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Got a new temp sensor and installed it. While it is not leaking as bad as the previous, it still does leak coolant. Tried to get a picture but there is a lot in the way. Looks like a couple of inside threads broke off either while removing the old one or installing the previous one.
Unsure what the next step here would be. I am hoping it is not a new intake manifold.
Odd problem. NPT threads are actually designed to be "cranked down". It's the whole point of the taper. Looks like both types often come pre-sealered.
If it was a water tank you'd just crank it down until it stopped leaking. Are you going by feel or using a torque wrench? Can you post a picture of the sensor? The thread marks will tell you how deep it's going.
The sensor threads down all the way to the manifold smoothly. No torque wrench, I was able to thread it about 80% of the way by hand then another turn or so with the socket put it as tight as it would go.
Does your camera have closeup mode? Usually looks like a flower in the settings.
It surprisingly does not... I can't get a better picture disconnecting some of the wires in the way. Perhaps tomorrow I will check them. I was thinking about getting a larger wrench and seeing if I can tighten it anymore. At this point what is the difference if I possibly cause more damage
The sensor threads down all the way to the manifold smoothly. No torque wrench, I was able to thread it about 80% of the way by hand then another turn or so with the socket put it as tight as it would go.
I would say from your description of being able to hand thread the sensor 80 percent tells me the sensor was possibly tightened too much previously. Thread damage in the manifold may allow you to do this. Whenever I installed one of those, the sensor was up to 80 percent in AFTER properly torqueing. Like I said before, 2-3 threads should still be showing after properly torqueing. If it goes beyond that, you may not get it 100 percent sealed with that manifold. If the sensor ground is established at the connector, you could try Permatex 2B on the threads of the sensor but be sure that the source of the coolant isn't from somewhere else first.
The original sensor that came with the truck was torqued down all the way to the hex. Found some gasket maker for cooling systems at Napa. Will try to get it installed again early tomorrow as the instructions state that it takes about 24 hours to cure.
I wanted to replace this sensor because I thought this was the source of the temp gauge fluctuating so much. Then I opened the radiator cap and saw nothing but rust. So I decided to replace a lot at one and here we are!
You could try some goo to seal the threads, but it sounds like you're just postponing the inevitable. With rust in the coolant system and a bottomed temperature sender, someone has already abused &/or neglected this thing. So even if you stop this leak, the resulting higher (correct) pressure will just blow something else out. So rather than waste this time, effort, & money just to spend more of each soon, I'd pull the manifold & install a better one. It probably won't be quick or fun, but it'll be quicker, less hassle, and cheaper than doing a bunch of wasted work first. A good way to see what you're in for is to get a junkyard replacement manifold. That'll also give you a good opportunity to collect some used bolts, since you'll probably need a few. Collect them from SEVERAL engines - not just the one you get the manifold from. Get at least one plenum bolt (to replace the T40 in the center), several of the short intake bolts, and a few of the medium ones (the one closest to the temp sender). I'd also grab some water pump & timing cover bolts for when you have to do that job.
These show 5.8s, but they're nearly identical to your 5.0L:
02-18-2019, 11:34 AM
