If anyone is in left field, I think I know who it is.....

 

I said a cap and thermo should cure it. I really don't think RUNVS had a bad sensor, I have never heard of one going bad and he made other corrections around the same time.
You're the one that said the sensor was on top.

 

Well, I thought I made it clear that I replaced the CHT and it fixed the problem. I can see that I had one sentence chronologically (that means in order of time) backward so maybe it was a little hard to follow...

Let me type slower so you can understand.

1) I replaced the THERMOSTAT. With the MOTORCRAFT unit. It didn't help at all.

2) I replaced the radiator b/c I suspected poor coolant flow. Since I don't do it half-assed I also replaced the water pump, hoses and the fan clutch. That STILL DIDN'T WORK!! And I did replace the cap with the new radiator - I did leave out that detail.

3) I THEN replaced the CHT. Holy crap - PROBLEM SOLVED!!! 100% a bad CHT. I supposed if you have never seen one - it must not happen. If it is electrical or mechanical, simply put - it CAN fail.

4) More years of dependable service followed...

There was ZERO COOLANT LOSS. No vehicle overheats without loosing coolant. If it can't find a way out - it will make one. The level in the degas bottle never moved and this issue went on for 2-3 months. Until I finally performed step 3!

So, I can honestly say that in your assessment of what the proper corrective action was in MY case - you are wrong.......sorry!

 

That's just great. RUNVS had a bad sensor, and Brent had a bad thermostat. Got it.

Enough of the back-and-forth, it's not helping anyone.

 

And back to the OP - who no one can now seem to find - lol!! The CHT is inexpensive and an easy repair. It's one of those things like a cap or a t-stat where the cost is worth trying it. Certainly cheaper than a radiator, water pump, etc, not to mention the coolant you need to replace when done.

I'm not saying it is the CHT in all cases either, I just know it was the issue in my case. As you can see, I replaced every external part in the cooling system - and still had the issue. It wasn't until I replaced the CHT that the issue was fixed. Let me be clear that was the LAST thing I did. I heard the intake manifold needed to be removed. I was avoiding that at nearly any cost. Once I got to that inevitable step, I then read on FTE about removing the alternator and "customizing" a wrench to fit in the valley to get the sensor!

Good luck!

 

I think it does help, it can be really frustrating to have it limp constantly and anyone reading this can benefit from all the info they get. Of course a sensor can go bad but my problem was more than a bad thermostat and he didn't cure his problem by just changing the sensor only. I wish that was the only thing he did so it would be positive that that was actually the problem.
Trust me; when you are plagued with the limping problem you will need all the help you can get. In fact just the removal of the alternator and the bending of the wrench was revealed here and new to me.............it's all good.
One more thing; the restarting of the engine and lack of heat is PART of the limping ritual not an indication of a bad sensor. The sensor only detects a malfunction in the cooling system.

 

My point was that you both made valid points. Continuing to bludgeon each other over them isn't helpful, that's all.

 

Bludgeoning, LOL!! haha, just some friendly banter, Tom! I only take offense to being told I'm wrong, not offended by another opinion or solution! It's all good.

 

No, he could have had a bad sensor but I don't know the chain of events he went through so I still have my doubts. If you ever had this mysterious, frustrating problem you would welcome all the info you can get and facts are still unfolding so no need to cut it short. When it happened to me nobody could help me and they only had the standard ideas; head gasket, new sensor, thermostat, etc. but I was plagued with it for 3 weeks until I gleaned enough info to figure out what was happening on my own. This thread should be extremely helpful to anyone with the dreaded problem.

 

I'm going to get a beer and some popcorn, then come back here and watch Brent talk to himself while he continues to bludgeon the dead horse until the horse tells him he's right!

 

I only said you were wrong about restarting and proceeding like nothing happened. That's part of the limping ritual (did it 5+- times) and then it goes into 50 mph max, low power, alternating cylinders, running on 5 cylinders. etc. You learned from me and I learned from you.

 

Of course he could have had a bad sensor, anything can go bad. Changing the sensor was my next step but the dealer is 55 miles away and I wasn't looking forward to digging under the intake.

 

..........

 

Hey guys, it's a been a few days.... Life is busy and this truck is only a secondary vehicle.

So I replaced the ECT. Easy to get to, took longer to get the tools out than to replace it. It did not work. In fact, this ECT leaves the gauge at ice cold even when the car is up to temperature. With the engine at temperature, it measured 2.52 k resistance. I did check the old sensor, which (at 85F) measured 3.6 k. As I was holding the old sensor in my hand warming it, the resistance started to drop.
Seems the new sensor is not the correct one.

Anyhow, with the gauge at ice cold, getting speed up over 55mph, suddenly the gauge pegged again and the coolant light came on. Service Engine Soon light was still on.
With all this "overheating" the truck hasn't lost any coolant, so I will go for the thermostat next as it is easier to get to than the CHT. After that, the CHT will be next.

As I mentioned, this is a secondary vehicle, and it is bloody hot in south GA, so it may be a week or two before I can provide an update.

Thank you all for your input!

 

Good to hear back from you.. Not so sure what's up with the coolant temp sensor being the wrong values. I've read that you can take a cheap 3/4" wrench and put a bend in it to get the CHT sensor out without having to remove the intake.

Good luck!