Overheating probelm

[Stodart]

 sti555 said:

so i just checked the thermostat and to my suprise it is opening when placed in boiling water..when removing the bottom radiator hose to check thermostat there was hot water coming out of the hose for a couple seconds max 500ml then the rest was cold which was about 2 litres this came out of bottom radiator hose.then about 2-3 Litres of hot water was slowly dripping from thermostat housing/engine side.the bottom hose gets no where near as hot as the top ..is this a bad waterpump.is there a way to check if the waterpumps gone ie run car with hose go through top tank..still the car uses no coolant or leaks any...one thing i did notice is that the thermostat housing had lil corrosion pieces on inside and they scratch off..so now im thinking its either a blocked radiator,waterpump,ecu,..the fans dont come on when i use the a/c either..im really stumped

Its sounds like a blocked radiator ; or ineffective water pump (corrosion build up) the water is hot then cold and corrosion present as you mentioned. the water isn\'t circulating properly so sensors - senders aren\'t getting the right info. perhaps?

but 1st / next would check water pump operation as can\'t assume that its ok without checking it

the same goes for fans / senders / sensors / etc are they all definitely ok?

a suggestion / way to check water pump operation is to take heater hoses off at fire wall not sure how easy they are to get at on your car.

this part is the primary cooling circuit when engine is cold water circulates between engine and heater core in a loop aiding warm up then when gets up to temperature the themostat opens ( the secondary cooling circuit) allowing water to flow / cool though radiator aided by fans when required .

start car when cold and run briefly enough to establish pump ok , probably need help for this hold heater hoses (extend hoses temporarily if necessary in order to make this work) into a bucket /container, watch flow rate / pressue while some one starts engine / swwitches off

if pump ok then its a good chance its the radiator.

subarus are prone to blocking radiators / heater cores, have had experience with this with in 2 of the 5 subarus l"ve owned. this can be avoided by flushing the cooling system every two years as suggested in owners manual.

lf its bad scale ie goes hard (white deposit) and can\'t be chemically removed radiator has to be taken apart and "rodded out" by radiator specialist after flow test check.

[Stodart]

just having another read of what you said to make sure l gave you the best advise and your idea with a hose in radiator is good to check / get an idea of radiator condition with bottom hose off to see how quickly water runs / flows out it, most of it should just take a few seconds in a surge

[Stoffa]

also a faulty temp sensor wont always throw up a code, they\'re only $30 odd so worth a try to rule it out.

just take it to a radiator specialist and get them to clean and test the radiator, cheap as

[titian]

 sti555']

[quote name='titian said:

Oh True : Missed that one.

Sounds like cooling is so good fans do not need to come on. If infact both work with diagnostic plugs connected.

One fan could be faulty. As no fan with aircon on

Why do you think it is overheating? Could be faulty indication on dash?

105C good temp for INLET to radiator (Upper Hose)

/quote]

i only think its overheating cause of temp reading on my autogauge water temp meter.and i find it strange fans go on in diagnostics mode but not after a hours drive and bottom radiator hose isnt as warm as top hose ,is 105 C a good average water temp for top radiator hose? my factory water temp gauge does\'nt go above half way tho..this doesnt explain a semi cold bottom radiator hose when it reaches 105C..what do your guys aftermarket water temp gauges read.

I reckon all is ok. 105 stable on the top hose. Thermostat will only open to maintain req operating temp.Lower hose temp will vary with load and road speed.

Dash indication also ok

Fans do operate in diagnostic mode. Not losing coolant.So what is the issue ??? Beyond me ??? ???

[sti555]

thanks for the feedback that gives me abit of relief,i just assumed at 105-110c from the top radiator hose the fans would kick in at some stage,and they dont seem to run when i use the aircon either..the only time they ever operate is in diagnostics..will see how it goes

[94 Leone]

maybe you have quiet fans?

[sti555]

All is sorted,just replaced a faulty Autogauge meter/water temp sensor and thermostat this morning.Now the new Blitz gauge peaks at 102C and drops to 95C but yesterday after running the car for 15mins the Autogauge meter went off the clock for 5 mins and read 120+ C which i never let happen and then magic,Fans come on.The Aircon fan did\'nt come on cause there was no gas in system :-[ ..also the Autogauge water temp sensor readings coming from a head hose.have it in the top radiator hose now and is running well.replaced my coolant for the 3rd time this week too haha. Thanks guys

 94 Leone said:

maybe you have quiet fans?

haha i wish it was that

[titian]

Crikey :D As suspected A :D No problemo