Odometer going ten times too fast

[Chromey]

Hello there.

I have recently bought a 1983 Westfalia Vanagon (LHD) and am having some issues with the odometer/speedometer. The van has a donor diesel Golf engine onboard, but I think was probably originally a petrol van, as the odometer has the 'OXS' marking (I am not sure if it is the original clock, but it only goes up to 85).

On my drive home from purchase, the odometer briefly stopped entirely, then restarted a few days later going ten times faster than it should - i.e. although the clock reads 107,145 miles, it is running like it is 10,714.5, so the far right digit turns ten times per mile, so is aging my van prematurely! The lower 'trip' clock is also not running in synch. Oh, and the speedo is about 10km too fast.

I am a mechanical imbecile, so will have to ask a grown up to fix it for me, but does anybody know whether a second-hand diesel clock (with glow plug markings) which goes up to 100mph is the right replacement clock for me to buy?

Attaching photos of my clock (OXS), and what I am considering buying to fix the problem below that.

Many thanks in advance for any comments...

[AngeloEvs]

It does sound like the speedo is the problem.

  You have to be careful when buying a different dash as there were a number of changes regards the orientation of the wiring socket, the order of the wires in the socket, the oil warning pressure system and the size of the speedo drive union, etc.    The major change occurred in 1986 so  you probably need an early dash pod or early speedo.    Also,  if yours was originally petrol it may not have the wire at the dash for the glow plug indicator -  may be another member will confirm if that is the case.

    

[davidoft1]

Isn’t the last digit 10ths of A mile ?

Check your speedo cable First

[Chromey]

.....

[Chromey]

It does sound like the speedo is the problem.

  You have to be careful when buying a different dash as there were a number of changes regards the orientation of the wiring socket, the order of the wires in the socket, the oil warning pressure system and the size of the speedo drive union, etc.    The major change occurred in 1986 so  you probably need an early dash pod or early speedo.    Also,  if yours was originally petrol it may not have the wire at the dash for the glow plug indicator -  may be another member will confirm if that is the case.

    

Thanks very much. Actually it does have the glow plug light, which takes a few seconds to go off when I turn the key. It’s a bit of a mystery. Maybe I will just buy the replacement clock and see what my mechanic makes of it...

[Chromey]

Isn’t the last digit 10ths of A mile ?

Check your speedo cable First

Thanks. Apparently the cable is fine.

If the last digit was tenths, then the clock would only go up to 99,000 miles which can’t be right. Looking at the past MOTs, it has gradually gone up by a few thousand per year to the 101k when I bought it. Now in less than a month it is at 106k. Thanks for your reply though.

[Oldiebut goodie]

The odometer on mine only went up to 99,000 with the tenths on the end. I never had a clue as to how many miles it had done. You may well have a Frankenstein dash.

[sarran1955]

Hello,

Thats right 99 999 miles or km,

On all older VWs since.........oooh whenever..

Cordialement,

[Chromey]

The odometer on mine only went up to 99,000 with the tenths on the end. I never had a clue as to how many miles it had done. You may well have a Frankenstein dash.

Thanks for the comment. Holy "pooh". So even if I buy a new clock, it will still tick at the same speed?? How does anybody ever know how many miles/kms they have done????

[AngeloEvs]

Most older speedos tend to err on the high side by as much as 10%.    AFAIK, you cannot do anything to the speedo itself other than adjust the position of the needle itself but you will probably find that  changing the speedo will solve your problems with the mileometer and indicated speed error.

[Mocki]

I can’t remember the outcome , or indeed the data right at this moment , but many years ago Sir Baxter of Brickwerks did a survey of speedo heads and the little number , of which yours says 805 which I think is the common one , but like I say I can’t remember the details, too many years ago 
however I think mine might be 805 and it’s reading 245,000 or so miles . 

[Chromey]

Most older speedos tend to err on the high side by as much as 10%.    AFAIK, you cannot do anything to the speedo itself other than adjust the position of the needle itself but you will probably find that  changing the speedo will solve your problems with the mileometer and indicated speed error.

Thanks Angelo. My speedo definitely runs quick, by about 10mph. From what others are saying, my mileometer problem cannot be fixed however, as I have just run out of numbers! As the clock only goes up to 99,999, so I am on at least the second time around (probably 3rd time round - which would mean about 5-6k miles per year since 1983)...

[Chromey]

I can’t remember the outcome , or indeed the data right at this moment , but many years ago Sir Baxter of Brickwerks did a survey of speedo heads and the little number , of which yours says 805 which I think is the common one , but like I say I can’t remember the details, too many years ago 
however I think mine might be 805 and it’s reading 245,000 or so miles . 

Thanks for your reply Mocki. When you say 'reading 245,000 miles', do you mean 45,000 on the 3rd time round? My 805 speedo only seems to goes up to 99,999 miles (with the final number being tenths of a mile), so mine has either done 107,000 or 207,000...hopefully not 307,000!).

[Chromey]

Hello,

Thats right 99 999 miles or km,

On all older VWs since.........oooh whenever..

Cordialement,

Thanks very much Sarran. Do you have any idea how DVLA treat this, as nowadays they list mileage on MOTs, but there is no accurate reading on my van. I guess you just have to live with not knowing?

[Oldiebut goodie]

DVLA don't care - it is not a legal requirement just a guide for future purchasers of a vehicle.( It is an offence to doctor the reading of one though)  AFAIK an odometer isn't a requirement under Construction and Use and Type Approval regs. either, only a speedometer.
( Sarran doesn't have DVLA in France, they have their own nightmares over there)