Coolant, temperatures and RadWeld

[JonRB]

After a 2+ year absence I've got a coolant leak and associated overheating problems again.

There is a definite leak, as evidenced by a small puddle of coolant just inside and in front of the front driver's wheel. Exactly the same place as last time.

If I keep the system topped up using the top-up procedure of filling the expansion tank, then the swirl tank, then bleeding the radiator, then topping the swirl tank again then the car is driveable.
However, I have to watch the temperature gauge as it is prone to overheating and needs manual intervention from the fan override switch to stop the temperature running away from me. However, I don't think the otter switch has failed as the fans do seem to kick in on their own occasionally, but obviously not effectively enough. I'm already running a lower temperature otter switch and thermostat, before anyone says.
I need to perform the top-up before every trip, and the car can lose up to 2 litres of coolant in a trip.

There is no mayo to be seen, so I am hopeful that it is not a head gasket failure.

My wife has pointed out that until her Lotus is back on the road then it isn't fair for me to spend money on my TVR having this fault fixed. That's actually a fair point - we've got lovely sunny weather and her Lotus is off the road pending a service, tax and road-going insurance.

So in the meantime, is there anything that I can do to alleviate my problem? Could I perhaps use RadWeld as a short-term solution and have a complete coolant flush when I get it sorted out properly?

[shpub]

Don't use Radweld - it can block the waterways and cause more problems than it solves. Good for a temp repair to get you home but nothing more. Take it to a specilaist and get the system pressure tested. That will/should help identify the problem.

[UpTheIron]

Jon,

The bad news is that no mayo does not mean no HG failure.

Does the coolant loss only occur / is more noticeable after a long run, or is it consistent regardless of how hard you "push on" or the length of the journey?

I had HG failure from waterway into the exhaust - so no mayo, and only evident on a longer (25 mile plus) run.

If a pressure test shows nothing, then a hydrocarbon test is worth a go (see www.frost.co.uk for a kit.

Having said that, neither pressure test nor hydrocarbon test showed up the problem with mine, and in the end it had to be an exploratory "heads off" job. Thankfully I had mine done under warranty at Hamiltons (Failand - just down the road from you I believe, and recommended I have to say).

However, it's not all doom and gloom:

- If you have a HG leak between exhaust and waterway then you will probably have an extremely pressurised cooling system - you may be able tell this just from the pressure in the bigger rad hoses when hot / engine running.

- The increased pressure will (in my experience) break every other part of your cooling system. As a result of my failure I went through a couple of hoses, 2 radiators and 1 water pump gasket. If these are all in one piece then I would be hopefully it is not the HG.

- Finally, and the best news IMHO, you have evidence of an external leak - the puddle of coolant - I wouldn't expect to see that from a HG failure...more like a popped radiator or leaky hose.


My bottom rad. hose still leaks occasionally, but is never evident after a run, but only after I leave the car to cool down - strange, but I just keep an eye on the coolant level instead.


Anyway, I hope this ramble helps a bit - I spent a long time solving my cooling problems and your earlier posts helped with that. If I can return the favour I will do my best.

Cheers


Paul

[JonRB]

Sorry to drag an old thread back to life, but thought I'd give an update on this.

The Chimaera went in to Dave Batty today to be looked at. Turns out that the rad is pissing coolant out of the bottom corner and needs to be overhauled.

So there you go then. Could have been worse.