ZDDP.............shelf life?

[John G.]

In case I missed it (checked the archives) does ZDDP oil additive have a 'shelf life', so to speak? .. Will (fresh) ZDDP degrade, over time, while simply 'sitting' in the plastic container?

It's been mentioned that one item of putting a car away for storage is to change the oil before doing so. Assuming an engine is in good overall operating condition (leak down rate): Will short drives and running the engine, say roughly 100-200 miles during the storage period, have a significant effect on the life of the oil (ZDDP)? .. Should the oil still be changed at 6 month intervals, no matter what? .. All these questions! ..

[Duke W.]

Re: ZDDP.............shelf life?

Im not sure about the shelf life of "ZDDP products", but the additives in engine oil including ZDDP can "drop out" over time, and I don't recommend having more than a two year supply of engine oil products. Same with some antifreezes, especially those containing silicates. Their shelf life is about two years due to silicate drop out. Sealed brake fluid is indefinite as far as I know.

Beyond this there is absolutely no reason to add ZDDP to vintage engines with OE/OE equivalent cams and valve trains if you use CJ-4 or CI-4 oil

I normally recommend changing oil annually just prior to storage for collector cars driven a few hundred to a few thousand miles per year, but lately I've been going two years on some of my cars because annual mileage is dropping to below 500.

A car should not be started and "warmed up" during winter storage, nor should the car be taken for short drives purely for the purpose of warming it up. If the car is stored inside and never or rarely sees condensing humidity, let is sleep.

If you do get a good winter day that allows you to drive the car for at least 30 minutes so it fully warms up and you actually want to drive it, no problem.

In the engine oil article I wrote about a year ago for The Corvette Restorer, I gave several Web references, and one of them has shelf life information for various automotive fluids. Given your NCRS number you should have received that issue.

Duke

[John G.]

Re: ZDDP.............shelf life?

Im not sure about the shelf life of "ZDDP products", but the additives in engine oil including ZDDP can "drop out" over time, and I don't recommend having more than a two year supply of engine oil products. Same with some antifreezes, especially those containing silicates. Their shelf life is about two years due to silicate drop out. Sealed brake fluid is indefinite as far as I know.

Beyond this there is absolutely no reason to add ZDDP to vintage engines with OE/OE equivalent cams and valve trains if you use CJ-4 or CI-4 oil

I normally recommend changing oil annually just prior to storage for collector cars driven a few hundred to a few thousand miles per year, but lately I've been going two years on some of my cars because annual mileage is dropping to below 500.

A car should not be started and "warmed up" during winter storage, nor should the car be taken for short drives purely for the purpose of warming it up. If the car is stored inside and never or rarely sees condensing humidity, let is sleep.

If you do get a good winter day that allows you to drive the car for at least 30 minutes so it fully warms up and you actually want to drive it, no problem.

In the engine oil article I wrote about a year ago for The Corvette Restorer, I gave several Web references, and one of them has shelf life information for various automotive fluids. Given your NCRS number you should have received that issue.

Duke

Duke ..

Yes, I did read the oil article you wrote in the Restorer. I'll be darn if I can remember the shelf life information, though (quasi CRS). I'll have to dig it up for a reread. . Thanks for the heads up and re-referencing the article.

The 100-200 driving miles during a storage period was a reference to a good winter's day drive, as you mentioned - certainly doable here in N Cal. The oil in the crankcase in my '64 has been in there well over a year, now. With extremely 'low miles' on the oil I just hate to dump it if it's not actually necessary to do so.

[Duke W.]

Re: ZDDP.............shelf life?

I didn't specifically discuss shelf life in the article, but one of the Web sites I referenced, http://lubricants.s5.com has a lot of good background information. Read all the "articles" and "reference" links.

It sounds like you really don't "store" your Corvette during the winter, however, you probably don't drive it weekly. Even if you live in the Sierra foothills there are probably plenty of sunny, dry days that offer a good driving opportunity.

As in my case in Southern California, I don't see any problem going two years on the oil if you're only seeing a few hundred miles per year, don't do "short trips" and the car doesn't sit for more than a month or two even during "winter".

Although oil color is not necessarily a good indication of oil condition, a good tight ring and valve guide seal and avoiding short trips will keep the oil clean and moisture free. My cars usually don't even begin to darken the oil until 1000-1500 miles, and, like you, I am reluctant to change oil that still looks like it just came out of the bottle.

Duke

[John G.]

Re: ZDDP.............shelf life?

Tight rings and valves - got 'em (engine refresh). The two year oil life time line given 'storage' conditions sounds good.