Jeepxj1988

Hi all...

Been reading this forum since I bought my first Jeep ( a 1988 Cherokee Laredo 6 cylinder standard transmission ) 2 months ago. Paid $400 for it. 275,000 km, runs great... so far I have replaced the rear drive shaft u-joints.

Tons of great info... and I hope someone can help me with my problem...

The radiator was leaking ( on the top left, as seen from the front of the Jeep ), so I decided to add some rad sealer... well, it sealed the leak fine, but...

Then it started overheating.... quickly getting to the 3/4 mark on the dial.

I must have sealed it TOO well.

Checked under the hood... the engine and hoses were hot, but the radiator was cool!!! I figured either blocked in the rad or just not circulating.

Started to take the radiator out... found NO coolant in the main hose that goes from the top left to the thermostat housing... I expected some coolant to spill out. Also found NO coolant in the hoses attached to the thermostat housing either. However, the plastic coolant tank is full.

Could all this be caused by the thermostat itself being blocked / sealed shut? I plan to get a new thermostat tomorrow morning, but I am interested in other opinions and advice.

Thanks in advance.

djb383

Sounds like the rad cap is bad, the cooling system is low and possibly the t-stat is bad also........maybe more.

PingPong

You have what is reffered to as a closed loop sytem. It is a pita to get all the air out of the motor. There are many methods out there, but they are all a pain. Do a search on how to burb a closed loop cooling system.


I recommend doing either the open rad conversion by swapping in a later model rad. I did this on my87 xj and have had no issues

firstime00XJ

You also may want to rule out any blockages. Sometimes radiator sealers can plug heater cores and lines. Does the temperature fluctuate or does it stay consistent?

Jeepxj1988

Thanks for the replies.

The heat increases like normal, but continues to the 3/4 mark, and will go down to almost the 1/2 mark, then back up again.

I checked, the electric fan is not coming on ( thats not what brings the temp down )

firstime00XJ

I think PingPong has it. This sounds like you've got an air pocket in your system. I would try to get the air pocket out, and then see how your Jeep does with temperature control.

98 JeepJeep

sounds like your dealing with the other results of the stop leak they dont tell you about.........

firstime00XJ

I was thinking the same thing until he said that the temperature fluctuates...so I'm thinking it could still be the results of stop leak they don't tell you about or an air pocket.

Jeepxj1988

Again thanks for the replies... I have since changed the oil ( the old oil was cruddie and black, but no coolant in it ) and did some checking of the coolant system ( took the rad out and the top hoses )

I found that the was a MAJOR blockage on the bottom hose off the plastic coolant tank... filling the hose for about 2 inches... cleaned that out, and now it behaves properly... slowly rises to about the mid mark and then the thermostat opens and you can see the temp drop and feel the temp in the hose that goes to the top of the rad getting hot ( as the thermostat opens ).

BUT... after I run it for a while ( maybe 15 minutes or until it heats up totally ) and then shut it down.... I hear a LOT of gurgling, and have seen hot coolant "pressure" itself out of the plastic fill tank.

All the hoses are ( properly ) hot, the rad is warm/hot, and the engine itself seems to be a proper hot when touched on top of the valve cover.

I think I need to "burp it"... sounds reasonable? Not sure how to do it... but I do have a hose "flush" kit installed.... if that makes it easier to purge the air.

Anyone else ever seen their coolants "gurgling" out after shutdown when its hot?

mud_digger

i got mine hot one day and it was gurgling when i shut it off and since i put my new motor in i have been having temp problems. i replaced water pump, thermostat, fan clutch, coolant flush. the temp is always fluctuating and never the same. i tried to burp the system and still fluctuates. i just changed the oil and there was no coolant in it. so idk what the deal is

bajaxj

I hear a LOT of gurgling, and have seen hot coolant "pressure" itself out of the plastic fill tank.
Anyone else ever seen their coolants "gurgling" out after shutdown when its hot?[/QUOTE]

I had the same problem in my 90 XJ until I replaced the radiator, thermostat, hoses and coolant. Its been fine ever since(about 4 yrs ago). I wish I would have known about the later system at the time, If I did I would have changed my radiator to a later style one. Well I guess Ill just wait till I need a new one.

rugerwallace

Yeagh I have had same issues with mine! 87Cherokee When I replaced the coolant for some reason it started overheatin my buddy whos got an 88 told me to burb it by either runnin it up and down some ramps or some kinda of incline like the dip right b4 you pull in your driveway I know it sounds crazy but i guess it rocks the ir bubble out of the system then he says check your resvoeir and see if its circulating! if it is you should be good to go so I did and It Worked not saying it will work for you but maybe worth a shot to BURP it!!

genXcherokee

My xj has a newer system that doesn't need this.....but I read on another post here somewhere that opening up the temp sensor a bit which is located on the same casing as the thermostat- until you don't see air coming out anymore will bleed the air out of the system.

genXcherokee

Do start with a cold engine- for safety's sake

Jeepxj1988

Thanks all who replied.... I did open ( remove ) the temp sensor and that did the trick... it just needed to be burped.