Overheating/leak

[Fez887]

So pre winter lockup, and on one of my last runs out, I had an issue with overheating resulting in water spitting out of the swirl tank. After some consultation with Steve Heath manual, I decided to change the pressure cap on the swirl tank as felt the old one just didn’t sit right. After fitting new cap and topping up fluids, I tested the car again by running it on the drive until it reached usual running temp, at which point water again began to spill onto the floor, this time from the main rubber hose running from the swirl tank to engine. (At the engine connection end). I now plan to change this hose and hopefully this will solve the issue.

Question is, Am I chasing a deeper problem here, or is this likely that I am just unlucky with both these issues happening simultaneously?

[magpies]

what is the state of the hose? Is it bulging / cracked or have other defect? Then could be just age, so then need to carefully check the other hoses - could do a winter draindown and renew all the hoses for next driving season.

If the hose is in very good condition then you may have another problem.

[Fez887]

There is no obvious issue with hose. The leak is at engine connection end and around clamp? - what might be other possible issues?

[Fez887]

......just to add I do think they are the original hoses...

[v8s4me]

What happens if you put the old cap back on?

[magpies]

Fez887 said:

......just to add I do think they are the original hoses...

30 year old hoses may have a problem

Best to change them, usual issue is what colour to have them

[Fez887]

Old cap mustn’t have sat right as tank would spit water from between top of tank and cap. With the new cap on the problem moved to hose. However, the hose issue may have been there previously but I was focused on water from tank.

Guessing it’s a process of elimination? Can there be a situation where there is an excessive pressure build up that forces water out of a weak point?

[S2Andy]

Radiator hasn't frozen in the sudden cold spell allowing the system to over pressurize and cause leaks?

[Colin RedGriff]

If the old cap wasn't sealing properly then the system wouldn't be pressurised (or running at a much lower pressure).

Putting on a proper sealing cap would make the system pressurise correctly which may expose other weak points. If you think the hoses are original you would probably be best off replacing all of them at the same time or you may well be continually chasing weak points.

[v8s4me]

Replace the hoses and clips as suggested above. Think twice about fancy silicone hoses though, I'm forever checking the joints on mine because they just don't seal as well as old school rubber ones. I think they are just too slippery. If you polish the rubber ones before fitting they will look just as good as silicone

[lancepar]

Assuming your coolant swirl tank is like my early Griff' without an overflow tank, If I overfill the swirl then when up to temp' mine burps
out the exccess to find it's own level. :

After that it's fine with no further coolant loss.

HTH

[v8s4me]

lancepar said:

Assuming your coolant swirl tank is like my early Griff' without an overflow tank, If I overfill the swirl then when up to temp' mine burps ..out the exccess to find it's own level. :..After that it's fine with no further coolant loss.HTH

Your Griff tank is much larger than the 'S' one so it allows plenty of room for expansion. The best solution for the 'S' is the "double-barreled" swirl/expansion tank combo made by ShaunS3. Get one!

[Fez887]

Thanks for feedback - will change hoses and clips and hopefully will resolve issue.

Re Swirl tank - mines early S2 (89) so swirl tank and plastic expansion tank.

Full replacement hose pack is going for some price at the usually TVR parts outlets, any suggestions on places to purchase?

[v8s4me]

Fez887 said:

Full replacement hose pack is going for some price at the usually TVR parts outlets, any suggestions on places to purchase?

Take the old ones to your local independent motor factors and see what they can match for you. The top hose ('stat housing to swirl tank) might be the hardest to match. NB you can manage without the bleed screw in this hose.

[Fez887]

Ok thanks....one last check - what’s the correct fill level for the swirl tank? I have always topped up and left about an inch gap at top previously and also filled the expansion tank?

[v8s4me]

You can fill the swirl tank to the top and it will find its own level. That's as long as you have the correct cap which allows coolant to bleed back as it cools.

[GreenV8S]

v8s4me said:

You can fill the swirl tank to the top and it will find its own level.

It depends which way round you have fitted the caps. You always want some gas volume in the pressurised part of the circuit. Ideally, if all the sealing faces seal OK and nothing leaks, you would fit a blanking cap on the swirl tank so that the header tank is pressurised. This means the air in there is heated (via tidal flow from the swirsl tank) and helps bring the system up to pressure.

[Fez887]

Yeah currently pressure cap is on swirl tank, as recommended in Steve Heath manual.

[GreenV8S]

That isn't the ideal but will work as long as it is the right spec cap and sealing faces are good. In that case you'll need to leave an air volume in the swirl tank and be sure to use a pressure cap with a return valve.

[v8s4me]

I've known the plastic expansion tank burst when the pressure cap is fitted to it. The tanks are at least 30 years old by now and the plastic has probably degraded so pressurising them is best avoided. Splash the cash and get one of Shaun's "double-barreled" combos and solve all the problems in one hit.

Edited by v8s4me on Monday 11th January 22:46