EOT/ECT delta question
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EOT/ECT delta question
Truck is a new to me 2003 6.0L with 156,000 miles on it. New oil cooler went in about 4000 miles ago. Just got a ScangaugeII hooked up, and today was the first long highway drive (45 miles) I had a chance to take.
EOT never got above 158*
ECT never got above 146*
Never saw more than a 13 degree difference between the two readings, average was 9* but from all I have read here, both numbers are quite low compared to normal. My dash temp gauge barely ever rises unless towing, I guess these readings confirm it is still working correctly. I'd say the ambient temp was in the mid 40's.
When I got off the highway and started the stop and go drive of the city, both temps went up to 160, with about a one or two degree difference. The dash temp gauge went up slightly from where it was on the highway.
So, my question is, what is going on? Are these readings low or normal? I suspect my thermostat isn't 'thermostating' correctly, and I have no idea what the previous maintenance history of the truck is.
I have a new thermostat on hand just need the time to install it.
EOT never got above 158*
ECT never got above 146*
Never saw more than a 13 degree difference between the two readings, average was 9* but from all I have read here, both numbers are quite low compared to normal. My dash temp gauge barely ever rises unless towing, I guess these readings confirm it is still working correctly. I'd say the ambient temp was in the mid 40's.
When I got off the highway and started the stop and go drive of the city, both temps went up to 160, with about a one or two degree difference. The dash temp gauge went up slightly from where it was on the highway.
So, my question is, what is going on? Are these readings low or normal? I suspect my thermostat isn't 'thermostating' correctly, and I have no idea what the previous maintenance history of the truck is.
I have a new thermostat on hand just need the time to install it.
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Stuck thermostat was my suspicion as well. I bought a new one from the dealership last week, haven't had time to install it. from what I've read on this forum, it seems a pretty straightforward job.
Two questions:
1) After changing the thermostat, should I expect to see both the EOT and ECT rise to 'normal' levels?
2) The thermostat I have (PN 3C3Z-8575-AA) does not appear to have a gasket included. Do I need to order this separately?
Two questions:
1) After changing the thermostat, should I expect to see both the EOT and ECT rise to 'normal' levels?
2) The thermostat I have (PN 3C3Z-8575-AA) does not appear to have a gasket included. Do I need to order this separately?
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Joined: Jul 2010
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I think I remember reading that the only way to accurately test eot ect temp variance should only be done at coolant temps over 190...
I will also say that when my thermostat went open my ect never went over 160-170... And always had a higher than usual spread... New thermostat shorter spread...
I will also say that when my thermostat went open my ect never went over 160-170... And always had a higher than usual spread... New thermostat shorter spread...
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I just read that the TSB in which the 15 degree test is described says the ECT must be greater than 190 F when measuring the EOT/ECT difference or else test results may not be accurate.
I'm almost 50* away from that point! I'll replace the thermostat this week and report the results.
I'm almost 50* away from that point! I'll replace the thermostat this week and report the results.
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From: wildwood, mo.
I just read that the TSB in which the 15 degree test is described says the ECT must be greater than 190 F when measuring the EOT/ECT difference or else test results may not be accurate.
I'm almost 50* away from that point! I'll replace the thermostat this week and report the results.
I'm almost 50* away from that point! I'll replace the thermostat this week and report the results.
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More Turbo
Joined: Aug 2006
Posts: 576
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From: midland, Ontario
The gasket is an o-ring. Sold separately if I recall correctly.
3C3Z-8255-AA o-ring I think this is it?
3C3Z-8255-AA o-ring I think this is it?
Last edited by DPorter; Jan 2, 2011 at 11:11 PM. Reason: add info
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Hotshot
Joined: Dec 2003
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From: Stuttgart, Ar
I couldn't find it any other way. It's just as well though. My housing was a bit corroded and just a thermostat would have required that much extra work to clean it to make it seal properly.
Hotshot
Joined: Dec 2003
Posts: 15,369
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From: Stuttgart, Ar
Ford part# 3C3Z-8575-AA
You may be able to find the motorcraft number at an auto parts store for a reduced price and it will be the same thing.
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I'm a bit confused, which, if you ask my wife is nothing new.
I have the thermostat (P/N 3C3Z-8575-AA) already. The o ring did not come in the box.
I looked up the o-ring (P/N 3C3Z-8255-AA) but is there a part number for the o ring and housing? Judging by the way things normally go when I attempt to 'repair' something, having a new housing on hand will be a time saver in the long run.
EDIT:
I found this:
Motorcraft RH152 Thermostat Housing
Is this what I am after?
I have the thermostat (P/N 3C3Z-8575-AA) already. The o ring did not come in the box.
I looked up the o-ring (P/N 3C3Z-8255-AA) but is there a part number for the o ring and housing? Judging by the way things normally go when I attempt to 'repair' something, having a new housing on hand will be a time saver in the long run.
EDIT:
I found this:
Motorcraft RH152 Thermostat Housing
Is this what I am after?