Oil

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Originally Posted by mitch cobb racing

have any of you guys ever used or years of schaffers?? Thats what I use in my race car... Seems to be good stuff and it's cheap. But I'm not sure how to get it from anyone besides race suppliers.

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They make gear oil the Denali folks swear by for diff oil. It is not cheap BTW.

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Originally Posted by zeake

I smell some bovine excrement but listen to some other experienced techs.
My tech said to keep synthetic if you are using it and if you have used regular for many moons keep regular so you do not develop leaks.

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I swapped to M1 at 140K in the Blazer. Yes, it leaks from the rear main and pan. It would have anyway. No, I refuse to fix it as it requires engine removal. Synth is slicker and might leak but swapping late in life causing problems is :ghey:

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Originally Posted by murdered_outgmc

I have heard not to switch to synthetics on high mileage engines also.

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See above. 4.3 spin #6 rod when they spin bearings. Not to jinx myself but at 215K miles and a lot of full throttle "blasts" it has great oil pressure and makes no noise.....and I swapped at 140K as listed above. I change it every 10K miles. Yep.

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Originally Posted by zeake

Think of it as an excuse to slap a 6.0 in it.

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5.3 - i'm keeping the 5 speed

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Originally Posted by GasGuzzler

...I swapped to M1 at 140K in the Blazer. Yes, it leaks from the rear main and pan. It would have anyway. No, I refuse to fix it as it requires engine removal. Synth is slicker and might leak but swapping late in life causing problems is :ghey:...

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mine leaked like a mofo as well... needed a quart about every 2000 - that was getting too expensive, so i was about to change back to dino juice.

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Originally Posted by GasGuzzler

See above. 4.3 spin #6 rod when they spin bearings. Not to jinx myself but at 215K miles and a lot of full throttle "blasts" it has great oil pressure and makes no noise.....and I swapped at 140K as listed above. I change it every 10K miles. Yep.

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sounded like mine was either 5 or 6. happened at about 4500rpm and that's when i saw that my oil pressure fell off a cliff. no warnings or noises at all... just happened while pulling off the interstate shoulder.

castrol 5-30 every 3000 miles works fine for me, especialy when i get the auto parts store special of the month with free filter.lol

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Originally Posted by Gladiator 6.0

castrol 5-30 every 3000 miles works fine for me, especialy when i get the auto parts store special of the month with free filter.lol

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same hear i use castrol 10w-30 works fine. its so cheap i change my oil every 2000 miles.

1 qt every 2000 is not that bad but I lose about half in 10K.

A lot has to do with what oil was used before and how often it was changed. Castrol GTX engines seem to come out perfectly clean after 100k but I've torn down a lot of Pennz and Quacker St engines that were gunked up with parafin so bad you couldn't see the valve springs anymore. Putting synthetic in an engine in that condition could cause the parafin to cut loose and settle in the pan possibly.

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Originally Posted by zebra

okay... so here's a question for all y'all.

my truck: 99 NBS RCSB with a 4.3/5-speed & 4x4

at 135000, i switched from 10W-40 conventional to Mobil1 10W-30 & Wix filters. runs great for a year and a half... but now at 148400, i don't know all the specifics, but it has something to do with a bad rod bearing, a broken rod and the engine can now be best used as a boat anchor.
i was told by the mechanic (who is a long-time family friend & very trustworthy as well as having been mechanic-ing for 40yrs) that it was because i switched to full synthetic, & it washed off all the shellac on the bearings, which then collected in the bottom of the pan & clogged the oil pump. then he showed me at the very tip of the dipstick where it was a bit darker & thicker. that makes me wonder why i never heard of anyone else switching to synthetic & having the same problem.

have any of y'all ever heard of that scenario?

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Originally Posted by zebra

...that it was because i switched to full synthetic, & it washed off all the shellac on the bearings, which then collected in the bottom of the pan & clogged the oil pump. then he showed me at the very tip of the dipstick where it was a bit darker & thicker. that makes me wonder why i never heard of anyone else switching to synthetic & having the same problem.

have any of y'all ever heard of that scenario?

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Yes...keep on reading.

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Originally Posted by zeake

...and if you have used regular for many moons keep regular so you do not develop leaks.

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True. To a point.

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Originally Posted by murdered_outgmc

I have heard not to switch to synthetics on high mileage engines also.

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+1

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Originally Posted by GasGuzzler

Synth is slicker and might leak but swapping late in life causing problems is :ghey:

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+1

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Originally Posted by RedHeartbeat

A lot has to do with what oil was used before and how often it was changed. Castrol GTX engines seem to come out perfectly clean after 100k but I've torn down a lot of Pennz and Quacker St engines that were gunked up with parafin so bad you couldn't see the valve springs anymore. Putting synthetic in an engine in that condition could cause the parafin to cut loose and settle in the pan possibly.

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+1

I am not saying I am the ultimate guru on this stuff, BUT most of you are correct in your thinking. From what I know, mechanical parts develop parafin and shellac deposits in the motor which (for some reason) keeps them running in a certain way. Motors, trannys, rearends, etc. If the motor has been run dinosaur oil its whole life--stick with it. DO NOT change to synthetic. BUT it is a different story when switching from synthetic to conventional. The same type of problems do not exist when swtiching that way.

So Zebra--to answer your question--your mechanic was correct.

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Originally Posted by Gladiator 6.0

castrol 5-30 every 3000 miles works fine for me, especialy when i get the auto parts store special of the month with free filter.lol

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thats wat i use too the green bottle

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Originally Posted by GasGuzzler

1 qt every 2000 is not that bad but I lose about half in 10K.

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yeah... but that gets real expensive with synthetic. with conventional, i was losing a quart every 3000

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Originally Posted by RedHeartbeat

A lot has to do with what oil was used before and how often it was changed. Castrol GTX engines seem to come out perfectly clean after 100k but I've torn down a lot of Pennz and Quacker St engines that were gunked up with parafin so bad you couldn't see the valve springs anymore. Putting synthetic in an engine in that condition could cause the parafin to cut loose and settle in the pan possibly.

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i usually used regular valvoline with a (now i know is horribly crappy) fram filter every 3000.

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Originally Posted by txarkitekt

...I am not saying I am the ultimate guru on this stuff, BUT most of you are correct in your thinking. From what I know, mechanical parts develop parafin and shellac deposits in the motor which (for some reason) keeps them running in a certain way. Motors, trannys, rearends, etc. If the motor has been run dinosaur oil its whole life--stick with it. DO NOT change to synthetic. BUT it is a different story when switching from synthetic to conventional. The same type of problems do not exist when swtiching that way.

So zebra--to answer your question--your mechanic was correct.

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thanks for the confirmation & explanation

ROYAL PURPLE ONLY HERE!