2.5td Alternator Belt Tensioner, Repair/replacement

[noz]

HI all,

Not that there are many 2.5TD owners compared to the other models but I thought I'd share my woes regarding the tensioner on the belt which drives the alternator and the Hydraulic pump. I tried to repair but couldn't find anyone selling the parts. However I did find a relatively cheap source for the entire tensioner. At the time of writing the cost from Citroen was 96GBP.

Here it is:

Cheers

noz

[Little&Large]

Hi Noz
I have made a couple of attempts at asking this question in posts with no responses,so I'll try here(probably where I should have started in the 1st place!).My serpentine belt seems too loose and the car is idling too slow at the moment.The combination of the 2 causes a fair amount of noise to come from the pulley area.Just increasing the revs slightly causes the sound (anyway) to stop.XMexecutive recommends idling at 950rpm with A/C,at this speed the sound stops,but I am worried that although the noise has gone,the belt may still be too loose.(it is idling at the 1st mark down from 1000rpm(-800rpm?)
The car came with a pretty comprehensive service history.Looking through it,it had a new serpentine belt fitted in September 2005,the adjuster was stripped and a new bearing fitted.In May of the same year it had had another serpentine belt fitted!Another 8 months down the line it appears to still be loose,or does it need tensioning on a regular basis(is this a common fault on this engine?).
It also had a new battery fitted just before I bought it.I would really like to get this sorted as the car seems pretty good apart from this.
Many thanks
Regards Rob

[noz]

Hi Bob,

Sorry I must have missed your previous requests. I have assumed you are talking about your 2.5 regarding this question?

I too would be worried about a loose belt for a number of reasons; premature belt wear, premature pulley wear, overheating with associated secondary problems charging problems, A/C problems and lack of LHM pressure.

I'm not exactly familiar with the A/C set up because I don't have any. However on the non-A/C the belt tension is manually adjusted. From memory the cars with A/C have two idler pulleys instead of the one. I think I even remember that one of them is spring loaded? What exactly is the problem with your tensioner(s)? Have you run out of travel? Are you sure that you have the correct belt fitted? The length of each belt is marked in cm on the outer surface. Belt lengths tend to go up in 2cm steps. It is not inconceivable that the previous owner has fitted the wrong belt. The correct belt for the 2.5 with A/C is 1882cm. Try to identify the length of your existing belt from the markings on the outer surface. Failing that, take it off and measure it with a tape.

Cheers

noz

[Gav]

I also had to change this belt on my 2.5, which includes air con, due to it fraying and eventually failing. Although to change the belt is relatively easy, the adjustment of tension was ney impossible due to lack of access. There are two tensioning devices around the belt:

one is an automatic sprung pulley which is accessible but not adjustable. If you compress the spring with an appropriate tool it allows the belt to be changed with ease.

the other is the manually adjusted pulley, however the allen key bolt is totally inaccessible behind the structure of the car.

Unfortunately my new belt is showing signs of fraying on the edge again after only about 10k. I suspect its because it is over tensioned or more likely one of the pulleys is not running true. Trouble is I am loath to sort out the adjustment because it menas doing lots of engine movements - instead i have a spare belt in the boot!

Probably not the answer you are after...

[Little&Large]

Hi Gav
Many thanks for your answer.Your problem is identical to mine!!Mine had 2 belts last year and the bearings on the adjuster were replaced as well.Mine is idling too low at the moment which I don't think is helping.
I am going to phone the Citroen Centre tomorrow to see what they say.There may be a way of adjusting it.However,I am not surprised that the adjuster is totally innaccessible!
I will let you know tomorrow what they say.
Regards Rob

[Gav]

i am curious why you think the idle is too low. I say this because mine idles at 800rpm when at a comlpete standstill.

I think the engine management reduces it slightly once you have reached a complete stand still because i notice when coming to a halt with the - clutch depressed - the engine sits at about 1000rpm, only when completely stationary will it immediately drop to 800 (or v.slightly above that mark anyway).

my air con is always on if that makes any difference. having said i will turn it off and see if the idling revs change at all.

[Little&Large]

Hi Gav
I have been advised by someone with a very good knowledge of XM's that the idle on 2.5's with aircon should be 950rpm.When I stop now I sit with my foot on the accelerator to idle it at 1000rpm and my noise disappears.I phoned the Citroen Centre today and he was well aware of the problem,he did mention the spring mounted adjuster,but did not mention the other one.To be fair he hadn't seen the car,but unseen quoted around £200 to replace the spring tensioner.
My 1st job is to get the idle increased and I'll decide whether to have it done there or at an independant garage.
I'll keep you posted.
Regards Rob

[Little&Large]

I forgot to say I will also investigate the size/length of belt on mine.1882cm!!
How on earth do you know soething like that Noz?

[noz]

Hi Bob,

All belts are sold by length in cm. Most manufacturers bury the length in their product code. I got the 1882 from the XM parts microfiche. Citroen use the length in their part code too !

Cheers

noz

[Little&Large]

Hello all
I have just got back from the Citroen Centre at Oxford.My 1st dealing with them has been very good.I phoned them yesterday and they told me to come down and they would have a look although they wouldn't be able to replace the adjuster if it was defective,due to time constraints.We(sorry-they!)found the reason for the loose belt....there was NO spring/adjuster present at all!!!!!The previous garage had left if off completely!Unfortunately they didn't have one in stock or it was simple enough to fit there and then so the car has still got to go back,but they did fabricate a temporary tensioner to tighten the belt partially.The correct idlling speed for a 2.5 with A/C is 800-850rpm.The belt on there was the correct length.
Phew!!!!!!That's a relief.
Regards Rob

[Robin]

You can get to the manual idler/tensioner by removing the ECU box and releasing the engine mounting bolts on the lower sub frame and then lowering the whole assembly on the upper bolts beneath the ECU just enough to get to the securing bolt for the tensioner. You will need to remove the steady bar that links the upper and lower mountings. After just pull both bolts up again and refit the lower ones.
I have just had to replace the automatic/spring tensioner and the Citroen cost complete is £128. The central pivot bolt has a needle bearing assembly around it and it seizes causing noises and belt wear through running out of line. Sorry but this is a Citroen only part.
You pre set the tension by locking it off tension with a 5mm bar and set the manual tensioner tight and then release the spring tensioner.
Sounds easy and it is really but you need to have done it once to grasp what is involved. It is worth removing the whole assembly to see what is involved and then it is easier to see what to do.
Robin.

[mebedforduk]

I can confirm Gavs method of belt changing

Mine with Air con, cant reach the hidden tensioner, the other has its torx screw rung off.

With a nice flat long beefy ali bar you can ease the left hand adjuster up on its spring and then slip off the belt, its fun getting the new belt back on but it does work.

Pity I didnt check that my new belt was the right size before taking off the old one....

Mark