Sign of needing change? Your thoughts

[icruse]

If an oil is staying right on the full mark at 3000 to 3200 miles and then within the next 600 to 1,000 miles goes down about 3/4 to 1 quart does that mean that it is weakening in its overall package and therefore should be changed?
I was wondering why an oil would stay fine for so many miles and then all of the sudden drop that quickly (by the way no particular brand, seen several do this).

Good Day,
Steven

 

[msparks]

Could be several things including a weakening of additive package,

Also could be excess oil getting past rings, because the oil has become dirty, either because of the air or oil filter.

Secondly the oil could have become too thin, dropping out of grade, which could also contribute to ring/piston seal??

These are some of my opinions, I'm sure others will chime in.

BTW, its funny how differnt types of oil will be consumed in a car. One brand would use say 1 quart in 3,000 whereas another would use hardly any, go figure!

 

[Quick_lude]

This is a common occurence in many of H22a VTEC Prelue engines. After the 3K km mark they start eating oil like crazy. It's been sort of deduced that since Honda uses two different suppliers for rings, one kind will burn a lot more oil than the other rings. I was lucky and got the "moderate" oil burn rings.

Unlike others with engines that consume sometimes upwards of 1.5L/1000km or driving!

 

[Patman]

The LS1 f-body owners that I know have a terrible time with Mobil 1. This brand seems to burn
more oil for them than others. Many report their consumption goes down 50% when they
switch to other oils! Oil burning is a design problem with these engines to begin with, but
for some reason (possibly it's thinner nature) Mobil 1 seems to make it worse for them. Not in
every case though, I ran M1 5w30 in my LS1 Firebird for the entire 28,000 miles I had it, and
did not consume oil.

 

[Spector]

LS1 Owners. Car & Driver has a note in current issue that part of the problem may be a weak PCV valve and if this is replaced oil consumption will be reduced. No idea if it works, just read it last night.

Also, if you drive your car mostly short trips for say 3000 miles then take one long high speed trip you may note a large decrease in oil on the dipstick. This is due to condensation having built up in the oil and it is burned off during the long trip. Happens to me once in a while.
Can also be the filter drain back valve. After several months mine does not always hold the oil and some days it reads high, (filter has released the oil) and other days it is lower (valve has worked). Not 3/4 of a quart but noticeable.

 

[Patman]

Yes, it's true, the PCV system is part of the problem on the LS1, it sucks oil into the intake. But
it's not the only source of the oil consumption. I know many guys who tried the PCV fix, and
even when the oil is not sucked into the intake anymore, their consumption is still pretty bad,
due to the rings. One friend of mine burns about a quart every 2-300 miles now. He's
scheduled for a rebuild very soon, but the shop is backed up so he has to keep dumping in
oil until they are ready. Another friend is also in the same boat. Both of them have highly
modified LS1s though (heads and cam package, both making about 400rwhp)

 

[sprintman]

Patman
This was a GM engine design problem, not an M1 problem. Ring flutter and low tension oil rings. GM have a totally redesigned piston/ring kit which fixes it. We have LS1's coming out of our ears here in Oz and all from HSV have M1 10W30 factory fill. Some went through oil like water, others use none. Holden (GM) don't like fixing them but will if pushed. I presume later LS1's had the change on the production line. Vey sloppy design/testing on GM's part which found strange as a previous SBC owner.

 

[Patman]

True, it is a design problem, however quite a few people found that consumption on these engines was a lot worse when using Mobil 1.