When reading my hawkeye auto temp I see the reading go up as it warms. When the temp goes past something like +142 degrees it suddenly drops to someothing like -40. Hence I don't trust the value. I'm not convinced it's really that high. Comparing this haweye value (read via the computers via the temp sensor in the auto) is always going to give a different value to measuring it manually. The auto's temp sensor is located on the engine side of the auto. So comparing it's temp to what we manually measure via the filler hole will be different too. It's down to the speed things heat up. Main delaers may use it... Should we? I think so. People often tell me they can see the temp with their phone and a plug in obdii adapter on bluetooth. Not really much use if the temp sensor is faulty or reporting incorrect due to the hawkeye or computers "voltage to temp" algorithum being wrong. Measuring it manually ourselve eliviates this.
You can't beat the system. Follow what mains dealers do. This is what they did to my auto and many others that go to them for diagnostic. They measure the sensor/solenoid resistance to see if they're out of range. If they are then that points to a potentual problem. Changing the auto oil without doing this is a waste of time, if the auto has a problem. Oil won't fix a solenoid or sensors measuing open circuit. If the readings are within spec then go to the next stage of changing the auto oil.
If you go down the route of changing the auto oil... then look at the big thread I put the link to somewhere above. The reason why I tell peeps to use this thread rather than the others that have popped up over time, is because it takes the reader through the stages we went through to work things out, complete the level checks ourself, and confirm what we did has worked for us. The vast majority of instruction on there is from rave, LR main dealer and haynes. As we discussed before some of the web content tells you to do the level check incorrectly. Like checking the level with the engine off, which is wrong. When the auto oil comes out catch it in a clean bucket or simular. If it smells burnt, or it's brown (not original colour) then that points to worn clutch/bands etc. Physical wear on those items.
It's your choice what direction you go in. The main dealer version is the best. They manually check the resistance first. A manual physical test of resistance. Nothing complicated or relying on trickery. Only then will they check the level.
