2005 Sequoia - Temp increase at high speed (1 Viewer)

[chetmanly2]

I have a 2005 Sequoia w/272k. Going up a ~3% grade at 65-70 mph the cruise control dropped out of OD so the engine was running at ~3-4k RPM (can't remember exact number). After about a minute the temp gauge rose to about 2/3 of the way toward H and stayed there until I cancelled cruise control and put it back into OD (still going 70MPH though). It's done that twice now under the same conditions - high speed and RPMs. Around town the temp gauge stays normal but it loses about 1-2 oz per day of coolant.

Any ideas? We've done a combustion leak test, no indication of HG leak. No coolant leak/crusty stuff anywhere visible either. Next step is to do a pressure test on the radiator.

 

[Jgrauman]

Check your tranny fluid as well. You shouldnt be losing coolant. If the rad is original, you are past the point of failure for these things. If you are on an aftermarket rad, I would look at replacing as well depending on the time it was replaced. Tranny is cooled through the lower portion of the rad and can crack, mixing with the coolant. Tranny fluid will turn pink/milky. Just a thought

 

[chetmanly2]

Thanks for the input. I saw the ATF cooler lines into the radiator last night. Checking the ATF is on the to-do list weekend.

 

[Weedhopper]

Sounds like it's overdue for rad, hoses, etc. Water pump if it's original. Putting a separate transmission cooler on the front of the radiator is a guarantee the coolant and trans fluid will never mix. Pretty easy to do when you are changing the radiator.