Hi Everbody, Here's the problem with my1998 outback:  the air conditioner started to cool then heat up then cool then the heater started to blow cold and then heat and the heat was hard to control, turn it down a little and it would go to cold, then try to warm it up a little it goes hot, and yesterday it overheated and the upper radiator hose sucked flat. What the hell is going on!!!!! Help Me.....

 

Charles..........

Could be any of these:

- Failed headgaskets;

- Failed water-pump;

- Failed thermostat;

- Failed radiator-cap.

 

First thing to do:

- get a new radiator-cap (the old one is clearly not working properly, if the upper-hose goes flat);

- refill the cooling system with coolant (including the overflow-bottle to the correct fill).

 

Then drive it and see if it still overheats...

It's usually a failing headgasket. 

 

But rule out simple things first.  Thermostat you can toss in a pot on the stove and see if it opens...this is of course assuming it's a consistent tstat failure, which i would expect. 

 

1. Check coolant level in the radiator and monitor it consistently - consistently depends how frequenty your symptoms are.

2. Take note how fast the coolant level is dropping in the radiator over days, weeks, months. 

3. Make absolutely certain the system is burped of all air - any air pockets can cause overheating. 

4. thermostat, radiator cap - OEM are preferred. 

5. check the overflow tank for bubbles - look at first start up, after an interstate run, and definitely look immediately if the heater blows cold again or car overheats. 

6.  do not overheat the engine - it will throw rod bearings out the block which is no fun. 

 

Now, questions:

A.  any recent work to the engine or cooling system?
B.  how long have you owned this car - did you just buy it this morning off the side of a dark alley for $150?  then it's probably got issues. 

C.  or has it driven flawlessly since you bought it new?

An EJ25D engine with bad headgaskets may also have bubbles in the overflow tank, or sometimes oily gunk in there as well.