Summer Oil

[hangun61]

My 96 S10 2.2 2WD 5 speed with 135K is due for an oil change. This past winter I have been using Valvoline Max Life 5W30. Should I switch to a 10W30 for the summer? I have always heard you should use a heavier oil for summer and a lighter oil in winter. Any advice or ideas?

[4x4 blazerguy]

I think 5-30 is TOO THIN period unless your winters are -50 below zero. I would run 10-30 year around.

[viggy58]

personally, after about 120k miles in my 01 v6 blazer, my oil pressure seemed a little low with 5w30 in the summer. i switched to 10w30 about 2 years ago and all seems well. the oil is cleaner at oil changes, and my oil pressure is stable at low rpm's.

[534BC]

I thought I was getting max life out of my oil. You two blow me away. You must drive a lot in a little time, like 50-60K per year?

[viggy58]

haha yea when i'm home i'll do about 400 miles or more in a week.

but my blazer will do 400 in a week, then sit for 2, then do 400 more, etc...
i travel in a company car for work for most of the year.

[dusty3]

I would be careful about switching weights. I am not saying that you can't change weights, just do your homework first and make sure that the new weight oil matches the recommended factory specifications listed in your owners manual. Some oils have higher levels of a compound called ZDDP and other additives that will clog your catalytic converter. This happened to me by switching from 5W30 to 15W40 oil. It took about 40,000 miles for it to happen. I found out how this happened by reading an article in Hot Rod magazine a few years ago. The newer style oils have synthetic compounds that burn cleaner for catalytic converters and oxygen sensors. Hope this info helps.

[old_master]

Originally Posted by 4x4 blazerguy

I think 5-30 is TOO THIN period unless your winters are -50 below zero. I would run 10-30 year around.

When an engine manufacturer specifies 5W30 oil, there's a reason for it. Bearing to journal tolerance is designed closer than ever in newer engines. The journal should never come in contact the bearing. When it does, that's when you hear the "hammering" sound. There needs to be a layer of oil between the bearing and the journal. The oil acts as a "cushion". If heavier oil is used, it will not "fit" between the journal and the bearing, which causes more damage from oil starvation. Switching to a heavier oil will increase oil pressure simply because the oil pump can't push the oil between the bearings and journals. As a result, the volume of oil passing through decreases. As the bearing and journal wear, the clearance gets larger, using heavier oil is a "band-aid" repair prolonging the inevitable. Bottom line, if you stray from the manufacturers oil viscosity recommendation, you're asking for trouble, and you'll get it, guaranteed.