Swirl Arm low cost repair!
 

Hi, I'm new to the forum and some this will help some of you! I have had the dreaded Swirl arm problem and many attempts at a repair left the parts so loose the the assembly only lasted a few miles before coming apart. I noticed the initial problem (broken link) was caused by the stepper motor being "overdriven" in order to calibrate the mechanism about every fifth time the engine was stopped. This is quite a common technique (I am an electronic engineer) for this type of arrangement. Anyway, the torque of the motor (when being overdriven) is sufficient to cause the linkage to break in time.
Once I understood this, I came up with the following solution, which has been rock solid for 6 months/10,000 miles.
(I hope the photo has uploaded OK)
Basically, I went to B+Q and got some right/angled aluminium extrusion and a rubber "foot" as a buffer. I cut a short length and drilled a hole in it so that the part could be fitted using one of the motor fixing points. I filed the hole so that it was a slot so that the position could be adjusted.
Next, I fitted the rubber foot as a buffer.
Finally, I fitted the part and adjusted it's position so that, when the calibration (overdrive) of the mechanism occurred, it used my part as a "bump-stop", instead of straining/breaking the mechanism. It is important the position is adjusted so that correct calibration is achieved, i.e. it stops the mechanism when fully extended, but JUST before it strains the arm.
No more trouble, simple to fit and costs only a couple of pounds.

Additional information
 

Forgot to mention - you can just see on photo that I fitted a small washer on the ball joint where the arm clicks in. This helped on an earlier repair attempt as it stops the arm rotating laterally when moving.

Swirl arm calibration
 

Hi Bic,

Very interesting to read your post, i noticed on my D5/185 that the arm at the swirl arm end had come off and although it was still attached to the motor/actuator end wasnt doing much !.. a bit of investigation revealed that one of the four tiny "clips" inside the socket thats on the engine side had broken, and it seems likely having read your post that its when it tries to calibrate the movement, pushing the link toward the front of the car fully, that it must have broken the socket end. I also noticed the first time I re attached the plastic linkage (with hand crafted bracket that holds the ball into the socket on the engine side) it moved the linkage over its full range before returning to normal position. I did wonder if this only happened if the link wasnt there, but perhaps as you say it does it once every number of cycles.

Does it rely on the resistance of when the link hits its end stop to detect its reached full travel? im guessing it must unless it has some other way of measuring the position, seems a bit crude either way, as the linkages dont seem to stand up to the strain.

Ive attached some pics of the linkage, it looks a bit different to the one in your pics, what year is yours? The elastic band in the pic is only to see if it would work before glueing the bracket in place ! (pics to follow)

How did you work out where to position the stop? having the link disconnected doesnt seem to throw up any fault codes, or perhaps it does but you cant see them?.

Hi.
The motor is known as a "stepper motor" and is driven by a series of voltage pulses or steps. The software in the system knows the position of the motor by applying a known number of voltage steps to the motor. In normal operation, the motor can "slip" i.e. the motor shaft position relative to the number of pulses can shift - hence the need to routinely re-calibrate.

This is done by applying enough steps to the motor to guarantee it will be in the end position, known as overdriving. The mechanism will mechanically stop the motor at the end of it's travel whilst voltage steps continue to be applied. This occurs at every 5th switch off of the engine.

Unfortunately, the torque of the motor eventually results in the mechanism breaking as a result of this calibration procedure. (Try holding the motor still during this process and you will see what I mean!)

The bump stop position is easy to set, just move the mechanism to the end of its travel by hand and set the stop in that position. My linkage is broken in the same way as yours but this fix has been fine for many months now and just works by taking the strain out of the system.

Someone on this forum took the idea and made a much better stop than mine (electronic engineers make rubbish mechanical designers!!), you should be able to find it if you do a search.

Hope this helps.

Bump Stop
 

Hi Bic,

Also read about a modified arm kit that volvo do, presumably this is a lot stronger and less likely to break? Apparently the actuator can be calibrated using the volvo computer thingy I wonder what this does ? as it sounds like it wants to calibrate itself every 5 switch off's.

