[thehunter012]

I was coming home from the lake the other day, freeway driving, and stopped to get some food. engine had been running a little hot but figured it was simply from the air temp combined with runnin on the highway. turned off my car and I hear a gurgling noise, followed by the sound of antifreeze falling all over the ground. finally made it home, and the engine was real hot this time. again when I got home, it boiled over and there was antifreeze everywhere. next day I made an auxiliary switch for my auxiliary fan, blew out all of my old antifreeze (which looked pretty old and dirty), installed a new Stant 195 thermostat, got a new 15psi pressure cap, and refilled with new 50/50. drove it around, worked great for a few days. yesterday I went to get gas and it did it again. antifreeze everywhere as soon as I cut the engine. got home, I let the jeep run, both fans on, and just watched the temperature rise. there was some coolant in the bottle. temp started to hit the red so I figured Id shut it off, and right when I did the cap exploded off and once again, antifreeze everywhere. I'm going crazy. my biggest fear is that i have a blown head gasket and the exhaust gases are superheating the coolant, increasing the pressure, and causing the pressure to go over 15psi, which then releases the pressure cap slinging the near-boiling coolant out as well. any ideas? btw it's a closed cooling system.

[dukie564]

Sounds like your water pump isn't operating correctly

[thehunter012]

I thought about it but did some research and found out that most water pumps leak before they go out. and I'm not leaking any coolant so I figured it was fine but maybe it's just not functioning properly?

[tangofox007]

The problem could be related entirely to the pressure bottle. If it fails to seal completely, the coolant will boil at a lower temperature and cause a "blowout."

I have seen the bottles develop cracks the leak pressure but not much fluid. Also, the bottle necks tend to soften with age and fail to seal completely.

[dukie564]

Originally Posted by tangofox007

The problem could be related entirely to the pressure bottle. If it fails to seal completely, the coolant will boil at a lower temperature and cause a "blowout."

I have seen the bottles develop cracks the leak pressure but not much fluid. Also, the bottle necks tend to soften with age and fail to seal completely.

above poster is correct.

If there is no cap on the radiator itself, you have a closed system
which DOES pressurize the plastic tank, period.
If its boiling inside the tank the tank may not be holding pressure,
does it leak?

Secondly, If you've been working on the cooling system and had the
hoses off, make darn sure you put the bypass and heater hoses back on
the right way. If reversed, the bypass hose will suck air in from the top of the
coolant tank and lead to boiling.
Observe:
Three hoses at the front. Big one (of-course) to the rad top.
Thermostat housing hose direct to heater core on/off valve and T's to top of recovery tank. Return hose connects to the metal tube rising from the water
pump and should depart from the bottom of the recovery tank (with a T
off the the heater core).

Third, you may have air in your system, and it you need to bleed the air out. I don't know how to do this on this year though.

personally, i would just get a radiator and overflow bottle from a 1991-1995 XJ to replace your system (they have open systems with the cap on the actual radiator) and save yourself future headaches as hoses and plastic components wear out. The closed system was a terrible idea / terrible execution anyways.

[thehunter012]

thanks. hoses are in correct position. and seeing as my overflow bottle is currently empty with all the blowouts, ill take it out and see it if is leaking any/redo the connections. anybody know how to properly remove all the air from a closed system?

[tangofox007]

Originally Posted by dukie564

The closed system was a terrible idea / terrible execution anyways.

The only problem with the closed system is the unreliable plastic pressure bottle and poorly designed cap. There are plenty of vehicles with closed systems (Mercedes being one example) that operate as they should because they have better-designed pressure bottles that seal with a conventional radiator-type cap.

The plastic bottle can be very easily (although not inexpensively) replaced with a metal tank. I have one on my '88 and have had no issues whatsoever since I installed it several years ago.

[tangofox007]

Originally Posted by thehunter012

anybody know how to properly remove all the air from a closed system?

Removing the temp sender at the rear of the head is probably the quickest option. Otherwise, the air usually works its way out in a few warm-up/cool-down cycles. You will know you are making progress when the heater blows hot air.

[cornbrizzle]

jeep replacement surge taks


Get something like these .




Brizzle

[thehunter012]

wait where is this temp sender at? not the furthest rear plug comin outta the top of the valve cover is it?

[cornbrizzle]

on the drivers side back of the head you will see a single wire and conn on the top of it, remove the conn. and use a deep socket to remove very carefully some times they get brittle with heat and age .



Brizzle

[thehunter012]

that diamond plated surge tank looks awesome, little expensive though.. hmm. wonder if it uses the same original 15psi cap? still gotta check for any leaks in the plastic bottle but then I'll refill and make sure to get all the air out

[tangofox007]

Originally Posted by thehunter012

that diamond plated surge tank looks awesome, little expensive though..

I spent more (collectively) on replacement plastic tanks than I spent on the metal tank. Not to mention lost coolant and the hassle of unplanned breakdowns that occurred at the worst possible times.

Originally Posted by thehunter012

...wonder if it uses the same original 15psi cap?

I use a 13 psi cap on mine, but you can choose whatever you like. I have a Wrangler with the 4.0L engine that uses an 18 psi radiator cap.

[thehunter012]

I went ahead and ordered the metal bottle. said it comes with it's own cap. I had taken out the plastic bottle and there were hairline fractures all the way down the sides. nothing that would've allowed much fluid, if any at all, but overall didn't look reliable. and it was just plain dirty. plus that diamond plated box looks cool. hopefully this'll take care of my problem cause I'm just tired of spewin antifreeze. it's embarrassing.

[tangofox007]

Originally Posted by thehunter012

...I'm just tired of spewin antifreeze. it's embarrassing.

I know that feeling. People honking and pointing at the stop light. But I have had none of that since I bought my metal tank.