[iiareandy]

Mystery solved.
For starters, let's remember two details about the Highlander transmission:
1) It has two cooling "devices". One is a fluid-to-fluid heat exchanger that uses engine coolant to quickly bring up the transmission to temperature after cold start (33493A on the pic below). If your HL is equipped with the tow package, it also has a separate transmission cooler to prevent overheating under heavy load (32910).
2) The transmission needs to be at 105F and the engine / torque converter must be running to refill the transmission to proper level.

Now, the refilling procedure is easy if one starts with a cold engine. All you have to do is to start the engine, wait until the transmission temp sensor indicates 105F, and fill the transmission with fluid until it overflows though the "straw" located in the drain plug.

Things get more complicated if you have to start with a warm engine / transmission. The transmission cools down faster than the engine and engine coolant. So even if the transmission cools down to 105F, it will get warmer as soon as the engine is started because hot coolant will circulate through the heat exchanger. So the dealer has two options. Either wait for several hours for the engine to cool down completely, or isolate the transmission fluid circuit from the engine coolant circuit. The latter can be done by removing one of the coolant hoses connected to the heat exchanger and plugging it during the transmission fluid change. A small amount of coolant is lost during this process (or a larger amount if the mechanic isn't careful).

This explains why the engine coolant level can be low after transmission fluid change.

@AnTrinh - you should learn a bit about modern cars before making stupid comments.

View attachment 408462

I don’t have the towing package. Currently back at the dealership and see what they say. Will update you guys. My dad said that the AC is kicking on along with the heat. The AC pipes gets cold when I have the defroster and floor fans on

 

[AZPedro]

then my

As in binary only ...closed to full open

 

[katekebo]

I don’t have the towing package. Currently back at the dealership and see what they say. Will update you guys. My dad said that the AC is kicking on along with the heat. The AC pipes gets cold when I have the defroster and floor fans on

It's normal for the A/C to turn on together with the defroster. All cars since the 1980s do it. The purpose is to remove moisture from the air so the defroster / defogger can be more effective. A/C should turn on when front defroster is selected or when the selector is set to defroster + floor.
It is also normal for the radiator fans to turn on as soon as the A/C is on. It It to ensure proper airflow through the condenser which is located in front of the radiator.
Your temperature issues could be bad / failing thermostat.

 

[Old Mechanic]

Typically a bad thermostat "fails" more open when the spring that controls tension looses one of its support brackets.
Takes a long time to warm up especially in winter, higher speeds it may actually run cooler and heat will not be as hot.

 

[bill.ruggirello]

Typically a bad thermostat "fails" more open when the spring that controls tension looses one of its support brackets.
Takes a long time to warm up especially in winter, higher speeds it may actually run cooler and heat will not be as hot.

How quickly do the 6cyl HL warm up in cold climate?

 

[Old Mechanic]

My Echo takes about two miles at freezing temperatures. The Highlander would probably do about the same, but it depends on how you drive it during warm up. I start and go, it takes forever for any engine to warm up if you let it sit idling. Start and go, leave the heat off until it is close to operating temperature, My neighborhood is .5 mile at 25MPH one way, a mile the other way. That slows down warmup times. I park so the rising sun deices my windshield, so needs little or no heater to defrost. Where I used to live it was .3 mile to the 4 lane main road and in summer it was warm within a mile.
At temps like 40 below you need to block the airflow through the radiator to NOT take any more heat out of the engine than you can manage. The heater core can cool the engine when you are at 20 below or lower.

 

[2005 es330]

A Grand to replace the thermostat and put in new coolant? That sounds insane, What year is your Highlander?

 

[iiareandy]

A Grand to replace the thermostat and put in new coolant? That sounds insane, What year is your Highlander?

2017 XLE. $125 for thermostat part and $600+ for labor and $190 for the coolant fluid change. When he told me $1000+ I was said no way, I’ll just take back my vehicle that’s way too much

 

[2005 es330]

2017 XLE. $125 for thermostat part and $600+ for labor and $190 for the coolant fluid change. When he told me $1000+ I was said no way, I’ll just take back my vehicle that’s way too much

I am going to go look the procedure up on that engine to see how much labor is involved. I do not know what they are charging per hour, $150 tops? so they are saying 4 or more hours? I find that hard to believe. Also those parts and fluid seem pretty excessive. toyota genuine 50/50 is like $25 per gallon jug, I think my lexus takes 2 jugs so $50, and an OEM thermostat I would think would be closer to under $40. But I would have to look that up. By the way, what engine is in that?

