Over heating results

[Chevy29]

Good afternoon,

As a new member this is my first and hopefully last post although I have found the forum most interesting reading.

Recently my 2010 NT DID overheated due to a faulty radiator cap. The dash temperature gauge rose to just before the red zone. It did not enter the red zone. As a result the check engine light is now permanently on and the engine runs on a little on switching it off. Prior to the heating issue it shutdown instantaneously. There is also an issue with the audio system button lights and AC temperature screen.

Can anyone advise what maybe causing the engine check lamp and run on issues?

The button lights etc appear to be a random occurrence as turning on the headlamps the buttons etc light up. If the headlamps are then switched off the button lights etc switch off as they should but if I then switch the headlamps on the button lights etc stay off. If I leave the vehicle for a couple of hours the buttons etc light up as they should when the headlamps are switched on. Any ideas how I can fix this issue.

Finally can anyone recommend the Icarsoft HNM11 OBD2 scanner of other scanning tool?

Thank you in anticipation.

- Darryl

[erad]

The lights behind the buttons come on when the parking lights come on. The is the first click of the switch (the second being the headlights). It could be that the switch is not turning off properly from the park position. Check that the parking lights go out and then see if the button lights are still on.

Regarding the HNM11 scanner, I have one and although it claims to read and clear codes, there have been a few codes which the unit could not clear. Overall, I have confidence in the unit and it is good values for money. It is relatively cheap insurance for you to check any codes which may come up and hopefully find the cause of the fault a nd clear it yourself rather than pay a lot of money to a mechanic to do it for you. It all depends on what you want to do with the unit. If you want to use it as a regular driving monitor (eg to monitor auto transmission temperatures etc), the HNM11 is too big and cumbersome. A Scangauge11 or Ulragauge is what you need and these units also clear come codes, particularly engine codes. The HNM11 unit handles a lot of things other than the engine codes - transfer case, transmission, ABS, SRS etc I have a Scangauge11 unit which can monitor up to 4 parameters, but the Ultragauge can monitor up to 8 parameters and has an alarm function which could be very handy.

[Chevy29]

erad,

Thank you for your response. The issue with the illumination of the audio buttons has not been resolved. The actual park lights illuminate as they should whether or not the buttons are illuminated and whether or not the ignition is on. I have found that if the ignition is on and the park lights are turned on the buttons will illuminate. if I then turn the parkers off and turn them on again the buttons do not illuminate. However if I sit and wait awhile I can hear a relay operate somewhere on the left front side (maybe behind the glove box) after which I can again turn the parkers on and the buttons illuminate.

With regards to the scanner since I experienced the coolant over temperature I have installed an Engine Guard unit which is set up to monitor the coolant and transmission temperatures. I require the scanner to read and hopefully clear codes only.

[Dicko1]

erad,

Thank you for your response. The issue with the illumination of the audio buttons has not been resolved. The actual park lights illuminate as they should whether or not the buttons are illuminated and whether or not the ignition is on. I have found that if the ignition is on and the park lights are turned on the buttons will illuminate. if I then turn the parkers off and turn them on again the buttons do not illuminate. However if I sit and wait awhile I can hear a relay operate somewhere on the left front side (maybe behind the glove box) after which I can again turn the parkers on and the buttons illuminate.

With regards to the scanner since I experienced the coolant over temperature I have installed an Engine Guard unit which is set up to monitor the coolant and transmission temperatures. I require the scanner to read and hopefully clear codes only.

Buy yourself an Ultragauge..

[erad]

Chevy29:
Further to Dicko's comment, I agree with the Ultragauge. They have much better versatility.

Sorry - I cannot comment reliably on the electrical issues with your car. I guess it is a relay sticking somewhere, but which one???

Regarding the engine watchdog, I have a watchdog and a Scangauge II. I have noted that the reading of the watchdog is normally 4 to 5 degrees colder that the Scangauge. This makes sense because the thermocouple for the watchdog is mounted in my case on the thermostat housing whereas the Scangauge is reading the actual coolant temperature. So depending n where you mount the thermocouple, you can probably expect a difference of that order.

Last week, I was towing my caravan up to Brisbane, and just North from Sydney, going up some long hills, the temperature climbed dramatically. Scangauge said 102 Deg C (it has never been that high before) and watchdog said 98 Deg C (that is what I have set the alarm to as well). OK - it was 45 Deg C ambient air temperature so whilst I was concerned, I knew that there was nothing wrong with the cooling system. Interestingly, the OEM temperature gauge showed the needle as barely moving - it didn't even go past the centre mark. As soon as I had crested the climb, temperatures dropped back to around 90 Deg C. Normal running temps are nearer 88 Deg C.

Coming home yesterday, the temperatures were of a similarly high level. Luckily I rarely drive in conditions such as those, but this is when having some accurate monitoring of engine parameters gives you a lot more confidence in what is going on under the bonnet.

[Chevy29]

erad,

I have decided to get an Ultragauge and put the Engine Guard on another vehicle on which it would be beneficial. I agree the Engine Guard reads below the actual coolant temperature but at least it does give a reading of the temp and you have the advantage of seeing the temp rise and fall as conditions change - not the almost ever stationary analogy dash gauge which rarely moves beyond the centre point of the gauge and when it does it's generally too late!

With regards to my overheating problem it came about while I was towing the caravan back from Bendigo prior to this I had not towed such a load. The next morning when the engine was cold on inspection I noticed both radiator hoses were collapsed. On removing the radiator cap there was a sucking sound and the hoses returned to their normal shape. On inspecting the radiator cap I found the rubber seal had expanded such that it was larger than the metal backing plate which has the pressure spring attached. in doing so it actually expanded over the backing plate to for a "U" shaped seal which also covered the coolant expansion outlet to the reservoir. When the coolant expanded the seal allowed the coolant into the reservoir but on cooling it did not allow any coolant to return to the radiator. The radiator took about 750ml to fill up.

I have replaced the radiator cap and intend to flush the engine and replace the coolant this week.

I have attached a couple of photos of the radiator cap to help explain the situation. I hope you find them interesting. In the close up of the cap seal you will note the impression of the radiator to reservoir outlet. The exterior of the cap looks as if it just came off the assembly line. Until I had the heating issue I had not removed the radiator cap and I have only had this vehicle since mid December.

[erad]

Chevvy29:
I think that you need to look further than just replacing the radiator cap. It could be that you have a leak somewhere - the fun part is finding the leak. If you have been towing a seriously heavy load on a hot day, it is possible that excess coolant will be pumped into the overflow bottle, and the buggered radiator cap will then prevent the excess coolant coming back into the engine. But even if that happens, the engine will heat up again until it reaches a temperature and tries to burp out the excess coolant. Theoretically, the excess coolant should stay in the overflow bottle - unless you have a head gasket leak (I always thinks of the worst possibility).

For starters, I would definitely replace the radiator cap with a good one. Then get a pressure test on the cooling system to see if it holds pressure or leaks under pressure. Then the next area to look for is the fan coupling on the radiator fan. This is the most common cause of overheating, especially under heavy loads.

For what it is worth, I have just completed a 3000 km trip to and from Brisbane in horrible heat (the first and last days were 45 and 41 Deg C respectively), whilst towing my 16 ft poptop caravan. At one stage, the coolant temperature was 102 Deg C for about 10 minutes but generally it sat on 88 to 90 Deg C most of the way. Naturally, I checked the oil and water each day before setting out, and the beast used no coolant and only 0.1 L of oil (if that much) for the whole trip. So you should expect that there should be no coolant loss at all.