V8Merc124
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HI all I tend to be long winded so I can give all the info I have. sorry!
I am talking about the thermostat switch found in the cross over tube that controls the engine fan part number 12338599
Im working with a 6.5 turbo set up that was one of these rather new or very little used demilled powertrains. So the engine and radiator were flushed and cleaned many times when I had it all apart. Power steering pump was already on the engine so its in good shape and has new fluids. This was all done about a year ago.
So the story goes that the fan would never kick on even at about 220 maybe more so I unplugged the TDM for a while so the fan would engage until I found time to chase its tail. The temp on the dash never really goes past 200 -220 with fan on so it is not over heating at all. During the install of this engine I replaced the cadillac valve and TDM with what appeared to be new items that I had got in a box of parts, they were in original packaging but open and looked new and clean.
Per a youtube video I tested the Cadillace valve with a electrical tester (know it works anyway cause unplugging it the fan kicks on) and it was within the ohm? limits they claimed in the video. Good so the mechanics are good. I tested the thermostatic switch and got continuity at cold (constant beep) and I removed the switch to use a heat gun and laser temp gauge to get it up to as hot as a I could and still continuity. I wasnt too sure if the heat gun actually was able to get it to 220 so I decided to order a new switch anyway. At this point you can shake your head
I decided to use a torch and "gently heat it", still never broke continuity but got up to at the least 220 lol. Yes I destroyed the switch, I will show you whats on the inside.
The new thermo switch comes in so I install it and idle the truck to see when it will come on (I wasnt too convinced with the heat gun and the torch could ruin the switch so didnt want to do that). I come back to the truck and see its at 180 on the dash and the fan is on already?!? I laser the crossover/thermo switch and it shows a similar temp of 180ish or so (my dash agrees). Ok so I shut it down and wait to start the test again but this time sit near it and see when it comes on. This time Im quick and check the dash. 160! what the heck!?? I laser and it agrees. I shut it down and connect the electric tester to the switch and let it cool to see when continuity will come back wait for the beep. It happens at about 120-130 using the laser, dash agrees. I am very confused.
I get an exchange for the thermo switch and just did the same as above. It comes on at just about 210-200 degrees, so I drive to see if I get the temp down to where it will shut off. Nope. It wont cool past a little under 200 and the fan is still on. Theres no way the engine will cool to the point where the fan will shut off. For those wondering on the brand of the thermo switch, it appears to be military with aluminum crimped on numbers on the wire. But no where can I see a part number. Packaging came in a zip baggie with a blue plastic net thing to protect the threads (at least for the first one).
I did check the time delay module for those wondering. I have a known bad one and I also have one from another truck that functions fine. That truck is 6.2 and comes on for sure at 220 and off at 190-200? I forget now. The 6.2 tdm did the same thing as the new tdm on 6.5 so I assume it is good as it behaved the same. The known bad tdm I have will not turn the fan on at all and I got the 6.5 up to nearly 240 before I switched the tdm back. All the TDM I have are KDS brand
So the question is, are there different switch temperature ranges? Where do I find one in the right range? Or what am I doing wrong?
I know the fan is supposed to cycle on and off as you drive and bounce between 220ish and 200 as I have been on a long drive in the 6.2 truck. I dont want the fan to be on constant robbing the power.
Thanks for any input you guys have. And let me know if there is any questions you have that I can write a novel about sorry!
I am talking about the thermostat switch found in the cross over tube that controls the engine fan part number 12338599
Im working with a 6.5 turbo set up that was one of these rather new or very little used demilled powertrains. So the engine and radiator were flushed and cleaned many times when I had it all apart. Power steering pump was already on the engine so its in good shape and has new fluids. This was all done about a year ago.
So the story goes that the fan would never kick on even at about 220 maybe more so I unplugged the TDM for a while so the fan would engage until I found time to chase its tail. The temp on the dash never really goes past 200 -220 with fan on so it is not over heating at all. During the install of this engine I replaced the cadillac valve and TDM with what appeared to be new items that I had got in a box of parts, they were in original packaging but open and looked new and clean.
Per a youtube video I tested the Cadillace valve with a electrical tester (know it works anyway cause unplugging it the fan kicks on) and it was within the ohm? limits they claimed in the video. Good so the mechanics are good. I tested the thermostatic switch and got continuity at cold (constant beep) and I removed the switch to use a heat gun and laser temp gauge to get it up to as hot as a I could and still continuity. I wasnt too sure if the heat gun actually was able to get it to 220 so I decided to order a new switch anyway. At this point you can shake your head
I decided to use a torch and "gently heat it", still never broke continuity but got up to at the least 220 lol. Yes I destroyed the switch, I will show you whats on the inside.The new thermo switch comes in so I install it and idle the truck to see when it will come on (I wasnt too convinced with the heat gun and the torch could ruin the switch so didnt want to do that). I come back to the truck and see its at 180 on the dash and the fan is on already?!? I laser the crossover/thermo switch and it shows a similar temp of 180ish or so (my dash agrees). Ok so I shut it down and wait to start the test again but this time sit near it and see when it comes on. This time Im quick and check the dash. 160! what the heck!?? I laser and it agrees. I shut it down and connect the electric tester to the switch and let it cool to see when continuity will come back wait for the beep. It happens at about 120-130 using the laser, dash agrees. I am very confused.
I get an exchange for the thermo switch and just did the same as above. It comes on at just about 210-200 degrees, so I drive to see if I get the temp down to where it will shut off. Nope. It wont cool past a little under 200 and the fan is still on. Theres no way the engine will cool to the point where the fan will shut off. For those wondering on the brand of the thermo switch, it appears to be military with aluminum crimped on numbers on the wire. But no where can I see a part number. Packaging came in a zip baggie with a blue plastic net thing to protect the threads (at least for the first one).
I did check the time delay module for those wondering. I have a known bad one and I also have one from another truck that functions fine. That truck is 6.2 and comes on for sure at 220 and off at 190-200? I forget now. The 6.2 tdm did the same thing as the new tdm on 6.5 so I assume it is good as it behaved the same. The known bad tdm I have will not turn the fan on at all and I got the 6.5 up to nearly 240 before I switched the tdm back. All the TDM I have are KDS brand
So the question is, are there different switch temperature ranges? Where do I find one in the right range? Or what am I doing wrong?
I know the fan is supposed to cycle on and off as you drive and bounce between 220ish and 200 as I have been on a long drive in the 6.2 truck. I dont want the fan to be on constant robbing the power.
Thanks for any input you guys have. And let me know if there is any questions you have that I can write a novel about
sorry!
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