Coolant temp gauge fluctuating during heavy traffic in heat

Hi guys, I am concerned of my coolant temperature gauge.

I have 2019 tacoma trd offroad and milieage is around 77500. I replaced engine oil a week ago and have enough coolant and fan is turning properly.

It was horribly hot today(33 degree celsius) while I was driving on highway no.2 from Edmonton to Calgary.
there was traffic jam because somehow F150 was burnt. All drivers and I had to slow down around 5Km~20km per hour for 15 minutes. After passed traffic jam, I noticed my coolant temp gauge reached and went up and down slowly 60 to 70 percent(not red line{hot}) few times. I turned AC off right away and just in case I pulled over and temperature became normal like 50 percent (center of gauge). I checked oil level and coolant and they were good and fan is turning too.

Do you guys think that it is normal and it can be happened? I never seen this before I hope it is not major issue guys I am planning to bring my taco to Korea one month later and If it is major issue and it happen again, I am gonna be really pissed because taco is very unique in my country.

I will keep my eyes on temp gauge and never listen music loud for now. Please give me advice guys.
Thank you.

 

My temp gauge is always around 12 o’clock but I am rarely in stop and go traffic. I would change the coolant and make sure the radiator fins are clear of debris.

 

Thank you so much for your advice! I will clean the radiator first!

 

Definitely get it checked out! No it’s not normal to go well past the halfway point, especially not in 33C/91F while moving. many live way further South and run way past those temps w no problems.
BTW- IF you did pull over to idle, this usually isn’t a good idea, airflow is what will cool.

 

You might also want to check the thermostat and make sure it is opening up like it should.

 

^This^ You could remove the thermostat & see if it improves. If it does, make sure to replace it.

 

Don't remove the thermostat. The thermostat seems to work fine, I'd start by cleaning the radiator/condenser fins, especially if they are muddy/dirty. Make sure the fan is working [hub is OK].

 

For some context, I've been stuck in Texas and Florida heat of 105 degrees plus and completely not moving for hours. The temp gauge never moved.

It does sound like something is wrong. If the temp spikes before you figure out what the problem is, you can switch from AC to heat with the blower on high. It'll basically use your heating system like a second radiator. You'll be miserable but at least the truck won't overheat and warp your heads.

 

I live in Texas in the DFW metroplex, lots of stop and go with really hot days 106f. My temp gauge stays right at the 12 o’clock position. As other suggest I would start with a good cleaning.

 

Thank you so much
definitely, it is not normal. After coolant temp gauge issue came out, I drove over 85~90km and gauge was normal.
I just checked coolant level both and they were good. I am going to clean my radiator first and keep my eyes on dash.

and another question is big fan always starts turning when I start up engine??


BTW- IF you did pull over to idle, this usually isn’t a good idea, airflow is what will cool. <- I was an idiot and I will remember your advise.

 

yea maybe thermostat or water pump.
there is no leaking on coolant so I will keep my eyes on dash. Thank you!

 

Thank you! actually I have no tools to remove thermostat haha. I will wash all insect from radiator and fans.
fan is turning when i start up engine right...?

 

Thank you and I will clean

 

Not sure if you can remove just the thermostat on your housing.

Certain models it just snaps in. I'm used to "old school" thermostats, $5~$10.

Some newer models you have to replace the whole housing, $100+. That's progress, lol.

Yes, fan should spin. Rinse that radiator off with a garden hose or take it to a car wash & "blast it".

You'll figure it out, Good Luck

 

Remove the plastic shroud on top of the radiator to access the narrow gap between the radiator and condenser. Flush it out with a garden hose . If you go off-road, that interstitial area may be packed with mud or dirt.

It's also possible your fan clutch is failing, so the fan isn't turning as quickly as it should be

 

THank you so much for you idea

 

Yes I can be ! I will go out and wash !

 

Yes the fan is always spinning. But there is a temperature sensitive clutch that engages (or should!) lock the fan in with heat. So while not engaged (cooler, not sure what temp?) the fan will still spin, but when it fully engages it is directly driven/locked in and spins much faster. When the truck first starts, it is usually locked in and you can hear the woosh for a few seconds. While driving, if/when the fan clutch engages, you can definitely hear the fan with engine speed. I am much further south, and rarely have heard this fan, other than start up.

In regards to cleaning. Try to gently flush from the back (engine side) forward first. Starting with the front will push more gunk in,, but may be necessary. Also, careful if you use a pressure washer! They can be used yes, but an aggressive nozzle can bend the thin aluminum fins. If you use a less aggressive nozzle, some distance, and common sense, you'll be fine.

 

I’m surprised people actually pay attention or worry about the temp gauge on a newish vehicle.

OP, 33C/91F is not unusual and not outside what the truck is designed for. Are you sure the tenp gauge doesn’t behave the same on other (cooler) days? If so, stop worrying. If not, then the suggestions given above seem decent.

I honestly have no idea how mine behaves as I’ve never watched it. I’m pretty sure the ECU will inform me if the water temp ever gets too hot.

 

Temp gauge only gives you a reference anyways, better to have a gauge that shows the actual temp (ScanGauge, Ultra, most new Android HU's).

Apples to oranges, my 4.0 T4R typically sits at 185 - 192 F when warmed up and city driving in the summer. Currently in a heatwave with temps sitting at 38 C / 100 F, and any uphill I will climb to 195 - 205 F, as soon as it levels out I'm back to normal in short order, temp gauge doesn't even move.