Engine Coolant Temp

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Mar 26, 2015 | 02:02 PM

smoke665

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Engine Coolant Temp

2006 F350 6.0. EGR delete, studs, all the bulletproof upgrades. New radiator,and external filter. everything should be good. However the last couple of months I've noticed that after it's warmed up and towing a load the ECT will sometimes run 10-15 degrees different under the same load. On a steep grade the ECT may climb to 215 before the fan kicks in, but once it does it drops the temperature rapidly. What I'm talking about is running along with the ECT in the 200-205, range, no fan and suddenly seeing the ECT fall to 190, then slowly climb back up to the 200-205. Its' almost like the thermostat may not be opening all the way or there's some type of obstruction in the coolant passages. These are off my Scan Gauge. Everything else seems fine, Oil temps are right in line (except when I get the drop in ECT the oil temp holds pretty much the same, though it will start to fall slowly). No coolant loss. Not sure if I have a problem or not.

Mar 26, 2015 | 04:01 PM

dannyboy950

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factory thermostat opens from 192 to 195.
Your numbers will be a little scewed since you are under load.
Delta is established by testing a full warmed engine driven on a flat road for 15 to 30 miles with no load at 65mph.

To me you are just seeing the thermostat opening and closeing from what I see.

Mar 26, 2015 | 05:32 PM

69cj

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From: Middle Tn.

Your temps look fine to me. Most people seem to be running on the cool side. Your temps are ideal in my op.

Mar 26, 2015 | 07:34 PM

WRABER

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Not concerned about the range, just trying to understand why it would suddenly go down without the fan coming on, then gradually work its way back up to the level it was. Sounds weird but its like the thermostat is opening and closing, or there's some type of temporary obstruction. Only stated the last couple of months.