How many years can I leave synthetic in before a change is necessary?

[Racer X]

Hi guys, its been a long time since I've been on the board, but I'm reminded of how much I enjoy it while searching for posts on my question.

I have Mobil 1 0W40 in a '91 Toyota MR2 Turbo. The oil has been in for more than a year, but I've only driven 800 miles on the oil. I read here some people recommending a change every 6 or 12 months, regardless of mileage or synth/dino, but I really haven't seen an explanation of WHY I should change based on time.

Obviously this is my garage queen, and I do autocross the car, so pushing the limit is not really in my best interest. On the other hand, if this oil can go 10k miles, changing it after less than 1k strikes me as a waste.

So, can anyone convince me that leaving it in for another year would be unwise? I know the shelf life of oil in the bottle is many years, is the oil pan really that much different?

Thanks!

 

[Al]

You are worried about a couple bucks of oil for a Garage Queen?? I'm not even gonna' try to convince you.

 

[wavinwayne]

Since you said you autocross the car, I'd change it. With that said, my father in law has a 60-something Dodge pickup that hasn't had an oil change in 7 years (but less than 1k miles). It's last oil change was in late '99 with Rotella 15w40. It still runs ok, & it's not sludged up, fwiw.

 

[Craig in Canada]

What is your climate like? Is there likely to be condensation in the crankcase diluting the oil and carrying sulphur and nitrogen acids?

That's more the issue than "shelf life" in the pan, I think.

 

[TomJones76]

People change based on time because oxidization and other failure modes that occur due to contamination can happen the WHOLE TIME the car is sitting there.
You might go years without it causing trouble, but most people draw the line somewhere under 13 months.

 

[mjpolge]

Instead of guessing, why don't you perform a UOA on the oil and see if the oil is any good?

 

[Bamaro]

quote:

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Originally posted by Al:
You are worried about a couple bucks of oil for a Garage Queen?? I'm not even gonna' try to convince you.

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I'm in the same situation but beyond the money which isn't very much, it just seems wrong to drain oil with less than 1000 miles that looks clean on the dipstick.

Not to mention replacing a filter which has hardly had to filter anything.

 

[Spector]

Previous owner of my twin turbo had the oil in for 18 months when I changed it, Mobil 1, UOA was fine. Current fill of Amsoil is going on 13 months. Obviously low mileage on this car.

So, another year culd be had with your current fill, depends on whethet you dive it at least 10 miles or so when you do start it, removes the condensation etc. Short trips?/ If so then chagne it

 

[hominid7]

If you are racing your vehicle, or using it for auto-cross, then i'd say your oil change is about 5000 miles overdue already.

 

[ekpolk]

I'll join mj in voting for a UOA, and I'd add Terry Dyson's consult too. Your usage is so "non-standard," that I don't think any general advice is going to be much help. Back a couple years ago, someone posted a five year UOA on IIRC a Porsche 911 that saw similarly infrequent use. You should hunt that one up and have a look. Amazingly, the oil was in pretty good shape. Knowing is so much better than guessing or speculating.

 

[pitzel]

At my former place of employment, we kept oil in machines for 40-50 years, with only filtration.

5-10 years with a good quality syn oil shouldn't be any big deal for your Toyota and that amount of driving.

"is the oil pan any different" -- my answer to that would be no.

 

[Jay]

quote:

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Originally posted by mjpolge:
Instead of guessing, why don't you perform a UOA on the oil and see if the oil is any good?

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I agree with mj.

At work we have a pair of emergency generators that typically run fewer than 30 hours per year. The generators have 84 gallon sumps, so we don't guess about when to change the oil. We do oil analysis yearly. Oil analysis has not indicated that we change oil in the last 5 years, and that's with dino oil.

In your case, I think you would only have to get the oil analyzed once, and you could use that as a guideline as long as your storage conditions don't change.

 

[vronline]

I'm a little confused... Why would you pay $40 (I'm guessing) for a UOA on oil that only has 800 miles on it? So that you can save $20 or so on an oil change?

What am I missing here?

 

[Laminar Lou]

quote:

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Originally posted by vronline:
I'm a little confused... Why would you pay $40 (I'm guessing) for a UOA on oil that only has 800 miles on it? So that you can save $20 or so on an oil change?

What am I missing here?

---

Well, it's about $20 ($16 if you preorder with Blackstone 6 at a time). But you were close.

I personally would test the oil just to have a level of confidence in the future that I could leave the oil in for over a year (since it sounds like it will be a recurring issue for him).

Yes, it is a little excessive. But you are on an oil forum. It's kind of our hobby to be fanatical about oil

 

[Laminar Lou]

quote:

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Originally posted by Laminar Lou:

quote:

---

Originally posted by vronline:
I'm a little confused... Why would you pay $40 (I'm guessing) for a UOA on oil that only has 800 miles on it? So that you can save $20 or so on an oil change?

What am I missing here?

---

Well, it's about $20 ($16 if you preorder with Blackstone 6 at a time). But you were close.

---

Correction, it would be $40 with a Dyson analysis.

 

[ekpolk]

quote:

---

Originally posted by vronline:
I'm a little confused... Why would you pay $40 (I'm guessing) for a UOA on oil that only has 800 miles on it? So that you can save $20 or so on an oil change?

What am I missing here?

---

A lot. UOA doubters miss several things. First, you don't necessarily have to perform UOA with every oil change. Thus the "bare oil change vs. UOA cost" comparison is invalid. You can learn all you need from occasional UOAs vs. UOA done with every OCI. Second, in unusual circumstances like this one, there's really no way to tell, other than UOA, whether your strategy, six months or six years, is safe. Your presumptive short OCI might not be short enough. How do you know? Third, people who own cars like this do so for reasons other than the purely economical and utilitarian. I take pride in knowing all I that can about my car, rather than hoping, guessing, and speculating about it, as you must. I actually spend almost $50 on UOA maybe 3x per year. I order particle counts in addition to the basic test and Dyson's interpretation. Weighed against the cost of a unnecessary oil changes, the cost of my UOA is hardly back-breaking. Finally, it's just plain more satisfying and fun to know about your car, rather than guess and speculate about it. If you don't want to do any UOA, that's fine, don't; but please don't pretend that your approach is best for everyone else.

Racer asked a perfectly legitimate question. The only way to answer it with any meaning beyond guessing and speculation is with UOA.

EDIT: One more thing to add -- look at all the GM owners of the 60 degree V-6s who've scored "saves" of their engines by detecting coolant beginning to leak into their oil long before it became critical and ruined their engines. Another advantage to doing UOA -- catching developing problems before they announce themselves in more dramatic and permanent fashion.

 

[Russ300H]

Lube Control and Molakule sell products that help with moisture in the oil. I think your oil would be fine, I would be concerned about contamination.

Not to say I disagree with the UOA recommendation, just I bet moisture would be your issue and those products are your solution.

 

[GROUCHO MARX]

Leave it in forever, it's your car.

 

[CosmicFlash]

Well GM's Long life spec says the approved oils can go up to 2 years. I don't see why you can't go that far with the M1...

 

[Patman]

I'm approaching the two year mark on the oil in my mom's car. I put in GC 0w30 in July 2004, and she only drives about 3 or 4000 miles per year so I didn't want to change the oil that soon, and I have a gut feeling that 2 years will be just fine and the analysis will show I could've probably pushed it further.