THERMOSTAT REPLACEMENT 101 Tech PicTutorial

[gdhillon]

I am some what confused, so the wire with the 2k amps runs directly off the batteries? And when the trucks on the alt puts.out 85 amps back to the batteries?

 

[riotwarrior]

I am some what confused, so the wire with the 2k amps runs directly off the batteries? And when the trucks on the alt puts.out 85 amps back to the batteries?

K this is actually an extremely important bit of information....I'll start a seperate thread for this *****!

 

[Blind Driver2]

I am some what confused, so the wire with the 2k amps runs directly off the batteries? And when the trucks on the alt puts.out 85 amps back to the batteries?

The total battery amperage runs through the big wire that goes to the solenoid, then to the starter. Both of those wires should be the same size.

When if alternator puts out 85 amps, never charge a dead battery with the alternator. You'll get that alternator hot enough to fry bacon.
Frying bacon will kill the alternator bearings and won't the windings any.

 

[whiteboyslo]

Very nice write-up! Can anyone explain a bit more about the little ball, though? What does it do, how did you remove it, what do you do if yours is missing, etc.

Mike

 

[icanfixall]

About the ball. The design is to allow trapped air to purge out of the cooling system back into the radiater. then when the coolant touches the ball it pushes the ball up to close off this pathway. Most times if you squeeze the top hose from the thermostat housing you can hear the ball clicking in the housing if its there and its not gumed up with corrosion.
About the hot wire being continuse hot.. Just follow the wire back to the solenoid and battery. Its always hot. So is the wire going to the glow plug solenoid. Its the yellow wires. Then the battery cable going directly from the two batteries down to the starter. That cable is always hot. If you feel this is not true just use a digital voltmeter and test this information...

 

[riotwarrior]

Very nice write-up! Can anyone explain a bit more about the little ball, though? What does it do, how did you remove it, what do you do if yours is missing, etc.

Mike

Good question and Gary's answer is spot on

About the ball. The design is to allow trapped air to purge out of the cooling system back into the radiater. then when the coolant touches the ball it pushes the ball up to close off this pathway. Most times if you squeeze the top hose from the thermostat housing you can hear the ball clicking in the housing if its there and its not gumed up with corrosion.
About the hot wire being continuse hot.. Just follow the wire back to the solenoid and battery. Its always hot. So is the wire going to the glow plug solenoid. Its the yellow wires. Then the battery cable going directly from the two batteries down to the starter. That cable is always hot. If you feel this is not true just use a digital voltmeter and test this information...

Gary, Quoted and placed in the thread! Thanks for the explanation!

 

[whiteboyslo]

Just wanted to bump this thread to add a pic I thought y'all would like.

My truck's been running at 205 (give or take 5 degrees) ever since I installed the temp gauge. It's an Autometer digital gauge with the sensor in the factory over-temp location. Not a bad temp, depending on who you ask, but it shoots up as high as 230s while towing fairly light loads on inclines. Not cool (pun intended), so I decided a new thermostat was worth a try.

First and foremost, this thread is a FANTASTIC write-up! Everything was spot-on, and really shows that, while this is way more work than it is on most other cars, it's not really that bad.

So, to try to prove to myself that the thermostat may be my problem, I threw the old unit and the new one in a boiling pot of water. I think these pics speak for themselves (new one is the one with the black bottom):

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This is after both units had plenty of time to soak. The old one is clearly not opening anywhere near as far as the new one, and it creaked and groaned something awful the whole time it was opening.

Given the low miles on the truck, I would assume this to be the original thermostat. Can't find any markings on it to suggest otherwise. And yes, the new one is a Motorcraft unit.

Got the truck torn down right now. Ran out of daylight, so I'll finish it tomorrow and report back with results. I'm also replacing the fan clutch with a new Motorcraft unit as well since it seemed to engage (or not engage) very inconsistently and erratically.

Mike

 

[Agnem]

Excellent write up! And most certainly tech article worthy. Instant fame. Off it goes.... Thank you!