How difficult to change timing belt?

Rick Lee · Rick Lee's Garage

I think I need a new timing belt soon in my '87 325is. I'm selling it to a roommate and I don't want it crapping out on him, right after I blow his money buying myself a truck. I've always taken it to the wrench for this job in the past. But 911 ownership has emboldened me. How tough is it to change a timing belt. Can I do it myself in an afternoon? And where can I get a good reference to walk me through it. Obviously, I don't want to pay for a new Bentley manual, when I'm about to sell the car. Thanks.

Wayne 962 · Wayne 962's Garage

The Bentley manual does cover this nicely - I would buy it and then resell it to him. Tell him that you'll replace the timing belt if he merely pays for the parts. He shouldn't think that this is such a bad deal...

-Wayne

phaques · 12-21-2003, 05:14 PM

Seems like somebody should have some tips on this project... it is such a hot button. Is the Bentley manual procedure good enough? Is this a job too important or too easy to screw up that you should let your mech do it? Just bought a 1988 325is (for $800) that needs a timing belt, and I'd like to try it myself, but somebody urged me that if I'm one tooth off I can bang valves, so I'm a little hesitant...

KC Ron Carter · KC Ron Carter's Garage

You brought back an issue worked in 2002 but I predated that also.

Here is a link with lots of pictures and references.
Save it to your favorites.

http://www.skumwerks.net/repairs_maint/tbelt.htm

Remember that Pelican is a retailer and needs to sell to support this playhouse.

Later,

phaques · 12-22-2003, 03:33 AM

Thanks for the reference, and the reminder.

phaques · 12-29-2003, 06:02 PM

A follow up question about the tensioner pulley: it seems like the pulley, once the tension has been set on the timing belt, gets bolted into position, so that if any slack develops in the belt, the pulley is not free to exert greater pressure on the belt, taking up that tension. Is this correct? Does the timing belt not stretch once it has been properly postioned with tension applied by the tensioner pulley? If this is correct, then the tension you set with the pulley when you tighten down the two bolts holding it in place does not change, and it is obviously important to get that tension correct,right? So how much tension is enough? Or, am I missing something basic here....
thanks.

randini74 · 01-03-2004, 07:52 PM

I've done it several times, but it's been a spell since the last one. If I remember correctly, the tensioner has just one position and the spring controls the tension.

Just get a haynes manual and jump into it. You can do it without romoving the radiator, just unfasten the shroud to phacilitat removal of the fan - a little trick i figured out that cuts the huge time off of the job.

When you're ready to take off the belt, use white out or something to mark the positions of the cam and crank against the engine case. This keeps you from having to find top dead center. Be careful to mark them so that there is no question as to the exact positions because of the point you made earlier about bangin your valves.

Depending on when it was done last, I'd throw in a water pump while I was in there too. You're buddy will never thank you for it, but he'll sure be pissed when it craps out on him later. $43.25 from Pelican. It'll just take a little longer and you'll feel better in the end.

Good luck