Pierre

I question the values and benefits of changing the oil in my car in the Fall if I've driven it only 100 miles or less during the Summer. The oil is still clear and looks and feels the same as it did the day I put it in.

Is it really necessary to go through the trouble and expenses of an oil change just because the oil has been “sitting” in the oil pan most of the summer?

Your thought?

Thanks

Pierre Joly

andy60

Pierre,

During the 1000 miles you drove your car contaminates like gas did move by your cylinder rings into the oil and condensation accumulates inside motor. I change my oil every 4 to 6 months no matter how many miles I have driven the cars. But, I have worked on motors/cars where the owner almost never changed the oil with no apparent problems. I like having fresh oil in my car because I never know when I may need/want to drop the hammer and turn 6 at 7,000 rpm.

SWCDuke

For collector cars that are driven a few hundred to a few thousand miles per year I recommend annual oil changes - usually in the fall at the end of the driving season, or just prior to storage if you store the car during the winter. I also recommend HD diesel engine oil (API service category CH-4, soon to become CI-4) for vintage cars without catalytic converters.

The HD diesel engine oils have a richer package of detergent, dispersant, anti-wear, and anti-corrosion additives. The additive packages in spark igntion engine oils have actually been reduced over the years because modern cars with quick warm-up and precise metering don't suffer as much fuel dilution, and the byproducts of additive combustion are not kind to catalytic converters.

If that hundred miles was acculumated on trips of at least ten miles in mild to warm weather where the engine was fully warmed up for at least 20-30 minutes, I say you would be okay to go another year. On the other hand, if that 100 miles was accumulated going on and off a trailer and short trips where the engine was not fully warmed up for at least 20 minutes I would recommend you change the oil and filter.

Assuming you do the job yourself the cost is only about ten bucks, and if you form a habit of changing the oil every fall, you won't forget. On the other hand, unless you keep good records and audit them regularly, you are going to forget when you last changed the oil.

Oil quality is tough to discern from visual appearance. Oil that looks clean can have a lot of fuel dilution if the car only sees short trips. On the other hand, dirty appearing oil may still have service life. The darkening is due to oxidation. The only way to really know the quality of the oil is to have it analysed by a lab, which is more expensive than changing it. That's why it's important to form a habit based on mileage or time.

Back when I used to drive my daily driver 15K per year I changed it every 5K miles. Now that my cars only see a few hundred to a few thousand miles per year, I do annual oil changes. The two cars I swap back and forth every six months - one my summer driver and the other my winter driver, I change the oil and filter before they go into storage.

Duke

66427-450

I pretty much agree with Duke, but I change it in the spring in my '66, when I get it out of storage. I start it every month during the winter, and let it run for ~30 minutes, (till warm and dry).

It just feels right/good to start out the season with fresh oil/filter, air filter, and plugs. BTW, I use Mobil 1.

Kid_Again

...THANK GOD nobody mentioned synthetic oil in this post....uh oh :eek:

Viet Nam Vett

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THANK GOD nobody mentioned synthetic oil in this post....uh oh
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Ok,I'll mention it. I use moble 1 15W 50. Let the SPARKS FLY!!!! I change the oil in late spring and it stays in the crank em up case till the next spring.
Both of the Vette's go out every week for a trip around the neighborhood. They are run about 10 miles each for about 1/2 hour till the water temp is up and the oil comes up to temp. After I terrorize the neighborhood it's back into the garage.

The only time they don't go out is if there is snow or rain on the streets. But they are run all through the winter. It looks cool to see the side pipes belching smoke in the cold air. I also enjoy watching the oil pressure at start up go to 60lbs at idol..
:lol: :lol: :lol:

66427-450

"......Ok,I'll mention it. I use moble 1 15W 50. . But they are run all through the winter. It looks cool to see the side pipes belching smoke in the cold air. I also enjoy watching the oil pressure at start up go to 60lbs at idol.........".

>>>>> 15-50 huh..... a little stiff for winter starts Bro. Those first few seconds are critical
:seeya

Viet Nam Vett

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>>>>> 15-50 huh..... a little stiff for winter starts Bro. Those first few seconds are critical
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Well, She's a no clacky clacky and no bangy bangy.......just silky slipy starts.
Oil pressure is instant no lag. When i switched to Mobile 1 Years ago I had spoken with one of there eng.'s on the phone. I went through the whole bit with him in regars to winter start up with 15W-50. The way he explained it to me was that as long as I didn't live in the far north country ware the temps average below o* I would be fine.

