03 Murano Engine Temperature Gauge indicates high Temp.

[rrhi]

Aloha from the Big Island of Hawaii.

I have a 03 Murano original owner with 66,000 miles that I brought from San Francisco when I moved here in 2012. My engine Temp gauge climbs to the 80% high mark when I drive uphill to a higher elevation where I live (Sea level to 1500 feet over 5 miles). This happens about the same time that my ears pop from the higher elevation.

Here is the history on this issue.

For 6 months prior my A/C would not come on immediately if the engine was warm and outside Temp was above 84 degrees. Last month engine overheated due to failed thermostat and thermostat assembly replaced. After radiator thermostat replacement engine Temp Gauge would climb to 80% mark at different times even if not going uphill, with or without A/C on.

I then replaced radiator cap, had cooling system pressure tested, and fans appeared to be working correctly. The Temp gauge issue continued and on a trip that involved going over cross island highway to 5000 feet engine Temp gauge climbed and I had to turn on heater to high to have it return to normal.

My mechanic recommended replacing A/C relay and cooling system relays. This was done and now A/C is functioning correctly and while driving/sitting in traffic in 91 degree temp after relays replaced engine Temp remained normal.

The relay replacement seemed to have corrected most of the issues except for the Temp gauge rising while driving to higher elevation. My thought is that perhaps this is just the gauge malfunctioning?

Thanks
Robert in Hawaii

[PapaSmurf2k3]

It actually sounds like the gauge is working correctly to me. If you're pushing the engine (always climbing a hill) for a long time, things get hotter for sure.

Was the radiator replaced with a factory replacement, or aftermarket? I wonder if beefing that up to a better radiator would help. Are there any blockages at the front of the car? Getting more air flow through the radiator will help too. Lastly, you could try adding some water wetter to see if it'll help.
http://www.redlineoil.com/Products.aspx?pcid=10
^Many places sell that, including autozone/advance I believe.
Let us know how you make out!

[rrhi]

No it's the original radiator and no blockages. I bought a infrared temperature gun and have been measuring the temperature by aiming the laser of the gun at the metal assembly at top of engine at the point just after the top radiator hose is attached.

When Murano dash gauge is in normal position (just below halfway point) temp ready 208 F. After hill climb and Murano dash gauge is at 60% temp gun reads 220 F. It was in the low 70's today so I will retest on a warmer day to see if Temp climbs higher as dash gauge does read higher when warmer.

I read that the Murano cooling system is a pressurized system so higher temps are normal. I just do not know what the temps should be. Probably need to research in service manuals.

[PapaSmurf2k3]

I don't think I'm aware of a cooling system that isn't pressurized...
220 is at the upper end of what I would call "normal". Lots of cars run cooler than that (195-205ish), but I know GM likes to run things hot (up in the 220 range).

I also wonder if your coolant was replaced with the correct mixture, or if its 100% glycol (instead of a mixture).
Typically you can run more water (like say 65% water to 35% coolant) and it will transfer heat better... and you should be able to do that seeing as how you're not worried about temperatures getting down to -40