Front Engine Noise at Idle

Hi Eric, Owner, All, I need some information and advice.

In October last year was detecting in the Vic Golden Triangle with wife and friends and late one afternoon when I started the Sprinter, there was a lot of engine rattle, lifted up the bonnet and confirmed it, the engine was shaking. When in gear the engine was smooth.
Decided to end our trip there and then and traveled back to Adelaide. Overnighted at Bordertown as I know a 4x4 Mechanic there who is knowledgeable/helpful. Next morning drove uneventfully back to Adelaide.

The Culprit turned out to be the Belt Tensioner which I replaced.

Did not use the Sprinter again until our Tassie Trip in December. 3 Days prior to getting onto the Spirit of Tasmania, on starting the Sprinter in Adelaide, noticed an occasional knock when at idle, no noise under load. Anyway decide it was not going to stop our trip.

In Devenport at a friend’s place, removed the belt and replaced it with a slightly smaller new backup, after checking all the pullies etc for wear… all good. Still had the noise and it was worse when the air con was running. Looking down on the drivers side at the vertical belt, it did not run smooth but wobbled, more so with the a/c on.

Back home in Adelaide, rang Mercedes Benz Parts Dept and asked what belt size should I be using and they said since I have a 2004 Sprinter with an aftermarket A/c ( Installed at the request of MB Oz when the vehicle was shipped in from Brazil, I understand) they were not sure but their records say use an 6PK2265 or a 6PK 2270. I was extremely doubtful that these would fit, but with much effort installed a 6PK2270 ( Put Sprinter in 2nd gear and gave it a push to get the belt on) Result… the vehicle was a noisy as ever, and had to cut the belt to get it off ( $42 Trade, $90+ Over the Counter)

So the question is, what belt is needed on a 313 2.2Lt 903, 2003/2004 Sprinter fitted with an Australian Airconditioner? A 6PK……….

I purchased a belt for a vehicle without a/c, installed it and the belt runs smooth, no noise and no belt wobble. I removed the A/c Compressor and my technical adviser says the A/c unit is OK, That’s not the problem. To him I and using the wrong belt, or my new Dayco Tensioner is faulty.

So B4 I purchase a Genuine? MB Tensioner, I would like to get the belt sorted, so appreciate your input ie a 6PK…………

Your comments and advice appreciated.

Peter

Peter.
Check your alternator pulley clutch, it should drive the alternator when you turn it clockwise and it should free wheel anticlockwise. The belt number is the lenght in MM, from your figures you need a 2275. Eric.

I agree with Eric, a bad alternator pulley can make the whole belt system jump around a lot.

6PK2275 is supposed to be the stock size for ones that came into the country already fitted from the factory with the AC compressor, a Denso model.


For ones that have the big Delphi SP21 compressor that was locally fitted (under dealer contract), the size is 6PK2345.


Its easy to tell the difference because the Delphi one has 4 mounting bolts, and the Denso only has 3 (the 2 you can see in the photo and a single one at the rear). Also the in/out ports are side by side on the top-middle of the Delphi, but on the Denso theres only one port top-middle and the other at the top-rear.

Since you could fit a 2270 on it with a bit of effort, I'm going to say yours has the smaller compressor wheel and 2275 should be right. 2345 is a huge belt and wont even get anywhere near tight on the small setup.

I know all this because I actually recently changed mine from local to factory setup. My Delphi compressor pulley was wobbling around a lot after 400k. It turned out to be the casting flange that the pulley/clutch is an interference fit onto on the compressor, was worn away such that the pulley/clutch always had a few mm of play. The flange that was worn away was part of the main compressor housing/casting. It was going to be a saga to add spacers due to the way the face was worn, and those Delphi compressors are very expensive compared to the Denso. The Delphi ones also have a habit of weeping/leaking,

So I changed the entire AC system to factory Denso using parts off a wrecked van.

BTW the AC performance is so much better with the factory denso compressor, condensor and piping etc.

Eric Re:
(Check your alternator pulley clutch, it should drive the alternator when you turn it clockwise and it should free wheel anticlockwise. The belt number is the length in MM, from your figures you need a 2275.) Eric.

The alternator checked out OK, It Drives both ways like a normal alternator, It may have been changed prior to my purchase. It also does not cause a problem with the smaller belt when the air/con compressor is not in the circuit ( ie removed). Am currently running the Sprinter with the smaller belt, its a 6PK 2200RB, including the alternator and new Tensioner, with no noise and no wobble.

Re the 2275 belt when I fitted the 6PK 2270, the alan key that was used to hold the Tensioner to release the belt could easily slip in and out, to me a 2275 just 5mm longer would be similar. ie the Tensioner was at maximum compression+ with the 2270.

Owner,
From your post, I have the 4 Bolt Delphi Air Conditioner Compressor and have run with a 6PK2345 belt for years, prior to the problem with the Tensioner in Oct2019.

But was/is the 6PK 2345 on your 316 with and Oz A/C Compressor the same design engine as the 313 but with more compression???. ie both the 316 and 313 used the same belt.

So, If the belt is the correct one, eliminating the alternator since there are no problems with it running the smaller belt without the A/C Compressor, that leaves the New Tensioner, which has no problems with the smaller belt, so its down to the Compressor.

I understand I can have the compressor checked out for around $200 with a “It tested out OK but still may be faulty” after a 2 weeks wait, or a new Delphi compressor at $600 Trade price. (and of course my Tech adviser restated that my compressor in his opinion is OK)

(I don’t have a problem in the cost to fix, just hate replacing something, that’s OK to eliminate it)

Comments appreciated.

