Switched Oil from 5W30 to 0W20 after 193 miles, watching mileage.

On the 4th of Dec 2014 I changed my oil @ 150484 miles. i used Pennzoil Platinum. It was a normal 5089 mile run. used a Fram TG4749 oil filter.

Later on I was reading in PC and the posts suggested running 0W20 synthetic oil. So I bought a 5 qt bottle of 0W20 oil. I didn't change the filter. My fuel mileage is down to 32 to 34 mpg in cold weather. Today on an engine warmup run I read 40 mpg @ 68 mph on flat ground, GPS reading, no wind, 35 degrees out. That gives me a base to see if the new oil will actually be better for the mileage.
I used Pennzoil Platinum again. New miles 150677 on Dec 22 2014

I checked the color of the used oil and it was just lightly darker than new. I poured the used oil back into the 5 quart bottle. The next oil change will be with this oil when it gets warmer outside.
I'll keep you posted as to the results.

Should I continue to run 5K miles on the oil or go to 15,000 ? The Valvoline 5W30 synthetic I used before was very dark at 5K miles. I checked the price between 4 quarts and a 5 qt bottle, the big bottle win every time.
That way I get top up oil for later at no cost.

My Fuelly.com ID for my 2004 Prius is Eclectic Electric. http:// Fuelly - Track and Compare your MPG eclectic electric

I haven't figured out how to tie the ID to PC yet.

 

Egads, there is less than a cup of oil in it! Not worth getting my arm oily.

 

Easy Rider 2, I think you may be right. But you know how sensitive these car really are, you need to see just how much difference there is. Once warmed up I find I can get 50mph on the MFD but the warmup kills much of the mileage.

CSS28, I'll try for 10K and note how dark the oil gets along the way.

Yeah, I'll dump the oil back in. I don't think that it is contaminated. it will get a new filter for sure.

At least I know that the engine is clean inside.

 

I couldn't figure out where the Fuelly img tag comes from. Thanks. Lee

 

When I bought the Prius it only took several weeks for the maint req lite came on. I drained some very black oil, not knowing the type. I then put Valvoline 5W30 Syn into the car. At the 5K oil change I switched to Pennzoil Syn Platinum. Later I read that 0W20 was better for winter. So I changed to that.

Yesterday was 1st day out, but warm, 40 degrees. The Prius seemed to run a lot better, increasing in mileage to 35.7 mpg.I don't remember what I started with though. Most of the driving was local with 4 people inside. Local ministry work with many stops, leaving the IG on. Even then I was saving fuel. So I hope this means that 0W20 works better. I'll keep you posted.

Thanks Doji for the tips.

 

Unless maybe it was a USED car with unknown maintenance history !!
It was a used car, but this my 3rd oil change. I'm experimenting right now.

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It has been too short of a time to really see if it helps my mileage but I think it will. The indication seems that the engine is running more freely now, and time will tell if it really is getting better fuel economy. I'm off on a trip soon so I will get a good long distance run. The actual saving will be on the shorter runs when the engine is cold and needs the thinner oil. That appears to be the case for me right now.

 

I just checked my oil and miles on the 04 Prius tonight. The miles is 155113 and the oil level is where it was when I changed it. I find that amazing, it hasn't used any oil. The color is about perfect too, and just starting to darken a bit. It is about 5K miles on the oil. The Valvoline got much darker before. The engine runs better from cold start, but runs the same when warm. I think that 10K is reasonable now before I change it back to 5W30, new filter though. I am glad the engine does not use oil, and it seems that it is running cleaner, or maybe I just flushed all the crap out of it.

Cheers, Lee
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