Do you mean you can move the stepper "arm" manually without any damage? to see where to set the bump stop?

Did you find any messages come up on the dashboard, or any fault codes need resetting when the arm failed on yours?

Thanks for the info,, v useful :)

Hi,
I have not seen the modified arm, but in theory any stepper motor driven mechanisms can "slip", i.e. not move physically when a pulse is applied.

This is only really an issue when no additional position sensor is fitted.(The software controls the position of the arm by applying a known number of voltage "steps".)

A good example of the calibration procedure is on some modern speedos where the clocks travel to max as switch on, then return to zero. Looks very nice, but this is actually the stepper motor calibrating itself by overdriving the needle, in the same way that the swirl arm is calibrated.

My fix just uses a physical stop to hold the mechanism when being overdriven, rather than letting the arm take the strain. Provided the stop makes contact JUST before the mechanism runs out of travel, it is a perfectly good fix and will save the arm taking any more excessive stress, which causes it to break, in time.

For this reason, I would think that, even with a new arm, the software would still require routine re-calibration.

The issue seems to be that the motor is VERY (possibly too) powerful and, as I found, when you strengthen one part, it was a matter of time before the next weakest part in the mechanism broke! I was concerned that, in the end, I would have to strip part of the engine down to repair internal parts of the linkage. The idea behind the bump stop is to eliminate stress in the setup, and to date, this has worked well.(You could always combine a better linkage with the bump stop, if you want).

Hope this helps!

Sorry, forgot to tell you the error I got.

When the arm broke, I would get the message "Engine Service Required" on the DIM, usually under hi throttle/revs when accelerating. This would clear and re-appear, I guess depending on driving style and the position of the swirl flaps when the mechanism failed

Looks like ill need to try the mod kit
 

The fix i had come up with to hold the ball joint on the plastic link into the butterfly on the flap control end doesnt seem to be holding up too well ! even with a bump stop as bic suggested, it certainly takes a bashing when it decides to "calibrate" every 5th to 6th engine off.

So im going to have to try the mod kit that volvo do, im not entirely sure how it works but seems you have to drill a hole in the butterfly? has anyone else fitted this mod ? ive heard comments on here that it also might not last too long but im hoping it will (but then i might just be being over optimistic!)

Has anyone had to resort to stripping the linkage down to fix it should this not work?

P/N for the mod kit is 31293291 apparently

I am just about to fit the mod kit to replace a previous mod I did with a split pin. The part numbers required are 8692676 for a new Swirl Arm (£1.99) and 31293291 for a Pin and retaining washer (unbelievably £4.95). You will need to drill a whole through the Ball Joint on the new Swirl Arm large enough for the pin to pass through. There is already a hole started through the ball as supplied, so just pass the drill through this hole until it passes out through the top of the ball ( I did this by hand with a small 2 to 3 mm drill bit). The next bit is very tricky, you need to make a hole in the socket where the ball joint connects, on the arm under the oil filler. I used the same drill bit here, but heated the drill to red hot and used the heat to melt a hole as it is just about impossible to get to. This hole needs to be in the centre of the socket in order to pass the new pin through, the arm and then through the newly drilled ball on new swirl arm and then fit the washer that comes with the kit.

Hi Rob, Could you post a pocture of the modification please. Brian

Hi all,

have collected the mod kit from volvo, but with the D5 in the 2007 S80 there is no side access to the butterfly looking from the front, you have engine casting to the right and a large alloy block to the left. Can you prise the butterfly off?


Regards


Joe

Butterfly
 

Does your swirl linkage look like the attached pic?, this was mine after fitting the volvo 'nail' kit, if you move the butterfly to where its shown thats the best access you have to make the hole in the butterfly, you cant remove the butterfly its part of the swirl flap mechanism, post a pic of yours...

pic that should be attached to prev post
 

missing pic

Hi Thassos,

no mines not like that, where you can see the cambelt cover, on mine there is a an alloy casting. I'll take a picture tomorrow with the induction pipe removed.


