A/C Off Due to High Engine Temp

[Markf19]

Thanks for the feed back fellas. I've been busy so haven't had a chance to respond.
The issue occurred again yesterday and this time the engine light came on as well after about 15min from cold start.
Pulled over shutout down called the RAA. The engine light warning was for low engine temp although the warning was the same as always "AC Off Due to High Engine Temp'. I assume because the temp gauge is dies it triggered this fault, albeit this was the first time the engine light has come on.
And this leads me to believe it must be a electrical fault as Sir Les mentions. What else could make the temp gauge completely die then come back to life?
The RAA tech connected his scanner scanner, cleared the warnings and ran the engine for a good 20min to monitor the temp. He couldn't get it past 103C and couldn't get the fans to kick in because they only kick in at 108C and 113C. So the car isn't actually running hot, it just thinks it is, and it also thinks its cold. WTF?
I drove the car around yesterday after this without issue. I've been driving it this morning as well without issue.
I'm dropping the car back to original the original mechanic later today and leaving it with him until it's friggin fixed so we'll see. I'll keep you posted.

 

[stooge]

Thanks for the feed back fellas. I've been busy so haven't had a chance to respond.
The issue occurred again yesterday and this time the engine light came on as well after about 15min from cold start.
Pulled over shutout down called the RAA. The engine light warning was for low engine temp although the warning was the same as always "AC Off Due to High Engine Temp'. I assume because the temp gauge is dies it triggered this fault, albeit this was the first time the engine light has come on.
And this leads me to believe it must be a electrical fault as Sir Les mentions. What else could make the temp gauge completely die then come back to life?
The RAA tech connected his scanner scanner, cleared the warnings and ran the engine for a good 20min to monitor the temp. He couldn't get it past 103C and couldn't get the fans to kick in because they only kick in at 108C and 113C. So the car isn't actually running hot, it just thinks it is, and it also thinks its cold. WTF?
I drove the car around yesterday after this without issue. I've been driving it this morning as well without issue.
I'm dropping the car back to original the original mechanic later today and leaving it with him until it's friggin fixed so we'll see. I'll keep you posted.

it sounds like it might be an issue with the wiring or plug to the sensor because you have changed the sensor and the problem is still persisting.
it could be that the sensor they put in was dodgy, unlikely but it does happen with replacement parts.

the issue could be the plug/wiring at the sensor or further down the loom and main connecting points but i would start at the sensor, the best time to try and diagnose it is when it is screwing around, getting in there are moving the loom around to see if it changes anything.

if this issue started after the mechanic did the work then he needs to fix it at his cost, he created the issue or probably damaged the loom changing the thermostat.

i highly doubt it is air in the system because it is designed to self bleed, you may get a high reading a short time after a coolant change but not like what is happening with you.

 

[UteDobbo89]

Commiserations Mark -- sounds like you've had a very frustrating time lately. I'd be interested to know how many kms your car has done, and where exactly the original coolant leaks were coming from to warrant the thermostat and water pump being replaced.

From your description of the symptoms it seems to me -- and remember, I'm no mechanic -- the problem is more electrical/electronic than mechanical. After all, the coolant doesn't actually get too hot, does it? Yet you get a warning message and the temperature gauge goes dead, which in itself suggests an electrical problem. Maybe some cable harness/connections were disturbed and/or not properly restored when the transmission was replaced? Electrical connectors can get very touchy as the plastic around them ages with time and heat.

In your place I'd take the car to an auto electrician to check what fault codes are present, and to try to trace the cause of the intermittent dead temperature gauge, as I think that could hold the key to your problem. Unfortunately to us laypersons, the mysteries of the BCM (body control module) and PCM (power control module) are unfathomable, and yet those two black boxes control almost every feature on your vehicle. Good luck!

Hi Sir Les
I am here because my August 16 VFII Ute Ls3 with 38500k has for the first time today, given me this message 5km into a Newcastle to Dubbo trip. My wife was not happy on a 30+ degree day!! To me, the annoying thing was it was so “out of the blue’ and killed the temp gauge. Last service September, and I have always had preventative maintenance performed on everything but the AC, which I never use unless the wife is in the car, so I assumed it was the AC as the the engine was fine got to Dubbo no problem. Thank you to you and all the other commenters for giving me an idea where to start looking to resolve this issue

 

[Sir Les]

You're welcome -- that's why we're here -- and I hope you sort it out. Don't forget to let us know if you do, and what the cause was. As an aside, I must say that only using the AC infrequently can give rise to problems in itself. The handbook recommends leaving the AC on 'auto', and the system will determine what HVAC settings are required, including when the compressor should switch on and off. An added benefit is that by running the AC more frequently, the seals in the system are kept moist and don't dry out, which can lead to gas loss.
My own experience is that auto mode copes very well with all atmospheric conditions (hot, cold, rain, fog, etc.). All I have to do is adjust the temperature occasionally to suit how I'm feeling on the day. However, this is for a sedan; I'm not sure if the same applies to a ute (although I don't see why it shouldn't).