Can I reject my approved used car because of a coolant leak?

I bought an approved used Mercedes-Benz C-Class (2016 model) several months ago from a Mercedes-Benz main dealer. It appears the car is losing coolant which was verified by a different Mercedes-Benz dealer. I will have to rebook the car in for further tests as they can't see any visible leaks and the pressure test they carried out came back okay. Would I be able to reject the car and ask for a refund or a replacement if the problem is not fixed?

Asked on 18 December 2017 by Tlogic

Answered by Honest John
Yes. But the problem is probably caused by nothing more than an airlock in the engine cooling / cabin heating system caused by the car sitting doing nothing while it was waiting for sale, then being used with the heater on a lot. An airlock in a pressurised system causes coolant to blow out of the pressure cap of the expansion tank. Purging the airlock should solve the problem.
Similar questions
I have recently purchased a new Ford Fiesta (not the very latest model) with a 1.0-litre Ecoboost engine. After returning from a drive around town today, I lifted the bonnet and noticed that the water...
I own a 2011 Volkswagen Golf Mk6 1.6 TDI, bought in in December 2015 from a local independent Volkswagen dealer. My mechanic noticed a water leak after I mentioned the coolant light coming on a couple...
My 2012 Toyota RAV4 is losing a small amount of coolant. The dealer checked it and topped it up but its already losing coolant again.
Related models
Much improved interior quality. More refined and better to drive than predecessor. Facelift diesels get new 2.0-litre 4-cylinder engines.

Ask Honest John

Value my car