Aux belt flapping and making a deep rumbling noise

[Zelandeth]

I was always taught that any turbocharged engine should be treated with synthetic oil due to the high temperatures encountered in the turbocharger. These can cause the oil to break down and excessive sludging to form.

How true versus how much this was the mechanic who told me just covering his behind I'm not sure.

[lexi]

Turbocharged commercials were doing millions on their turbos before synthetic came along though. When the first FX4 Taxi with the Nissan 2.7 turbo came out, the drivers were using good mineral oil and knocking up 400k on them. Millers told me at that time that their top diesel oil FXE I think, would only protect me better in really cold start ups. For XUD, they said their Multifleet mineral was plenty good as all their mixed fleet oils were turbo suitable. The other main advantage of synthetics is the better spread of viscocity. They jump the numbers much better, from say 5 or 10 to 40. Minerals are really at their best at say 10- 30 or 15- 40.
The super modern engines need these thin or stretchy oils, so Synthetic is best for them

[CitroJim]

I've always practised very regular and frequent oil changes...

[johnny625]

Much to my relief virtually all of the vibration of the belt and the associated rumbling has gone away after fitting a clutch/damper pulley on the alternator. Off the shelf the pulley did not fit perfectly right on the alternator and the pulley was sticking out a bit in comparison to the other pulleys. Nevertheless things are easy when you have a friend with a metalworking lathe.

Five mins of machining the pulley on the lathe and we have achieved a perfect fit.


However I have another possible issue. Is a boost leak on a XUD easily audible? The turbo sounds normal to me, no smoke on boost, however the car feels down on power slightly. I have checked the D seal, its not broken but it seems a bit flat or squashed to me. No oily residue which would suggest a boost leak. Can actually the inter cooler itself leak?

Now granted the weather is very hot approaching 40 degrees C during the mid day. Does this affects XUD's greatly? I know that naturally aspirated cars are affected negatively in terms of power during very hot weather.

I just have so many questions, sorry.

[CitroJim]

Boost leaks usually are audible...

Is your intercooler a top-mount or a front-mount?

If the former they suffer badly from heat-soak in hot weather and that could account for it...

Biggest boost related problem with an XUD is perishing of the little boost sense pipe that goes from the inlet trunking to the injection pump.

[johnny625]

The intercooler is top mount one. I guess it could be just heat soak then. Nevertheless, I do think about installing a boost gauge anyway. Just to check the boost.

[CitroJim]

Good idea on the boost gauge!

I had a Pug 405 TD with a top-mount intercooler and that suffered terribly from heat-soak in warm weather and slow-moving traffic...