Yeah, it has something to do with burping the system, but I've yet to figure out why he'd use it for just that. I thought maybe it had another purpose. It's all new to me, guess that's why I'm so curious about it. This Jeep is a 4.7L, with a 195 degree thermostat, and a 5.7L radiator in it. There must have been some sort of an overheating issue that sparked the enginuity. It's mine now, so I'm hoping to figure it out. Looks like I'm the only one sporting a ball valve on the bleeder, just wish I fully understood why, lol!The previous owner was a Jeep enthusiast, lots of off-reading I think. I guess he knows why he'd put it on there.
Does the 4.7L fan shroud and electric fan bolt right on to the 5.7L radiator?
The stock cooling system is mostly adequate (if barely so) for the engine. The thicker core on the 5.7L radiator might be a decent upgrade, provided the electric fan and shroud work properly with it.
A 195F thermostat (90C) is standard for this engine. That's the right thermostat. If you put a cooler thermostat in it (or if the previous owner did), it's really important to fully adjust the "tune" to match the thermostat.
If your "tuner" only says he/she is setting fan activation temps to match, they aren't fully adjusting. There's no power or economy to be gained from a lower thermostat temp on this engine, even if you fully
tune for the lower temps.
Maybe the previous owner was a railroad buff? Maybe there was a whistle attached to that valve and a pull cord run into the drivers area.
I don't see a point unless cooling is as constant battle for the prior owner. I'm battling a cooling issue due a removed clutch fan by a prior owner and nothing added to make up for the needed air difference to help with cooling. A bigger radiator is nice though. It sounds like the prior owner tried to improve the cooling system. Without knowing the work done exactly that would lead me to believe it could be causing the problem your having too. I wonder if the ball valve has a seal issue?
Are you sure yours left the factory with a mechanical fan and clutch? Most did not have that option. That was "heavy duty engine cooling" and was part of the "Trailer Tow Group" optional equipment.
To check, go to https://www.jeep.com/webselfservice/...etServlet?vin=
and after it complains that no VIN was provided, click in the location bar on your browser and put your VIN after the "vin=" at the end of that URL. It will give you a PDF file of the "build sheet" for your Jeep.
If you don't see "Heavy Duty Engine Cooling" on the list for your Jeep, yours didn't get a mechanical fan and fan clutch.
My experience from the past week or so (more research in progress) is that the stock electric fan will adequately cool the 4.7L without the mechanical fan in most conditions. I am going to have my fans reprogrammed to activate at 207F-210F degrees. The stock settings seem to wait until 216F-217F, which IMO is cutting the margin a little thin. At 18PSI (new radiator cap), the coolant shouldn't boil until over 225F, probably over 230F if it's mixed between 50:50 and 65:35 for coolant:water.
With a weak pressure cap, it's certainly possible for the thing to boil off coolant at 215F to 217F before the electric fan cuts on.
On ours, even sitting still, with the new cap installed, but with old coolant, an old water pump, no mechanical fan, sitting still either engine idling, or engine running unloaded at 2000 to 2500 RPM's, the electric fan cut on by 217F, and within less than 60 seconds, the fan would cut off when the engine coolant temp dipped below about 194F.
On another forum, I had a report from a Dodge Ram truck owner who removed the mechanical fan and clutch on his 4.7L V8 Dodge Ram truck and even towed a trailer for long distances with it without the mechanical fan and clutch. He carried the fan and clutch around with him, especially when towing, but never needed to put it back on.
Also, if the ball valve has any issues sealing, you'd see coolant seeping out the top when you stop. I doubt that would be an issue, but it would be obvious if it was leaking around the ball, though perhaps less obvious if it's leaking from the pipe fittings below the ball valve, though.