MPG after timing belt replacement - Toyota Nation Forum : Toyota Car and Truck Forums

filter · 05-08-2011, 05:47 PM

On the first tank of gas after having my timing belt replaced (by the dealer), my mileage dropped by 2.5 mpg, from the usual 20 (+-.5) mpg to 17.5 this time.

Is there anything about the timing belt replacement procedure that could go wrong that could cause this?

worthywads · 05-09-2011, 11:20 PM

Yes if put on incorrectly the timing could be off, it controls the timing.

But I wouldn't rely on just one tank.

1/2 ton giant · 05-23-2012, 07:59 PM

They could have effed with your timing by mistake. It is very easy to do when your not paying attention.

filter · 05-23-2012, 08:59 PM

Yeah, I may not have worded my orginal post very well, but I was trying to ask whether the timing belt could be put back on wrongly without the tech noticing.

I posted this a while back, and the mileage (and I think the power, too) is still down from where it was pre-timing-belt-change. But since the CEL hasn't come on, I have just been living with it.

JesusJones · 05-29-2012, 12:51 AM

My gf has a 89 celica. Her dad changed the timing belt and swore up and down he put it on right. ( he works in an air hanger )

The car felt like a dog. It still drove but it didn't have that pep I remembered. Gas mileage was just a little down. Nothing was off enough to really throw any red flags in my mind.

One day with some beer on hand and time to kill. I decided to check the timing belt for myself. It WAS off by one tooth. After putting it back on properly the car was back to normal.

If it feels like it lost power and your mpg is down take it back to the dealer.

filter · 05-29-2012, 08:21 AM

How did you check it? I'd like to check it myself if I could.

JesusJones · 05-29-2012, 11:55 AM

The process is different for different vehicles but it is usually along the lines of :

Removing the top timing belt cover

turning the crank pulley until the timing mark is lined up with the 0 degree mark.

then checking the camshaft pulley's mark. There is sometimes a hole or a dimple somewhere on it. If it is facing straight down turn the crank over one more time until it is lined up with 0 deg again. Then the cam pulley mark/dimple should be straight up. If it is not pointing straight up your timing is off.

Google is your friend here for finding detailed instructions