How many damned t-stats do I have to go through to fix this ****?!?!? I swear, if I get another t-stat this weekend I'm going to get a 180ยบ.

 

just to be doing, try running with no t-stat. it should run pretty cool, and likely turn on cel. see if it does that, or continues to run hot.

 

Well, I went from OKC to Rockford, Ill and back over Labor Day weekend (1,700 miles round trip) and she ran hot the entire time. When I pulled in for gas, I would pop the hood to see that the overflow had spurt into the engine bay. Same story each time, almost a gallon of coolant low. As I would get back onto the Interstate, the needle would shoot to almost 240ยบ , drop to 190ยบ, and then hang at 215ยบ. So long as I was moving, it was fine, but if I had to stop, she'd climb. If I put it in neutral, while stopped, and revved the engine, she'd cool down. That led me to suspect the water pump.

Tonight, I *finally* got the time to pull the pump. As I removed the accessory drive bracket I came upon a bolt to the water pump, located behind the idler pulley, that was LOOSE. I'm wondering if this caused the water pump to suck air into the system, which is why I always bled it, which didn't make a difference. Once I get some daylight, I am going to inspect everything and decide if I want to take it in and exchange it for a new unit.

I think I am on the right track. If anyone thinks I am crazy, let me know.[&o]

 

Yeah, I think you're crazy. If it were my truck, I would have been pulling my hair out but nature is beating me to it. lol
Seriously though, you may be onto something although, did you have any leaks at that bolt? Seems under pressure it should have seeped or something. Could it also have cocked the water pump enough (or at all) to have caused it to drag. Just thinking outloud. Also, something mentioned above about while you're moving, you're good. When stopped the temp. goes up. While this is normal even in a well cooled engine, albeit the temp. readings, that seems to lean toward a blocked radiator too. Either internally or externally. Again, thinking outloud.
As always, good luck!
WC

 

Yesterday I spent the day chasing around trying to get the clutch fan removed from the old pump. I took my pump back to O'Reilly and had it warrantied out (it hasn't been a year yet) and paid the difference for a *new* pump. There was a big difference between the two in that the new pump had a bit more resistance in the spin, whereas the rebuilt unit spun faster. If a water pump spins too fast then it will cavitate, and cavitation creates air pockets. Got the new one installed yesterday and let the sealant on the seal cure overnight. I also got smart and wrapped the bolts to the water pump in teflon tape. FYI WayneC -- the water pump wasn't cocked due to that bolt that I stated was loose and was partially out. Also, I did not see any seepage from that one bolt. Very strange. Also, while at the steamshow in Wisconsin, I scored an old Craftsman needle style torque wrench, which is more accurate than those clicker turds offered today. $10 and I used it on every bolt for the pump I'll be damned if I'm giving that thing up.

Today I buttoned everything up, topped off the coolant, and fired up the truck. I watched the coolant level and burped the system (the truck has been on ramps since Friday night) and it went smooth. When the t-stat opened the coolant level dropped bigtime. I topped everything off and even had the heater on to circulate fluid. She ran for a good while and stayed locked at 195ยบ. Boy am I happy! I have to tinker with the bracket for the air cleaner, button everything else up, and then take her for a test drive. I am very confident that I finally nailed it, because when I would burp and add coolant before the gauge would be at the cusp of 200ยบ, whereas now there is a comfortable margin.

I'll post an update after the test drive.

 

Sounds like you might have it thisXXXX scratch that... You HAVE got it this time! Positive thinking and all. Well, I'm pulling for ya.
WC

 

OK, took the truck for a test drive last night and on occasion she'd jump a bit past 210ยบ and then plummet to 190ยบ before stabilizing. I ran five miles up the road and back home again (up and down some hills), so I know the engine was getting a good workout. This bobbing of the gauge tells me there is just a bit of air working its way around in there.

This morning, I drove the truck to work. We got a cold snap in Oklahoma this morning with the outside temp being 57ยบ. About a mile from the house the temp spiked to 220ยบ and then plunged to 195ยบ. All the way to work (35 mile drive) it would bob slightly to 200ยบ and back to 195ยบ. At one point, during a stop, it dropped to around 190ยบ. Needless to say, I am *VERY* pleased that I finally got this nailed down, and I can drive with great peace of mind. I plan on parking on a better incline at the house, on ramps, and work to bleed out the remainder of the air. I hear just a bit of water rushing from under the dash, but not like it did before.

Thanks to everyone who followed this thread and offered up advice. I hope it was a learning experience for some (such as those recommending yanking the heads!!! [:@] )

 

Glad you got it figured out. As a rule, never buy the cheaper line of rebuilt parts from the chain stores. Usually there will be one with a 1yr warranty and one with a lifetime. For example, on alternators and starters, Oreillys carries 2 rebuilt brands one with a lower warranty. My understanding of what happens is the one with the shorter warranty (and lower price) did not undergo a complete rebuild. They took the part and replaced the broken (or worn out) part within it, cleaned it up and then resold it. The one with the lifetime warranty had a complete internal rebuild of all wearable parts, essentially a used case with new internals. At least, that was how it was explained to me when I worked there part-time a couple years back.

 

Good point. When I am at the FLAPS and see people quibbling over $2 for lifetime brakes, I laugh and shake my head, as I always get the lifetime. Well, it is a lesson learned in this point and I have some further knowledge for future troubleshooting.

 

Just an update. The truck is running great and I burped the remaining air out of the cooling system today. My driveway has a slight incline, so I put my oil change ramps out and drove the truck up on top of the ramps in the drive. I pulled the cap, fired it up, and let it warm up. After a few moments the upper hose was getting damn hot, while the lower was cool. It was never like that with the old waterpump. I would squeeze the upper hose and hear a choking/gurgle sound. I topped off with some coolant just above the cores of the radiator and then went back to work on the upper hose. A few minutes of squeezing and next thing I know there's just an occasional surge of coolant with each squeeze and no more gurgle sound.

I love it when a plan comes together!