Oil change interval for seldom-driven car

[Spector]

quote:

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Originally posted by widman:
Last year I analized the oil at 7 months/4000 km and found high lead (52 ppm). I'm not passing 6 months again. (99 4Runner turbo diesel)

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Well, hate to inform you but changing the oil at 2 months or 5 months will not eliminate your high lead count. Why, sure you will get 26 ppm at 2000 km but that is not reduced wear that is the exact same wear. All you have done is changed the oil but not reduced the problem and the additional wear is not caused by leaving the higher lead count in their in the first place. The higher lead is caused by the infrequent starts, perhaps not heating the oil up for a long period, lugging the engine etc. Don't fool yourself by changing more frequently to avoid a particle count it doesn't make any difference if the wear is average all the time. Now, if the TBN were low, or you saw high fuel, all wear metals spiking up etc. but simply changing the oil more frequently to reduce a particle count on lead will give you a lower number that you can sleep with but has not altered the cause of the problem at all!!!! You still have the same wear per 1000 km

[ May 27, 2003, 07:14 PM: Message edited by: Spector ]

 

[Patman]

quote:

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Originally posted by Eiron:
Patman,

How 'bout he changes it at 6mos (like he was planning to do anyway) & runs a used oil analysis on that? Then he can decide if he wants to go to 12mos based on that data? If he decides to go to 12mos, he then runs a 2nd used oil analysis when he changes that oil & looks at that data. If it looks either good or trashed at 12mos, it's a no-brainer. That way, he's only running two used oil analysis & getting all the data he needs for his choice of either once or twice a year changes.

Make sense?

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Sure, that would work too, I guess my idea was the super cautious method (but probably overcautious, knowing me)

 

[Eiron]

What?! A guy with more than 58 qts of motor oil & 10 filters on-hand being "overcautious" about car care?! Nah!

I agree that your method would give more accurate data, but most folks don't want to do any used oil analysis at first (OK timzak, there's your warning!), so I'm just thinking of how he can get the data he needs with the least trouble & expense.

-Greg

 

[asenna]

I know what I would do.

Fill with Mobil 1 and put on a Wix filter and take the car for a good spin on the highway at least once a month. In a years time change oil and filter.

Take the money you saved on oil changes and testing and buy a good quality wine and enjoy.

 

[davefr]

What oil characteristics are most important for seldom driven vehicles where you want to maximize oil change interval? (ie >1 yr.) (I'm talking about seldom driven vs. low mileage such as a collectors car)

Synthetic or conventional?? Is Diesel/fleet oil better?? Lot's of Moly?? How about ZDDP? I don't think Calcium is critical but what about high TBN?? If synthetic, should it be Group III, IV, or V (ester)?

 

[theguru]

Someting i started doing on an infrequently driven car is to before starting it is to disconnect the ignition system and turn the motor over until the oil pressure light goes out. Then reconnect and start normally.

Also, batteries (lead/ acid especially) do not last long if they are allowed to go flat. I've bought a small automatic charger (1600ma) which will keep the battery charged up. Whilst you can put a normal charger on there once a month, the tendency is to forget to do it or to leave it on and the battery is overcharged (also bad).

Unfortunatley, infrequently driven cars tend to deteriorate in ways that daily driven cars don't. Seals to air conditioners/ brakes/ motor etc dry out. Give it a monthly drive of say at least 20miles.

Here in Aus the Nissan dealers send reminders for services every 6 months.

As said previously, I think it is not the oil deteriorating, but the stuff that has contaminanted the oil is more the concern.

[ June 01, 2003, 03:59 AM: Message edited by: theguru ]

 

[timzak]

theguru,

I do drive it at least once a week (might only be a few miles to the market), so I think I'm okay. Sometimes I'll convince my wife to take the Stang when we go to Target or Lowe's together (she loves the refinement of our 03 Accord--her daily driver). I do try to get it out as much as I can, but I did notice that the miles are building up very slowly.

I have a spreadsheet file that records maintenance intervals for my cars, and I'll often predict the date of the next oil change based on average miles driven per day. My last prediction for the Stang was well over a year from now, that's when I thought to create this topic and maybe change my way of thinking.