Ok I have a question for you guys my 88 xj with a closed radiator system keeps boiling over the coolant bottle. It didn't overheat it was at about 150 degrees when it started to overflow. What would cause this to happen because it's very frustrating at this point.

Thank you
Eric

 

start by replaceing the cap,those caps go bad after a couple of years,or you can put a big hose clamp on it to keep it from poping off,what its doing is the system is getting hot and expanding like normal but its pushing the cap off happened to me to.

 

I just bought the new bottle 3 hours ago it didn't pop the cap off it just leaked out of the cap.

 

then try putting a hose clamp on it,let cool all the way down tighten the cap put on clamp

 

Hmm I don't think will fix the problem though. There's most likely a problem with the system. If I clamp down the lid wouldn't it just blow off because of the pressure?

 

No,when I changed my bottle when I first got mine it started doing the same thing,I played around with it,asked around on here and got the same advice,worked great.that cap is only screwed down all the clamp is doing is keeping it from pushing up.

 

Well I tried everything else so I might as well give this a try thanks for the advice.

 

It will work,I was skeptical at first to.

 

so that didnt work at all, it stilll overflowed so im gonna order the steel tank from macradiators.com that should solve it hopefully

 

try flushing your system. my 88 was doing that and i flushed the system and it was fine. my heater core was blocked and the pressure would blow out the bottle.

 

Best fix is a later open style radiator. I just had to by a new one row and it was $109 or about $60 for a used one at the local pull a part. There are some changes to be made to the heater and radiator hoses but it is self explanatory when you look at them. This swap gives you an open system with a regular radiator and cap
clint

 

I've never flushed a system before they have a kit at walmart is that any use or just do it by myself?

 

if its still blowing the cap you have other issues,try flushing the system really good,also make sure that its burped really good to,did you try replace the heater control valve yet.

 

What's the heater control valve and where is it located?

Also I'm not entirely sure if I burped it correctly, is there a way to check if it is burped all the way?

 

Check out my thread https://www.cherokeeforum.com/f2/rad-replacement-51417/ . I am going through the same ting with my 88, I'm changing it over to an Open system using a Rad out of a 93. The only two things you have to modify is a bracket for the over flow bottle, and run a jumper where the current temp switch plugs into the wiring harness, this will run your electric fan any time the key is on or you can use a switch. As for the heater hoses run them straight to the core, the hose that comes off the pump goes into the top tube at the firewall while the lower tube's hose connect to your thermostat housing. This might be your best route if there is a lot of miles on your rad and it could be starting to plug up.