Talk Morgan Forums Morgan Sports Cars Morgan Plus Four, Supersport & Plus Six (CX & CXV Generation Vehicles) Radiator fix

The revised radiator mounting, along with the lower pressure cap, and reduced coolant level has not prevented any further radiator failures

I’ve been contacted by a dealer , who having fitted a third replacement radiator on a Plus Six in year, had the third radiator last less than 80 miles….

I’ll be working on a solution soon….

I changed my leaky radiator
With replacement, new cap and 50% full fluid
I have done 2500 kms since, without problem ... for the moment ...

Not a minute too soon by the sound of it Simon. You will have a strong market for such I'm sure.

FWIW it's taken me a couple of months and a 1000 miles to completely cure minor hose leaks on my Roadster which despite nipping up hose clips when hot, kept re-appearing and in differing locations including T piece, top and bottom hose. Finally cured by extra hose clips on the lower two of bottom hose connections and ensuring coolant filled to no higher than mid mark on header tank.

Lets hope so Richard I know Hawki's new to him plus four has had 4 rads in 18 months.

I had a major leak on my radiator which was very efficiently replaced by Adam at MelvynRutter (under warranty) - this seems to have fixed the leaking.

To answer John V6’s question about the engine coolant cap being changed - attached are some photos - the original cap has a red “Stant” printed on it, the new cap has no such printed text. When the cap is replaced the header tank is drained and refilled with 500ml of coolant (and a sticker applied to the side of the tank).

No idea if these two things will permanently fix the radiator blowing again, but I hope they will!

Old cap as installed (note there is a second similar tank and cap, just visible under hood - that is the aircon coolant):


New cap:



New cap and sticker installed:

Strangely , after i had again a leak with le third radiator and the new cap , no drops on the garage floor even i have made two times 350 km .

The second tank is for the chargecooler not aircon

I'm intrigued by this discussion (although I don't have a problem with my Roadster radiator as far as I know), because I have previously owned TVRs which featured a "swirl tank" (or "swirl pot"). This article explains: https://www.merlinmotorsport.co.uk/...system-header-tanks-in-your-race-car-323
I recall there was some discussion among TVR owners as to which of the caps should be "pressure relief" type, and which simply plain. In my last TVR, an S3, also with a Ford V6 (2.9) engine, I had a swirl pot with a pressure-cap above the thermostat. The overflow just had a cap, as the level never reached more than about half. This is probably all basic stuff for somebody who knows more than me about Morgan cooling systems, and will probably be able to explain which of our cars if any have swirl pots.

I don't see it as a hydraulic lock situation Jon. The coolant vapour pressure above the level in the header tank reflects back through the incompressible coolant to pressurise the radiator. Increasing this vapour volume with lower coolant level and futher controling it's pressure with release cap was supposedly the radiator fix. I understand CX rads have still failed after this though

I wonder if it is not a quality problem of the radiators. Mine at 12,000 km.

We changed the cap and checked the level at 8000 KM. We drove around Spain with a temperature of 35°C and not a drop under the car.

Uneven manufacturing quality may be the explanation.