Isuzu bulletin confirms oil use bull****

[BigSwede]

My 99 Trooper didn't burn any oil with Mobil One 5W30, but it only had 65K on it when it got totaled so who knows what it would have done later on.

Personally I think the synthetic would be better for keeping the oil ring holes clean, due to less sludge and varnish formation.

[SlowPro48]

Could be. I imagine when it's that close to the combustion process, the temps are high enough to cook even synthetic oil though - and then it doesn't have the detergent to clean up after itself. The main advantage of a diesel spec oil is lots of detergent - and lots of moly - and that's why I use it. It's gotten my old pickup truck to 320,000 miles now with no oil burning - but then I've never tried synthetic in the VX for a direct comparison so all I'm doing is speculating that my VX is better off (from an oil burning standpoint) with thick, high detergent oil. I guess I should try some Mobil 1 in the VX for the sake of science but when I used Mobil 1 in the YZF it led to such a dramatic increase in oil consumption that I didn't want to try it out in my VX. There's a big difference in running low and trashing the bearings in a 13 year old sport bike that you only use for riding around in circles on the weekend and pitching a rod through the block of your main transportation.

I personally think there's more to the story than just oil drainback holes. There are people like me using molasses and doing fine and then there are plenty of people such as yourself who are doing fine with lightweight, low detergent oil. There's some other variable in this equation. Maybe more than one. That's the way it is with my life in general - whenever something goes wrong it's usually not one thing - it's a convergence. I bet there are some Isuzu engineers out there in the world who know what the problem is but we probably won't ever hear about it. Maybe someday one of us will delve into an oil burning engine and inspect it thoroughly before it goes caput instead of waiting until it starves a bearing and then replacing it with a whole engine or long block. It's hard to diagnose the problem via old school methods what with catalytic converters mucking up your visible emissions experiments. In the good 'ol days you could tell whether the oil was sneaking past the rings or past the valve seals by when you saw smoke. If it was a puff of VE upon cold startup (after sitting for a while) but it went away after a few seconds it was a classic sign of oil sneaking down the valve guide. But when that happens in your VX, did the VE go away because it was the result of small amounts of oil that accumulated in combustion chambers overnight as a result of leaky valve seals? Or is the smoke from a lot more oil sneaking past the rings on a continuous basis - and it goes away not because the oil burning stopped but rather because the catalysts fired up?

[BigSwede]

I personally think there's more to the story than just oil drainback holes. There are people like me using molasses and doing fine and then there are plenty of people such as yourself who are doing fine with lightweight, low detergent oil. There's some other variable in this equation. Maybe more than one.

You may be right, it sure doesn't seem like there is a consistent problem for all, nor a consistent fix for those with a problem. At one point I suspected a convergence of the oil rings and the EGR system in some mysterious way, but I know some with clean EGR systems and use Rotella who still have oil burning...so I don't know really.

Too bad the earlier 3.2Ls aren't an easy swap, my Trooper burns close to zero oil. I burned maybe 1/4 quart on the last Moab trip, that's around 3000 miles, wheeling and all. And yes that was with Mobil One 5W30.

[89Vette]

I personally think there's more to the story than just oil drainback holes. There are people like me using molasses and doing fine and then there are plenty of people such as yourself who are doing fine with lightweight, low detergent oil. There's some other variable in this equation. Maybe more than one.

Like how often you change oil? That's a biggie. Longer intervals gives more time to accumlate debris in the oil -- and clog up the holes.

Where you drive. More rural areas with dirt roads lead to higher induction of dirt.

Mean temperature. Hotter areas might get to higher temps where more "ash" and carbon in the oil contributes to contamination.

Brand/Type of oil. Even if it's molasses, good molasses is better than cheap stuff.

Luck. How you drive it and what the exact clearances for each motor measure out. How the rings fit. Parts to have a tolerance with variance.