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I bought my beloved XF (2011 3.0 Diesel) 6 years ago, at 12 months old with 12,000 miles on the clock. It is now 7 years old, with almost 90,000 miles (hasn't been used much for the past 3 years). I intend to keep it for a few more years yet, so being a responsible owner, I just had a new timing belt fitted at the local dealership (£625 "deal" from Jaguar). Jag recommend replacing it at 7 years or 112,000 miles.

I'm convinced the (3-litre V6 diesel) engine sounds a little bit smoother now (always felt good, still does), but that must be placebo effect, surely? Replacing the timing belt is just avoiding a problem in the future, isn't it?

I've never had a new timing belt fitted before, not sure what to expect. All the pistons and cylinders are the same 7-year-old kit, so I must be imagining it?

Please tell me if I'm wrong
 

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In 1979 I bought a new Rover SD 1 and after a few weeks I noticed that the engine was noisy, not accepted by Hartwells of Abingdon at the outset. I continued to complain and fortunately on the last occasion a technical adviser from Rover was on the premises. He was asked to give his view. After a few minutes he took the Service Manager in to an office and I could see that they were looking through a file of technical bulletins. After a few more minutes I was told by the Service Manager that they were going to replace the belt. Afterwards the car was beautifully smooth and silent, that wasn’t my imagination :)
 

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I'm convinced the (3-litre V6 diesel) engine sounds a little bit smoother now (always felt good, still does), but that must be placebo effect, surely? Replacing the timing belt is just avoiding a problem in the future, isn't it?
Worn timing belts or (more likely) the tensioner can cause rough running and/or suboptimal valve lift timing. So, you may very well be noticing something real.




P.S. I have no idea why Jaguar/LR/PSA use timing belts on their V6 diesels, vs using the much better/more durable/more reliable timing chains as they use them on the 3.0V6 Petrol. Prob because those derived from the AJV8 petrol, I guess.
 

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Worn timing belts or (more likely) the tensioner can cause rough running and/or suboptimal valve lift timing. So, you may very well be noticing something real.

P.S. I have no idea why Jaguar/LR/PSA use timing belts on their V6 diesels, vs using the much better/more durable/more reliable timing chains as they use them on the 3.0V6 Petrol. Prob because those derived from the AJV8 petrol, I guess.
I did a search on the net. The short version is:

Timing belts are lighter and run smoother - resulting in better fuel economy and less noise. Also a lot cheaper to make. Only disadvantage is that they're less durable and need to be changed more frequently than timing chains. The process of changing timing belts or chains is time consuming and laborious.
There is also a longer version:

Timing Belt - Advantages
  • Precision registration and timing with no loss of high torque carrying capability
  • Minimal vibration and chordal effect
  • Positive slip proof engagement
  • Wide speed range, especially important when the entire speed range is developed from a single source
  • Virtually no elongation (stretching) due to wear
  • High mechanical efficiency, as much as 98% when properly maintained. By contrast, chain drives are in the 91-98% efficiency range, while V-Belts average in the 93-98% range.
  • Power transmission efficiency is not lost with use
  • Clean operation, no need for lubrication
  • Reduced noise
  • Long, dependable trouble-free service
  • Excellent abrasion resistance
  • Rust resistant
  • Resists chemicals and contaminants
  • Increased drive design options
  • Weight savings
  • Safety issues
  • Economical operations:
    • No need for expensive drive enclosures
    • No need for lubrication systems
    • No need for tensioning devices
    • No adjustment needed due to stretch or wear
    • No cost for lubricant or disposal fees
    • No worn sprocket replacement
    • No ongoing maintenance costs for roller chain
    • Energy savings
    • Reduced costs associated with "downtime" on top of lost productivity
Timing Belt - DisadvantagesOur own experience has shown that the timing belt is not perfect in every situation when comparing it against a chain drive. Being able to recognize timing belt limitations helps us to educate our customers in making the right decisions on their particular applications needs.

  • Availability of numerous chain sizes allows for the use of smaller pitch diameters and/or number of teeth while achieving the desired ratio
  • Higher speeds and power capacities
  • Detachable chain links make installation easier in some instances
  • Need for accurate initial alignment of drive components
  • No slippage
  • Higher drive ratios at shorter center distances
  • Lower bearing loads
  • Less affected by temperature or humidity
  • Less affected by oil and grease
 

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My timing belt will be changed at my cars next service. It's being done on the 10 year anniversary at jaguars recommendation, not 7. Car is 2009 model.
 