And you know what??? He was correct. Both motors in the Vette's have no problem turning over or building oil pressure instantly. They turn over the same in the winter or summer.

If I could I would replace the blood in my veins with Mobile 1... Dat's Some Neat Stuff
:yesnod: :yesnod: :yesnod: :yesnod:

Kid_Again

...ok, lesse here...let's say the purchase price of a bottle of the synthetic stuff is, oh, for the sake of rounding, let's say $5.00....the cost of acquistion of the raw materials, per quart, is, oh, say $0.50, and the bottle and purty cap (color IS an important point-of-purchase discriminator) is $0.10...so, the $4.40 you pay does to direct marketing costs.......

...and WHO said marketing wasn't slippery?????? :nono:

Viet Nam Vett

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...and WHO said marketing wasn't slippery??????
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And your Point being???????............................ .....................................

Are you telling me that they lied to me??? :cry :cry :cry

I believe every thing that every mfg tells me. Because they show me charts and graphs and famous people hold up there products and tell me it's true.

When Richard Petty told me to use STP... I ran right out and bought it. When Dale Ernhart said ...go to your GoodWrench Chevy Dealer for a tune up and oil change I did that too.

So, If all those people tell me that these products work, who am I to doubt them........ :lol: :lol: :lol: :lol:


[Modified by Viet Nam Vett, 11:56 PM 12/10/2002]

Kid_Again

...oh GOD no, i wouldn't say that you were lied to....i'm just trying to suggest that when SOME people are presented with DATA (like the information that makes them an informed consumer, for example...as it were), they get distracted easily and go for the purty colors...

NOT that there's anything wrong with that, you see...i have the same affliction with that vaguely evil irridescent red in the Water Wetter bottle -oooohhhh, pretty colors :crazy:

62fuelie

The only real reason to change oil even annually is to get rid of any acids that may have formed as a result of condensation. Running the engine until it is throughly warmed up prior to storage will take care of most of this. More frequent changes are a waste of time, money and natural resources. The oil change industry has brainwashed a lot of folks into thinking they need to change their oil every 3K miles. What rubbish. 5-7K miles is a much more reasonable interval. On heavy trucks the interval is usually 15Kand many of those on oil analysis go much more.

SWCDuke

Many studies over the years have indicated that over the life of the average automobile engine, about 80 percent of all wear occurs during cold start and warmup. Therefore, you should not start the car unless you want to drive it. Cold starts are the enemy!!!

By changing the oil prior to storage, you are assured that there are no contaminants such as acids that will cause corrosion during storage, and the whole inside of the engine is coated with fresh, clean oil.

The argument for oil analysis is valid, but an oil and filter change is usually less expensive than an oil analysis. That's why I use one year apriori. BTW, even though new Corvettes can go up to 15K miles with synthetics and their oil quality sensor, GM STILL says an annual oil change is required, regardless of mileage or what the quality monitor reports, in order to maintain warranty coverage.

Regarding commercial equipment, such as big rigs, they have HUGE sumps - on the order of four to eight gallons, oil coolers, and they run long average trip length. If you drove 200 - 800 miles for every cold start your oil would last longer and so would the engine. Plus, they use the HD CH-4, CI-4 oils that have higher concentrations of the additives that are critical to engine life!

Since the synthetic issue has been bought up in this thread again, I'll reiterate the reasons to use or not use synthetics.

First, just about any oil will provide basic engine lubrication, including the cooking oil in your kitchen. The real issue in matching an oil to an engine is the additive package. The detergents, dispersants, anti-wear, and anti-corrosion additives must protect the engine from extremes that are occassionally encounter in service. In the case of engines that may not be operated frequently, corrosion can cause more damage than wear due to mileage accumulation. This is why HD diesel engine oils are superior for vintage cars. They have a greater concentration of anti-corrosion additive, and the additional detergents and dispersants will hold more blowby contaminents in suspension. Older design engine blowby is more damaging because they don't have precise fuel flow control of modern engines and blowby is better handled by the richer detergent and dispersant package in HD diesel engine oils. Finally, the additional EP anti-wear addtives are there when you do a cold start after the engine has been sitting for weeks, or months, and they will protect the engine from wear during the critical cold start and warm up mode.

The last issue is oil oxidation. Over time oil oxidizes and the greater the average operating temperature or peak temperature, the greater the rate of oxidation. This is were synthetics have an advantage, and it is their only real advantage - they oxidize more slowly, which converts to longer life - especially on modern cars that don't consume the additives as quickly.

