Engine Coolant Temp. sensor leak

AbsoluteZero

Original poster
Member
Nov 21, 2011
211
I recently replaced the thermostat and ECT sensor. The ECT was torqued per the shop manual. A couple weeks ago noticed a small amt. of coolant dripping down the side of the block. It appears to coming from the newly replaced ECT sensor. I recall in the recent past someone posted a similar problem with a leak with a new sensor but I can't find details. Did the original poster remove and reapply thread sealant, just retighten the sensor or something else?
The leak is small. When first found I washed down the block and it seemed to have healed itself but a trip to Bryce Canyon pulling the Coleman produced engine temps in the 220 range on some of the grades. I noticed the leak was still present.
Thanks
 

jbacklund

Member
Dec 16, 2012
118
I had the same issue after replacing the sensor. Tried tighten it further but didn't help. Had to remove it and used additional thread sealant. No more leak.
 

AbsoluteZero

Original poster
Member
Nov 21, 2011
211
jbacklund said:
I had the same issue after replacing the sensor. Tried tighten it further but didn't help. Had to remove it and used additional thread sealant. No more leak.

Did you use Teflon tape or something else? I've also got a teflon thread sealant in paste form that I've used on pipe.
 

djthumper

Administrator
Nov 20, 2011
14,956
North Las Vegas
AbsoluteZero said:
Did you use Teflon tape or something else? I've also got a teflon thread sealant in paste form that I've used on pipe.
The thread sealant should work fine
 

KNBlazer

Member
Feb 8, 2012
811
I installed an Ac Delco last year with no leak issues... what brand did you use? I'm weary of fitment issues and have bought everything Ac Delco, aside from the brake pads...
 

AbsoluteZero

Original poster
Member
Nov 21, 2011
211
KNBlazer said:
I installed an Ac Delco last year with no leak issues... what brand did you use? I'm weary of fitment issues and have bought everything Ac Delco, aside from the brake pads...

Used ACD 213-963
 

Mark20

Member
Dec 6, 2011
1,630
I too had a leak. Basically too much teflon tape from the factory. No more than 2.5 wraps. Otherwise it balls up when you torque it and never seals.
 

AbsoluteZero

Original poster
Member
Nov 21, 2011
211
As follow up, I removed the ECT sensor, cleaned the threads (not much evidence of the original sealant), applied a couple wraps of Teflon tape along the full length of the threads and reinstalled. I didn't use a torque wrench but tightened until I was confident the copper washer was snuggly in contact with the block.
After a week's worth of driving no apparent leak.
 

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