A/C Blowing Hot - Temp Gauge Spiked

[mitchel1]

1999 Subaru Outback – 130K Miles

3 MONTHS AGO

We were driving in traffic with the A/C on and the car started to overheat, I shut the A/C off and as soon as we moved the temp went down. Traffic stopped and the temp when up, we turned the heat on and once traffic kept moving the car never overheated again.

I took it to my trusted local independent Subaru mechanic and he inspected the car and did not think it was a head gasket. He did notice the coolant was very dirty and looked rusted, he flushed the system and we never had a problem again.

TODAY

We were driving with no problem, 85deg. outside and the A/C running fine. Suddenly the Temp gauge started to climb, A/C blew hot air...we started to move and everything was fine.

20 miles later, 2 blocks from the house...the A/C started blowing hot, the temp gauge spiked...I shut off of the A/C, turned the heat on full blast and made it into the garage.

I heard a leaking sound and there was coolant all over the floor. I opened the hood and looked in the overflow tank and it was full to the top. I got a flashlight and looked under the car (not that I know what I’m doing) and noticed fluid leaking from somewhere towards the front of the car, but could not locate the area because it was dripping from lots of areas, it must have sprayed all over the place? 30 minutes later the overflow tank was empty.

Any ideas as to what might of happened?

Thanks!

Mitch

 

Edited August 31, 2014 by mitchel1

[rverdoold]

At first I would have thought in the direction of the thermostat but that one must have opened since the overflow tank water was 'boiling'. I am curious if the front ventilators work, as the car starts to overheat when there is no airflow through the radiator. In order to test this connect the two black connectors under the dash, this will put the car in self diagnose mode. If you turn on the ignitions the ventilators will start to run in a pulsative mode  (on/off cycle).

Option two, broken or bad water pump, but this would also spike the temp while driving.

Option three, broken pressure cap of the radiator, or radiator leak, but this would not spike the temperature, only if you are at high altitude.

Option four, Crack in hose, you have been loosing coolant and it slowly starts to boil out the system since there is less water to cool. A small crack will also spray water everywhere. 

Option five, indeed the blown HG.

 

I would let it dry up, test if the ventilators are working fill it with water and start the engine to see if there any leaking pipes, most prone are the ones leading and coming from the radiator.

Remco

[Luvn737s]

Clogged Catalytic Converter and fan relay, 2 separate problems. At least that's my guess. I had a Mazda that exhibited the same symptoms.

[Fairtax4me]

Need to check both radiator fans for operation. If the fans don't work, it wil overheat while sitting in traffic. Also need the fans to run for the AC to cool properly.

 

Easy check: look under the dash on the drivers side, you'll find two bright green plugs that fit together. One wire in each plug. Connect them, turn the key to the ON position. Do not start the engine.

This puts the ECU in Test Mode, and it will cycle all of the relays and solenoids on the car. This causes the fans to come on in roughly two second intervals. Both fans are two speed, so the fans will run low speed, then high speed, then turn Off. This will repeat until you turn the key Off.

Make sure both radiator fans run at both speeds.

[MilesFox]

I would guess inefficient or corroded water pump or radiator from the first instance, but now it has boiled over suspect a HG. LEt the engine cool down, burp out the air pockets. Then inspect for bubles while it is running. If no bubbles, go ahead with inspecting the WP and rad

[johnceggleston]

i have a similar issue with my 98 obw w/ej22 swap.

the AC will occasionally blow HOT air and the temp gauge starts to over heat.

if i cycle the AC on /off, it begins to cool and the temp returns to normal.

 

i do not understand how HGs, coolant leak or bad water pump could affect the AC blowing cold.

if the compressor is turning, then it is making cold air???? right????

 

i suspect a relay,

but i don't really know enough to know this even makes sense.

Edited September 1, 2014 by johnceggleston

[mitchel1]

Thank you everyone for the great information...I am going to take the car to my local Subaru shop (not the dealer) and see what he finds.

The car has been awesome for 15+ years and I always said I would drive it till it died or became to expensive to maintain...I sure hope this does not end up being the "thing" that kills my car.

I'll post an update as to what they find.

Mitch

Edited September 1, 2014 by mitchel1

[mitchel1]

UPDATE

Well...it's the Head Gasket.

The cost is $1600 (including labor) for the Head Gasket

OR

$2100 (including labor) for the Head Gasket, Timing Belt, Water Pump, Idler Pulley's, Spark Plugs and whatever else is in the area that goes with this type of maintenance.

I plan on driving it for many more years so I decided to go with the $2100.00 option. Seems like in the long run it would be silly not to get the other items changed while they're already
in there.

Thanks!