ECT question
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Mountain Pass
Joined: May 2015
Posts: 128
Likes: 8
From: Cottonwood, California
ECT question
I have searched the forum but couldn't find information that seemed to match my issue.
2005 6.0, 80-85 degree outside temperature, truck fully warmed up, driving down the level freeway at 65 mph for over 20 min with 192 ECT and 196 EOT.
My ECT wil suddenly jump DOWN to 176 or so and then slowly build back to around 184 and level off there. EOT will remain at or close to the 196 it was already at.
Does this sound like a TSTAT issue?
I replaced the TSTAT last summer with a for OEM because it was never getting to 190.
That worked fine but now I have seen this ECT drop a couple of times over the last week or so.
It doesn't seem to drop like this on all trips, just occasionally.
Any thoughts?
Thanks,
Art
2005 6.0, 80-85 degree outside temperature, truck fully warmed up, driving down the level freeway at 65 mph for over 20 min with 192 ECT and 196 EOT.
My ECT wil suddenly jump DOWN to 176 or so and then slowly build back to around 184 and level off there. EOT will remain at or close to the 196 it was already at.
Does this sound like a TSTAT issue?
I replaced the TSTAT last summer with a for OEM because it was never getting to 190.
That worked fine but now I have seen this ECT drop a couple of times over the last week or so.
It doesn't seem to drop like this on all trips, just occasionally.
Any thoughts?
Thanks,
Art
Fleet Mechanic
Joined: Jan 2017
Posts: 1,666
Likes: 181
Seems odd that the EOT will stay at the temp it was at if your t-stat is actually opening and staying open long enough for the temp to go down 20 degrees....I'd be looking at the sensor myself (or wiring nearby). Of course a new t-stat never hurts...
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Mountain Pass
Joined: May 2015
Posts: 128
Likes: 8
From: Cottonwood, California
Hi EXSwap,
I thought sensor but after a cold soak the are within 2 degrees of each other, then I swapped them and I still get the same ECT drop every once in a while.
Wiring looked OK, nothing obvious.
Guess I will try another new TSTAT since it is easy and cheap to see if that solves the issue.
Thanks,
Art
I thought sensor but after a cold soak the are within 2 degrees of each other, then I swapped them and I still get the same ECT drop every once in a while.
Wiring looked OK, nothing obvious.
Guess I will try another new TSTAT since it is easy and cheap to see if that solves the issue.
Thanks,
Art
Thread Starter
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Mountain Pass
Joined: May 2015
Posts: 128
Likes: 8
From: Cottonwood, California
Hi Bismic,
Yes, the level is at the "new" full level.
I guess I'm puzzled because with the truck fully warm and fairly warm outside temps I assumed the TSTAT would be full open when running down the road at 65 MPH.
So I'm confused as to why the TSTAT would be a factor in the temp dropping so quickly.
Thanks,
Art
Yes, the level is at the "new" full level.
I guess I'm puzzled because with the truck fully warm and fairly warm outside temps I assumed the TSTAT would be full open when running down the road at 65 MPH.
So I'm confused as to why the TSTAT would be a factor in the temp dropping so quickly.
Thanks,
Art
Token Redneck
Joined: Jun 2007
Posts: 9,335
Likes: 344
From: Breckenridge, TX
It's sticking, and when the fan kicked up it dropped ECT? Lot's of things impact fan clutch lockup, so if you weren't watching the FSS and FDS PIDs you might not even notice if the fan goes to one of the first two lock-in stages, but the increased airflow on the cooler drops ECT before the tstat can close down.
Running the A/C when this happened by chance?
Running the A/C when this happened by chance?
Thread Starter
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Mountain Pass
Joined: May 2015
Posts: 128
Likes: 8
From: Cottonwood, California
Hi Texastech_diesel,
Interestingly I did watch the FSS (not sure what the FDS PID is/does) and the rpms were in the same range before during and after the ECT drop.
Never appeared to increase just before the drop.
I'm stumped but I figure a new TSTAT is worth trying regardless of it is the actual cause.
Thanks,
Art
Interestingly I did watch the FSS (not sure what the FDS PID is/does) and the rpms were in the same range before during and after the ECT drop.
Never appeared to increase just before the drop.
I'm stumped but I figure a new TSTAT is worth trying regardless of it is the actual cause.
Thanks,
Art
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