2006 Tundra - running hot? need advice...

Just bought an '06 Tundra back in April to replace my '14 Tacoma 4x4 that got totaled last year. The truck seems to run hot on warmer SoCal days (90's to triple digits) when I want to use my a/c - the first i noticed was when sitting in the Cane's drive thru on Mother's day and started to smell coolant at the same time that my a/c stopped 'cooling'. I shut off the a/c and watched the temp gauge move from slightly above center to slightly below center..never spiked. I found later that day that my radiator cap was leaking so i replaced.
Couple weeks ago it warmed up again and it felt like my truck was heating a bit too much so i purchased a bluetooth OBDII reader and the Torque Pro app to monitor...things...mainly coolant temp for now...so many cool things tho!...but coolant temp...lol

findings... normal op is about 188 when it fully heats..jumps to about 192 but stays about there.. it has spiked a few times up to 200/205 - usually at slower speeds (traffic or frequent stoplights) - when it hits above 195 i will power down the compressor until i start moving steadily again and the temp drops below 190...
I was expecting to see some sort of drop when temps raised at initial warming of engine due to the 'opening of the thermostat' once the temp reached thermostat limit (170 F OEM spec i think?) but the temp went up progressively until 188ish...

my guess is that the thermostat is failing unless this is normal behavior.. thoughts?

 

Yep, those temps sound pretty normal to me. Other than the radiator cap issue, whats prompting you to dig deeper? Does your truck feel like it gets heat soak after sitting in a drive through?

 

239° is when our Transmission Overheat dummy light comes on. I’ve read guys towing get in the 210-220° range readings on our trucks.

 

not just drive thru.. stopping at red lights at offramps after driving for several miles.. I could just have new truck owner of an old truck paranoia... but the throttle position sensor failed during one of the 'overheats' before i changed the radiator cap i'm just trying to make sure it's not something deeper than just the radiator cap and that if it is I can catch it before it causes any damage

 

I just added the correct transmission temp gauges to Torque Pro so i can track those temps along with engine coolant. Looking for Oil temp and Oil pressure PID codes now...

 

2 things. I'd clean the front of the radiator/ac condenser with a soft brush and low pressure water first. If you still have problems look at replacing the fan clutch.

Your temps don't sound out of line but neither one of those is going to cost a fortune or cause any harm but if they give you peace of mind it's worth it.

 

We bit high but not terrible. Could just be a weak fan clutch or a worn out radiator.


I’m at a steady 182-188 in 96 degree weather.

 

My 00 tundra did something slightly similar a few days before the “fail safe” thermostat went out. When I did my timing belt at 300k I thought heck why not have a thermostat that will fail in the open position when it fails and not leave me stranded? Well like 20k miles later I noticed my obd2 reader telling me temps were slightly hotter on a summer day than normal. I usually never run hotter than 188 or so because it’s a185* thermostat. Towing or pulling long hills in summer I have seen it get to 192 or maybe a touch more. If I tow a heavy load up a steep grade for a while I’ve seen it hit 202*. But my dash always remains in normal range. But last year after noticing a few times where it got close to 200 just idling and driving normal then it would seem to go back to normal for a while, but then I was cruising a back road ay obd2 said it was at about 210 and I knew something wasn’t right. I was a couple miles from a friends house and I barely made it there. I think it jumped up to like 230+ within a mile. I actually turned the heat on and rolled my windows down because it was already about 95* outside. That helped dissipate some of the heat, but when I got to his house we took off the thermostat and it just ran cool till I got home. Next day I went and just got a regular thermostat because the failsafe failed me lol.

 

Wow really? During winter I'm never above 188, now in the summer the highest its ever been was 194 one time, I'm usually sitting at 190 in stop and go and 186-188 while moving

 

You guys have probably seen this chart before, but here's a reminder. You can over-cool your engine. If your worried your radiator is not cooling your transmission fluid quickly enough, install a larger atf cooler.

 

Any sweet chart action on over cooling your transmission?

 

Hand,
None that I've seen. But remember, in a transmission, auto or standard, wear is expected and designed for. That's why you have a filter screen in autos and you drain the gear oil in standards. Also remember that a transmission can endure lots and lots of wear before it fails. In an engine cylinder, a few thousandths of wear can be the difference between rings sealing, or not. Worn cylinders with 60 psi compression vs 150 psi.

 

When’s the last time the coolant has been changed? The temps sound reasonable but the AC still should be cool even at idle. It will be a little cooler with air moving but with my job, there is times where I’m cabbed up for over an hour and I’m running the AC full blast not moving.

