Oil Change Interval

[nitewolfgtr]

I own a 2001 Toyota Prius and I was wondering what is a reasonable time between oil changes? 3000miles? 5000miles? 7500miles?
Also, I noticed that alot of people on this forum emphasize on not overfilling it more than 3.5qt. Now, does that only imply to the current Prius models or also for the Classic Prius?
Thanks

[Rest]

Don't make more into the process than what it is. Just follow the owners manual with regards to mileage and how much oil to use. There is no magical number, like 3000 miles changes that came from the 60's. Those days are long gone, engines and oils are much better.

[nitewolfgtr]

<div class='quotetop'>QUOTE(Rest @ Apr 25 2007, 12:23 AM) [snapback]429577[/snapback]</div>

Don't make more into the process than what it is. Just follow the owners manual with regards to mileage and how much oil to use. There is no magical number, like 3000 miles changes that came from the 60's. Those days are long gone, engines and oils are much better.
[/b]

The problem is when I bought the car, it didn't come with the owners manual so I don't know what the recommended interval for oil change is

[Bill Merchant]

If your car were under the original warranty, I'd say every 5000 miles. You can do what you want, however. Unless you are driving on sand in the desert, you shouldn't need to change your oil at LESS than 5000 miles or 6 months. The Prius is gentle on oil. If you run synthetic oil, such as Mobil 1, you could probably go 10K-12K miles on a change, or once a year. With conventional dino oil, maybe 7500 miles/8 months. If you are really interested, check out Bob Is The Oil Guy and do some used oil analysis.

[john1701a]

Toyota recommends every 7,500 miles. I do too, since I owned one and changed the oil on it.

Also, you'll find this helpful... Classic Prius USER-GUIDE

[Rest]

<div class='quotetop'>QUOTE(nitewolfgtr @ Apr 24 2007, 10:24 PM) [snapback]429580[/snapback]</div>

The problem is when I bought the car, it didn't come with the owners manual so I don't know what the recommended interval for oil change is
[/b]

Buy one then!

[ekpolk]

I would consider running one or more UOAs (used oil analysis) on the car, with the oil you choose to use before deciding what OCI to stay with. According to the guy who interprets my results, there are a fair number of Prii which show rather substantial fuel dilution of their oil. If such dilution reaches a critical point, it can be a serious problem. My car has shown heavy dilution on one UOA, so I'm watching it carefully. Mine is an 04 that I bought Toyota Cert Used so I've also got a 100k drivetrain wty to preserve. Toyota's recom for the second gen car is 5k miles, so I'm going no further than that for now.

Here is a link to a thread discussing that UOA: Click here.

[jayman]

<div class='quotetop'>QUOTE(ekpolk @ Apr 25 2007, 03:01 PM) [snapback]430001[/snapback]</div>

According to the guy who interprets my results, there are a fair number of Prii which show rather substantial fuel dilution of their oil.[/b]

I'm wondering if a handful of Prius cars have this issue, just like a handful of Toyota's had the sludge issue. I've never had fuel dilution based on my UOA.

I'm sure the EU market Prius - with their 12 month or 10,000 mile interval - would have had issues by now if fuel dilution is widespread.

[dmckinstry]

<div class='quotetop'>QUOTE(jayman @ Apr 26 2007, 05:47 AM) [snapback]430397[/snapback]</div>

I'm wondering if a handful of Prius cars have this issue, just like a handful of Toyota's had the sludge issue. I've never had fuel dilution based on my UOA.

I'm sure the EU market Prius - with their 12 month or 10,000 mile interval - would have had issues by now if fuel dilution is widespread.
[/b]

As you may or may not recall, my first analysis indicated fuel dilution. For some reason or other, I haven't gotten the second analysis back. It was sent in nearly 4 weeks ago. I'll have to give them a call to see if they didn't get it. Either that, or the report got lost in the mail, or my wife put away (she doesn't toss it) the mail before I got to see it.

Dave M.

[ekpolk]

<div class='quotetop'>QUOTE(jayman @ Apr 26 2007, 07:47 AM) [snapback]430397[/snapback]</div>

I'm wondering if a handful of Prius cars have this issue, just like a handful of Toyota's had the sludge issue. I've never had fuel dilution based on my UOA.

I'm sure the EU market Prius - with their 12 month or 10,000 mile interval - would have had issues by now if fuel dilution is widespread.
[/b]

I suspect it may be either one deviation or defect that appears in only some Prii, or it's a combination of factors that if they appear together in ANY Prius, result in excessive fuel in the oil. Now what those factors might be, I don't know -- it's just my current theory. I will be watching my future UOA to see if it's a consistent thing. Also, it could well be happening in Euro Prii, just without ill effects. We have several cases here (and at BITOG as well) of owners successfully using xw-20 oils in their cars. This being the case, I'd not really expect problems, at least wear related ones, until the dilution got really outrageously high. I had 1.78% dilution in Penz Plat syn 5w-30, and it had just dipped into the upper end of the 20 wt range. My wear numbers were pretty stellar anyway. I very probably could have run this oil out to 10k miles with progressively increasing dilution, with no ill effects. That said, all this begs the question of there the trouble threshold lies for a Prius that's dumping fuel into its oil. More homework to be done. . .