Cooling system ‘t Kreng

A short update on the cooling system of this car. After fitting a nice new aluminium radiator she was used for our traditional Easter Monday tour. Everything turned out to be fine with the temperature gauge sitting slightly lower compared with the old (slightly leaking) radiator. And the low coolant level warning light didn’t come on. Until I was less than a mile away from the location for the start of the event.

As the temperature gauge still was at its normal level I drove on to the start. And with the car in a parking space I could inspect the damage. Sure enough there was a serious leak from the radiator side of the top coolant hose. Actually one I had expected as I have a tendency to tighten them only as much as is necessary to prevent damage to the ageing hoses. And with some heat in them the hoses get soft and could be tightened a little. Easily rectified with a small socket set I had brought with me especially for this purpose. Though the weird thing was that the coolant level hadn’t dropped much. At least not enough for the low coolant level warning light to switch on. The tour itself turned out to be rather uneventful from a cooling system point of view. And it was a nice drive!

But pretty soon after I started on my homeward journey, the low coolant level warning light switched on again. As the temperature gauge showed a rather healthy level, I decided to ignore the light and drive home. And sure enough when I arrived home there again was a leak from one of the coolant hoses. Be it a very small one. The coolant level hardly had dropped in the header tank.

And that got me thinking. So when I used the car for a local trip this weekend I kept an eye on the instruments and the coolant hoses. The hoses remained free of leaks and the low coolant level warning light didn’t switch on. Why wouldn’t it switch on now? The only conclusion I can come up with, is that with the tiny leaks there was also some pressure loss in the system. Resulting in a change of density of the coolant fluid and as such a change in the conductivity of the coolant, triggering the probe in the header tank. Seems far-fetched but I can’t see another explanation. Anyone a better explanation?