I’d rinse everything out and check the coolant level/quality. Radiator could be getting plugged but they are cheap and easy to do ($160 and an hour). You could also toss in a bottle or Royal Purple coolant addictive. That stuff actually works.

 

186 to 192 range during normal running with outside temps in the 80s and 90s. It jumps to 194 when i stop after running for a while and will even get up to 200 sometimes sitting in traffic. other day it got to 210 and released coolant from a new radiator cap - seems to have failed the radiator cap (duralast $11 cap...) since it has been releasing coolant from the cap now for 2 days under normal driving. I'm thinking i probably should replace the radiator (nearing 200k on the odo...)? Dunno when the coolant was last changed - i bought the truck with 180k in April and have not replaced the coolant.

 

I think the fan clutch is suspect. Couple of youtube vids to help determine this. Also, if the radiator tank is brown (check for date stamp on it) or over 10 yrs old, replace it. Luck.

https://www.youtube.com/watch?v=4oq6i_Jc3hM

Bad clutch can cause a/c issues too...
https://www.youtube.com/watch?v=BR-uLMTaOXY

 

fan does not spin freely ..it moves without a whole lot of effort but will stop moving within 5-10 degrees if i try to spin it hard...engine was cool enough to remove radiator cap. i will attempt again when hot.
added royal purple additive. going to flush radiator soon and add the red water wetter when i refill with coolant instead of purple. will monitor coolant temp during upcoming drive to see if there is a reduction in coolant temp as a result of the additive.
upon inspection of radiator and transmission cooler - they are slightly dirty and have taken a few rocks (more-so the trans cooler). coolant appears to be colored correctly inside (not brown) but still probably good idea to flush and refill with fresh. my reservoir was almost empty when i went to add the wetter a moment ago so i filled to the line... I will be doing the coolant flush next week sometime unless situation warrants sooner..

 

I also did some testing with the a/c - recirculate works well regardless of engine temp. fresh air a/c will start to warm if intake temp gets above 140, which typically doesn't happen unless i'm sitting (based on the numbers that i have been able to monitor).

 

My clutch fan did not spin freely either, yet when my mechanic took a look, he held it then had another mechanic start it, he could hold it easily, its not expensive and has much to do with airflow at low to no speeds.

Another possible culprit to low speed low airflow is what is Between the a/c condensor and radiator. Remove skid pan if necessary and look up between the two, clear out any debris. If off road moderatly and that space even though covered with skid pan fills the lower half with grass and debris, reducing air flow, just a thought to try to eliminate anything that may reduce airflow. Luck.

 

So I may have uncovered (and worsened) an issue by replacing the radiator cap. maybe the cap was not faulty to begin with (especially the new one i bought, and then replaced ) i've been losing coolant less slowly over the past few days ...

https://youtu.be/meMlxzpDwL8

Started the truck while parked in the driveway, making sure i turned it around to point the exhaust into the street instead of my front door and to my doggies Starting temp was about 142 deg F
Watched the temp go up on the ODB2 gauge (torque pro) steadily climbing - after it hit 168 i went to check the thermostat return hose - it was already warm ... but couldve been that way already. i did not check it initially but still need to check if thermostat is stuck open so will retest from cold start. while i was checking the hose, i was watching the radiator cap to see if it was going to start doing something...instead i saw what i filmed....
In response to the fan clutch - I can hear the fan engaging when warmer but when i moved it around hot or not it did not seem to offer any difference in resistance. i figure i may as well replace that, along with the radiator, hoses, probably thermostat+gasket and hope the thermostat housing is in good shape or replace that too. Radiator looks like genuine Toyota - probably original?

 

Just purchased a radiator. looking for the fan clutch that i can pick up tomorrow

 

purchased fan clutch and thermostat and gasket. going to purchase the hoses tomorrow and maybe new clips for trans cooler connections if needed along with coolant.

 

You found the problem, cracked tank. Very common on plastic tank radiators of all makes after they reach 10 yrs or so, they could last longer but why risk it. Its gonna be Sweet engine and passenger cooling after this!

 

So repairs are underway and i found an improperly installed thermostat upon removal of the housing. Can you tell me why it is not correctly installed? How should this really be positioned? If you've replaced this one, you probably already know
https://youtu.be/nbkAOjYPS_M

oh - big crack in the radiator. i'll post pics later.

 

Vent on the thermostat appears to be on the instead of at the top.

In the end not a huge deal just helps burp the cooling system faster.

 

Inquiring minds want to know;

What thermostat temp range are you installing on this job ?