On 1 Dec 2020, at 16:49, ngtnewington Newington via groups.io <ngtnewington@...> wrote:



Another snippet on the learning curve.

Back in September I noticed a hole in the bottom of the intercooler which was blowing air. I was convinced that it was a pin hole in the aluminium casting, and became worried by it.

Just to remind everyone the intercooler cools the compressed air from the turbo with sea water prior to combustion (Boyles law).

So I filled the hole with epoxy and ran the engine as normal and achieved full boost pressure. I then flew home to the UK and have been looking into this.

It turns out that in the past in very cold countries where there may be condensation, some water would build up in the intercooler and this could freeze and damage the intercooler. So Volvo decided to drill a  very small drain hole, never mind that it was mostly filled with paint, the pressure would blow that out and any moisture and some oil residue that would collect in the intercooler.

So it turns out that I do not have a fault and that I need to drill out the epoxy. I estimate that the hole is about 1mm diameter.

Further research has led me to some diesel engine performance orientated web chat rooms. Some people put a small screw in the drain hole as they achieve better performance with extra boost pressure. Not something that I need worry about, but clearly no short term harm done by filling it with epoxy.

So if when running the engine you run your hand over the intercooler and notice air blowing out of a very small hole it is normal and nothing to worry about.

Nick

S/Y Amelia AML 54-019 Leros