quote:
Originally posted by heyjay:
I have a 2000 GMC Sierra with Vortec 5.3 litre V8. The truck motor is based on the LS1 except it has an iron block with aluminum heads, otherwise the same basic design: coil-per-cylinder up integrated ignition, oil pump at the front of the crank, etc.
I tow a 8,200 lb 5th wheel, which is pushing the maximum allowable for my 4.10 geared truck. I have noticed a lot of valvetrain noise running Mobil 1 5W-30 in hot summer towing, somewhat less so running Mobil 1 10W-30.
Oil consumption was 1 quart every 4,600 miles running M1 5W-30, 1 quart every 6,800 running M1 10W-30.
FWIW the Helm shop manual recommends a 10W-30 under towing or heavy use conditions.
I tried Mobil 1 15W-50 in summer of 2001 as I've had good results with this oil in the past. The valvetrain was silent, even towing in +110 F heat. Had zero oil consumption over 7,200 miles.
I have also used Delvac 1 5W-40 in my personal vehicles in the past and will soon be using this in my Vortec.
Jerry