Hey everyone!
So, its been bloody hot up here in the Winnipeg area. Bloody hot to me equals about 35C or 95F. As I've stated before, we do occasionally tow a 28 foot travel trailer. This week I towed it to a campground about 40 minutes from my house, so not far at all.
I have a Superchips tuner with Diagnostics that allows me to monitor inputs from selected OBD inputs, one of which is ECT or Engine Coolant Temperature.
Under normal conditions, I see the reading at 190F pretty much all the time. While towing the trailer home yesterday, I saw this value increase to 208-210F. It was hot out, I was going about 105kph (65MPH). It was a little windy. It never exceeded 210F. But I do not recall it ever having run this hot while towing before, it usually stayed under 200F. And for everyone's edification, no CEL codes and the temperature gauge on the dash never moved at all.
I did a quick check of the coolant level once it cooled off, and both the reservoir and the radiator are at the proper level.
Today, while not towing, and the outside temp being somewhere in the same range, 35-38C or 95-100F, I drove to Winnipeg. I noticed that on the highway my ECT reading was around 195F. Slow down for stopping, and it would jump to 198F and once we got into the city, I actually saw it get up to 205F at one point. Once again, no CEL, no movement on the dashboard temp gauge.
My question is, what is the normal operating temperature or ECT value for this truck? At my high mileage I begin to wonder if:
1. Thermostat sticking - I did replace with a Nissan Genuine thermostat and new coolant about 4-5 years ago. I am due for a coolant change, so maybe I will do the thermostat at the same time.
2. Water Pump impeller failure - Due to high mileage, the water pump may not be as efficient as it once was. I don't think its ever been changed. I got the vehicle with 100k kms on it, and I've never done it. Thoughts?
3. Pressure leak somewhere - I feel that if this was the case, it would be losing copious amounts of coolant, and it is not. Found a drippy hose clamp a few months ago, and every so often I add about 2 cups of coolant (once a year or so), so if its leaking, its not leaking very fast. Also the oil analysis I did last summer showed no coolant in the oil at all.
4. Cooling fan/Fan Clutch not working properly - I did replace the fan clutch about 3 years ago with a Nissan Genuine part. It seems to be working, so I don't think this is the problem. The aux fan also spins, usually with the AC system. I've never noticed it kick in due to high ECT reading, but I've heard other people talk about this. I do not recall the temperature threshold required for this to occur.
5. Hot air recirculation - I did replace the radiator a couple years ago. I recall stuffing the foam strips back around the rad that help it seal up to the shroud, but it definitely wasn't as well sealed as it was before. Maybe I should do a better job of sealing it...
Any other thoughts on this? Appreciate any input!