[New Owner Questions] 2004 Prius - Fuel Economy, Battery Swap, Gas Gauge & AC Noise

US EPA


The system's calculated fuel economy is a guess.

Hybrid battery replacement requires no resets or configuration.

You have bought a rather complex car. Try to find a shop that knows them.

In theory (but not normally) the ac may become loud when low of refrigerant. But it might be the radiator fans which always run with the ac.

Fuel tanks have a rubber inner liner (bladder) which makes the gauge unreliable when close to empty. Don't trust the gauge to be repeatable near empty. You may run out of gas.

 

the gauge is really a guesstimate, you can even make your ave fuel like "99.99" if you want to.. best method is calculate it manually, that is reset the trip meter and fill when it's almost empty and then calculate. It's normal for the AC to be that loud at that age, I'll be concerned if it's not making any noise and not cooling. If it's not cooling there might be a code for it that say low pressure on refrigerant, you can check the sight glass if there's refrigerant flowing.

 

Learn how to hypermile if you want to play games with your hybrid. Other drivers will hate you but you can be the captain of a rolling video game.

Most of us just drive it, brake early when possible and are happy getting two or three times the mpg than the big suvs and trucks. I am sure I have saved $20k in gas with the v alone. It takes high mileage per year to get real savings considering everyone eventually buys one new hybrid hv battery or many used hv batteries.

I keep up with traffic and ran 345,000 on my oem pads and rotors. Never changed an alternator or belt and like the full blast ac that iis possible when the engine is off at a traffic light.

Gen2 engines are generally very solid unlike the later gen3s. Brake boosters have been known to fail and have no rebuilt options.

Transmission problems are a thing of the past that were routine 35 years ago (Honda) but never considered in one of my four Toyota hybrids (two 2008s, a current Rav4 and Prius v). Original refrigerant as well.

 

I started out with a Gen 2 (2009), then got a Gen 3 (2011), then a Gen 4 Prime (2017 PHEV). The display on the Gen 3 was a little more helpful on that. You could see the effect of your braking and gas pedal a bit better. It also has buttons for changing some of the settings (PWR/Normal/ECO and an EV mode that did almost nothing on the Gen 3 regular models). I think that's the sort of thing you were looking for, but there's no magic setting there either. PWR/Normal/ECO mode seem to only alter the throttle response curve, just a little. EV mode is basically useless unless you have the Plug-in version (Prime in Gen 3). There's a bigger difference if you have a plug-in hybrid, which has a few miles of true EV range. If you didn't have the extra battery, there are so many exceptions (one of which is you're going more than about 17 MPH, another if the ICE engine isn't at full operating temperature...) that automatically kick you out of EV mode that it becomes useless.

The only thing you can really adjust in the Gen 2 is the way you use the gas and brake pedal. When braking, when you can, use a lighter touch for longer. (You'll learn to look further ahead when coming up to traffic lights and start reacting to them earlier.) The Consumption screen should start racking up the green (what looks like turtles to me) icons. That's energy regenerated, which is put back into the battery and used to power the car at some point. Like all cars, when you mash the gas pedal, your fuel economy goes down. When you brake harder than just a little bit, you'll start to engage the friction brakes (the brake pads, discs, drums, and shoes that you're used to on regular cars. The extra energy isn't put into the battery to be used from these, just thrown away as heat. Of course, don't try to do this all the time. If you need to slam on the brakes, do it without hesitation.

Of course, this is a perfect recipe to pissing off the people behind you. I look in the rear-view mirror to before doing any real hypermiling. I figure I'm not in anybody's real way when coming up to a stoplight, so I brake easier for longer. If I've got time, want to take it easy, and nobody is behind me, I try to ease into the gas pedal.

One of the things you're fighting is the short commute distance. That engine has to reach full operating temperature before the computer will allow it to shut off the engine so you're not going to get the most out of that Prius.

I typically refuel when I've got only 1-2 bars left. You really don't want to run a Prius dry.