Coolant loss

[cmd000]

I have a 2010 ka 1.3diesel. Seems to have a coolant loss. 

Put a pressure test on the car and left it for a hour. Pressure not dropping, however noticed a very light drip on the ground from the rear of the engine.

Any ideas as I can't see anything on YouTube.

Not over heating and no water in the oil when dipped.

Any suggestions/ help would be very much appreciated. 

[unofix]

Faulty expansion tank cap and/or faulty expansion tank. Both common problems.

[cmd000]

1 minute ago, unofix said:

Faulty expansion tank cap and/or faulty expansion tank. Both common problems.

Replaced cap and bottle.  No signs of water loss from this area.

Seems to be coming from the back area of the engine. 

Would this be connected to the heating system?

Any further suggestions welcome.

 

[unofix]

I would do a hydrocarbon test of the coolant so that you can 100% rule out any exhaust gasses getting in to the coolant system.

For example: https://www.amazon.co.uk/RELD-Cylinder-Combusion-Universal-Motorcycles/dp/B07RS3N98V/ref=sr_1_2?crid=1X6H61L8A4CSJ&dib=eyJ2IjoiMSJ9.Wo3Iym37RzKQQB2QvocmeM1_V5gyEQco5vqLPTSe6ttecu2jlN19kRg8hOswnBfzDcKhKFFLZpwr69q53rAkroOOoSLchhkQ6qQENkBUjGnFnWIyyh2YvZ2R2AShWZ9vmjiJr778La-7BppM4pGxW2b4G3pfJqDYHKteMRHdySw7KK8eY6LMg9bLloGfTf6BKjn53rXMbM3zBRlrh9-wu-Cq2qZZgqxrEwLNmqlZ1mafC1ZRWZfv5xMczCC6pNCIC5_hvZl5ad6k4FqMfNIbwAr1raF94nixhCuCVUYulMI.O3jvAvLkv-T8V31JiQBQ4iPKKFQXSwuIMqS_JQ1LO8w&dib_tag=se&keywords=engine+hydrocarbon+test+kit&qid=1714426578&sprefix=engine+hydrocarbon+test+kit%2Caps%2C133&sr=8-2

[cmd000]

Thanks a million.

I will give this a go first and if it stays blue then it's something else.

As long as I can identify the issue I cab get it fixed.

Appreciate your help