Cooling help needed

Ok, I know there are alot of threads about cooling on here, but I couldn't find the answer....I think I know what the problem is, but I'm looking for conformation or other points of view.....so, here goes.

My jeep had been hacked from the previous owner, so the heater core was missing, so they bypassed it, and I thought my preasure bottle was cracked because it would heat up fast, as in, fire it up and not even get one mile from the driveway and she's hittin 240....the fluid in the preasure bottle would boil, so my thought is that my preasure botle is cracked or there is a leak in the system and not holding preasure, causeing it to boil at a lower temp.

So, since my system was hacked up and I thought I needed to replace the bottle, and I hate "burping" the system, I converted it to an "open" system this way: http://www.geocities.com/bigbadxj/Open_System_Switch/open_system_switch.html

I cut into my upper hose, and had no water in it at all! Installed everhting and filled up the system, it took about 3/4 of a gallon of distilled water...I fired it up and let it idle, in about 6 minutes of idleing the temp guage read 240 and still climbing, so I shut it off. While it was idleing I was watching, and even though the motor got hot, no water ever expanded into the overflow bottle (mine is white, unlike the one in the link). I checked the upper radiator hose, its got preasure on it, but its cold! I put my hand on the radiator and it also is cold! I crack the cap, the preasure is released into the overflow bottle, I remove the cap and the water inside is clear, so obviously it didnot mix with the other coolant (what was left in the preasure bottle and hoses was obviously green)....further inspection is that the water pump is brand new (installed my previous owner) So, my thought is that he put the wrong pump on and it is flowing backwards, so all the water I poured in, was preasurized against the thermostat, and water is being traped in the block and heating up fast.

Wow, I wrote alot.

Any opinions are welcome.

Thanks,
Justin

Pull your thermostat. It may not be opening, or it may be the wrong one, or it may have been installed incorrectly. They're cheap -- be a big spender and buy the genuine Jeep t-stat from a dealer and try that.

Ok, I figured that I would replace the thermostat if I replaced the waterpump, but if it was just the thermostat sticking then why would I have preasure on the upper hose and the water be cool, not 240 degrees like it is in the block?

Justin

sounds like a blown head gasket.

jneary said:

sounds like a blown head gasket.

Click to expand...

What are your indications...that was my first thought, but I checked the oil, and it was clean, coolant in the preasure bottle (before I removed it) was light green, no sign of oil contamination, all I get in the upper hose/new radiator cap is clean clear water no mixing of the water I added and green coolant, and I can't find any sign of bubling or compression in the coolant, although I don't have access to a CO2 sniffer to be sure.

I guess tomarrow I'll try to drain some out of the bottom of the radiator to check it there since I don't seem to be getting any flow in the upper hose.

Thanks,
Justin

You really need to follow Eagle's advice. There will be no flow in the upper radiator hose if the thermostat is stuck closed. However, the whole system will be pressurized. There is a small bleed hole in the thermostat to let the pressure through and it would also pressurize back through the pump and lower hose. I would not bother pulling the pump untill you REPLACE the thermostat with one from the dealer.

MoFo said:

You really need to follow Eagle's advice. There will be no flow in the upper radiator hose if the thermostat is stuck closed. However, the whole system will be pressurized. There is a small bleed hole in the thermostat to let the pressure through and it would also pressurize back through the pump and lower hose. I would not bother pulling the pump untill you REPLACE the thermostat with one from the dealer.

Click to expand...

10-4....its on tomarrow's agenda....so if it will allow both hoses to be preasureized, will it cause the ratiator to reamain cool?

Justin

Yeth...If the thermostat is stuck or installed backwards you will not get any flow from engine to radiator. It will be a REAL closed system.

I'm not sure it applies in this case, but when I replaced everything in the cooling system on the 88 MJ, I filled it with water, and some flush chemical. I tried Eagles method of burping the closed system, but the thing just rapidly overheated. I think I had a huge bubble near the water pump, and no fluid was flowing. I back flushed it, and slowly added coolant through the pressure bottle and through the upper radiator hose, along with some rocking back and forth. This seems to have worked, I've had to add very little coolant after that, and the thing runs cooler than ever.

So I think it is possible to have so much air in the system the waterpump won't work.

Fred

Ok, so I picked up a new thermostat at the dealer today.....probably not going to install it today due to rain, but anyway...I've read on the board here that there should be a small "bead hole" however in the new thermostat there are no holes, I asked and the guy told me that it was the only one it called for.

The part number I got is:

1-83501426ac

Anyone else confirm this number?

Thanks,
Justin

bust out the drill and put a little hole in it then. The OEM one with the hole has a little ball-valve thing in it, but I've never had any problems just drilling a small hole.

if you want to make sure you get all of the air out, remove the heater hose from the thermostat housing. then fill the ystem, that will force the air out of the housing. when the coolant flows out steadily, reinstall the hose and top off the system. the head gasket can be blown and not leak into the oil. there could be a void in the gaket between a combustion chamber and a water jacket. if so, the engine's compression would push the coolant back out to an opening, like the radiator cap. its worth checking out.