I've got to change the timingbelt on my mom's Toyota Sienna (FWD van) and I'm having trouble loosening the crank pulley bolt.

Any pointers?

 

big breaker bar

 

Can you use the starter. Stick a socket on the bolt with a 24" breaker bar, jam the bar against something solid and blip the starter. With the ignition system disconnected of course. Check which way the engine rotates first to make sure the bar is jammed the right way. It's not always possible with sideways engines because of room though.
Or an impact wrench if you can beg, steal or borrow one.

 

Those transverse FWD engines..yuck. Changing the dang spark plugs requires pulling the dang engine almost. I don't envy your predicament. Good luck.

 

i see your doing it for you mom she better be paying you lol

 

Yep been there, pulled the back 3 only to find they were still in good condition.

I've got a compressor powered impact, but I guess it's a wussy one.

I'll try the starter method. Is there anything i should be worried about when doing this?

 

Just make sure the socket stays on, I find 6 point deep ones work better. And don't let the breaker bar fly around, brace it well.

 

How to hold the crankshaft to loosen (or tighten) the pulley bolt:
One method I've used for years on many different engines is to pull one spark plug and thread a small cord (like clothes line) into the cylinder. I make sure it is just past the firing position (on a clockwise engine) and at the bottom of the stroke. Put in as much cord as possible and then turn the engine backward. The cord will prevent rotation without doing any damage (all valves will be closed at this point) and you can put as much torque on the bolt as you want.
To tighten, the engine should be coming up on the compression stroke when you put in the cord.
g'luk.