alternator belt routing

JD79 · Apr 8th, 2010, 01:37

I'm trying to work out why my alternator belt has been rubbing against my timing cover. A fw weeks back it finally hit the tensioner plug and ripped it into the timing belt itself.

On my vehicle, the belt loops around both the crank pulley and the water pump pulley, then onto the alternator pulley., which brings the tup length of the belt up against the timing belt cover near the raised bit where the plug should sit, if it wasn't now in a dozen pieces.

I notice that on VADIS, the belt does not loop around the water pump pulley. Can someone out there with a 940 let me know how theirs is set up?

CTCNetwork · Apr 8th, 2010, 02:19

Hi,

Alternator should be powered by the crank wheel.

If you have AirCon, that will also be running off the crank wheel.

The water pump is also driven off the Crank wheel but itself runs the oil pump.

You'll notice there are three groves for belts on that Crank wheel. The fitting order is:
1) Water Pump belt.
2) Alternator belt.
3) AirCon belt.

Ergo, whoever changed the belts last fitted the belts back incorrectly if your alternator belt was next to the cambelt cover!

Des. . .

JD79 · Apr 8th, 2010, 02:29

Thanks Des

,

The order of the belts is as specified above, but because my alt belt goes from the crank pulley up to the water pump pulley, then across to the alternator pulley it passes right next to the raised bit on the timing cover through which one accesses the tensioner. Because it is raised there, the belt is in slight contact even though it is the middle belt.

If I were to run a new belt from the crank pulley straight to the alternator, it would eliminate this issue. However, it would leave the water pump pulley being driven only by the one belt, which means that if the belt breaks, my engine is up for scrap. I don't know if it is preferable to run with the current setup, sans the tensioner plug, and keep the redundancy on the water pump drive, or to change it.

Out of interest, has anyone ever had a water pump belt break, leading to catastrophic engine failure?

fowlerman · Apr 8th, 2010, 11:05

My 940 only has one belt driving the water pump which is correct according to the diagram in the handbook. This shows front belt A/C only, middle belt alternator only, rear belt power steering + waterpump. This is, of course, UK spec. car, not sure where Hervey Bay is and possibly it is a different spec. where you are. I would think that the loss of P/S if the belt snapped would give enough warning before any serious damage to the engine occurred.

Pete.

JD79 · Apr 8th, 2010, 11:22

Cheers Pete,

The same idea occurred to me on the way home. Unless I'm driving down a very very straight stretch of road, I should notice loss of power steering very soon. I certainly noticed it when the engine died after the timing fault. I think I'll go ahead and get a new alternator belt, and replace the water pump/powersteering belt with the best money can buy to hedge my bets. Probably a volvo belt

Apr 8th, 2010, 01:37	#1
JD79 Member Last Online: Mar 5th, 2011 06:14 Join Date: Feb 2010 Location: Hervey Bay	alternator belt routing I'm trying to work out why my alternator belt has been rubbing against my timing cover. A fw weeks back it finally hit the tensioner plug and ripped it into the timing belt itself. On my vehicle, the belt loops around both the crank pulley and the water pump pulley, then onto the alternator pulley., which brings the tup length of the belt up against the timing belt cover near the raised bit where the plug should sit, if it wasn't now in a dozen pieces. I notice that on VADIS, the belt does not loop around the water pump pulley. Can someone out there with a 940 let me know how theirs is set up?

Apr 8th, 2010, 02:19	#2
CTCNetwork Forum Support Team Join Date: Dec 2004 Location: Liège, Belgium View Photos By: CTCNetwork	Hi, Alternator should be powered by the crank wheel. If you have AirCon, that will also be running off the crank wheel. The water pump is also driven off the Crank wheel but itself runs the oil pump. You'll notice there are three groves for belts on that Crank wheel. The fitting order is: 1) Water Pump belt. 2) Alternator belt. 3) AirCon belt. Ergo, whoever changed the belts last fitted the belts back incorrectly if your alternator belt was next to the cambelt cover! Des. . . __________________ Density:- Not just a measurement ~ It's a whole way of Life.! ! ! I drive a Volvo, Please Don't Get In My Way! OldVolvos4Ever He shows up. People die. He vanishes. People should not be afraid of their governments. "He'll deliver more justice in a weekend than 10 years of your Governments should be afraid of their people... "V" courts & tribunals. Just stay out of his way." "I plan to."

Apr 8th, 2010, 11:05	#4
fowlerman Master Member Last Online: Dec 3rd, 2021 10:00 Join Date: Mar 2007 Location: blackpool	My 940 only has one belt driving the water pump which is correct according to the diagram in the handbook. This shows front belt A/C only, middle belt alternator only, rear belt power steering + waterpump. This is, of course, UK spec. car, not sure where Hervey Bay is and possibly it is a different spec. where you are. I would think that the loss of P/S if the belt snapped would give enough warning before any serious damage to the engine occurred. Pete. __________________ Guy Fawkes-the only man to get into parliment with the right idea! "Tha can alus trust a mon as tucks is shirt inside is underpants" Sir Jos Fosdyke, Tripe magnate.

Apr 8th, 2010, 02:29	#3
JD79 Member Last Online: Mar 5th, 2011 06:14 Join Date: Feb 2010 Location: Hervey Bay	Thanks Des , The order of the belts is as specified above, but because my alt belt goes from the crank pulley up to the water pump pulley, then across to the alternator pulley it passes right next to the raised bit on the timing cover through which one accesses the tensioner. Because it is raised there, the belt is in slight contact even though it is the middle belt. If I were to run a new belt from the crank pulley straight to the alternator, it would eliminate this issue. However, it would leave the water pump pulley being driven only by the one belt, which means that if the belt breaks, my engine is up for scrap. I don't know if it is preferable to run with the current setup, sans the tensioner plug, and keep the redundancy on the water pump drive, or to change it. Out of interest, has anyone ever had a water pump belt break, leading to catastrophic engine failure?

Apr 8th, 2010, 11:22	#5
JD79 Member Last Online: Mar 5th, 2011 06:14 Join Date: Feb 2010 Location: Hervey Bay	Cheers Pete, The same idea occurred to me on the way home. Unless I'm driving down a very very straight stretch of road, I should notice loss of power steering very soon. I certainly noticed it when the engine died after the timing fault. I think I'll go ahead and get a new alternator belt, and replace the water pump/powersteering belt with the best money can buy to hedge my bets. Probably a volvo belt

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