Joe

hopefully there will be a picture along soon......

as you can see there is now a large casing which appears to be something to do with the cooling system, there is no way to insert the pin from behind. Thankfully someone has already drilled a hole through the butterfly, now all I have to do is find a way to get the stay washer onto the end. Any ideas?

I can see your problem !
 

Thanks for posting a pic, i can see your problem now !

It looks like someone has used the volvo 'nail' kit already, but i dont know how they have fixed the far end (casting side) only idea i can think of is using some sort of suitable bonding agent to glue a pin or similar in place, and maybe make a different linkage. But you really need a stop to ensure it wont get overloaded and drop off per the usual !

Hi Thassos,
I put the nail in! There was already a hole through the butterfly because the previous dealer had bodged up some wire and solder through the arm and butterfly, however the wire had stretched and the arm was moving but the butterfly was not.
Suprisingly the nail as it is, is holding it in place, I will try over the weekend to fit the slip washers.

Joe

Hi guys been directed to here ive got a s60 d5 55 reg had the car about a week when the arm popped off the garage put it back on and orded the upgrade at the same time its lasted a few month but broke all together at the ball yesterday the bump stop seems a better fix than the volvo upgrade the indy i bought the car off used to be a volvo dealer and have been great there fixing it again for me masters of spennymoor nice garage for a change lol forgive my grammer and spelling :-( ps if it goese through cycle every 5-6 starts its going to break alot i do 2 nights a week delivering pizzas cant complain to much its the reason i can afford to run it in the first place ;-)

Swirl arm thanks
 

I got the dreaded engine system urgent message yesterday and thanks to this forum especially bic7 it is now fixed. My experience-
I found a split pin the same diameter as the hole left in the arm after the ball had broken off. I put it in a vice and, using a hammer, I flattened the head so that it would not foul the head casting. I heated it and easily passed it through the engine lever. I attached the arm, bent over the split pin and trimmed the ends with a pair of wire cutters. That took about 5 mins.
I made bic7's end stop with an elongated mount hole. I mounted it and nipped the screw up. I then operated motor without the swirl arm attached(every 5th engine stop) and allowed it to nudge the motor lever to push the end stop. I backed it off a tad and tightened it and attached the arm. This took about 10 mins. Job done.
Isn't it disgraceful that the best the mighty Volvo can do is offer a £700 repair when someone like bic7 can apply a bit of logic and see what is going wrong. There is very little resistance when the arm operates so it is obvious that something else is applying excessive force - the motor when it calibrates.
I have a code reader and this problem does not show a code. From what I read the message will go away after a few days of operating

inv never seen alloy casing like that ever before

I can't see the pictures.
Is there any way to see them?
Thanks

(missing) pictures
 

It seems to be a problem with the site since it was moved to a different host recently, which pics are you referring to?

Hi
I have a disconnected swirl arm on my newly acquired S60 185. I was planning on using a 3mm diameter bolt, nut and washers. Are there any issues with such a permanent fix and any pictures or advice on a 'bump stop' ?
Many thanks

I would use the volvo kit...
 

Not sure which kind of linkage you have (post a pic...) but the volvo 'nail' kit is a well thought out one, but needs a 2mm hole, see pic attached, if you use a bolt the head would foul the casting (see the red line on pic) even with the volvo kit you need to remove a bit of metal from the casting so the nail head doesnt foul the casting when in the opposite direction. Kit is P/N 31293291 and only a few quid. Making the hole in the right place is the hardest bit, have some tips on this if you need..

Hi
My link arm looks like yours. When I reconnect the arm is it just a case of moving the flap to match the motor/arm position?

