Yeah, normally with an airlock the temp rise very high and then suddenly drop when the pressure builds. The other giveaway is the heater would be cold as the airlock would stop the coolant circulating.
Does sound like a faulty stat, but poor circulation from the water pump could be a reason.
Dealer replaCed stat so I dOnt have the old one
Just some lateral thinking here … could the coolant temperature sensor or wiring be at fault ,thus sending false data to the ECU and triggering the low rev limiter ?
It’s gotta be something simple …
Many many years ago I kept getting a flat battery on a Manta …kept getting auto electricians to check the charging system … and time and time again I would get a flat battery and kept telling them the charging system was at fault … time and time again they would say that it wasn’t… Stalemate !!
I had driven through a Ford a few days earlier and ingested water,the motor hydraulic locked and bent a conrod… after a while I managed to start the car , it ran with heavy vibration … but it ran !
I didn’t have time to swap the engine for a couple of weeks so continued to drive it oh so gently…
The reason for the continued battery flattening was that as I drove at no more than 1200 or so rpm , the voltage regulator didn’t energise the alternator and as such it didn’t commence charging…
The Auto Electricians of course did !
The reason for posting this is … LATERAL THINKING … sometimes we look too far into a simple problem !
Agreed - sometimes we do. It is back at the dealer again now so we’ll see what they say, but ultimatly if they replace the stat, water pump, temp sensor and fill and bleed (correctly) the coolant system then there can be nothing else can there?
Right - progress hopefully.
Had a call from Stratstones today and they have spoken to a Lotus tech at the factory and ‘they have seen this problem before’. They are sending out a modified thermostat to the dealer - no idea what is modified about it, but will ask more details when I can.
I may actually ring them tomorrow and ask them to take a photo of it before they fit it, just to post up on here to help those who may want to sort theirs out in future.
Fingers crossed eh!
Nice news 
[quote=itguy]Right - progress hopefully.
no idea what is modified about it,
Fingers crossed eh! [/quote]
This one works!
Would be nice to find out the real difference though