65 degrees Blue Skies in South Louisiana today. Put the top down and go for a ride. Cruise Control set at 74 on Interstate. CEL and Restricted Performance come on at the same time. Looked at Temperature Gauge and it's in the Red. Pulled over. Opened the Hood. No Steam no signs of Fluid leaks. Engine actually seems to be running cooler than normal. Get back in the car and start. Everything normal. Go about another 20 miles and it happens again. Stop and check. Everything seems normal. This happens once more before I can get home. Normal again. Check for Code when I get home. P0116. Any suggestions on where I should start or change.
Thanks for any help.

 

I would guess a sticking thermostat???
Probably opens and closes normally most of the time but every once in a while it sticks closed, then SNAPS open.

Just a guess.

bob

 

 

Have you installed RealGauge?
If not I urge you to do so.

 

Since the Car did not overheat. I don't think it was the thermostat. Coolant level is good. Seems it may have been ECT Sensor failure. Is there a way to test Sensor or do you just change it?

 

Many time thermostats are sticky or intermittent. It is still by far the most likely suspect to start with. ECT sensors do not fail all that often.

With a $10 Bluetooth code reader (search 'ELM327' on eBay) and an Android phone or device running the Torque app you can read the temperature the ECT sees.

Do not drive the car until this is resolved. Overheating can seriously damage this aluminum alloy engine in a flash.

Consider RealGauge once the problem is resolved so you can keep better tabs on the cooling system, and have an audible alarm for overheating and low oil pressure in addition to a true analog temperature readout.

 

Torque Pro "may not" read the coolant temp. It's just a bug in the program that manifests itself only on some cars. DashCommand is an alternate Android app that seems to work for cars when Torque Pro won't

 

my car is just giving me a headache
new thermostat
new water pump
new overflow reservoir
flushed system with new coolant
i have no idea where the coolant is going
checked oil and ehaust for water signs

 

You should have a coolant system pressure test run. That usually locates the source of small leaks.

 

my issue with the car is more than a small coolant leak
it seems to be pushing the coolant back into the lower tank for the overflow
when the car is off the radiator hoses are being sucked down from some vacuum
i open the reservoir and it releases the hoses

 

Try a new pressure cap, they're not expensive and have been known to cause those symptoms. You said you don't know where the coolant is going, but then reported that it ends up in the atmospheric tank.

 

Pulled the Thermostat Housing to change Thermostat. I can't figure out how to remove the old Thermostat from the Housing. 2003 XK8 Vin SAJDA42C432A34419.

 

It is tough but you push it down and twist it

 

I got the old one out but the new one doesn't match.

 

Part number AJ82697? If so it should go in as the pin bit will compress.

 

Thanks. It does compress. I didn't try pushing on it. Now to get it back together.

 

Never had so much trouble changing a Thermostat. Does anyone have a trick to get the new Thermostat in the Housing?

 

I now know the Trick. It's Hand Strength that my almost 69 year old Hands don't have enough of. Brought it to a much younger and stronger Friend and he put it together without any problem.

 

Good to hear, they are a bit of a sod.