Need Help

I am totally stumped...Flushed the closed Coolant System today, new thermostat, and new radiator (old one had a leak) and had this one on hand...Start the Jeep and it stays at 210F with both fans running but the reservior keeps boiling over...nor does the water level in the reservior go down...How does this happen...went back and got a new thermostat and same problem..lost...Please help..

is the lower hose collapsing? sounds like something is plugged up.

AIR in System!!!!!or Collapsed Hose

Finally got the thing filled..is there a "process for getting the air out of the system??There wasn't a collapsed hose..I ran it to 210F then turned it off...let it cool and then added fluids...did the process twice and now is running fine at 195F...For future reference is there a way I can PREVENT air in the system???

91XJBUBBA said:

Finally got the thing filled..is there a "process for getting the air out of the system??There wasn't a collapsed hose..I ran it to 210F then turned it off...let it cool and then added fluids...did the process twice and now is running fine at 195F...For future reference is there a way I can PREVENT air in the system???

Click to expand...

there is a temp sensor on the back of the head next to valve cover on the driver's side, 7/16ths I think, pull that out then add coolant till is comes out of there. That is usually where the air pocket is.

Justin

91XJBUBBA said:

Finally got the thing filled..is there a "process for getting the air out of the system??There wasn't a collapsed hose..I ran it to 210F then turned it off...let it cool and then added fluids...did the process twice and now is running fine at 195F...For future reference is there a way I can PREVENT air in the system???

Click to expand...

This is a common issue with this system, and if you do a search you might find references to "burping" the system. That's basically what you did, except that you don't have to shut it down. When I had my 87 I would start it up and run it with the cap off and the tank nearly full. As it heats up, it burps and swallows the tank full of coolant, you add more coolant, and repeat until it stabilizes.

On pre-98 models you need to set the climate control to hot so the heater valve opens, otherwise you can get air trapped in the lines

It sounds like thermostat was on backwards though. Spring goes inside the engine

I've had a faulty radiator cap cause a similar issue on a Ford. I'm no expert though.

Just for Shitz and Giggles, how about starting your threads with Year/Engine/blah/blah/etc.?

Closed system (A**uming):

1. Drill two holes in the thermostat flange, far enough in from the outer edge so that the gasket/housing won't cover them. Drill them 180 degrees apart. Install thermostat with one hole at 12 o'clock, and the other will be at 6 o'clock.

2. Park the XJ nose down on an incline. Carefully remove the temperature gauge sending unit from the driver's side rear of the head. Add coolant through the pressure bottle (not a "reservoir") until all of the air is expelled from the system. Reinstall the sending unit.

3. Use a Volvo 740 2.3 L engine cap on the pressure bottle, Stant part number 10244. It will seal tightly on the bottle, OEM or aftermarket, it sits lower so it won't impact the underside of the hood when the pressure bottle expands and that will reduce cracking in the pressure bottle, and lastly it has a higher pressure rating and will raise the boiling point of the coolant.

4. DO NOT fill the pressure bottle more than 1/3 full. The other 2/3 of the bottle is to contain the heated and expanded coolant.

RE #3 above: does the Volvo cap have a better designed gasket than the Jeep one as well? I always had trouble with mine because the gasket displaces if you over-tighten it, but doesn't seal well if you don't almost over-tighten it. If the Volvo cap has a better gasket this recommendation should be stickied or FAQ'd or something.

Matthew Currie said:

RE #3 above: does the Volvo cap have a better designed gasket than the Jeep one as well? I always had trouble with mine because the gasket displaces if you over-tighten it, but doesn't seal well if you don't almost over-tighten it. If the Volvo cap has a better gasket this recommendation should be stickied or FAQ'd or something.

Click to expand...

Well, Ecomike and I have had ZERO problems with these so far.

One of the common problems with the aftermarket bottles and caps is they "strip" and won't tighten, and as you know w/o pressure there goes your boiling point. Some use a hose clamp around the cap, others have tried wrapping the bottle threads with tape. So far the Volvo caps have proven the "better" fix.

Thanks for the insight...Jeep WAS running fine..Drove around 40 Miles yesterday stayed right at 195F and around 30 Miles this morning and ran great. Jumped back in it this afternoon and drove 10 miles and the temp rose to around 220 before I shut her off..Is it possible that the water pump is working off and on? Should the next step be to completely remove the thermostat and see how it runs? At 220 the Pressure bottle was obviously boiling over...Now What???

Sorry...Its a 91 Xj 4x4 I6 Closed system with a new radiator and new thermostat...

91XJBUBBA said:

Sorry...Its a 91 Xj 4x4 I6 Closed system with a new radiator and new thermostat...

Click to expand...

Do 2 and 3 from my post above, you may have some air trapped or a lack of pressure on the system--boiling point will be lower w/o pressure.

Make sure to replace the radiator cap. It can cause exactly what you are seeing. I would hate to count how many I have seen fail. They look perfect, but they don't hold the pressure. A radiator cap should be 16#. They should be replaced every two years.

I did the combination of everything you guys posted and not sure what part fixed the problem but its FIXED! Jeeps are a funny thing and I find it amusing that someone had to figure out to park the Jeep on a hill and then drill out the thermostat and ect...ect...I love it...Thanks for the help I would be scratching my head if it wasn't for ..Will be going red with next pay check!!