I've searched in here but haven't really found the awnser. I have a 1990 4.0 with auto the previous owner out a open cooling system in it and it keeps getting air in the.lines in turn overheating. My question is what can I do to did it. All parts are under year old. Need to get it fixed with high school student budget and quick as it is my dd any help would be great

 

Does it build up pressure in the cooling system then over heats

 

Something has to be letting air in the system if all parts are new and its been properly burped.

 

^this..good question what free said

 

It does build pressure and haven't found any leaks and it has been burped

 

How do u know air in the lines is causing overheating? How old is the cooling system? What maintenance has been done? The bottle must fill from the bottom and must always have some coolat in it especially when the motor is cold. The bottle must be vented, no pressure build up in the bottle. Radiator cap must function correctly, it is a 2 way valve.

 

my old jeep (1990 closed system) had the slighest seep on lower rad hose, block attachment, never noticed it, looked like oil if anything

finally found it after hearing air gurgling one day, then found I was low over 1 gallon of coolant


get on your back with flashlight & look for leaks

may try pulling temp sensor out to burp it .. drivers side, rear end of block .. i think

.. renix pro's should comment on that 1 .. I never did it, got lucky with a shop fix

 

Radiator cap works and the bottle doesn't but with the newer cooling system the previous owner installed everything and just threw it in so I don't understand a lot of it

 

As I said mine is a 1990 but last owner had a 92+ system put in and I don't really mess with the cooling system

 

franken - cooler?

maybe just an open rad on sealed system ? .. I almost tried that .. someone else should comment

you have pics ?

 

I can post some pics tomorrow

 

from what ive read / thought about doing .. the conversion needs to be done complete (sealed to open)

I got lucky with my sealed, so never went there

now I have a 93 w/ open system, way different tubes / routing, etc..

on my 90 / closed .. tryin to get heat to work .. I broke heater valve in 1/2 .. I mcgyvered it w/ hacksaw ... to get to work .. then problems started & would not go away, especially air in system .. thought I had a bad head gasket

finally got everything replaced / routed correctly / flushed .. worked fine since

 

Yeah I'm starting to think about taking it in and done properly but h.s. budget limits that Haha

 

wheres this plastic bottle ? motor area, passenger side up near dash ? held down by a rubber strap ?

or somewhere else ?

 

It's ziptied in front of heater control valve not where it should be