Any totally Synth folks out there?

NewbieZ71 · January 13, 2002

If so, what did you change to synth and when? Isnt the rear diff already synth?

01z71 · January 13, 2002

Yeah, the rear diff. is already a synthetic. I changed the front & rear at 15,000 miles. I changed the oil to synthetic at about 7,500 miles.

Robinhood · January 14, 2002

I use Amsoil synthetics. Engine oil at 5,000 and rear diff. at 10,000. I would recommend changing the rear diff. fluid early. Found a little metal debris on the magnet just like the first engine oil change on the tip of the magnetic drain bolt. Pull the cover and replace the gasket, don't just drain and fill.

Import Hater · January 14, 2002

I made the switch to Mobil 1 at the first oil change. Probably about 2800 miles if I remember right. If they're willing to fill from the factory with the Corvette, then there's no reason to wait to put it in with any new engine.

Rob

radrado · January 14, 2002

The early 99 C/K's did not come with synthetic rear axle lubricant. These differentials had a RTV sealant. Synth will attack this sealant.

EDZ Z71 · January 14, 2002

Just changed the oil for the first time in my AV Saturday. I put Mobil 1 5w30 in. The truck has about 2500 miles on it. I ran my 94 like this until 140k and never had any problems. I also changed oil every 5k. Could probably went longer but didn`t really feel comfortable doing it too much longer.

CMNTMXR81 · January 14, 2002

I made the switch to Mobil 1 at the first oil change. Probably about 2800 miles if I remember right. If they're willing to fill from the factory with the Corvette, then there's no reason to wait to put it in with any new engine.

Rob

The Vette's engine also already has some break-in time done at Bowling Green.

Either way, these LS1 derived engines work best if you use Dino oil until about 6,000 miles. From there, switch to a synthetic if you wish. Reason being is that they still are doing a little break-in up until this approx mileage.

It's funny seeing dino numbers of one with a 1,000 miles then re-dino'ing the same stock motor at 8,000 miles. I've seen some pick up 10-12 hp at the rear wheels due to this as the motor "loosens" a little.

GreenRado · January 14, 2002

I changed to Mobil1 5w30 ~ 9K miles. Change every 3.5K to 5K miles now.

With the rear diff - we had a little issue. Checked the level ~ 1000 miles, and couldn't feel the level at all - also had recently noticed some ominous burning odors - first chalked up to new vehicle stuff burning off hot exhaust.

Pulled the drain plug and about 1 CUP flowed out! Punkin absolutely clean - no leaks anywhere! Filled to 1" below bottom of filler opening, and has ben working fine since.

Methinks I was lucky on that one! ;)

Haven't found a synth to match for front punkin, so using Valvoline.

Speaking of front, just had to replace the pinion seal. I don't have time to mess with it so paid the dealer $82. Hated paying that, as I have replaced them before, but not on GMs.