[grumpysnapper]

Its a very long, and maybe boring, story…

For a couple of years now I had been getting some idling issues and a slight degree of breaking down at very high and sustained revs.

My engine guy was a bit mystified… the Motec was showing nothing, and everything else was seemingly ok.

On the days when I was using it hard on a dirt circuit it would also go into limp mode towards the end of a long day.

Very high intake temps.

I live in a fairly warm to hot part of the world, so discussing it with the mechanic we both were comfortable that it was most probably the simple explanation of a small motor at sustained high revs, producing a lot of power, going sideways (so not a clean airflow) with the legacy of a massive amount of heat sink from hours of “play” (by the end of the day the gear stick is burning hot… almost untouchable).

Then about 6 months ago there was a horrendous noise from under the front of the car…the electric pump for the supercharger had thrown a wobbly.

Replacing it, I found the entire intercooling system was dry…bone dry! Super weird, absolutely no leaks I could find anywhere…pump, hoses, radiator… nothing.

Confused..I was totally sure I had checked its level in the last few years…and it was fine. In the time before the built engine it was almost pointless checking…there was never any loss.
But maybe I hadn’t filled it after the rebuild? Maybe the mechanic drained it at some point and didnt refill? Had I just not noticed a leak?

So refilled it with a different coloured coolant so I could easily spot any specific leaks from that system over the normal cooling system.

Sure enough after a week or two the level had dropped a little.
But still no visible leaks.
Top up, then same again.

Top up, ring Harrop… “that sounds strange, should be zero coolant consumption…should last years… have you checked every inch of pipe, the back of the front cooler…all the hard to reach/see things?”. Yep I think so, but I’ll triple check under and behind things. Nothing.

Next rally day comes, I pre mix and load up 5 litres (!) of supercharger coolant for the day…just in case.

A small amount missing when I arrive at the track. Top up.

After a couple of hours….lots missing , maybe 750ml.

Top up. Before lunch another whole litre gone.

Afternoon run…check…empty. Dry.

So of course you know how it ends.

Take supercharger off, a pile of bright green dried up gunk in all intakes and spread on the back of the throttle body and inside the intake casing.

Ship to Harrop…tear down, failed intercooler cores. Right side the most clogged/messy. But crap all through them both.
Both replaced and a service for the whole unit while its there.
Harrop were super quick and efficient, and it wasnt as bad as I thought it would be cost wise.

The unit has been worked pretty hard for around 8 years, but they said it was highly unusual, might have been due to that specific coolant type (although the stuff I used was within spec), might have been through fatigue in this specific type of use (vibrational issues), might just have been a couple of dodgy cores.

Bolted back on, no idle issues, clean revving and more power (its funny how you don't notice a gradual decline...) …..full strength and smooth. Happy.