2009 Nissan Frontier overheat condition at idle

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Feb 27, 2006
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Hi all,
My brother's Frontier starts to head into the red on the temp gauge when at idle. As RPM's go up, the temp gauge goes back down.
I'm completely unfamiliar with these vehicles, but I know he's replaced the radiator and coolant within a year and has generally maintained it very well since new. More than 100k on it. He says no air bubbles in the system and coolant is full.

Could a partially stuck-open thermostat cause this?
Is there a temp sending unit that is known to fail on these engines?

Any advice is appreciated.
 
These things had an issue with the transmission cooler leaking coolant into the trans fluid. Make sure that this is not happening. I had a 2007 Fronty and loved it but remember this as a sore point.
 
Just because you don't see air bubbles in the reservoir/filler neck doesn't mean there isn't air somewhere.

Does this vehicle have a fan clutch? Is it spinning at idle when the engine is overheating?

I think these also have a second electric fan for the AC. Is that working properly?
 
Just because you don't see air bubbles in the reservoir/filler neck doesn't mean there isn't air somewhere.

Does this vehicle have a fan clutch? Is it spinning at idle when the engine is overheating?

I think these also have a second electric fan for the AC. Is that working properly?

It does have a fan clutch AND that second electric fan. He says they are both working ok.
I'll take the trans cooler info back to him, @Boomer
 
That sounds like water pump to me. It overheats at idle but as you increase the RPM the temp goes back down because you are
just getting more coolant flow.
The vanes could be worn. It is a 12 year old vehicle with over 100,000 miles on it. It could be time.
 
- Make sure the fans are working. I have also seen a case (in a Honda) where the fans were spinning, but that apparently wasn't fast enough, because the car was overheating at idle. Replacing the fans fixed the issue.
- Definitely check trans fluid. If it looks like a chocolate milkshake - your ATF is mixed with coolant. Very common on Frontiers, Xterras, and Pathfinders of that era. I see the radiator has been replaced within a year, but there is always a possibility that it had a factory defect and failed that soon.
- But I'd start with the fans, check electrical plugs on fans as well. If those aren't making a good contact - fan speeds are effected. Fan clutch could be slowly failing too.
- Thermostat replacement could be a good idea if it hasn't been changed in a while.
- And last, but not least, I know a guy who was hunting overheating issue for months, until finally replacing his water pump. What he found was that passages had lots of residue (blocking the coolant flow) and couple fins on the old water pump were missing... Never found them either... New water pump and manual cleaning of the water pump area fixed overheating. Until the truck got totaled years later.
 
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Sounds to me like it could be a thermostat. If you are going to guess at what it is, start cheap. Any of those parts that have been mentioned here are pretty old and could use replacement. Hopefully one of the cheap ones (Thermostat , radiator cap) fix the situation. If not then on to the more expensive stuff.
 
Fan clutch is an easy guess, an IR gun can tell you when the radiator is hot enough to kick the clutch in. I wouldn't rule out air pockets in the cooling system causing the WP to cavitate & not move coolant (or it has corroded/missing impeller vanes).
 
be aware the frontys from 05 to 10 have the tranny cooler issue + it CAN destroy your tranny if its a slush box $$$$. big write up + fix on frontier forums
 
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