In addition to the fine advice offered I would add that you should find a new mechanic. His price is outrageous.
--
David Hunter

Benski gave you the best advise even if your new to working on a 240. Greg

If you have an impact wrench, you will not need the special tool to hold the crank shaft.

There is a pretty good FAQ on this topic in the 700/900 FAQ section. The engine is the same:

http://www.brickboard.com/FAQ/700-900/EngineSealsBeltsVent.htm#Changing_Timing_Belt_Procedures_for_B23_B230_Series_Engines

I'm a Volvo newbie as well (though I've done a bit of tinkering on old Saabs).

You should definitely do this repair. It's pretty easy and rewarding.

You should however have the right tools and you should know where to get the correct parts.

Tools:
-Bentley Manual for 240 - The bible of Volvo 240 repairs. Will give you step-by-step instructions. Check Amazon.

-Torque wrench.

-Some kind of larger wrench/breaker bar to loosen the cam shaft nut.

-A 24mm socket for the cam shaft nut (these are slightly uncommon, but check Sears).

-Cam holder tool. This is ~$39. Check Eeuroparts.com (alternative is rope trick - do search on this board).

-A set of metric socket wrenches.



You can find most of what you need at Eeuroparts, FCP Groton, of ipdusa.com.
As Benski said, you should just order the tensioner if you don't know how old it is. It's easy to replace. You should also do the accessory belts - you need to remove them anyway to get to the timing belt.

Good luck. It's fun and easy. Will probably take you 4-5 hours. You'll feel more like a shadetree mechanic when you're done. :-)

Also look up the "flametrap" and order that and replace it as well, since you probably don't know how old it is.

Jesse
'88 245DL, m47, 175k miles.

You've come to the right place. This is a fairly simple job, if a bit time consuming the first time in. You can search timing belt replacement and "rope trick" here and get a plethora of answers. You and your friend can then judge if you are up to the task. I would recommend the following possible additions to replacing the belt as long as you are in there cleaning up the mess.
1. New timing belt tensioner. If is anything less than perfect, change it out. Less than perfect is any roughness or noise when it is spun, any side to side play in the bearing, or anything that will lead you to believe you will not have to get back into it in another 50k mi. They are cheap enough at about $45.00 to just do as a matter of course. IPDUSA (ipdusa.com)sells complete kits that have all the jazz I'm alluding to here.
2. Seals for the cam, crank, and layshaft.
3. New water pump, belts, and hoses, and hose clamps.Obviously change out your coolant at this time. Green stuff is fine.
4. Check your accessory bushings for oil contamination, and change them out if they are looking suspect.My personal favorite is poly bushings, but they come at a premium price.
5. Make sure that your crankshaft pulley is in good shape. If I recall, these have a rubber section in them which can give up the ghost. You'll have a chance to inspect it when you are changing out the crank seal.
8. Good luck, we'll talk soon, I'm sure.
6. Check your fan clutch for worn out bearings or any looseness while you've got it off the car as well.
7. Write down on a place that is visible inside the engine compartment when the next belt change is due, and smile that it is a long way away when you are done.