advice needed on coolant issue

[free45]

Hi i went for an mot today and some coolant was leaking and the mechanic said there was bubbles coming up any idea what this means for the rx7? I imagine rebuild? The rx7 has had one mot and failed on brake pads and discs and tyres and whole in exhaust. All has been fixed putting brand new tyres all round and brand new brake pads and discs too. Any idea how much the car would be worth if i wanted to sell up. Its a 1993 twin turbo rx7. Last owner had 2 new turbos in it but lost his receipt so not deffo sure. Car starts and idles well. Drove real nice down to the test station. Any advice would be much appreciated.
Cheers