My Dilemma!

Purchased a Jimny on a 55 plate just under a year ago for a tad under 4k. All went well until a few months ago when a check engine light appeared. Diagnosed as a Catalytic Convertor problem and a new exhaust system was fitted as well as a new coil pack. Moving forwards 3 months engine overheats and water is squirting out of the radiator just below the pressure cap on the engine facing side of the radiator. 
I was 100 miles from home a had to call rescue services. The mechanic who came out pointed out that the radiator wasn't that old. This I already knew as I was told when I bought the Jimny that the radiator had been replaced in the past.

Got towed home and I fitted a new radiator. I was told to fill the new radiator with water and add some Steel Seal as a precaution just in case the head gasket might have blown.
My dilemma is that I now want to sell the Jimny and I was offered a fair price to PX my Jimny against another. I wanted to be honest with the dealer and I told him about the radiator etc. He then told me that because of this it's only good for spares to him and slashed his valuation in half.

Ever since I changed the radiator the Jimny has been as good as gold. I have used a Block Tester which told me that no exhaust gasses are present in the coolant. Oil is fine. 
As I have said I want to sell the Jimny. Thinking of taking it to an Auction site and keeping quiet about the radiator issues but I would hate to sell it and someone else gets a lemon.

I have spent a lot of money and time on the JImny. It's bodywork is free of rust and has been treated with lanolin in all the usual places that can rust.
Sell and keep quiet on the assumption that all is well as it seems to be or be upfront about the past issues and let a Jimny go cheap to salve my conscience .

It sounds like you might have a small head gasket problem, if water was leaking in to the cylinder it might caused early failure of the catalytic converter (excessive heat and water vapour in the exhaust), then the radiator failing and overheating are all signs.

If the rest of the car is good then it’s definitely worth replacing the head gasket, I don’t know how much it costs on a Jimny, but around £500 is a typical figure at your local garage.

As to tell anyone, I agree with James, if it was a private sail then yes, if it was going to a dealer then maybe not, especially if it is running well at the moment. Think of it this way, it might have had the problem when you bought it, that would explain the new radiator.

Robin

I also think it was hurt when I purchased it. I also think the dealer who sold it to me was unaware of it's issues. I checked the Jimny over before buying it and as already said apart from having a new radiator everything else was fine.
I have decided to purchase another Jimny from a reputable dealer (not saying the other dealer was iffy). The reason why I don't want to throw any more money at it is it has done 133,300 miles and if I get the head gasket replaced who knows what else will fail further down the line.

The one I am picking up soon has only done 58,000 miles and has a good mot history. I think I will try WBAC or stick on on sale spares or repair.
I might keep it for a month and swap some parts from the poorly Jimny to my new one. The alloy wheels and the new radiator being likely candidates. The exhaust system on the old Jimny is less than 6 months old but I think I might leave that on as I was told it was a nightmare to fit by the garage that fitted it.

£1500 to do mine recently but they did more harm than good with the rest of the car!