Talk Morgan Forums Morgan Sports Cars Morgan Plus Four, Supersport & Plus Six (CX & CXV Generation Vehicles) Plus Six radiator failure - again

The 3rd radiator will soon be going into our Plus Six, the last one lasted just over 6 months. We are getting the latest variation and a ECU flash.. The replacement is good news, the not so good news is that the previous replacement lasted so few miles and time. The car is driven more in touring mode than wide open throttle sports and I always let the engine warm up before a drive and wind down after a drive, aware of the engines warm up period and the fact that it is a turbo engine. We have had a huge list of many failures over the ownership period, all addressed by the dealer and factory, but the car is pushing us toward selling it.. It is firmly in the " last chance saloon "..

the ECU flash was done last week on my plus four . It is related to the radiator failure . It is about the opening and the closure of a thermostat avoiding an thermal failure of the radiator.

Guessing they both have ECU controlled thermostat's.

Looking at B58 equipped BMW owners comments, most seem to report that the engine sits at 108°C when fully warm with absolute max of 111°C. These figures are OBD2 read though.

Thats interesting Thierry, thank you. The old fashioned cooling system "stand alone" mechanical thermostats were always operated by wax or alcohol to open/close over a set temperature range on their own. For the ECU to take control of coolant flow in the system there must be at least one electronic controlled thermostat on the engine. I had better investigate this a bit more..

Hi Richard, I am thinking you are correct. The ECU must manage the temperature and thus cooling flow around the engine.. It must be very precise, as the variation given between fully warm and Max temp is very little.

I think the advantage of ECU coolant temp control is that increased power demands particularly with a turbo engine allow anticipation of increased coolant temperature rather than the "closing the gate after horse has bolted" action of a conventional thermostat. It also removes dependacy on the calibration of same.

Clearly the disadvantage, in this case, is when it doesn't work you need a new radiator (or three).

Is it simply a matter of incorrect settings or is there an actual failure of the system ?

Hence MMC ECU flash. That's not to say they may be grabbing at straws at this stage hope I'm wrong though!

I hope so too Richard but I know people who have had 10 radiators. The swirl pot was clearly an attempt to limit thermal shock so hopefully this will help.
I believe BMW warned MMC about the cooling design, but this might be a rumour.

Adding complexity just adds more things to go wrong.

That shouldn't be the case but that's MMC for you.

I wonder if Toyota are having rad failures in the Supra. Somehow I doubt it.