It's getting time to replace the timing belt again...my 1993 Le has 290K miles on it.

at 230K, it overheated on accident and the headgasket needed to be replaced.

As I think back, I'm sure my mechanic used an aftermarket belt instead of OEM belt from toyota. I didn't request at the time to ask and spend the extra dime for an OEM part.

Just curious....Does replacing the belt improve performance at all? how are the aftermarket belts as for quality compared to OEM belt from toyota?

with the mileage that are on the car and all the maintenance I've done, the old car doesn't have the acceleration like it used to. I could provide a whole list on all the sensors, vacuum lines and things I've done to ensure i can get the best performance and miles out of the car.

I still average about 385 total miles per tank of gas with my mix of city and highway driving habits. now, it's summer time and the drag on the engine with A/C on sinks my average mileage to about 340 miles per tank of gas.

any thoughts?

 

As to the belt, no. The belt locates the position of the cam and crank pulley. Any name brand belt should do this just fine.

Belts are made of different materials, some are supposed to be better then others but all should last the recommended belt change period which for newer cars is 90K miles.

One issue with belts is noise. Some brands make more noise (whine) then others.

You might do a compression test. An engine with this many miles is bound to have a lower compression then when new, this will effect performance.

Determine if the gas you have been using now has alcohol added, this will decrease MPG.

 

I did notice that the engine was louder (noisy) after the belt was replaced along with head gasket that was replaced. that was about 60 miles ago when that work was done. The mechanic I used came recommended and specializes in only rebuilding and reinstalling engines. it was my mistake not to ask for OEM parts for such an important job. the mechanic did use aftermarket parts, but I have no clue of the brand. I later discovered that the intake manifold and exhaust manifold gaskets he used were crap (IMHO) and caused vacuum leaks I needed to fix. Based on that, it makes me wonder about the quality of the head gasket and what effect that may have on the engine performance.

the intake and exhaust manifold gaskets from toyota that I used as replacements are both in one piece each. the aftermarket gaskets were in several pieces for both the intake and exhaust. I eventually replaced both intake and exhaust gaskets myself.

(What a biatch of a job the intake manifold was!)

what cost-effective fuel additive would you recommend to improve performance when filling up the gas tank as summer time is here and alcohol is used to lower emissions in the hotter months in Texas...??? I've used the Marvels Mystery oil before and it seems to work alot better than other $2 brands. My MPG in the summer time declines a bit to about 320/City total miles per tank of gas due to the added alcohol and A/C running all the time.

any thoughts on what an aftermarket head gasket can have on engine performance?

Keep in mind- I still get great MPG. I Just don't have the acceleration like I used to. It seems like I remember the engine having more acceleration from startup at an intersection.

thanks!