Overheating diagnoses?

[01pathfinder7]

01 pathfinder runs excellent uses a little oil but it's nothing serious. Sounds amazing can hardly hear it run.

Bought about three months ago past owner had a new rad installed within the last 8months.

Been driving it almost daily on hour long drives no sign of overheating at first. Would being to climb in temperature when driving up Hill but could be controlled with 3000rpm and heat on full defrost would keep it at half.

After hour long drives it lately seems to show signs of overheating at idol again can Lower by 3000rpm or driving. Haven't driven it farther than an hour worth in one push.

I have a new thermostat but have not yet had it installed. I have been trying to burp air out for a while but I think I have it all now but would take suggestions on new methods. I am picking up a no spill funnel tomorrow however.

Top rad hoses gets hot. Lower rad hose stays cold but the thermostat and engine near it is hot to the touch.

Thanks sorry for the long post.

[fueler]

Sounds like thermostat to me. I have no experience with fan clutch on 2001 VQ35 but if it is nissan mechanical style viscous fan clutch then i would replace that too

[yeldogt]

Make sure the fan is spinning at the same speed as the belt with a warm engine -- the fan clutch is designed to slip when cold ... it could be faulty. It may be allowing the fan to slip when the engine is warm. As you climb a hill the RPM's and speed can drop and the load on the engine increase -- if the fan is slipping .....not enough air is being forced through the radiator.

Sometimes -- with an older vehicle more then one part is the culprit. Make sure it has the proper coolant mix and the main thermostat is correct -- with a new radiator obviously something has been going on with the truck.

[01pathfinder7]

Looking at the thermostat installed currently today I noticed there is NO coolant by pass hose. There isn't even the attachment for the hose on the current thermostat. Nor did I see an old unused hose.

My new and unused thermostat has the connection for this hose so I'm not sure what to think but am I wrong in thinking something strange is going on

[01pathfinder7]

I read it's because it's a manual sorry