Another Slight issue with my S2000.

Basically there is obviously a very slight leak somewhere.

If i fully bleed the cooling system, all runs fine however there is a slight smell of coolant under the bonnet, and once stopped and left to cool down the coolant from the expansion tank does not drain back.

if i open the Rad cap after cool down, it will be noticeably low on coolant (because its in the expansion tank), and air has obviously got into the system as the heater will be stone cold. It will then take around 20 mins of bleeding to get the heater back/air out.

in the last few months its had a new radiator, water pump, thermostat so it "shouldn't" be either of these.

At the rear of the engine, there is a fair bit of white water marks, and some rusty looking pipes around the heater pipe/control.

There is no sign of water drops/wetness anywhere.

This is what the rear pipes look like:





Does anyone have any ideas, as I'm now a bit stumped!

Cheers

 

buy/rent a pressure tester kit and go to a quite place.
then pressurize the system (cold) and listen for the hiss from the leak.

 

Or fire up the car and let it idle. When the coolant gets up to temp you should be able to see where its leaking from. Novel approach I know

 

Seems like your heater is leaking. The cheap way would be to block off the heater, because don't no body want to rip up the dash just to get to that thing. I would remove the carpet on the passenger side and see if you have any water in there.

 

Thanks, well I think I've found the leak.

The top radiator hose, where it joints the engine (it splits off to the heater etc). Is just weeping the tiniest amount, when hot, you can just see a bit of steam coming from it.

The hose is held on by the standard spring clip.

What's the best way to make this seal?

And it's going to be a right bugger to get to with the intake manifold etc in the way.

Cheers

 

In my experience, more times then not this calls for a hose replacement. That would be the safe bet if you want to do it right. And yeah its not the most fun job if you have big hands and arms.

 

It's not horrible if you have a lift, or access to one, you can do it from underneath. It also helps if you can remove the tensioner, and the alternator.