Real time help - Temp Problem?

[Leandro]

Hey folks
I'm in the middle of a long road trip and my LX seems to have temp problems.
I'm checking the temp real time with Torque app and coolant temp is around 200° all the time in the highway.
Outside temp is around 90 in the heat of Florida, I set my cruise control at 70mph (75mph GPS because I have bigger tires) approx 2600 rpm.
It oscillates between 197 and 203 in flat terrain. While crossing TN, around Chattannooga, in long inclines reached 212 easily and once got to 220, always temp came down fast on the decline. I didn't worry much because the temp gauge in the cluster never moved from the middle, so I assume that Mr T thinks this temp is fine.
I've searched the forum and found contradictory opinions, one post said that it was fine, that temp in the heat is normal. Other post said that it was too high and replace t-stat to start, and move up to fan clutch, radiator, and water pump.
What do you guys think? Should I keep going? I have another 1500 miles to get home.
Should I swap the t-stat ? If so, what do you guys use for the gasket? Silicon/gasket maker or the actual gasket? Or both?

Thanks in advance.

 

[Spike555]

You're fine. Rinse the radiator with a garden hose to remove dust and pollen, those act as blankets on the radiator fins and hold in heat.
But, you're fine. You're working it hard because of the oversized tires and the extra load of gear and family.
You. Are. Fine.

 

[flintknapper]

You'll likely make it home just fine....but I consider those temps to be higher than normal.

I'd dump the cruise control thing for a bit....slow down to 60-65 mph and see if that doesn't make a difference.

If it does...then just slow down, get home and then work on finding the issue(s) when you have more time and don't face the possibility of being broken down on the road.

If your radiator cap is old...stop and get a new one someplace, check your coolant level at the same time. Those are two easy things to do.

T-Stat could be done on the side of the road if you had to...but I doubt that is your problem.

 

[Spike555]

You'll likely make it home just fine....but I consider those temps to be higher than normal.

I'd dump the cruise control thing for a bit....slow down to 60-65 mph and see if that doesn't make a difference.

If it does...then just slow down, get home and then work on finding the issue(s) when you have more time and don't face the possibility of being broken down on the road.

If your radiator cap is old...stop and get a new one someplace, check your coolant level at the same time. Those are two easy things to do.

T-Stat could be done on the side of the road if you had to...but I doubt that is your problem.

Keep the cruise, just slow down.

 

[Leandro]

Thanks for the responses
Coolant is at the right level, I check it at every refuel.

 

[Robinson13]

Stat comes with a new O ring seal.

I’d start off making sure there is good air flow through the radiator. No bugs, dirt, grass seeds, or too many bent over fins. Pull off the fan shroud and flush with garden hose pressure from engine side, a pressure washer will easily destroy the fins if not done correctly.

It’s never any fun to mess with possible issues on a road trip. I’d trouble shoot a bit more and try to get home. If necessary drive at night. Maybe even slow down a bit. 197 and 203 still gives you plenty of wiggle room before a boil over. Assuming everything else with the cooling system has been maintained.

 

[nissanh]

Also, don't keep the AC blower fan at max. Once the cabin cools down (about 5-10 minute drive), bring it to speed 2 or 3.

 

[Spike555]

Also, don't keep the AC blower fan at max. Once the cabin cools down (about 5-10 minute drive), bring it to speed 2 or 3.

I know what you're thinking and it is a old wives tale.
The a/c is either working or not. It does not work harder when you have the HVAC fan set to high. It cycles the same no matter what fan speed you're using. I just leave it on "auto" anyway and let the HVAC do whatever it thinks it needs to.

Same thing with your cruise control "working harder" when you are pulling a trailer, old wives tale, all the cruise is doing it taking the place of your foot on the throttle. It only knows more throttle or less throttle.

 

[flintknapper]

I know what you're thinking and it is a old wives tale.
If you are referring to the idea that the compressor somehow 'adjusts output' to the mode selected then yes...'Old Wives Tale' or just a misunderstanding by folks of how it works.

The a/c is either working or not.
Yes, the compressor is either on...or off.

It does not work harder when you have the HVAC fan set to high.
Correct the compressor does not work 'harder' but it can work less 'frequently' (cycle more) under certain conditions.

It cycles the same no matter what fan speed you're using.
No. It cycles according to the evaporator temperature. Evaporator temperature will be determined by the cabin temp (as it slowly removes heat from it) and the number of complete air exchanges. Fan speed has a lot to do with that.

After the cabin has cooled enough to become comfortable...if you decrease the fan speed...within minutes you will note lower vent temps (typically 2-5 degrees from high speed). Of course, there is a trade off...its cooler air...but less of it. Just the same...the reason for the cooler air is because the evaporator has had more time to remove/exchange heat from the air going across it. In other words..there IS such a thing as 'optimal fan speed'. The evaporator itself is more likely to reach a temperature (at low fan speed) that will cause the thermistor to cycle the compressor off. The more often the compressor is off the less load on the engine.

Now...having said all that, there are conditions when your compressor will NEVER cycle, its just too darn hot out. AND...feeling cool (for humans) depends not only on the cabin temperature but also 'air flow'. Because we cool most efficiently by means of evaporation (moisture from the skin). Ultimately...there are gains to be had by adjusting fan speed....under just the right conditions, but for most folks, they would do well to do as you suggest: After it has cooled down, put it on AUTO and forget about it.