Synthetic oils are not "more slippery", and they will not increase fuel mileage or power to signficant levels compared to conventional oils of the same SAE grade. Synthetics can also be an advantage in climates with huge temperature variation through the seasons since synthetics generally have a wider viscosity range without the addition of VI improvers.

Neither of these two advantages - greater oxidation resistance or wider viscosity range is much of an advantage on a collector car that is driven a few hundred to a few thousand miles a year in mild weather. You pay more for synthetics, but the benefits might not be there.

The final issue is oil leakage. Apparently some early synthetic blends reacted with older seal polymers and caused seal shrinkage. Supposedly this issue has been addressed with both newer synthetic blends and newer seal polymers that are more compatible, but if you have an original unrebuilt engine, or your engine was rebuilt over ten years ago, it might be wise to avoid synthetics for this reason, alone.

Duke

ghostrider20

In my vette I use Rotella 15-40. I change it every 3000 miles. I enjoy working on my vette and it is done as winter maint. and once in the middle of the summer. So twice a year. $20 bucks, big deal. In the winter I also glass blast my plugs and some other odds and ends stuff. Puttzing with my vette does for me what TV and a recliners do for others. I wheeled the big screen out of the family room and into the garage 3 years ago. So the PITA issue is not relevant for me.

Between dad and I and the girls we have 16 vehicles most of them get oil changes every 5K. I have a 92 full size blazer I changed the oil in that every 3K. In my blazer I run 15-40 in the summer, 10-30 in fall and spring, and 5-30 in winter. Trans and transfer case get serviced every 30K. Chasis lubed every other oil change.

Mark

Kid_Again

...i have used the diesel-grade dino oil since i saw duke's original post here, did some addn'l research and satisfied myself that it makes sense....works for me....

...i want to clear up a misconception i may have left you with - i do not think that syn oil is more slippery - it is their MARKETING department that i think is slippery...oil is a commodity...i agree cold starts are the problem (i know, i saw that on TV, so you know it's got to be true)

66427-450

As always, thanks for the input Duke. I'm just finishing up a replacement BB engine for my 66, and I'll take a hard look at using the HD diesel oils. I also need to look into the oil filter options out there..... for this engine I'd be interested in the Long (because of the increased amount of filter media) screw on filters. I usually change filters frequently till the assembly lube/"building related contaminates" are all removed (I always prefill the filters by the way).

INMYBLOOD

I too have been using Delo 15-40 in my classic's with 350cid's. The only place I can get it is a boat supply store. Runs about 10$ a gallon. What's up with that I need 5 quarts :lol: Works great in the boat engine too.

Viet Nam Vett

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First, just about any oil will provide basic engine lubrication, including the cooking oil in your kitchen.
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Mix a little Garlic & Butter...oregano and Wal-La... Big Block..Souffle.... :jester

JohnZ

A quick anecdote about cold-start wear; a college roommate of mine went on to become the Maintenance VP for the Penn Central Railroad many years later, and I spent a weekend with him at the King of Prussia, Pennsylvania Penn Central Maintenance Center many years ago. He indicated that cold-start wear was such a major concern for the huge turbo-diesel locomotive engines that they NEVER shut them down, from the day they were delivered from GM's Electro-Motive Division until they came in for overhaul at 5 million miles; even if they were off-line for the winter, they left them idling all the time to maintain even temperature distribution through the engine block to minimize bore and bearing wear. Their experience indicated that one winter cold-start caused as much engine wear as 100,000 miles of line service, so they never shut them down - idle fuel was a lot cheaper than more frequent overhaul intervals :eek:

SWCDuke

I've got some studies on oil filters too - SAE papers. When new an engine can generate a lot of particles from run in wear. This plus assembly lubes can lead to early oil filter plugging, so changing the filter in the first few hundred miles is a good idea, but the oil is okay to run for the full duration.

Once breakin is complete engines generate very few particles, which leads to an argument that the fiter can be run longer than the oil. They're cheap, so I still replace the filter with every oil change as removing the filter also removes the old oil it holds. So maybe removing the oil filter and emptying it out and reinstalling it is okay, but for the price, I just change it once a year along with the oil.

Once the engine reaches end of life particle generation goes up.

The bottom line is that the larger filter may not provide much benefit, but it won't hurt anything either.

Modern cars keep coming out with smaller and smaller filters. The deal seems to be that better component cleaning and ever more precise machining reduces the particle generation during breakin, so the motorcycle sized filters on newer engines are okay.

Duke