[mike1967]

would suspect with that code its thermo housing , would also check no coolant leaks as this can add air to around the temp sensor area and also flag a mismatch code for temps , would always replace the plastic link pipe from thermo housing to water pump as these crack all the time 6-8 years life span common before heat and plastic breaks down, would also change coolant while its apart, if water pump over 70k would also include that for piece of mind and its coated pulley and aux belt,

 

[mike1967]

these engines should keep coolant level same all the time should use zero coolant, common issues i have found with them is the header tank cap if it dont hold the pressure the coolant will travel in to header tank and push the air pocket in header tank in to the top of the head and the thermostat housing ie then coolant sensor is in air and not coolant and will flag such a code,, as when first start until reaches higher temps the coolant stays around sensor,, but as pressure climbs the cap leaks and air then suddenly hits sensor ,, ie thats why it happens after a while driving,
another thing that happens is the plastic kink pipe breaks inside the back of water pump the rubber seal then moves slightly and only leaks with pressure and movement vibrations from the engine so only leaks when driving up the road,,, best way to tell is drive car until fan in and out and then leave a piece of card under the car for a few hours,, when come back where ever you have a wet spot is where leak is,, if under the water pump most likely that link pipe,, but would do all 3 things at same time if replace them, thermo housing , water [ump. and link pipe,, i would also fit new header tan cap as only around £15 ish to replace,

 

[mike1967]

To ALL,

I replaced the entire thermostat and reset codes. It was a PIA because guess what, a new wiring harness was needed to plug into the thermostat. No one had it! They ship you the thermostat housing but do not ship the wiring harness conversion.

It’s been a couple weeks and no codes even after a treacherous winter storm.

Here is my KB on the subject. The thermostat sensor sits atop the thermostat. While I have not been able to find any recalls, I truly believe it was a design flaw.

The new thermostat has 2 sensors requiring an adapter for my year/make/model. I had to go to a German auto mechanic and get the correct adapter wiring harness for the new 2:1 sensor. Now that there are 2 sensors, 1 below and 1 above, it appears the thermostat is more efficient.

Best to Everyone!

the thermp housings have one sensor and one heater for piloted thermostat ie controlled when to open via ecu and not like the old type waxstats , see this a lot harness failures so common on them , new one over £450 from dealer if can get one oil leaks and coolant leak can destroy a harness if left uncleaned over time changes the resistances, the need of new jump cable harness when changing from old type thermo housing to new type with different connectors thats why its needed