^^^^^ expand for replies

 

[DirtDawg]

I recently went through the same ordeal. Higher than average temps, but not enough to overheat. My gut said t-stat so I swapped mine out. Boom, instantly back to normal temps. I tested the old t-stat in boiling water and found that it only was partially opening.

Those are not normal temps. Baby it and watch your temps until you get home and then do some investigating. T-stats are cheap and easy to swap.

 

[Leandro]

I recently went through the same ordeal. Higher than average temps, but not enough to overheat. My gut said t-stat so I swapped mine out. Boom, instantly back to normal temps. I tested the old t-stat in boiling water and found that it only was partially opening.

Those are not normal temps. Baby it and watch your temps until you get home and then do some investigating. T-stats are cheap and easy to swap.

That is exactly what I thought, t-stat half stuck and restricting flow. I have an aftermarket spare that I carry all the time just in case, but will try to get an OEM locally and swap it.
Checked the radiator fins and they are bot that dirty, but that's what I can see from the outside. Will try to rinse it anyway.

Thank you all. I can't say it enough, what a great community this is.

 

[94SRUNNER]

I also went through this recently. Temps were running similar to the OP. Swapped in a Napa unit and saw some reduction in coolant temps. I wasn’t satisfied, so ordered the OEM unit and temps went down to the normal range.

 

[flintknapper]

I recently went through the same ordeal. Higher than average temps, but not enough to overheat. My gut said t-stat so I swapped mine out. Boom, instantly back to normal temps. I tested the old t-stat in boiling water and found that it only was partially opening.

Those are not normal temps. Baby it and watch your temps until you get home and then do some investigating. T-stats are cheap and easy to swap.

They are easy to change out thank goodness. And just because its a Toyota product doesn't mean it can't/won't fail. The one on my LX failed (stuck closed) and it was only about a year old (OEM T-stat).

Luckily the radiator didn't boil over until right as my wife was pulling into her work. That is what prompted me to put a ScanGauge in the LX with strict instructions for her to look at it once in awhile. She never noticed the temp gauge on the dash...but in all fairness...it has such a large dead spot in it...you'll be overheating before it starts to move anyway.

 

[LandCruiserPhil]

Is your AC condenser fan working?

 

[94SRUNNER]

Should I swap the t-stat ? If so, what do you guys use for the gasket? Silicon/gasket maker or the actual gasket? Or both?

Thanks in advance.

@Leandro in regards to your original post regarding thermostat replacement. It does not require a silicon or gasket maker type of material or any gasket. The thermostat has a rubber o-ring like seal that fits around the outer edge of the thermostat,(See picture). The thermostat is seated and the aluminum housing is re-installed. The o-ring makes the seal.

 

[Spike555]

^^^^^ expand for replies

I leave it on "auto" and only adjust the temp, summer temp is 72, winter temp is 75. The "auto" turns on/off recirculation, defrost for the windshield, vent, floor, fan speed...whatever is needed to cool/heat the cabin.
After being parked in the 98*F heat all day it turns the fan on high, recirculate and cools the cabin, as the cabin cools it lowers the fan and turns the recirculation off.
I can speed up the cooling of the cabin by opening the rear vent windows for a few min, this lets the fan push all the hot air out of the cabin. But I don't do this. I let it do it's thing. It's started to lower the fan speed by the time I hit the first stop light a few hundred yards away from work.

Same thing for the winter, it turns the fan speed up as the engine warms. Fan goes to high on really cold days once there is enough engine heat, usually around 150*F then it slows as the cabin warms. And with the a/c compressor still engaging the windows to not fog up because the aircon is removing the moisture (melted snow, humid breath) from the cabin.
And heating the cabin does not take long. Half the time I think the fan is off because it's so quite.
These things are really really well insulated so heating and cooling does not take long. And because I park with the back of my truck facing west the cabin is not so hot when I get out of work as the sun is to her back with the tinted windows and the sunroof shade is always closed to keep the heat out too.
I have a thermometer inside the truck, 98*F outside temp, only 115*F inside. Not that bad.

Now in the winter I park FACING the west, that way the sun helps keep the windshield clear and because the wind comes out of the north west the snow does not pile up and drift on the front of the truck as bad.

I love the full auto climate control. Set it and forget it. More brain power is freed up for me.

 

[Leandro]

View attachment 1756749

@Leandro in regards to your original post regarding thermostat replacement. It does not require a silicon or gasket maker type of material or any gasket. The thermostat has a rubber o-ring like seal that fits around the outer edge of the thermostat,(See picture). The thermostat is seated and the aluminum housing is re-installed. The o-ring makes the seal.

excellent, thank you. that makes it even easier to replace.

 

[Dwight S]

If you buy a Toyota T-stat, be sure to buy a new gasket, the Toyota one does NOT include it.

 

[Leandro]

Just bought the t-stat from the local dealer, it didn't come with the gasket, had to buy separately, $9 for a piece a rubber.
Tested the new t-stat and opened fine on the stove, now waiting for the truck to cool down to replace.

 

[flintknapper]

Just bought the t-stat from the local dealer, it didn't come with the gasket, had to buy separately, $9 for a piece a rubber.
Tested the new t-stat and opened fine on the stove, now waiting for the truck to cool down to replace.

Good deal. There may or may not be some scaling on the T-stat housing. If so...clean it up so the gasket fits flat. And remember the 'jiggle valve' goes in the 12 O'Clock position.