Bongo Fury

Can anyone help Monica? She's based in Gloucestershire. Have told her to keep an eye on responses.

I have an S reg V6 Bongo with multiple problems which could all be interlinked.
A few weeks ago I noticed that the Bongo doesn`t go up hill as effortlessly as before.
It had a service and a new exhaust. The compression test showed 11 bars on all cylinders. He said the oil was extremely clean and there are no signs off a cylinder head problem.
On the way back to my place the mechanic noticed that the fans don`t kick in. We replaced the temperature sensor which did not solve the problem. He checked whether they are working in general which they do.
He bypassed them and they are running permanently at the moment until the switch has arrived so that I can switch the fans on manually.
The car sounds different to before and is getting louder when going uphill. It also has excessive fuel consumption.
On two occasions when I started it up it fired up and then sounded as if it wanted to stall.
I just started it up again and it was absolutely fine.
Have you got any ideas what the problems could be?
Any advise would be greatly appreciated.

the v6 does run very cool, especially in these balmy temps were in at the moment, a quick test of the fans is to put the aircon on if it works.
you need to establish if its running on all cylinders all of the time, excessive fuel or unburnt fuel may damage the cat.
i would check the lecky side of things, dizzy /cap/leads and make sure its running on all cylinders first.

Did the problems start before or after the service?

I wouldn't expect the fans to start up on a normal run, why does the machanic think they should, and are we talking radiator fans or scavenger fans?

These points may help with diagnosis.