Non starter code 121 mass air flow?

[Laird Scooby]

Originally Posted by griston64

Haynes manual is every 50,000 miles or 5 years,whichever comes first

Is that a Haynes manual for the 940 Mark? I ask because mine (for the 740/760) quotes 40k or 4 years but mentions later recommendations are 5yrs/50k miles but doesn't mention the round-tooth belt. I suspect if you look at the pretty pictures on the timing belt change section the pictures will show a round tooth belt?

[Laney760]

Hi Dave. Hope you are keeping well. Yes, I agree, 100 thou seems steep. Also I need to ask the Volvo indi in Wales whether they fitted me a genuine Volvo or aftermarket belt in 2017, I think that must make a difference too?

[griston64]

Originally Posted by Laird Scooby

Is that a Haynes manual for the 940 Mark? I ask because mine (for the 740/760) quotes 40k or 4 years but mentions later recommendations are 5yrs/50k miles but doesn't mention the round-tooth belt. I suspect if you look at the pretty pictures on the timing belt change section the pictures will show a round tooth belt?

It is indeed Dave.

[griston64]

My 1996 940 is round belt so Ellie's will be the same

[griston64]

I'm pretty certain 93 cars onward were round toothed belts.

[Laird Scooby]

Originally Posted by Laney760

Hi Dave. Hope you are keeping well. Yes, I agree, 100 thou seems steep. Also I need to ask the Volvo indi in Wales whether they fitted me a genuine Volvo or aftermarket belt in 2017, I think that must make a difference too?

I'm as well as i ever manage thanks Ellie, hope you're good too?

I do know of a few cars where 100k or close to is the norm for timing belts but as far as i've known Volvos over the years, 40k give or take is more like it, same goes for the majority of the rest of the cars on the planet.

Any aftermarket/pattern belt should be up to the job of running the engine for the specified interval - if it was a Gates or Dayco aftermarket then you won't have any worries as they are OE spec, i think Gates is Volvos first choice with Dayco being second, on my Rover (Honda engine) Dayco is first with Gates second and that has a 96k/8yrs interval but what neither Honda or Rover tell the customer is that the water pump is a service item at 120k so the belt has to come off again!

Kind of irrelevant, just added that for context as the water pump isn't needed to be changed on the red block engines as it isn't driven by the timing belt. It was more for comparing the intervals.

If you remove the top timing belt cover (3 bolts i think then lift it up) you might even be able to see the manufacturers name on your belt.



Cover is 19 in that pic, bolts are 21, 22 and 23.

The big question is after having your belt replaced in Wales did you have it retensioned after 600 miles? If not, i'd urge you to get it renewed ASAP as it's likely to be slack by now and if it's slack, it can jump and/or strip teeth more easily.

If you do have a look to see what brand of belt you have Ellie and you notice a sort of "shadow" on the flat side of the belt where the teeth are then it almost certainly needs changing. I'm not 100% sure on what causes this effect, i call it "ghosting" as it's like a ghost image of the teeth but it has always gone hand in hand with a worn belt.

[Laney760]

No, it wasn't retensioned Dave, thanks for the heads up! Would a slipping belt affect power? I feel sure the 940 is still down on power a little bit, I'd put it down to age and compression but it did seem to just happen overnight so to speak.


Yes, I am very good thank you!

[Laird Scooby]

A slack belt certainly put the power down on my last 740 Ellie, particularly noticeable on hills. Fortunately it didn't jump any teeth on mine but if yours has done it "overnight" it's possible it's jumped a tooth and the timing is now one tooth retarded on the cam and by extension of that, the ignition as the distributor is hung on the back end of the cam.

The turbo probably mitigates this somewhat but it was very obvious on my 740 (no turbo! Similar output to yours though) so i'd say get it checked and/or renewed ASAP and this time remember to get it retensioned after 600 miles.

Good to hear you're well and avoiding the Kung Flu!