Early DG - Combustion Leak and UV coolant loss testing kits

[airheadboxer]

Hi, I have two questions relating to tracking down water loss:

Firstly has anyone tried the combustion leak testing kits that detect combustion gas in the coolant water?

(for example this sort of kit: https://www.ebay.co.uk/itm/BT-1-50ml-CO ... SwTuhdZwKy" onclick="window.open(this.href);return false;)

If so, how successful was it for you? I know from a couple of threads there were references to them, but I haven't come across any first-hand followup comments about the result or effectiveness.

I've just used a combustion leak kit and tested twice to confirm the results and it shows no combustion gas present in the coolant (I'm not surprised as I hadn't seen any bubbles in the tank), but of course the small print says that a very low level of leak may not be detected.

Secondly - on the basis of the combustion leak test being "OK" - I'm now looking at using a UV test kit where you put a chemical in the coolant, run the engine and then use a UV light to look for the leak (e.g. https://www.ebay.co.uk/itm/Ring-RLD2-Ca ... Sw~flb~VHe" onclick="window.open(this.href);return false;)

Does anyone have any experience of this method please?

Thanks, and Happy New Year.

[kevtherev]

Our coolant has a very distinctive smell (when hot) and taste.
I had a leak, couldn't find it.
So I hired some ramp time at my local garage.
Let the engine warm up and left it running

The system runs at 1 bar, when fully warmed up.
It didn't take long to find a couple or three weeps at various joints.
It was evaporating as soon as it appeared.
The smell was clear.
No wonder I couldn't see it.
One was the radiator hose and the other was at the thermostat.

[airheadboxer]

Thanks for your comments kevtherev.

Since I seem to have had the OK to no obvious CO2 in the coolant water from my earlier testing, and from kevhtherev’s comments, I’ve had a more critical look at my hoses. I can’t smell it, and I don’t intend to taste it (see kevtherev’s comments ) but I’ve found at least one fairly certain witness stain from a hose on the thermostat complete with just a hint of antifreeze colouring.

My defence for not spotting this earlier is that I was brought up on the sight and smell of blue antifreeze, and I could detect that a mile off. This pink OAT stuff doesn’t seem to be so obvious (to me anyway).

My experience of using the CO2 coolant test is that:
- the “37mm - narrow end, 41mm - wide end” bung on my kit fitted perfectly in my header tank.
- remember that you are testing with the cap off the header tank. This means the coolant, as it warms up to thermostat opening temperature, will expand a lot more than maybe you’d expect. To offset this you’ll need to monitor the coolant level in the header tank and lower it before inserting the tester. If you don’t, the coolant will enter the test tube and mix with the test fluid and invalidate the test.

I’m going to toddle off and do the necessary. If I need to use the UV leak detection stuff I’ll update this thread with my experience.