I started out with a leaking radiator. I didn't want to run any leak stop so I opted for a radiator swap. I had been running about 210 with an OEM 195 T stat. since I was going to be draining the fluid to do the radiator swap I flushed the system and changed radiator, hoses and T stat. (Failsafe 180) jacked up the right wheel and ran it for a while to try and get all the air out. I buttoned it all up and went for a drive around the neighborhood, seemed to stablize just over 200. top off the tranny, I think all is good.

Today I drive to work and it starts a steady climb and goes right on up to 240ish right when I am on a long bridge with no where to get out of traffic. I get to the far side and pull over as she hit the red line at 260. I figure I am SOL at this point. radiator cap and all hoses held, I am catching a ride to work tomorrow and will try to get her home from the parking lot I dumped her off in.

At overheat top hose hot as a cheap pistol.
Bottom hose cool, both hoses hard.
Heater blowing hot enough to chase you out of the cab.

I am thinking either bad Tstat. It was wide open as can be at 190 in a pot on my stove If I can make it home, plan is to yank the T stat and see if she can stay cool with out one. failsafe says it will fail full open, but...

this water pump cooled the system before I swaped a leaking radiator so why would it fail one day after a new one. No leak from waterpump area no play in the fan.

Any advice would be greatly appreaciated my wife hates my truck (regular cab) I don't need to give her any more ammo.

I am afraid even if I solve this issue with a new Tstat as a cheap fix that going that hot I may have screwed up a ton of other stuff. (head gasket, or heads themselves) Not happy right now.

Stock 5.9 except for a 180 T stat that runs 260.

 

I hate to say it, but it sounds like the thermostat went in upside-down.

 

That was in the back of my head, but should be spring side down just like the other one came out right? I have seen that enough on here that I was careful to look and not saying it is impossible, but pretty sure unless a FailSafe is complete back wards from the OEM I am 99% that ain't it. Unless of course when I got a 180 TStat it meant it is configured 180 out from original.

 

to get the truck home, remove the t-stat completely and test drive it around a parking lot. it should stay very very cool. it doesn't matter if it leaks a little bit.

remove the new stat and test it in a pan of water on the stove. use a cooking or meat thermometer to be exact, but it should be wide open at 195, well before the 212 boiling point.

i'll bet its bad.

yes, it is installed with sensor/spring down in the manifold.

 

I was actually HOPING that maybe the failsafe was spring side up and it was going to be as easy as admitting how dumb I am.

That is the plan to try the quick parking lot T-Stat pull to get her home and see how it goes. Glad I got that little tab off the T-stat housing this weekend.

 

its easy to get the t-stat out without removing anything else. i've done it on mine a couple of times. leave the hose attached, remove the 2 bolts. don't drop them. rock the housing loose and pull it out by the hose. a good bit of coolant will spill. seems like it takes a long extension or two.

you might can reduce the coolant spill slightly by removing top hose at radiator and holding it down. this lets some of the spill occur there rather than on top of the motor.

those failsafe's are supposed to work. if it doesn't fail open like its supposed to, i'd be really pissed and save the damn thing and the receipt for evidence.

 

if you go with something different, get a Stant Superstat at Advance or other for about $10. its got a lot more material than the cheapo $5 one.

 

Just to be sure..........



Otherwise, sounds like a junk T-stat.

Unless you had your belt off and somehow managed to get it wrapped around the water pump backwards..........

 

Just food for thought. I got 3 bad stats in a row. Then I decided to get smart and get a stat from a different store. I think there was a bad batch.

 

What should be resolution:

After work I pulled the T'Stat, and drove home 10 miles never coming more than one needle width above the 130 mark.

Beffore I put it in I tested the T-stat and it worked, wide open around 185-190 so I said good enough. What wasn't good enough was my part purchase. I watched the guy look up my part on the computer and it should have been a Failsafe 7244, I remember watching him look it up and yell the right numbers to the guy who brought it out from the back. Then we looked up some other stuff. Problem is, he handed me a 7242 which fits in the housing, but doesn't have room to open up. I put it in right but it was the wrong part.

I feel like an idiot, I do my own work because I don't trust people to take pride in what they are doing, and to save a few bucks. But I let the guy give me the wrong part and I put it in. Lesson learned, now I have to hope it wasn't too costly of a lesson.

I'll let ya'll know if they let me exchange the part. If not i cash out my autozone rewards and go to advance across the street.