 

[AnTrinh]

Mystery solved.
For starters, let's remember two details about the Highlander transmission:
1) It has two cooling "devices". One is a fluid-to-fluid heat exchanger that uses engine coolant to quickly bring up the transmission to temperature after cold start (33493A on the pic below). If your HL is equipped with the tow package, it also has a separate transmission cooler to prevent overheating under heavy load (32910).
2) The transmission needs to be at 105F and the engine / torque converter must be running to refill the transmission to proper level.

Now, the refilling procedure is easy if one starts with a cold engine. All you have to do is to start the engine, wait until the transmission temp sensor indicates 105F, and fill the transmission with fluid until it overflows though the "straw" located in the drain plug.

Things get more complicated if you have to start with a warm engine / transmission. The transmission cools down faster than the engine and engine coolant. So even if the transmission cools down to 105F, it will get warmer as soon as the engine is started because hot coolant will circulate through the heat exchanger. So the dealer has two options. Either wait for several hours for the engine to cool down completely, or isolate the transmission fluid circuit from the engine coolant circuit. The latter can be done by removing one of the coolant hoses connected to the heat exchanger and plugging it during the transmission fluid change. A small amount of coolant is lost during this process (or a larger amount if the mechanic isn't careful).

This explains why the engine coolant level can be low after transmission fluid change.

@AnTrinh - you should learn a bit about modern cars before making stupid comments.

View attachment 408462

any auto trans has the a line carry trans fluid and the line going through the bottome of the rad one way coming out the other way so the fluid can cool down, tow package has been offered for lots of make not just toyota, it just mean they add another external fluid cooler, u get one even with a fan sometimes. sometimes they even add pws cooler, so u don't really shine light on watever u thought i don't know. and who the hell drain coolant to refill trans fluid??? unless it's u then i guess u're a genious.

 

[2005 es330]

I see the Thermostat OEM also with a new thermostat housing for $74 and the same parts show $53 at my local Toyota dealership.

 

[Joncogar]

Sounds high to me.

 

[wheatthin]

The dealership said that the thermostat was stuck open. Asking price to replace the thermostat is $784 and $190 to change coolant

Sound good, maybe they should throw in the $385 car wash while at it!😁

 

[Seankel]

Thanks for sharing. I had a similar experience after changing transmission, transfer case and rear differential fluids. Engine temperature was OK, but the coolant expansion reservoir was completely empty after about 3000 miles after the fluid change. It was at the full mark right after the other fluids were changed, but dropped to nothing after driving for a few thousand miles. At first I though I had a coolant leak, but I topped it off and it is holding steady.
Apparently the dealer does something to the coolant circuit when changing transmission fluid. That's the only explanation I can find. Weird.

No, coolant is not touched . That is a TOTALLY different system.

 

[RT27]

The dealership said that the thermostat was stuck open. Asking price to replace the thermostat is $784 and $190 to change coolant

How cold is it outside.my camry runs cooler when below 50 outside

 

[iiareandy]

How cold is it outside.my camry runs cooler when below 50 outside

Temperature was varying. I drove it in colder temperatures in the past and never experienced this before

 

[iiareandy]

I see the Thermostat OEM also with a new thermostat housing for $74 and the same parts show $53 at my local Toyota dealership.

Dealerships are fucking ripoffs. Never going back there again

 

[iiareandy]

I am going to go look the procedure up on that engine to see how much labor is involved. I do not know what they are charging per hour, $150 tops? so they are saying 4 or more hours? I find that hard to believe. Also those parts and fluid seem pretty excessive. toyota genuine 50/50 is like $25 per gallon jug, I think my lexus takes 2 jugs so $50, and an OEM thermostat I would think would be closer to under $40. But I would have to look that up. By the way, what engine is in that?

V6 engine

 

[kdpo1990]

$1k LOL

See the if that helps.
I would totally change thermostat my self.
On his channel you can also find video on how to change coolant. I’ve changed coolant on my 2010 Camry and 2014 Avalon Hybrid after watching his videos. Trans fluid as well.

 

[AZPedro]

The dealership said that the thermostat was stuck

called that one