 09:43:45 AM

Title: 1948 and back, 346ci oil consumption
Post by: Richardonly on February 04, 2012, 09:43:45 AM
Hi again all.

My 1948 346ci WITHOUT an oil filter does seem to use some oil although there is certainly no smoke. The manual states to check the oil level at each fill up.  This can be quite often as this vehicle gets about 8-10 miles per gallon.  It is the 60s Fleetwood model.

Do others with this engine consume oil and what is your avg mpg?

What do you feel is better to use?  A straight weight non detergent oil or a cleaner multigrade oil?

Thanks for your input.

Richard
Title: Re: 1948 and back, 346ci oil consumption
Post by: Fred Pennington 25635 on February 06, 2012, 01:46:09 PM
Non-Detrergent oil is what should be used without a filter.
Detergent oils suspends the dirt in the oil so it can be removed by a filter. Without a filter the dirt circulates through the engine and can cause damage to bearings, On modern engines the oil goes through the filter first before going to any lubricated parts.

Non detergent oils allow the dirt to settle out in the pan and anywhere else oil will pool in the engine. This is where sludge comes from.
The maintenance schedule for these engines recommends disassembling the top of the engine and flushing with kerosene once a year to clean out sludge and to always change oil hot to pull as much dirt out with the fast running oil.

That said, allot of people do just fine with detergent oil.
They don't have the sludge issues and if you change oil frequently and don't drive much you will never find out how much ( if any ) it will shorten the life of the engine.

You need to make your own choice, based on your use.

Good Luck

Fred P.
Title: Re: 1948 and back, 346ci oil consumption
Post by: 47bigcadillac on February 12, 2012, 07:33:33 AM
don't forget to add some ZDDP Plus to the oil
Title: Re: 1948 and back, 346ci oil consumption
Post by: Brett Baird on February 12, 2012, 03:20:49 PM
Fred & Rob are correct, non detergent is what was intended for these engines, and ZDDP is a must.  With that said, I use 10w30 with ZDDP in my '41.  I do not burn any oil.   

You asked about mileage.  I averaged 16 mpg mostly freeway driving 650 miles to and from Las Vegas for the Grand National in 2009.  I haven't checked my city mileage, but suspect is is around 10-12.

Title: Re: 1948 and back, 346ci oil consumption
Post by: Richardonly on February 13, 2012, 08:10:17 AM
Brett,

Yowwwwwwwwwww.  I thought there was something wrong with my mileage at 8mpg.

Perhaps that is why there is black soot in the tailpipe.  I did some checking on the carb and found the 2 screws in front to be turned out 4 full turns.

I set them at 1 1/2 out, but have yet to check to see if there is any difference.  Does seem to idle smoother BUT it is dead of winter here and the chock is shut.

Thank you for the info.  Also, if gas is mixing with the oil, that may explain some oil consumption.

Thanks again to all of you,  Richard