Overheating for a second, then returning to normal temp quickly???

Alright guys this has happened 2x in 2 days in a row now. Driving under normal conditions nothing crazy at all. 95K miles. 2017

All of a sudden I get a overheating warning and a beep from the dash. Quickly look at the gauge and confirm it is overheating, and then before I can pull over the warning goes away. And then with-in 30 seconds the temp gauge is back at normal operating temperatures.

Truck is running fine, no leakes or smells.

 

Sounds like it could possibly be a connection issue on the sensor. I have no idea where the sensor is located.

 

Describe normal conditions. Hauling or towing? Passenger count? Stop and go traffic? Highway speeds? 90 MPH? Length of drive (miles and/or time) before this happened?

 

Could be as simple as an air bubble or the radiator cap. Check both. On the cap, make sure all the gaskets are present (see below). If/when it happens again, pull over anyway to see if it looks like the expansion tank filled with fluid briefly and then emptied back into the radiator again. I had that happen on a Tacoma once where the radiator cap was on it's way out, not reliable holding pressure.

 

Both times this happened on about a 15-17min-10mile drive. with about 10-12 min of highway speeds 70-85mph. The overheating would happen about 13-15 min in to the drive. After exiting the highway. But I have driven a few times today longer distances and nothing happened.

 

I wonder if the thermostat was stuck closed for a moment...could be the t-stat, or a piece of rubber from the cap that kept it from opening only to eventually bounce out of the way... Easy enough to check the cap after the engine cools.

 

I thought also that the thermostat could be stuck closed.

 

Could try an obd reader scangauge or ultra gauge and see if your temps are really fluctuating or a bad gauge.

 

As stupid as it sounds, how is your coolant level? Sensors pick up fluid temperatures better than air temperatures.

 

Possible causes 1)Intermittant tuck closed T-stat, 2) Bad coolant temp sensor 3) Radiator cap not holding the proper pressure, 4) You've got air in the coolant system and need to get it out, 5) Wrong mix of coolant/water that caused some localized boiling (for that matter, freezes the water), 6) Hopefully not, early signs of a head gasket failure. You can "burp" some combustion gases into the coolant system, cavitates the water pump, overheats until it purges some of the air and then all looks fine. It repeats this cycle until there is a gross head gasket failure. Smell the coolant and look at it's color. Hope that helps.

 

Sounds like coolant could be low, same thing happened on my work truck

 

Here is a development. It has happened 2 more times now. And I'm starting to think its the dash gauge cluster malfunctioning.

The radiator cap is holding pressure. And the fluid isn't low. I have a OBD2 reader installed and when it was sending the over-heating warning Torque was showing a temp reading of 204-205 degrees. I think thats with in normal operating spec?

I have a hypertech speedo calibrator installed in the dash and I wonder if that is messing with the gauge cluster. Also when I have filled up on gas the last 2 tanks the fuel gauge wouldn't go all the way to full it would stick around 3/4 full.

 

The logical thing to do would be to disconnect the Hypertech device and test drive for some days, I would suppose.

 

Agreed. Just gotta rip apart the dash. Luckly im getting good at that.

 

Ya, once you know what you're getting into it goes much quicker.

 

hypertechs have caused cluster issues before and is where I would start troubleshooting.

 

Sounds like your on the right track

 

Update. It has done it 2 more times now. I have been able to monitor the temp on the Torque app and i can see the temp climb up to 250 ish and then drop quickly. I think I'll start with the thermostat. Since this is reporting from the OBD2 port.

 

If your seeing that the vehicle is actually sending periodic temp fluctuations. I wouldn't suspect thermostat, maybe a temp sensor going bad.

 

Any idea where those are located?

 

Not exactly sure, I suspect mounted to the block near the thermostat, did a few internet searches and didn't find anything that showed where it's mounted on 3rd gens. Maybe someone else can answer that question.

 

There's one right next to the upper radiator hose where it connects to the water crossover pipe.

Edit, found a picture. I know it's a Supercharged engine, but the location is the same although the water crossover pipes are slightly different.

 

Hello @jmevis - What was the final diagnosis and outcome? I am experiencing exactly the same issue.

 

OP hasnt been on in over a year, maybe truck exploded

 

The most likely cause is a thermostat issue. Thermostat may be going bad. You can take it out and put it in boiling water if it doesn't open its bad.

You could like a previous poster said have an air bubble. If you do you can get rid of it by letting the truck get COMPLETELY COOL and removing the radiator cap. Next turn on your truck and let it run until it's at operating temp for minutes. Put your heat on full blast to make sure it doesnt overheat. Top it off if it needs it and put the cap back on. Any air bubbles should come to the top and pop so to speak.

 

I actually drive a Toyota Highlander and I am also having this issue. My issue is only happening when I use the heat in my car and then I get a “leak” but it only seems to leak after I’ve used the heat. From what I am reading, I should have the thermostat checked?

 

I am experiencing this same issue. It happened twice today on a 30 minute drive home from work. Anyone else experience it and found a tried and true solution before I start to troubleshoot the issue?

 

This just happened to me on the way to work. Anyone find a solution?

 

Once the engine is cool, check that the lower portion of your radiator cap didn’t break off. I see it happen to people a lot. It can get lodged in the cooling system and it restricts coolant flow. The radiator cap should be replaced from time to time as a maintenance item.

 

This happened to my 08 where I was losing coolant due to suction bottom piece of my radiator cap broke off. Fortunately it never got lodged or ever intermittently showed signs of overheating. I ended up buying the red TRD radiator cap.