filter changes

OEM filters always fit perfectly.

If you mean engine air filter, IMO I'd go Toyota.

(Filtration of dust is the issue, less filtration = more air = more horsepower.)
(OEM is a compromise, yet designed for the car)
(Plus the filter size and seal fitting the air box perfectly...hence OEM recommendation.)
I do not do the price difference in the engine filter case.

Cabin filter is not so important IMO.
Purolator brand, for example, makes a carbon cabin filter for @$20 where Toyota's is $40.
That's your call.

Either way many use aftermarket filters...good luck in your decision.

 

I always go with OEM, but that's my preference... I haven't tried the aftermarkets on the Prius before, but I've had aftermarkets for other vehicles. I've noticed some aftermarket filters, I feel the quality is poor... and some are equal quality. I would compare the price and check which one gets the best bang for your buck. Just make sure the quality is equal or better than the OEM. Make sure to change them out periodically as well, 15k miles for cabin and 30k miles for engine air filter.

 

While you should check and change your filter -- I don't think it's your problem.

Both filters are very easy to change. The Toyota OE filters are not expensive. With many cars ... I tend to do filter maintenance more often ... So I often buy good aftermarket filters for all the cars at once online.

The engine filter can be changed in 5m. The problem with the spark-plugs: to remove them you have to take off the wipers ... so it requires more tools and time.

They last for 100k.

 

Here are a few possible causes that are pretty easy to check:

• Have you replaced tires
• Lower tire air pressure
• Overfill on oil
• Any recent service that might affect your mileage

 

Check the voltage of your 12V battery when the car is not on. It may be that the car is trying to charge it constantly.

 

IMHO, the cabin filter is designed more to catch larger debris than "filter" the air, so I buy whatever looks good on Amazon. The last one was made by a company with a silly name, Potauto.

The engine filter is a little more important, so I use Toyota filters I buy at the dealership parts counter and install myself. From what I saw, dealership prices are very competitive, so why not support the local dealership a little?

 

You should be able to tell from the service invoices if they've changed either of the air filters. At any rate, for a 2010 with that mileage I'd suspect they have.

I'd just check the filters first, as mentioned above it takes about 5 minutes to pull out the engine filter, once you get the hang of it. I don't recall the instruction being in the owner's manual (which is shameful, Toyota).

You release/raise the hood, the filter housing is the black plastic box, front and centre. It has two spring latches you pull off. Then you need to lift and waggle the lid to free two hooks at the rear edge.

Once loose it can be pulled up enough to get hold of the filter and slip it up and out.

The bottom (I believe) will be the side the air comes in on, accumulates dirt. A minor amount is fine, won't measurably impact performance, and will not impact mpg, due to computer controlled fuel/air mix. Only needs changing if it's seriously clogging.

FWIW, our 2010 is still on orig. filter at 60,000 km, with just minor blackening. Our area gas pretty clean air though, I think.

 

The Engine Air Filter is pretty easy to change, and you don't have to buy the filter at the dealer, so you can close the loop on that quickly and cheaply.
If you're not sure whether or not it's been changed, then I would change it anyway.

Who suggested spark plugs? (perhaps the same person that said they would be $300 to replace?)
IIRC, Spark plugs are good for well over 100,000 miles (120K?) so whoever made that recommendation may not be the person you want working on your car, especially when there are things like tire pressure, PCV valve, and 12v battery that can be checked.

Do you check your oil level every now and then?
If not, then now is a good time to start.
At least every thousand miles is prudent for an 80,000 mile car....AFTER you've determined that your car does not drink or smoke.

Good Luck!

 

Filter location. Note the hose exiting the top of box is running air to the throttle body. This is the clean side. Air flows into the filter from the underside: that is the side that collects dirt.



(There's some minor variations in this image, the brake fluid reservoir up near the top is in a different location, but the air filter location is the usual.)

 

FWIW, that 60,000 km Mendel mentioned is about 37,000 miles. I just changed mine for the first time at 48,000 miles and it probably could have gone another 48,000 miles. I used to just hold them up to the sun and if I could see light, I'd blow them off and put them back in. I just figure 50,000 miles was enough and it's not like they are super expensive, so I new one couldn't hurt.

And even though I bought mine at the dealership, any reputable filter will work just fine. Even the cheapest will work, just might need to be replaced earlier and might not filter out the same sized particles as the OEM. It all depends on how picky one wants to be.

And while the computer will adjust for a dirty filter, that probably changes the amount of fuel used. However, I can't see a filter causing a 6 mpg drop. My mileage is down at the moment. I bought new tires and the temps are now in the stratosphere at 115's.

 

Where the suggestions from a dealership? It seems like they're just guessing, and yeah, the engine filter can be easily ruled out, without replacement, just inspection, for starters.

And spark plugs too, it's early for that, and very likely they're fine. I've removed ours a couple of times for inspection now, there's a good video here on what's involved:

Nutz About Bolts Prius Maintenance Videos | PriusChat

How suddenly has your mpg dropped? Just in the last tankful?

 

It's a good idea to replace those filters, but they won't restore a 6mpg loss.

First: How do you know you're down 6mpg? Are you certain?
I would begin by attaching an OBD-II scanner to the car and see if the computer is reporting any diagnostic errors.