Cooling system proplems

[Guest]

One day on the way to work a few weeks back out of the blue my GTB wagon got really hot and the heater was cold. I assumed that the water pump had died as the engine wasnt using any water, so not a head gasket.

I just took the water pump out today and it looks nearly new, its not corroded or anything.

I just read the sticky'd post on bypassing a blocked heater core, but...

I tested it by plugging the garden hose into each of the waterpump hosing outlets (the 2 small ones) and it seems to have perfect flow through the heater core.

Can anyone think of anything else it could be????

[slydog]

thermostat? or radaitor? cheap and easy things to check

[Guest vf20/21bg5]

I wouldnt have taken the waterpump off as it could have been just a simple air lock in the cooling system....cause that happened to me twice now......as soon as it happened i just pulled over and left the rad cap on but removed the top pipe into the expantion tank carefully without getting burnt(use a rag) and a whole lot of air comes coughing and spluttering out, then turn heater on hot(ignition on) remove the cap and top up the tank untill water comes flowing out that hose to the top of your tank again which meens the blockage is cleared, put pipe back on and away you go!...well thats allways fixed air blockages for me, if you had an air lock that is? but subaru cooling systems are renound for it

[Guest]

It definatly wasnt a an air lock,...i bled it carefully and even took out the thermostat but it just does not seem to be circulating water.

With the new water pump in it went ok for 1 day and just now on the way home the heater went cold and its back to overheating!

I just dont see wtf is going on. Its not using any water, it just wont circulate it, at all...the heater isnt even a tiny bit warm.

Anyone got a theory???

[Guest vf20/21bg5]

That so doesnt make sence ay....if you are running no thermostat and your waterpump impellers are still pumping and your radiator is sweet,plus your fans are kicking in as should be, you shouldnt overheat! are your fans kicking in? is your bottom rad hose hot or cold?

[Guest]

bottom hose is always cold...fans come on but no heat to draw out of radiator.

The only thing I can think of is that there is a blockage in the heater pipes so it doesnt circulate the water back to the thermostat so it never opens...but i checked that with the garden hose and it flows perfectly.

Got me beat....

[Koom]

If you start with a cold engine, and run it up without the radiator cap in place, does it blow bubbles out of the header tank? Has it pushed lots of coolant out of the overflow bottle in the past? Could be a headgasket.

[Guest]

No its doesnt....not until it gets hot.

Its never used any water, and still doesnt, unit it overheats and blows it all out.

[Guest vf20/21bg5]

interesting 8) :

[Guest]

I bled it again last night, and it was back to normal....heater working, maintaining temp.

Then....driving along, heater goes cold and it starts overheating again.

I waited until it cooled down, took the cap off the water tank and it was nearly full.

Pulled the bottom hose off the radiator and there seemed to be plenty of water come out.

I took the thermostat out, put it all back together, bled it and and seemed to be ok but the heater is not very warm, because its losing all the heat out of the radiator.

Then...heater goes cold again....grrrr

WFT????

[Guest vf20/21bg5]

Replace the thermostat!...i think you have a faulty one!...sounds just like the problems my tuners had the other day, thermostat was sticking now and then.......either that or ALIENS are in your cooling system ;D

[Guest]

I have replaced the thermostat, and Ive tried it with no thermostat and there was very little difference.

I give up...

Anyone want to buy a 1997 manual GTB wagon...goes well, no issues at all.

[Guest vf20/21bg5]

Parcially blown head gasket me think

[DRFVDR]

I would try the heater core bypass( water from a hose will still get thru a blocked heater core)

BUT i would suggest a blown headgasket as has been mentioned before

Get it checked by someone who has the correct gear and knowledge.

[Guest]

Yeah it must be the head gasket its starting to idle a bit rough too,...grrr

[RFS]

this happend to me in my bc5 turned out to be blowen headgasket i thought it was my waterpump too

[soopersubaru]

Blocked radiator! heater doing the cooling until the load comes on.Or fan/fans not running up to full speed.

pour boiling water over the thermostat to check operation. Should open fully at 80C.

If you keep overheating it...It will be a blown head gasket if its not already.

[rex-leggy]

hes replaced the thermostat. sounds like a headgasket to me also

[Flippymoi]

Does the block flow? I read you flowed a whole lot of things but there could be a blockage in the block somewhere. Rather unlikely though I would have thought.

[Guest]

 DRFVDR said:

I would try the heater core bypass( water from a hose will still get thru a blocked heater core)

BUT i would suggest a blown headgasket as has been mentioned before

Get it checked by someone who has the correct gear and knowledge.

+1

[mondo]

Japenese radiators fail after only a few years, you can put a hose through it and plenty of water will flow through, but it could be 50% blocked.I had a similar problem to this, air was getting in the system causing a air lock, it turned out to be a hairline crack in the block,A bottle of Goss chem weld fixed it.

[Joker]

a few years?

or they can last 10....

[RFS]

 JoKer said:

a few years?

or they can last 10....

mines 20 years and mint as...glycol for the win