Slight overheating problem

I've noticed lately that my ultra gauge has reached 210 degrees a few times. It has always ran at a steady 203 at normal speeds and cooler when slower. I thought my thermostat may be stuck or something, but I had something odd happen this weekend.

I paid close attention to engine temps on a 2 hour drive to where I was camping. I had a lot of gear in the bed and two other people inside the cab with me. If I was cruising at 65mph at 2000 RPM, it would run 206-208 degrees. But when I was going up really steep hills running 3200 RPMS at 65-70mph, it would actually cool down to 194.

If I'm cruising on flat ground doing 45 it will hit 208 pretty regularly. I thought I may have a fan issue as well, but I don't know enough about them to say that for sure. I know the fan runs when I'm idling, that's a for sure thing.

Any ideas on what could be going on? And is it normal for the engine to cool down while having a larger load on the engine? I figured it would be the opposite.

 

This seems to be a common problem and was an easy fix.

My temps were in the 205-210 range right after replacing a new thermostat. Make sure (as per the FSM) the jiggle valve on the T-stat is facing down (6 o'clock position) and not facing up 12 o'clock like you would think.

As soon as I switched it to the 6 o'clock, the truck instantly ran at the desired 190 temp.

My advice: Before you do anything else, make sure you're at 6 o'clock...

 

Interesting. Ill take a look today and see what I find.

 

Did you change anything recently or do any kind of service related to the cooling system?

X2 on the jiggle valve, but if you haven't touched the thermostat recently, it's not likley the cause.

 

I have not changed anything related to the cooling system. Just oil changes and I did the suspension but nothing related to cooling.

 

Have you checked the coolant level? Almost sounds like a bubble of air that is overcome by higher RPM's.

Weird though, if you don't have a leak, unless your engine is consuming coolant, which would be REALLY bad.

I'm not ruling out the jiggle valve; just seems unlikely if you haven't messed with the thermostat. However, both this and checking the coolant level are inexpensive.

 

Coolant levels are good. I added a tiny bit over the winter but it was barely anything. It's been at the same level since. I just checked it a couple minutes ago. I also drove around some after work and noticed it ran around 199 a lot of the time, which is cooler than it has been. But I did see it spike to 207 briefly while I was cruising at 1800 rpms at 55mph. Then I revved up and went to 70 at 3500 rpms and it went down to 194. You think a coolant flush would be a good idea?

 

Could be a slightly sticky thermostat.

I guess depending on your mileage since your last flush, it might not be a bad idea to flush it and replace the thermostat (with proper jiggle valve orientation of course!).

I would do the cheapest/easiest things first and proceed from there if those don't work.

 

I couldn't even find the thermostat haha. I know where the general location is but I couldn't spot it. Only looked for like 2 minutes though. Mosquitos are something fierce this year.

 

Maybe those skeeters are clogging up your radiator. j/k

 

Haha I wouldn't be surprised. I probably should rinse my radiator fins anyway. I've never done that.

 

I just checked the weather and it's 78°F up there? Is that unusual?

 

Hell yeah it's not normal. It's been 75-85 for almost 3 weeks straight where I am. Currently it's 89 on my deck in the sun. I've lived here my entire life and have never seen weather like this. I can't stand it haha. I'm all for 60-65 or overcast.

 

I was getting ready to post 'it can't be hot there so I doubt it's dirty fins on your radiator' but thought I better check the weather first to make sure.

I checked two websites to make sure I wasn't seeing things with temps in the high 70's.

You guys must be dying up there, especially with the sun out until almost Midnight.