What should the normal operating temp of my '01 4.6 be, as indicated for instance by the odometer display trick?

After a faint suspicion that mine might not be fully warming up, I checked it on my 17 mile commute home from work yesterday, which included 10 or 11 miles of 70 mph interstate. The ambient temp was 57F. The engine temp stabilized at around 82C or 83C (180F or 181F). I'm thinking that is a little too cool, and a replacement thermostat may be in order. At 164k miles, it still has the factory thermostat, which is supposed to be rated at 195F.

I had suspected recently that it was taking a little longer to warm up in the morning, and that the heater output might not be as hot as usual. Of course, I was also second-guessing myself and saying it was only my imagination, since we were experiencing a bitter cold spell (relatively speaking for us here in Louisiana.)

 

195 deg F - 205 def F or thereabouts ... mine usually gets there within 3-5 miles, even in this Arctic ais mass crap. The TFT take a lot longer to reach a decent temp, though ... (why is that by the way?)

 

Thermostats offered, - there's only one that's in the high 180's, pretty sure it's 187. Then as follows 192 (the best IMO) 194 and 197. I would guess MGD is correct, which is why I've had the best luck with 192's. I've had problems with the last two.

 

Keep in mind, that temp you are reading is cylinder head temp, NOT water temp. They're not necessairly going to be the same thing.

 

Keep in mind, that temp you are reading is cylinder head temp, NOT water temp. They're not necessairly going to be the same thing. Also, the temp at the cyl head may not be the hotest temp o the system. That's going to be at the thermostat, which is where the water exits the engine.

Don't go chasing a ghost that doesn't exist and start throwing thermostats in it to fix a problem that's not there.

 

Yea, I think they did change that in 01 on the 4six, it was 99 on the 5four's. ECT's measured coolant temp. Eventually that job was given to the CHT's.

 

I have both ECT and CHT on my truck. My gryphon monitors them and I've had both of them on the display for awhile before and my experiance was they both have the same reading ALL the time.. I quit monitoring cht figured that was redundant.

 

You have that sensor above on the 99 ? Behind the alternator ? I thought they wiped them out completely in 99 on the 5fours.

 

The gryphon has both though so you'd think there would be 2 separate sensors. I've not paid attention to where they are..

 

I remember reading somewhere that the odometer display was CHT. However, my understanding was that CHT and ECT were usually nearly identical, which agrees with jethat's observations here

So, back to the question of "What's normal?" I think I remember checking the temperature in the same manner several years ago when the truck was newer, and seeing stable temps of around 95C or 96C (203F or 205F), which agrees with MGDfan in the first reply. I am still thinking that 180F is too cool for normal operation, and about the only thing that could cause that is a thermostat that is stuck partially open.

 

Yes, you do not want to run these motors that cool. They are designed and run most efficiently at 200+.

 

My '05 does not have a factory coolant temp sensor and reads/interprets CHT as Galaxy said. I recently installed an Isspro coolant temp gauge (for which I had to drill had to drill and tap the t-stat housing for the sensor). When the dash gauge is dead centered, the coolant is reading 195-200. WHen I did that, I wanted to replace the t-stat with a high flow (like a RobertShaw) but there wasn't one available (plus I nearly got laughed off this board for even asking ... sniff ( : < ). Danged if I didn't forget to write down which temp t-stat was in there.. .which I have now zoned out.

 

Being the OP who started this thread by asking "What is the normal operating temp?", I thought I would resurrect the thread with a follow-up report. I replaced the thermostat, which was the factory original, with a Stant Superstat. Operating temps, as indicated by the odometer display trick, went from 82C-83C(180F-181F) before the swap to 91C-92C (196F-198F) after the swap. Apparently the original thermostat had lost its calibration.

Anyway, I am happy with the new temps, as I am fairly sure that is where the truck is designed to run.

 

Well, i ran mine for maybe 9 hours of interstate driving yesterday, with some stop and go through Atlanta. The o.a. temp was high 80's, low 90's. My truck was running right at 200 for the cht. I just recently got my Gryphon, and this was the first warm weather i have had so far. I was a little concerned at first, but if this is normal, then all is well. I know the dummy gauge on the dash was in the normal place it always runs.

 

Both the 4.6L and the 5.4L have 2 coolant sensors. One for the block and one in the head.