When you replaced the thermostat, did you test the new one before you installed it? I always put the new one in a pot of hot water on the stove and veryify that it opens at the correct temperature and that at the max temp it opens the correct amount. I’ve had to return more than one thermostat to the auto parts place becuase the one they sold me didn’t meet the shop manual spec. On my Corolla, the spec says at 95 deg C (about 200 deg F) it is supposed to be fully open, and it should have opened at least 8 mm from the shut position.
I did test the new stat before installing.
The dealer just called me. They said they drive the truck and trailer 6 miles and could not get it to run hotter than 197. They said the timing is correct but that there is nothing else they can do without seeing it run hot themselves. They did say that the orange coolant I have in it needs to be flushed out, especially since I also have some green coolant in there too. I did not know they two colors were different and should not be mixed.
So, I OK’d a coolant flush at $120 and I’m going to pick up the truck and trailer tomorrow, fully expecting it to run hot on the way home.
“expecting it to run hot on the way home.”
Don’t take the truck home, they need you to drive it untill it gets hot so they can diagnose the problem. Some mechanics are too lazy to drive a vehicle more than six miles so I guess it is up to you.
BTW I’ve seen vehicles come in with two types of coolant in the cooling system, it looked like a lava lamp. Not good for efficient heat transfer. Your coolants may have been compatible though.
Here’s something to consider:
I recently worked on a van that was running too hot.
The coolant was old and neglected (but it was the correct type)
After doing a drain and refill (radiator and both banks of the block) with fresh coolant, it wasn’t running hot.
" I’ve had to return more than one thermostat to the auto parts place becuase the one they sold me didn’t meet the shop manual spec".
This is why I only use OEM thermostats (and most other parts) on Japanese cars.
Thermostats from Honda look better made than those from the parts store.
I picked up the truck from the dealer this morning. I got 5 miles down the highway and I saw the needle start climbing. I turned around and went back and a tech got in the truck with me. We drove the same route at the same speed and the truck never got hotter than 206 and the needle stayed at normal.
I dropped the tech off back at the dealership and started driving home. I got about 15 miles away and see this:
The tech told me that if I were to take the trick back to the dealer they would not know what else to do except replace the parts I’ve already replaced. I’m so tired of chasing this issue
Is that as hot as it gets? This may be why the tech doesn’t want to get involved, the gauge may never stay in the center when towing.
A new radiator may help, clogged tubes is a common cause of running hot. I’ve replaced radiators on cars less than 5 years old for running hot. I have also replaced new aftermarket radiators with OEM because they didn’t perform well. I don’t have faith in “boiling out” an old radiator. They used to remove the tanks and rod out radiators but with plastic tanks it may not hold up, it’s trash.
I’m not familiar with this Nissan but I have worked on many Dodge trucks/SUV’s that the fan clutch didn’t engage untill 220 degrees, they were designed that way and the temp gauge stayed in the normal range.
The fan seems to spin the same speed 100% of the time. If it changed speeds, I can’t hear it.
This radiator is about 3 years old. I guess replacing it is my next step after compression checking the cylinders and vacuum test.
The needle goes WAY higher than that in the summer. It was 68 degrees today. If it was 90 degrees the needle would have been pegged. It’s only going to start running hotter and hotter until I can’t drive it again until Fall.
@nissan11 I still think you should connect that supplemental electric fan and rig it so that you can engage it when needed.
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A fan in front of the radiator? Won’t that block air flow on the highway?
MANY vehicles have the condenser fan (for the AC) mounted in front of the condenser
In fact, many vehicles have 2 electric fans
Technically, that supplemental fan would be in front of the condenser (which is, by its very nature, in front of the radiator)
I would look into a 2 or3 row radiator. If your truck only overheats under load in hot weather that shows a system that just doesn’t have enough cooling capacity.
If I put a fan I front of the condenser would it need a shroud? The shroud is what I picture blocking most of the air when the truck is moving.
@nissan11, fan shrouds improve the efficiency of the fan, not block airflow. The fan shrouds on the engine side are shaped to draw as much air across the full width of the radiator as possible. The ones mounted on the front are more open, having just a shroud ring around the blades.
Will a fan in front of the condenser push more air through my radiator at 65 mph than if there was no fan? I just can’t see how a fan there is going to make my truck run any cooler on the highway.
A fan is not going to help at highway speeds. They are there for cooling at low speed and when you are stopped. I would get the truck leak down tested. Have the heads been off? Maybe a gasket blocking the cooling jacket ports.
The head has never been off. Changing valve cover gaskets is the only thing close that has been don’t to the top of the motor.
This is kinda of silly, but has the system been bled to make sure no air is trapped?
Many times, by myself and a dealer.