I think 48K is a little on the over kill to be fair.
The trusted indie I use recommends the 1.9jtdm to be done around the 60K mark. The 159 I had was actually done at 72K, the GT I had was done at 65k.
90K is ridiculous, and any private owner leaving it that long must have balls of steel (or something else of steel if they are female....).
I don't think 48K is overkill though. Sure there are plenty of failures after 60k, but the incidence of failure increases markedly after 48K. It all depends how 'risk averse' you are. Or rather, is it really worth the risk given what may happen if you do leave it after 48K?
The waterpump problem is also 'time dependent'. There is again a marked increase of failures after four years. On 'average' mileage, four years often coincides with 48K miles. It really does makes sense to change the timing gear at this point and do the waterpump at the same time.
Here is a summary of the stats taken from the current JTD mutlivalve waterpump failure thread from those reporting complete failure and damage:
1)Cumulatively up to 36,000 miles, there are 'only' two failures at 4.76% of total frequency.
2) Between 36,001 and 48,000 miles the cumulative failure rate increases to 23.81%.
3) Between 48,001 and 60,000 miles the cumulative failure rate jumps to 61.90%.
4) Between 60,001 and 72,000 miles the cumulative failure rate stands at 85.71%.
1) Cumulatively up to 2.9 years there is 'only' one failure at 2.44% of total frequency.
2) Between 3 years and 3.9 years the cumulative failure rate increases to 24.39%.
3) Between 4 years and 4.9 years the cumulative failure rate jumps to 60.98%.
4) Between 5 and 5.9 years the cumulative failure rate stands at 87.8%
Is it really worth the risk leaving it til 60k? I don't think so. Anything over 60k or 4/5 years? I agree with you, utter madness, Russian roulette....