Engine oil recommendation

I've used Mobil 1 for years and think it's great. The engine seems to run more smoothly with it compared to dino oil, but that's probably my imagination.

 

I use Mobil 1 5w30 synthetic. You can get a 5 quart jug for around $22. I recommend using only 3.5 quarts. It will still be close to the high mark, but not over. 4 quarts is a bit too much.

 

The Toyota oil recommendation is on the oil dipstick cover.

 

3.5 US quarts of 5W-30 synthetic oil; whatever name brand is on sale at Walmart at the time you decide to buy oil. When on sale a 5 gallon jug of synthetic oil sells for ~$22.

 

Then go buy an owner's manual. It's full of Prius-specific stuff that you need to know. See also the maintenance schedule at
Toyota Parts and Service

 

I use Mobil 1 OW-20 synthetic. I believe I get about 2-3 more mpg vs dino. In Japan OW-20 is recommended for the 04-09 Prius. The reason they didn't use that standard in the US was the availability of product.

Have fun with your car.

 

I wonder if another reason might be hotter summer temps in portions of the US: NV and AZ deserts, Death Valley in CA, etc.

A couple of years ago I tried Toyota 0W-20 in my 2004 while still in southern CA, during the winter. That seemed to improve mpg the same extent that you had noticed. However the engine started to consume oil (at the rate of 1 quart after 5K miles) and this has continued (although at a lesser rate, 0.5 qt after 5K miles) when I switched back to 5W-30 synthetic.

So I advise caution to 2G owners thinking about switching to 0W-20, who live in relatively warm climates and whose vehicles have logged more than 50K miles.

 

Agreed. Although I ran my '04 Prius most of its life on Mobil 1 0W-20 with ZERO oil consumption, our summer temps rarely exceed +35 C. OTOH the winter temps can hit -40 or a bit colder

Thing is, when I compared Mobil 1 0W-30 to Mobil 1 0W-20, there was NO difference in summer fuel economy that I could determine. There was a minor improvement in winter fuel economy

I had good used oil analysis results, so kept using the 0W-20.

My FJ was another matter. I am sitting on all this Mobil 1 0W-20, and discover the 4 litre V6 is approved for xW-20. Tried the 0W-20 as a "winter" oil and had horrible used oil analysis results.

YMMV in more ways than one

 

And here is something surprising about Mobil1 oils. If you think the 10W-30 would be better for hot summer driving, which would be logical, you would be wrong. The cSt @ 100°C for the 10W-30 is 10.0, while the cSt @ 100°C for the 5W-30 is 11.3. The cSt @ 100° C range for 30 weight oil is 9.30 to 12.49.

 

Jayman, are you saying that you got slightly better winter FE with the 0W30? I would have thought the thinner oil (0W20) would give better FE in very cold conditions. ???

 

I got to this thread a little late, but wanted to add that I've been using regular Pennzoil 5W30 in a 2006 with 98K miles and it seems to be OK. I've been buying the big container (5 quart) at Wallmart for about $12 or $13 and putting in 3 quarts, which brings the level to halfway. The oil level hasn't been dropping in between oil changes every 5K miles.

 

No, that was poorly worded on my part

In very cold winter temps, eg <-25 C and especially -40 C, I had a slight improvement in fuel economy running Mobil 1 0W-20

Otherwise, there was no difference between Mobil 1 0W-30 and Mobil 1 0W-20

 

This site has access to owner's manual etc.
Toyota Owners Online | Official Toyota Owners Website

 

0W30 Mobil 1 and the dealer put it in without a question. Cold climates maybe 0W20.

 

I used to just cut an old 2 liter pop bottle in half. Loosened the filter, then slipped the old pop bottle over top and continued to loosen it up. Any spillage went into the pop bottle

My FJ, the filter is right on top of the motor, and is upside down. There is a catch basin under the filter, and the catch basin has a small tit at the lowest point

So I use an empty 1 liter pop bottle - shove the bottle up into the tit, loosen the filter, perhaps get 200 ml into the pop bottle, and not spill one drop anywhere

At first I was leery of the FJ oil filter location. Now I love it, very easy oil changes. Naturally the 2010's went to the dreaded cartridge oil filter