Peter

PeterInSa said:

Hi Eric, Owner, All, I need some information and advice.

So the question is, what belt is needed on a 313 2.2Lt 903, 2003/2004 Sprinter fitted with an Australian Airconditioner? A 6PK……….

I purchased a belt for a vehicle without a/c, installed it and the belt runs smooth, no noise and no belt wobble. I removed the A/c Compressor and my technical adviser says the A/c unit is OK, That’s not the problem. To him I and using the wrong belt, or my new Dayco Tensioner is faulty.

So B4 I purchase a Genuine? MB Tensioner, I would like to get the belt sorted, so appreciate your input ie a 6PK…………

Your comments and advice appreciated.

Peter

Click to expand...

My Sprinter has Airmaster rear aircon. A dummy pulley is fitted where the OEM compressor would normally be fitted. An aftermarket compressor is fitted lower down, and runs on a separate V belt. The Serpentine belt is indeed a 6PK2265. I Second the motion on checking the alternator clutch ! Have already had to replace mine.

Peter.
You alternator pulley is no good, you must replace it with the correct unit, it will have caused the tensioner problem and will rattle the ac pulley. Eric.

Eric, Thanks for your help, but to a non mechanic, I cannot see why when the smaller Fan belt that does Not go around the AC Compressor, does Not make a noise or wobble when it goes around the Alternator Pulley/Tensioner etc etc.

Will do some more research eg:
https://sprinter-source.com/forum/showthread.php?t=71911&highlight=alternator+pulley

Peter

PeterInSa said:

Owner,
From your post, I have the 4 Bolt Delphi Air Conditioner Compressor and have run with a 6PK2345 belt for years, prior to the problem with the Tensioner in Oct2019.

Click to expand...

Somethings not right here. When I swapped out compressors, the 2345 I had been running forever was way too loose on the new compressor with the smaller pulley. You are saying yours went from having a 2345 to a 2270 with the same compressor, that just doesn't seem possible. Something must have changed when you changed the tensioner, are you sure the belt is routed correctly? And the tensioner was exactly the same as what came out and has been released properly?

FWIW I changed my tensioner to a Dayco APV2232. I think one of the mounting bolt flanges isn't thick enough, I need to re-mount it, but it has been running fine as is. I'm running a 6PK2275.


BTW the alternator pulley isn't supposed to "drive both ways". It is supposed to be driven in the correct direction and freewheel on overrun in that direction. The freewheel is a little tight so it does seem as if it drives both ways but it doesn't. The best way to test is to spin up the alternator in the correct direction, then stop the pulley - the alternator should freewheel on the pulley.

This is the 316 T1N layout...

Peter,
Either you are not testing the pulley correctly or the shorter belt is/was loose and slipping on the crank, three people on this thread have said its the pulley so just believe it. Eric.

Re (2345 to a 2270 with the same compressor,) To do this the Tensioner was hard Over, ( lock pin was loose) and the belt had to be stretched to fit the Alternator pulley.( with vehicle in 2nd and a push)

As above Belt layout, Same Belt layout for the 313.

Vehicle has done 150,000Km rather than changing the Alternator Pulley, with the purchase of a special tool and potential problems, plan on replacing the alternator as well.
https://europarts-sd.com/item.asp?PID=2226

Any recommended After Market brand alternator. Don't need a large charge current as Solar charges Home and Vehicle batteries.

Thanks

Peter

Dont get aftrrmarket, get Bosch. I recently upgraded to a 200A bosch (biggest factory option) and it didnt cost much using a 20% off ebay voucher.. Even cheaper than some 90A ones.
https://www.ebay.com.au/itm/Genuine-Bosch-alternator-BX625020/323656685512

But did you check if your existing pulley freewheel is ok?

Will take the alternator off hopefully this weekend, will check the pulley then, and look at a pulley only option.

Hi owner
A big alternator may be good. But if it charges the house batteries direct you
must be careful that they are capable of accepting a large rate of charge under all normal conditions when flat. Just pointing that out for general information.

As for the belt length. A tape around the pulleys in the correct sequence and holding the tensioner fully back and then fully foward, will give two lengths to use to see a very close correct belt length for the flat multi-rib belts. You should never have to "turn them on" to the pulleys as it risks breaking a cord or the ribs.Usually means that the pulley sequence is incorrect, as had been said or the wrong belt.

Note the special tool to use for the clutch pulley is simple and cheap on ebay and use a rattle gun and should be easy to get off. From memory there are two types and europeans use the other one. I carry mine in the truck !
Jaahn

Its fairly easy to check the pulley with the alternator installed. I would do that first.

MW re (Its fairly easy to check the pulley with the alternator installed. I would do that first.)

I am over it, during our trip to Tassie (Dec/Jan)on some hot days ( 35C+)did not run the Air Con because of the belt wobble, wary of a new belt break, and with parts supply in some parts of Tassie not readily available, and a ship to catch back to the mainland, no excuses if you miss the boarding and maybe weeks delay in getting a new berth, when the alternator comes off, if I can change the pulley will do regardless, if not will replace the alternator.

New Alternator pulley in, running with smaller belt, Air conditioner install next week with normal belt.

Old Pulley on the Alternator was sus.

Air Conditioner Compressor is in, and fitted a new normal belt and.... no belt wobble and smooth running engine.

Thanks Eric and Owner for your advice and "all" for your comments. As a non mechanic, I still cannot see with a smaller belt not going around the air conditioner compressor, the problem was not evident, but was definitely the alternator pulley.

Thanks again

Peter