How it works
 

Yes you can just re-connect it, basically every 5th engine switch off (engine needs to run then be shut off) ie you cant mimic this by turning the ignition from off to on 5 times!, you will see the stepper drive fully in each direction, i think it uses the load /current on the motor to detect when its hitting the limit, and will then reverse the direction till it hits the limit the other way, this is basically what over stresses the link (mine had one of the 4 plastic retainers inside the socket broken off). I would definitely recommend making a rubber stop to stop the stepper arm very close to its limit (this bit takes some adjusting as it only calibrates every 5th switch off) a pic of my attempt attached (unfortunately some recent changes on the forum have meant old pictures with posts have been lost for the moment). Also some info on what the swirl throttles do, worth taking some time to drill the butterfly carefully as its a fairly expensive job to replace the swirl throttle's (all plastic part), but if you follow the above you should have something that wont fall apart again anytime soon :)

Thanks for the great reply, I have contacted my nearest dealer but the computer system was down! The parts guy has promised to call me tomorrow and get the kit ordered. Re the bump stop, what is it made from and where does it go? Any pics?
Once again, thank you

bump stop
 

The bump stop is in the last pic, (not adjusted up correctly there) see the arm coming out of the stepper, top rhs of pic, made from some ally angle bracked and a block of rubber glued onto it (not the most elegant) but works nicely..a better pic attached

Hi
I picked the kit up today and fitted it this evening - quite a fiddley job, especially getting the clip on !

I used an old soldering iron with a removable pointed tip (filed down to 2mm dia.) to melt the hole in the butterfly. I also found it necessary to file the little raised square on the left side of the butterfly as it was stopping the pin from sitting square.

The car did seem to start and tickover better, although i haven't driven it yet. Perhaps the swirl valves had been left in the wrong position when the arm came adrift?

Is there just a bump stop for 1 direction?

Anybody know if this kit is only available from dealers or can it be ordered online?

the nail kit
 

The kit is volvo engineered part, so yes only through dealers, its only a few quid (probably one of the cheapest parts youll ever fit to your volvo!) , i would try someone like rufe if you dont have a dealer near you its something they could post easily, just depends how quickly you need it, you can of course do your own thing with something like a bolt or a model aircraft style linkage, but why bother, the volvo solution is perfect, and shouldnt drop off again,, mines been going strong for 25k miles with no issues, but do consider adding a stop for the stepper so that it isnt overloading the linkage when it calibrates every 5th engine off.

OK...I will have a chat with a dealer at some point but as my car is showing no messages, has no flat spots and otherwise is driving fine I wonder if there is a point in getting it fixed?

stuck open?
 

The throttles are most likely left in the open position when the arm dropped off, if you want to know what they do some info attached, . . i would imagine it will do less mpg, if the throttles move into the closed position you might notice more of a difference..

Hi All,

Congrats for your very useful info and comments re the swirl arm thing. I had a "engine system service required" message on my wife's 2008 XC90 D5 and going through your threats i managed to at least find where this thing on the engine. Swirl arm apparently is on, no sign of it falling apart and it does move fully back and forth when switching on/off. What i noticed when switching off the engine is a prolonged high pitch sound coming from exactly the swirl motor area, which stops after a few seconds...any ideas???

Swirl Linkage Missing
 

I also have a xc90 d5 with a missing swirl linkage. It does not seem to be causing any issues other than the dash warning(I have ordered a replacement linkage). But the main thing I am most concerned about is that there is a build up of oil on the area where the swirl linkage connects to the head. Is this normal considering the linkage is missing? All the other pics I have seen are free of oil in that area.
My other concern is, the bit that connects from the head to the linkage bar is missing. I have circled the bit that is missing on mine. What is this part called?

------------

Sorry Thassos... Im only new to this forum. Not sure what you mean by "---------".

he had a senior moment and deleted what he posted:thumbs_up:
mike

Ahh thanks Mike.

Looks as though the part is called the swirl linkage "butterfly". Mine is totally missing. I can see and turn the metal pin/rod that connects to the swirl flaps in the head.
Is there a fix for this? I have a replacement linkage arm but nothing to connect it too. All of the other post have had the butterfly bit to connect too. Im worried it will require the entire swirl flaps to be replaced. Anyone know if you can buy this and connect the "butterfly" bit to the swirl flap rod?