From too cold to too hot: 04 pathfinder issues

[nickelghandi]

So my 2004 Pathfinder LE is a few months old to me. When I bought the truck it had 114k miles on it. The temp gauge was reading low, my scan gauge reported a fwt of 130-150 after being driven for over ten minutes. I had a p0128 error code. I drained all my old coolant, pulled the thermostat and sure enough it was stuck open. I replaced it with an autozone duralast thermo myself (I did the procedure correctly). I filled my radiator, bled the system, and figured problem solved.. Well now my pathfinder consistently runs at a minimum of 204 degrees Fahrenheit and peaks around 221. This seems too hot to me especially with the recent cold temperatures outside reaching -3 in KY where I live and drive. It hasn't overheated fully and the gauge in the dash reads below halfway. Its not my scanguage because it works accurately in my 99.5 PF and anything else I plug it into.
I measured the temp of the coolant coming into the radiator with a very accurate infrared thermometer. It read around 200 when the scanguage was reading 214. 200 seems normal for the return line. I struggled to get a good reading from the new thermostat as its kind of hard to get at with the engine running but I usually got around 155-170 fwt at the thermo. This also seems normal.
I have no leaks and recently replaced my cap with one from the dealer. I had the dealer bleed the system to rule out error on my part. The only thing I haven't done is pull that new thermo off and test it.
If I can't figure it out, I'll take it to the dealer again and have them diagnose and fix whatever it is so there goes $200 at least. I thought I'd ask here first and maybe save some money and time. Anyone had this issue before? If so what fixed it?


Thanks guys. I love this forum.

[Towncivilian]

The easiest way to check the proper operation of the thermostat is to take it out, boil it in a pot of water, and measure when it is fully open (this procedure is described on LC-19). It should fully open at 170F; my Pathfinder's typical coolant temp is stable at 176 - 195F typically. Cooling system is completely original save for coolant of course, and the hose between the radiator neck and the overflow reservoir (replaced due to sweating).

[doode]

I had a 1992 - 3 liter V6 that with an autometer temp gauge hooked into the upper rad hose

It saw 180 F under normal conditions, would rise up to 240F sitting in traffic due to a faulty fan clutch.

I now have a 99- 3.3 liter, same set up and consistently see 200F under normal conditions and peaking at 210F during the summer in traffic.

I bought the 99 used, T belt, water pump and T-stat was changed over 100k ago and I have owned it for 2 years now.

I'd say its normal ??

Factory temp gauge never reads higher than 1/2

[nickelghandi]

The easiest way to check the proper operation of the thermostat is to take it out, boil it in a pot of water, and measure when it is fully open (this procedure is described on LC-19). It should fully open at 170F; my Pathfinder's typical coolant temp is stable at 176 - 195F typically. Cooling system is completely original save for coolant of course, and the hose between the radiator neck and the overflow reservoir (replaced due to sweating).

I believe the thermostat is working correctly though. And the dealer told me after they bled and tested it that this was all normal. My 99.5 runs at 175-195 like your PF so that's what I'm used to seeing. Could it be the sensor is reading the wrong voltage but the system is designed to get a proper reading while my scanguage is not?

[nickelghandi]

I had a 1992 - 3 liter V6 that with an autometer temp gauge hooked into the upper rad hose

It saw 180 F under normal conditions, would rise up to 240F sitting in traffic due to a faulty fan clutch.

I now have a 99- 3.3 liter, same set up and consistently see 200F under normal conditions and peaking at 210F during the summer in traffic.

I bought the 99 used, T belt, water pump and T-stat was changed over 100k ago and I have owned it for 2 years now.

I'd say its normal ??

Factory temp gauge never reads higher than 1/2

Okay. Maybe some just run hotter than others then. In my above post I mention my 99.5 Pathfinder never goes higher than 195 even in the summer with the A/C on full blast yet my 2004 consistently sees 205+ in the dead of winter with me running the heat. I'm going to check my thermostat when I get the time to pull it off and if itsoperating normally then I guess I'll just accept that its going to run at that temperature.