In my basement, there is six bottles of Castrol 30W oil that I purchased in 2004. Can't remember why I didn't use them as soon as I got them. My truck needs an oil change, and I was thinking of using the three years old Castrol 30W motor oil. All of them are still sealed in the bottles. It's for an old engine, a '79 400. Would it cause any harm?
Aurg, the engine has low oil pressure when used with a lightweight oil. Now it has 10w30, and it barely register any pressure while warm. Needs thicker oil to compensate with over 200,000 miles on it.
just like beer, soda, and bottled water, motor oil will go bad if not used by the use by date.
there is no such thing. the use by date is nothing more than a way to get people to by more goods.
back in the good old days before we had smarter than us advertising agency's, we drank beer and soda that sat in the refrigerator for over 6 months, and used motor oil that sat on store shelves for years, and nothing ever happened.
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I've used motor oil that was 5 and 6 years old, unopened of course. If its older than that, I still use it for anything that needs oiling like keeping my drill bits cool while drilling steel and lubing the joints on tractor 3 point hitches. So just because its old doesn't mean its no good.
Aurg, the engine has low oil pressure when used with a lightweight oil. Now it has 10w30, and it barely register any pressure while warm. Needs thicker oil to compensate with over 200,000 miles on it.
Straight 30 weight oil is not heavier than 10W30, except at cold start - and that is not where you have a low pressure problem. You are not doing the engine any favors by using straight 30 in it. 10W40 would be a much better choice, or 20W50 if you really need it to keep the pressure up.
The use by date is often accurate. If you drink diet sodas you will rapidly findout that diet sodas taste odd after the use date and if you go too long they taste nasty. Canned foods will often have a strange metallic taste if stored too long. Other products will break down or separate. So the use by date is a good recommendation. It doesn't mean the product is expired, but you should evaluate it and use it as soon as you can after expiration.
We manufacture a lot of things here with use by dates. In general those dates are the dates where we will guarantee the product. After that who knows.
The problem with any perishable product is that the manufacturer cannot control how the product is stored. Heat and extreme cold is slow death to perishables. Typical laboratory stability testing is done at 40 degrees C, about 105F. This temperature is easily reached in a storage shed, garage, trunk of the car etc. The usual staility test is that for every month at 40C you use up about 3-6 months of the product life. Since we can't control how our customers store things we give them only a year of expected life.
Some products will go for 10 years, some will die shortly after the expiration date.
Motor oil, from what I have read and experienced usually has problems with things precipitating out and settling to the bottom of the bottle. So possibly the additives in the oil are no longer active or available for use. Grease is much worse, if it is too old it WILL separate and is no longer useful.
In general the best tool we have to guage product quality is the old fashioned Eyeball-o-meter. Look at the product, if you can see distinct layers of the product or sediment, then usually something is wrong. Sometimes all it takes to fix it is a good shake.
Sodas in can to oil is like apples to oranges. Aluminum, in spite of the protective oxide layer is soluble in many acids, and that will mostly responsible for the funny taste. Same for many acidic foods (i.e. tomato paste) stored in tin cans. However, the same food items should last a lot longer in glass (or even plastic) jars and bottles.
Anyhow, oil has several "failure modes" in an engine, but those simply can't happen in an unopened plastic bottle. The only real possibility is separation; however, as long as everything can be poured into the engine, the mixture should get homogenized pretty quickly.
The oil is just fine. Most of my stash is 3 or more years old. It should keep 5 to 10 years easily. For long periods, beyond several years, I would avoid freeing temps and excess heat, say over 80 or so. Also shake the bottles before pouring in. Shaking is a good idea or new or old oil.
Thicker oil isn't going to do much better on a 400 with over 200,000 miles on it. I've ran 20W50 in my Galaxie with a 400 the last couple years to keep it alive but I never take it on highway trips. Low oil pressure on high-mileage M blocks is pretty common. Even now, with 20W50, my 400 has 0 pounds at idle when warm and maybe 25 if I'm lucky with the throttle all the way open. And it only has 150K on it. I don't even keep up the tags now.
rubydist, thanks for the clarification. I'll just go and purchase cheap 20W50 oil. I'm still an idiot with the oil stuff...I just know what I know with these old engines.
TallPaul, then the climate has shortened their lives considerably...the basement is hot in the summers and extremely cold in the winters.
fmc400, yup, it is. I kept running 30W in my old F-150 when it was on its last legs. I never knew it wasn't any different than 10W30 oil until now. ARGH! This one, it's likely tired...but the kicker is, the compression is still around 150PSI. It doesn't burn oil except when I stomp on the pedal...but then again, the valve cover leaks oil. I'll throw in heavier oil and see what happens.
I'm never serious unless I should be.
