Dealer replaced the timing belt on my 2002 Acura and my mileage dropped from 20-22 mpg to 17-18 mpg. Dealer claims this is due to summer vs winter gas. This sounds like a snow job to me, but I’m not a “skilled mechanic”.
If your mileage is lower with “summer gas” than with “winter gas”, then–yes–this is a snow job. On the other hand, if the drop in gas mileage coincided with the advent of a winter gasoline blend, then you need to wait until the summer blend is available before you come to a conclusion on this.
You didn’t say if the car ran worse after the timing belt job. If they screwed up the job it would. If you think they didn’t do the timing belt correctly take it to an independent shop for another opinion. You should expect to pay for their time. There is only so that can be done over the internet. The only way to know for sure is to have someone check it out.
Thanks for the info. The repair was made a few weeks ago hence, all other things being equal, my mileage should go up if the switch to summer gas has been made in MD.
If the mileage has really dropped that much and that quickly then I might suspect that a timing mark on a camshaft, etc. is off a tooth or two.
It’s quite possible to have something off a tooth and one may not even notice a performance problem at all, but it can make a huge difference in fuel economy.
For what it’s worth, this is one of my gripes about mechanics; and I’m one.
Whenver a timing belt is replaced it is always recommended that the engine be rotated through by hand several times before starting it. After several rotations the timing marks should be reinspected to make double-sure they’re aligned.
This is even more critical with an interference type engine and unfortunately, many mechanics simply replace the belt and never recheck their work.
I would also hope they replaced the water pump and belt tensioners at this time. If they did not, then they have erred there also. Hope that helps.