Oil Consumption Question

[Schredder]

Hello,

I have a 1997 Chevy Z71 with the 5.7 vortec engine that I purchased this last July.

This past week I took an extended trip (@1300 miles with some mountain driving) for the first time since owning the truck. I decided to check the oil last night.... and discovered the engine had used approximately 3/4 of quart.

I was somewhat disappointed to discover this because previously with a mix of city and highway driving the engine was only using @ 1/4 quart every 3000 miles. What is the cause for this?

The engine currently has 103K miles on it. I have also completed one Auto RX cycle and plan to do another. This was completed before this long trip.

Thanks,

Chris

 

[Blue99]

Mountain driving will put more of a load on the engine, so some additional consumption is to be expected.

Also, with dino's, oil consumption may be minor until past the mid-point of the OCI, when the additives are being depleted, and then the consumption rate generally increases.

I always like to change the PCV valves every 20K miles on the GM V8's. The 3 bucks is a low cost method of insuring that a stuck open PCV is not allowing vacuum to pull full time from the crankcase to the intake manifold.

 

[Triple_Se7en]

Yep... the more/longer highway miles near 80-MPH causes my older vehicles to consume more also. Plus... there is still approximently one quart of leftover rinse from your Auto-Rx cycle still in your engine from your last OCI.

Doing an oil change just prior to long trips (no Auto-Rx residue there) (or) a bottle of VSOT just prior to the trip "may" or may-not have prevented that in this first-time consumption scenario of yours.

 

[Schredder]

Thanks the responses guys! Changing the PCV is one of the first things I did when I purchased the truck.

Off topic but another thing I have noticed (and not happy at all with) with this truck/engine is piston slap when starting cold.

Of course, I purchased the truck in the summer time, so I did not notice this. Also, thinking back, when my father-in-law and I showed up to test drive the truck, the engine was already warmed-up... oh well, live and learn.

 

[JohnnyO]

I think that extended highway driving at a higher speed and rpm will consume more oil than the same number of miles in town at less rpm. JMO.