[Kaj Hallstrom]

One of the most important maintenance issues on a 968 is the timing belt. It requires proper and on time replacement after 45000 miles (or 5 years)

I had mine replaced on my '94 cab about a year ago. I also replaced water pump, balance shaft belts, all the rollers and you name it. There was no talk about coming back for any adjustments. I now read comments, on and off, from various sites how important it is to have your belts re-tensioned. This concerned me, so I called my Mechanic (a 30 year 924/944/928/968 expert) to find out what to do. He said there was no need for adjustments as long as the car was running smooth. The belts are self adjusting I was told.

Comments please!!

 

   

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[Ernie]

I thought the general consensus was 4 years, Kaj. I would like it to be 5 years and I could squeak another year out before replacing mine! I had to go back after @1000 miles for adjustment of the balance belt, IIRC. Maybe others can chime in?

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[Kaj Hallstrom]

I guess in some climates it would be 4 years.

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[ds968]

My understanding is that an adjustment is needed at 2000-2500 miles after installation , and nothing more after that until it's time to replace it.

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[williamoss]

What about us drivers who might only drive the car at about 3000 miles per year, so in 5 years 15,000 miles. Do I have to replace the belt at that 5 year mark, My car is kept in a heated garage?

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[MCL968]

Are we actually talking about the tension on the balance shaft belt? The timing belt has a hydraulic tensioner. Or, are we discussing the cam timing? Very different things.

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[Kaj Hallstrom]

We are talking any adjustments after belt changes, not cam adjustments. I just get so many conflicting answers to this that I am left confused and dazed.

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[ds968]

What about us drivers who might only drive the car at about 3000 miles per year, so in 5 years 15,000 miles. Do I have to replace the belt at that 5 year mark, My car is kept in a heated garage?

Belts longevity and recommended change intervals based on mileage, age, environmental facttors, driving " style " , etc. is an entirely different story and one subject to much debate ; there are a couple of other threads here with more posts addressing that topic, but as far as tensioning is concerned, and at least according to my mechanic , in spite of the hydraulic tensioner doing its job, a new belt stretches so much in the first couple of thousand miles that a manual check and small adjustment is not just the prudent thing to do, but more often than not, it's necessary for an ideal tension . After that initial break-in mileage the stretch is supposedly negligible so not an issue for the tensioner to deal with for,the rest of the belts lifetime .

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[williamoss]

thanks good answer

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[94SilverCab]

We are talking any adjustments after belt changes, not cam adjustments. I just get so many conflicting answers to this that I am left confused and dazed.

Kaj,

 

Please let me very clearly respond to YOUR question. Your belts should be re-checked for tension 2,000 miles after they have been replaced. If your mechanic is good he will not charge you for this service, it should have been included in his original price.

 

The first statement is fact, the second is opinion.

 

Has your question been satisfactorily answered?

 

Jay

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[Bulti]

It's not possible to adjust the cam belt's tension. This is indeed taken care of by the hydraulic tensioner.


A new balance belt should indeed be re-tensioned after 2000-2500 mls (3000-4000 km) according to the manual.


My balance belt did stretch a bit but after adjustment it remains 'stable'.

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[williamoss]

Can someone explain to me a non mechanic. If there is an automatic adjuster built into the loop of the belt how do you adjust the tensioner? Since I assume the automatic adjuster is under a spring like pressure pusher that will go outwards as the belt stretched what do you adjust in the first place?

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[ds968]

It's not possible to adjust the cam belt's tension. This is indeed taken care of by the hydraulic tensioner.

A new balance belt should indeed be re-tensioned after 2000-2500 mls (3000-4000 km) according to the manual.

My balance belt did stretch a bit but after adjustment it remains 'stable'.

Hmm, so the only belt adjustment is to the balance one ? Could have sworn my mechanic was talking about both belts being adjusted after a couple of thousand miles but I may have misunderstood him .

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[MLB]

Correct, as Bulti said above, only the balance shaft Belt can be adjusted, and assuming you drive 3000 to 5000 miles a year, have the balance shaft Belt checked and readjusted after one year. Check the shop manual for the exact intervals, as Jay and Bulti mention above.


The timing belt has a hydraulic tensioner, unlike the 944. There is no adjustment for the timing belt on a 968

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[Kaj Hallstrom]

CONCLUSION:

 

Timing belt is self adjusting.

 

Balance belt needs tension after 2000 miles (or one year) (approx)

 

Is this where we are?

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[Ryan]

CONCLUSION:

 

Timing belt is self adjusting.

 

Balance belt needs tension after 2000 miles (or one year) (approx)

 

Is this where we are?

Yes this is finally correct.....

 

All 8 valve 944s had to have their timing belts tensioned however when the first 944S 16 valve came on the market followed by the 944S2 and finally the 968, the tensioner was automatic. All 16 valve engines had a wider belt as well. The balance belt system is the same as on the 944 and has to be retensioned at one point after initial stretch from break-in. 

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[Bulti]

CONCLUSION:

 Timing belt is self adjusting.

 Balance belt needs tension after 2000 miles (or one year) (approx)

 Is this where we are?

Indeed, but the manual does not mention 'one year'. Only the mileage is what counts. Makes sense to me.


@ William: the tensioner is hydraulic and pushes on the belt at all times via a lever and pivot point. There is nothing to adjust, it's 100% self adjusting.

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[MLB]

Yeah sorry about the 1 year comment; i just meant to emphasize dont forget to have the BS belt tension adjusted, no later than the following season. (Driving this type of car here in wisconsin is totally a seasonal thing)

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[flash]

ok - here is the real skinny on belts:

 

they must be replaced after no more than 4 years, REGARDLESS of how few miles on the belts.  research shows that there is also a maximum of 45k miles allowed.  this may be REDUCED to 3 years, under conditions such as track usage, and/or use in an area of wide swings in climate

 

the balance belt is to be re-tensioned at 2400 miles after changing, and AGAIN every 15k or 1 year, whichever is FIRST.  the manual actually does mention this, but you have to read it carefully.  they really did not do a good job on this.

 

the timing belt is self tensioning

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[az968]

Very timely discussion for me, my car goes in for annual service in a week. Been one year and 2900 miles since balance shaft belts replaced, along with the timing belt.  I didn't see that in the service manual, I guess I need to read it more closely, as I haven't been having that done annually, unless my mechanic was doing it and just not explaining it to me.

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