I am lookiing for some advice on what grad oil to use in my 1995 Monte Carlo Lw w/3.1 V6?
The Car has 115000 Miles on it now and is running well.
When I purchased it approximately a year ago with 95000 miles on it, I read the manual and the tags under the hood and was using the recommended 5w-30 oil (Castrol GTX) and also added STP oil treatment. (Have been using it for 24 years, n reason to stop now)
I change My oil every 3000 miles and use a quality filter. (Fram or ACDelco)
Approximately 6 months ago I was driving and the "low oil" light went on, I checked the oil and I was over 2 quarts low!
I was sure that the engine might leak a little (most do) and since the car had over 100000 miles at this point, I figured it might have an oil ring seal that might be a little "loose" and causing it to use some oil.
Next oil change I started using 10w-40 oil (Castrol GTX) and also added STP oil treatment as before, this seemed to alleviate this problem for the most part, as I have not gotten a "low oil" light since.
The Question really is, will using this thicker grade of oil do any harm to this engine?
I do know that they often recommend the 5w-30 in order to obtain better fuel economy, but that is not my main concern.
If anyone has any experience with these egines and has any input, it would be greatly appreciated.
Thank you
Lenny

 

Several things here. 1st and foremost, the thicker oil will make your engine work harder, and IMHO is NOT the thing to do, but personal opinion. In the summer, I actually run 0w-30 oil. I'd stick with 5w-30.
You do have a fair amount of miles, but I have more than that on my '04. I've ALWAYS run "full" synthetics, but then I have a supercharger, and that's what's recommended for them. Anything less can actually void the warranty. We have well over 600,000 miles on full synthetics, and recommend nothing less.
Again, opinion, lubricants have evolved a LONG way in the last century. I believe in using current technology. I put Mobil 1 in our '82 Olds with 70K on it.
Filters: Big variation of opinion here, but typically the basic Walmart Fram is one of the cheapest filters out ther. Get a NAPA Gold or a Purolator. There are other good ones, also. AC Delco is Chinese, as is the basic Fram.
If you want to use Fram, get the Fram XG.

Here are a few links to check out:
http://www.300cforums.com/forums/gen...dissected.html
http://people.msoe.edu/~yoderw/oilfilterstudy/oilfilterstudy.html
http://people.msoe.edu/~yoderw/oilfilterstudy/oilfilters.html#recommended

BTW, I get most all my oil at Walmart in the 5 qt jugs, and I go 6,000 miles between changes. I use NAPA Gold filters exclusively.

As for STP, I don't believe in adding my own additives to the oil, ESPECIALLY anything as thick as molasses. That's why I run 0w-30 oil in the summer.
My 2 cents.

 

a little more info on the low part did you do a oil change befor the check or after? the second is the bottom of the motor what is going on with it? is it covered in oil? or is it spotless? are you seeing a poof of smoke when you start the motor? or do you hear a noking sound before the change of oil type? also keep in mind ford and chevy are netorius for a quart or two just dissapear. it uses the oil mainly beats it up till it turns to vapor. i have to add 2 quarts into my silverado as well into my mustang if i drive them on a regular both vehickels have 110k on them and dont burn any oil it just beats the oil till its vapor. i just rebiult the silverados enginbecause the head went is was spotless exept the normal weir and it gave me an excuse to up grade every thing. new barings oil pump seals. but a little more info on yours

 

I response to the Question about the low oil light, it came on when I was nearing to be due for an oil change.
I do not see any smoke, and the enginge underneath is not especially oily, maybe a little bit of oil here or there but I am not leaving puddles or even any spots.
I agree with some engines "using" oil, but most of my experience is with the small-block V-8s which I know you can run a couple of quarts low and the engine will not experience a mechanical breakdown, these smaller engines I have less experience with and I am mostly concerned about running low on oil or not lubricating the engine properly. What is your opinion on the engine oil grade and the filter choices that were posted by others?

 

Personally, like Wayne said...I use Full Synthetics, and have since day one! My engine has 87K, and burn no oil.

I would not be surprised if you are burning a little oil. 2 Quarts in 3K seems like a lot to me though.

It will not harm your engine to use 10w-40...especially an engine that is using oil and has that many miles on it. But your fuel economy will drop a little.

I would not use STP in anything. Look in your owners manual, I am pretty sure it says DO NOT put any oil additives in your oil. Just use the recommended oil, and change it. IMO, 3,000 mile oil changes are WAY over rated. If I was running conventional oil (which won't happen now, but I used to in my truck) I would go with changing it every 5K. On full synthetic, I go 7-9K between changes, and my oil is always still golden brown when I change it. My oil life monitor says change oil about every 8K, and the car does not know i'm using synthetic oil.