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In 1979 I bought a new Rover SD 1 and after a few weeks I noticed that the engine was noisy, not accepted by Hartwells of Abingdon at the outset. I continued to complain and fortunately on the last occasion a technical adviser from Rover was on the premises. He was asked to give his view. After a few minutes he took the Service Manager in to an office and I could see that they were looking through a file of technical bulletins. After a few more minutes I was told by the Service Manager that they were going to replace the belt. Afterwards the car was beautifully smooth and silent, that wasn’t my imagination :)
Similar tale, I had the first SD1 V8 sold in Worcestershire 1976 that was fine but when I part ex'd it in 1978 the new one had a rattle. I had to get very assertive with the dealer to sort it however Rover did replace the belt and it was fine after that ;)
 

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I’ve just had the cambelt changed on my 2009 3.0 v6 diesel along with and service and a number of other fixes. After about 60 miles the auxiliary drive belt failed and the water pump collapsed, not a great Friday night! The jaguar dealer initially said they didn’t touch anything in the area, but then said they did remove the auxiliary belt, the RAC recovery people suggested over tightening the belt could have broken the pump pulley. Jaguar then said that they usually replace the water pump at the same time at the cambelt, but this was never mentioned to me.

Has anyone that has used the 3+ servicing offer of a cambelt replacement for £625 had the water pump changed at the same time? Was is recommended or even included in the £625? It seems very strange that if that part is normally changed at the same time that they would do it without... Any advice or experiences would be useful thanks.
 

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I’ve just had the cambelt changed on my 2009 3.0 v6 diesel along with and service and a number of other fixes. After about 60 miles the auxiliary drive belt failed and the water pump collapsed, not a great Friday night! The jaguar dealer initially said they didn’t touch anything in the area, but then said they did remove the auxiliary belt, the RAC recovery people suggested over tightening the belt could have broken the pump pulley. Jaguar then said that they usually replace the water pump at the same time at the cambelt, but this was never mentioned to me.

Has anyone that has used the 3+ servicing offer of a cambelt replacement for £625 had the water pump changed at the same time? Was is recommended or even included in the £625? It seems very strange that if that part is normally changed at the same time that they would do it without... Any advice or experiences would be useful thanks.
When I took my car to Jaguar (Stratford Tottenham, serves the Mayfair customers) I asked them to change any other belts in the area. Which they did, and charged extra £40 or so. I used the fixed price servicing. No mention of changing the water pump. However, their service was shocking. I had to go make 4 trips in total to get the service I'd originally asked for. I would suggest finding a local Jaguar specialist. In fact, I'd be happier taking my car to the local kwik fit rather than jaguar again.
 

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When I took my car to Jaguar (Stratford Tottenham, serves the Mayfair customers) I asked them to change any other belts in the area. Which they did, and charged extra £40 or so. I used the fixed price servicing. No mention of changing the water pump. However, their service was shocking. I had to go make 4 trips in total to get the service I'd originally asked for. I would suggest finding a local Jaguar specialist. In fact, I'd be happier taking my car to the local kwik fit rather than jaguar again.
We are a Jaguar independent 2 ex Jaguar techs having a go at working for ourselves we do 3.0 cam belt for £450 inc with no extra labour just price of parts for water pump and aux belt. We also can do rear belt for extra charge.
 

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We are a Jaguar independent 2 ex Jaguar techs having a go at working for ourselves we do 3.0 cam belt for £450 inc with no extra labour just price of parts for water pump and aux belt. We also can do rear belt for extra charge.
Hi, Where are you based?
 

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I bought my beloved XF (2011 3.0 Diesel) 6 years ago, at 12 months old with 12,000 miles on the clock. It is now 7 years old, with almost 90,000 miles (hasn't been used much for the past 3 years). I intend to keep it for a few more years yet, so being a responsible owner, I just had a new timing belt fitted at the local dealership (£625 "deal" from Jaguar). Jag recommend replacing it at 7 years or 112,000 miles.

I'm convinced the (3-litre V6 diesel) engine sounds a little bit smoother now (always felt good, still does), but that must be placebo effect, surely? Replacing the timing belt is just avoiding a problem in the future, isn't it?

I've never had a new timing belt fitted before, not sure what to expect. All the pistons and cylinders are the same 7-year-old kit, so I must be imagining it?

Please tell me if I'm wrong
Why on Earth doesn’t Jaguar mention timing belt replacement in its service book?
 
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