I have an 2000 es 300 lexus... how do you line up the timing marks after you re[place the belt? do you really have to take off one ofthe cam gears to change water pump?

https://www.youtube.com/watch?v=VXY_-cuGdhg

You must go back and remove the timing belt to re-align the marks for the cam and crank. There is no other way to adjust.

Toyota Tundra 2000 Present How to Replace Timing Belt and Water Pump...

Hi. Thanks for your question. For overhead cams ypu can refer to https://www.reliable-store.com and download the entire service manual which includes all the information along with the diagrams for better understanding. Good day!

I would suspect the belt again. You may want to pull the cover and check the marks on the gears. One of the cams could have jumped a few teeth.

i think you will have to be more specific here as iam not sure exactly what you mean ,if the timing belt has marks on the back for timing then as you turn engine the belt will only align up with these marks once every 500 or so turns ,so long as the marks are correct to start with and none of the gears have moved when appluing the tension to the belt then their is nothing to worry about ,just make sure the bottom pulley nut is tight and you applied some locktight on the thread then no problem ,if you had put white paint on the gears/backplate then you see that when you turn the engine they line up again but the white lines do not

the crank sprocket has an indention in it and it lines up with the small protuding dot on the block. the cam gears have recessed marks in them, and they line up with the v shaped cutouts of the back of the timing cover.

Sorry for the delay.
I am personally going back to answer your unanswered question. I do not know if you still need the answer, but I am going to answer it in case you still do.

Click on the following direct Link. It has the Timing Belt/MARK(S) Diagrams that you will need, complete with Instructional and Directional Diagrams.

Again my apologies...
Let me know if this helped, or if you have additional information or questions. Feel Free to contact me at FixYa.com!
http://www.2carpros.com/car_repair_information/year/1993/make/lexus/model/es_300/1993_lexus_es_300_timing_belt_diagram_marks.htm

the marks on the cam sprockets point up and they should align with the marks on the rear timing belt cover (behind the sprockets)

try a cheap fix... buy a couple bottles of gas line antifreeze and put them in the tank either right away or at your next fill up of gas. it sounds like water in your gas.

Robert