940 Crank Pulley Sideways movement.
 

Hi, I am looking to purchase a 940 at some point and have found one I'd like to take a look at. On the MOT history there is listed some advisories in the past -

Crank pulley uneven rotation
crank pulley has sideways movement

As well as a persistent oil leak. They have replaced the crank shaft seals related to the oil leak and the cam belt recently to fix this.

What could cause the crank pulley movement? Could this be a symptom of an underlying problem or have created other issues I should inspect for?

Having been stung in the past I want to be as clued up as I can on inspection.

Cheers.

I'm not saying i'm right on this but i've heard the vibration damper (aka crankshaft pulley) has a habit of doing that on 940s so a replacement is called for.

From what i understand (might be wrong again) there is a metal plate at the back of it, a solid rubber centre piece and then the actual pulley part on the front.

If the bonding agent/glue has shifted, the damper part (rubber bit) will also shift and be out of line. This could cause excess movement on the crank itself leading to damaged oil seals, i can't believe anyone would renew the seals without replacing the cause (the pulley/damper itself) but i suppose someone might have done.

I must reiterate, this is my "best guess", i've not heard of a 740 doing it although i suppose they could as well but i've only had 740s and my 760 which is a different engine anyway.

is it still doing it?

Both the seal and belt require removal of the pulley. If it was on an advisory, it would likely be replaced at the same time

I'm unsure, I've not been to see the car yet but it was listed for a couple years as an advisory. Just trying to arm myself with a bit more understanding before looking. They specifically mention replacing the seals and belt but not the pulley, trying not to assume they just did it right!

So if it didn't break and got replaced it's not likely to have caused any more problems? This is my main concern, not super educated on cars but learning.

This vibration damper is prone to fail. The most harmfull situation is to twist only. There is a inner stub, mounted on the crank, and a outer ring. You will see the tdc marks etc on this. Between both is a ring made of rubber. This will crack and lose parts. Sometimes the rubber start to move out. Often to the rear side. You will listen to a squeeky sound. The rubber will rubb on the cover of the timing belt. If the pulley is wabbeling or moving to the side or the marks are not really on tdc: change it as fast as possible!!!!
If the pulley got lost his outer ring the damage will be hughe. The original ones last about 200 000 miles and around 20 years. The aftermarket max 100 000 miles and between 5 to 10 years only. Idiot will renew the seals and use the old broken pulley again.
Idiots will change the timing belt without having a closer look to the pulley and wonder about the engine after. Running bad or even won't start. Timing belt out of position. I bought good car cheap in the past because of this "tune" ;-)
Do a full stage 0 tune if you buy the car.
Be a Happy volvo owner in the future, regards, Kay

Thank you, the car is approaching 200k miles so that makes sense. I have contacted them for more information, to check if it was replaced at the same time, they did mention an 'idler' replacement maybe they meant the pulley. Maybe not a big deal if I can replace it myself (seems to be about £100 part?) some bargaining power!

It would help if you could see the paperwork for the job that was done. If it lists the seals and a Vibration Damper (also sometimes called a Harmonic Damper) then it would be fair to say the whole job has been done properly.

Also if you start the engine, let it idle and look at the crank pulley/damper, if it's wobbling about like a car on the fairground waltzer there's a fair chance it was only the seals.

If it looks bright, shiny and new and runs as true as can be, there's a very good chance it was all done.

If in doubt, blow it out. There's usually more than one Volvo available for sale at any given time. ;) :D

The "idler" would have been for the cam belt.

No reason why you can't replace it yourself, socket set, lump hammer, new damper and some Loctite Threadlock and a torque wrench.

Right size socket on the bolt, T-bar on the socket, push it in the correct direction to undo (With the T-bar pointing down, underneath the car the end of the T-bar needs to go towards the passenger side), give the end of the T-bar a clout with the lump hammer and the crank pulley/damper bolt should come loose.
Undo it the rest of the way, pull the pulley/damper off, fit new one, refit bolt after applying a few drops of Threadlock to the threads, tighten to specified torque setting.

In the absence of a torque wrench, pretty tight!

You'll need to loosen the alternator and PAS belts before you start and readjust them on completion.

I'd hazard a guess the damper wasn't replaced when the seals were done, they probably did the seals to get rid of the oil leak so they could sell it and it becomes someone elses problem. ;) :D

Indeed, not a huge job but seems it was done to seal up the leak and pass the car along - oil leak has been persistent for many years, harmonic balancer was not replaced, will be giving it a miss. Car had plenty good parts - 940 celebration model but this sort of neglectful ownership doesn't sit so well with me, need to be cautious, another will be along soon!

Thanks for help all round!

No problem at all, i'd rather spend time helping you avoid a money-pit with never-ending faults and help you with sorting a few minor faults on an otherwise good car than try to get to the bottom of a whole series of faults on a neglected but cheap can of worms. I'm fairly sure most others think similar. ;) :D