Oil Change Interval

[john1701a]

When changing oil in on my Classic Prius, I was always impressed by how good condition it was still after 7,500 miles. My pre-hybrid car certainly wasn't that easy on oil; in fact, it looked & felt terrible after just 3,000 miles. So, I wasn't exactly receptive to the idea of a 5,000 mile change interval for my HSD Prius.

But now that I'm at 60,000 miles and currently have no garage (the foundation is being rebuilt), the consideration of waiting longer is now foremost in my mind... especially since I've been religiously using synthetic.

What are other owners thoughts on this? How often are they choosing to do changes and when are they breaking from the standard routine?

[efusco]

We just had a thread discussing this ( http://priuschat.com/index.php?showtopic=2...p;hl=oil+change ).

Like you, I think that at the 60k mile mark--out of the standard drive train warranty, I'm going to give serious consideration to extending the intervals to at least 7500 miles if not 10k. It certainly seems that there is not that much wear on the oil to start with, then with the ICE running only ~50% of the time that we're driving anyway that such an extended duration is likely to be OK.

I do think I'll send in the oil for analysis after the first extended change just to be sure that my speculation is confirmed with something more objective.

I've also thought about moving to one of the extended life Mobil synthetic oils...but I'm not sure that that is even necessary. I'm just hitting 50k myself, so I don't need to worry about it much until next Spring. If someone else decides to do this and get an oil analysis showing it's OK to go 10k, then I probably won't even bother with my own analysis.

[tochatihu]

Hi John, synthetic oil has always tested well in Prius for up to 10k miles, by which time its total base number is starting to get low. We have seen *very* little evidence of wear metals accumulating in the oil. I used to change my oil filter at the 'midpoint' but am now letting one filter go the whole way.

I am also a fan of engine oil analyses, which are really the only way of knowing what is in there. It could be argued that those are particularly important for extended oil intervals, but in fact everybody would be better off knowing what's going on inside. At the same time, in Prius, oil analyses usually are very boring. Whether the engine is simply very accurately machined, or if the 'hybrid lifestyle' really reduces wear during startups, 'lugging', and fuel enrichment during 'high load operation', we really don't know.

For extended oil change intervals, the possibility of accumulating ingesting dirt in the engine (which can cause abrasive wear) is obviously increased, so it becomes even more important to confirm that the engine air filter is maintained in good condition.

There are other threads here about 'bypass oil filters' which if I understand them correctly, may allow the Prius to go even longer on one batch of oil. Essentially out to the oil's true lifespan, whatever that might be. That modification will be of interest to some Prius drivers.

[john1701a]

I've been well aware of the growing interest in this topic. The hybrid system is obviously far less demanding on the engine than a traditional vehicle. So there is definitely potential to forge our own routine. Those other message threads discuss WHY.

On this thread, I specifically would like to know HOW OFTEN.

[aaf709]

<div class='quotetop'>QUOTE(john1701a @ Sep 6 2006, 02:45 PM) [snapback]315427[/snapback]</div>

On this thread, I specifically would like to know HOW OFTEN.
[/b]

Currently I'm going with 5,000 on synthetic.

[Frank Hudon]

for those of you in cold climates in the winter time I think if your an average driver who does 2 15 mile trips per day, to work and back, and the OAT is at or about freezing I think a change in the late fall and again in late spring is probably all that's really needed. 10,000 on a synthetic is probably about as far as I would want to go but a UOA will tell for sure. I just did a holiday trip and in 3000km the ICE only operated 68% of the time, and this was gone over in the thread that I started on it. As far as I'm concerened that works out to 2000 and change Kms I just looked at the oil and it's clean as when I put it in 4 day's before the trip. I'll change it again in the spring unless some extenuating circumstances occure in the meantime.

[Sho-Bud]

In The Netherlands, Toyota recommends oil change every 15,000 km.

[jayman]

<div class='quotetop'>QUOTE(john1701a @ Sep 6 2006, 04:45 PM) [snapback]315427[/snapback]</div>

On this thread, I specifically would like to know HOW OFTEN.
[/b]

You can only get a legitimate answer to your question by doing a Used Oil Analysis, like I have. Overall, with Mobil 1 and the Toyota filter, putting almost 7,000 miles on Mobil 1 0W-20 over winter short trips, was nothing. Clearly, at least with Mobil 1, the oil is good for much more.

I would suggest the EU oil change interval of 12 months or 15,000-16,000km should work ok if you use Mobil 1.

Once you have over 6,000 miles on the oil, a sample every 1,500-2,000 miles would be helpful to establish baselines. The sample is usually less than 80ml, so you're not removing a huge amount of oil. What you want to track are wear metals, TBN, insolubles, etc.

<div class='quotetop'>QUOTE(Sho-Bud @ Sep 9 2006, 01:02 PM) [snapback]317017[/snapback]</div>

In The Netherlands, Toyota recommends oil change every 15,000 km.
[/b]

Believe it or not, here in North America, especially the U.S., there are many folks who believe if they run over 5,000km on the oil, the car will self-destruct

[puppetmasta]

I would be very interested in some of the oil wear results.

I definitely agree that the Prius should be able to handle longer wear than most cars especially when you feed it mobil 1 syn

John, btw, just used your oil change guide for my first oil change on my '06, thanks alot for putting that together. Was a piece of cake with your guide

[MechaJohn]

Where does one go to get used oil analyzed?