Evening people, I was just working on my van calibrating my dash after maket not the point, just did a 5 mile round trip first half fine then when I came to drive home i had no power it was topping out about 30 to 40, but the revs were still going up but my speed stayed the same
Clutch. See if you have adjustment on the butterfly nut on the clutch cable. A good test is to pull on the handbrake and try to drive off in 1st, very light throttle. You should be able to stall the bus easily. If not the clutch is slipping.
It is still likely to be the clutch. It will slip as it gets warm or if it has oil on it. Try it when it has had time to cool down. You should have some adjustment on the butterfly nut where the clutch cable reaches the gearbox.
That sounds like it is running on 3 cylinders. And tapping away badly. has it lost oil from the clutch/engine join at all. do you have oil leaking from the join between the engine and gearbox underneath?
Could be an oily clutch from the gearbox side- slips at speed - once happened to me at 65mph going up a hill..on my T1 the general effect was to loosen the T1 specific flywheel 8 dowel bodge up and lead to the engine being replaced. At least your T4 flywheel is properly bolted on .. The oil seal on the gearbox input shaft gives up. In that case the oil coating the underside of the engine will be sticky and sulphorous smelling. The oil from the heat exchangers might be a rocker cover leak running down from above. Check gearbox and engine oil levels. The engine to me sounds as clattery as a lot of T4 engines.. is it hydraulic tappet ?
At some point, if you don't get an easy fix, I would change the oil and see what the stuff that comes out looks like? What you don't want to see is oil that looks metallic and shiny. I agree with Mike, the clatter could simply be a noisy hydraulic lifter, my mates late model 2 liter type4 sounds like a bag of spanners being shaken up, but runs really well.
I think it could be hydraulic as it's an American import but that's all I'm basing it on I'll need to dive deeper. So I'm at work today but off for the next 3 days. So oil change 1st point of call. Then I'll check gearbox oil level. Then no idea what next