Fans stay on ... HELP PLEASE!!!

[Guest keltik]

Im pretty sure an a/c malfunction would result in the fans running full time....but if this problem is only occuring after the engines reached operating temp then that seems unlikely....so nevermind

[Guest]

Bugger sorry I misread your first post ...

Heater going luke warm = heater core blockage or air loacked due to headgaskets

Bypass the heater core with a loop hose and I bet your problems disappear

[Guest keltik]

Isnt he saying the heater is going cold because the fans are over cooling?

[Guest]

if that was the case then a faulty thermostat would be the issue

heater core is an important part of these cooling systems, it must flow perfectly !! As the return water from this opens the thermostat

Hence if return water is cool then thermo wont open and engine will overheat

Common as, vehicle has overheat issue during colder months

(ie when heater used, making return water to thermo is cooler. Which is not an issue when heater core has full flow)

[Guest]

 Ichi Ban']

[quote name='crizpy said:

today i changed the temperature sensor and replaced the relays the 4 black ones in a row in fuse box of engine bay... not sure if theres any others...

took for a drive .. and same problem grrrrr.

im out of ideas

/quote]

You must carry out clear memory so ECU will read new sensor properly

( at the moment the ecu is in a "safe" mode which need reset to clear other wise ecu goes on a standard temp of 50deg and runs fans continuously )

when i blead the system after changing the sensors .. i reset the ecu ...

when fans turned on .. the were switching on and off as usual while it was idling .. then took for a LONG drive and not too far down the road .. fans came on again and didnt switch back off..

I also have the water noise behind dash indiacting air in the heater core ... This has been around for a long time ..

maybe heater core has a air lock or is blocked up as suggested below..

But could this cause fans to stay on ?

[Guest]

 Ichi Ban said:

Bugger sorry I misread your first post ...

Heater going luke warm = heater core blockage or air loacked due to headgaskets

Bypass the heater core with a loop hose and I bet your problems disappear

if i had a head gasket problem wouldnt I get some over heating ? i dont get any bubbling in the overflow and oil is very clean..

but i think you could be right with heater core blockage or air lock..

If i bypass the heater core does that mean I have no heater :'(

[Guest]

also when i rev the car ... i get the heater core bubbling behind dash (mostly when cold but a wee bit when warm aswell)and the temperature gauge lifts a few Millimetres to its normal operating temp .. my theory on that was the water circulates faster when i give it a rev and runs hotter water that hasnt been cooled by the fans past the senser..

[Guest]

Do these vehicles have a fan switch that Turns them on and off as repco have a listing for a fan switch ?? or is that the same as the Water temperature sensor under the alternator with a 2 pin plug?

When the fans do come on there is a faint click or relay type click under the driver side dash ... Is there another relay in there ?? or is that the comp clicking the fans on ?

[Guest]

 crizpy']

[quote name='Ichi Ban said:

Bugger sorry I misread your first post ...

Heater going luke warm = heater core blockage or air loacked due to headgaskets

Bypass the heater core with a loop hose and I bet your problems disappear

/quote]

This is and easy test to do

And sorry .... you wont have a heater for this test

As for temp not showing overheat . Gauge is steady between 75deg and 105deg (so kind of hard to tell by gauge)

 

if i had a head gasket problem wouldnt I get some over heating ? i dont get any bubbling in the overflow and oil is very clean..

but i think you could be right with heater core blockage or air lock..

If i bypass the heater core does that mean I have no heater :'(

[Guest]

Update ?

[Guest]

 Ichi Ban said:

Update ?

I gave the cooling system a really good bleed.. jacked front right up and had it running for 45 mins or so topping up ..

whilst being bleed the fans coming on and off as usual..

on the long road test ... Now fans come on and stay on at Ilde.. Little bubbling from heater core after a good bleed..

so when fans come on at idle The temp drops a Bit and they dont switch off.. If I rev the car To a High idle ... \

temp gauge lifts and fans turn on and off as usual when its being reved...

Other symptoms..

When heater is off Now fans seem to operate as normal and temperature stays where it should.

When heater is on It doesnt go very hot ... If i rev it It has and Instant burst of hot air.

So what it seems is that water isnt circulating through the heater core verry well. and when Revved It flows better ..

But Ive also Read that the vehicles Need the heater core operating %100 and if it is blocked then the car will over heat ...

]conclusion ...

water is now flowing better with Air out of it But still

Water not curculating verry well at idle

Possibe blocked heater core..

water pump ?? The water pump was replaced 2 years ago and 40,000 K ago Wouldnt think it would be faulty this quick.. Also If water pump is going wouldnt it over heat rather than stay cool. and also would then temp still be playing Up when the heater is off..

Next step .. Im either going to take heater hoses off and waterblast through them... Or remove the heater core and replace with second hand one .. I had a thought to get a Laser Heat Temp reader Onto the radiator In pipe and out pipe also the heater hoses.. But im not sure that is possible with the heater hoses being under the intercooler

[Guest]

Heater core !

Your test results are exactly match heater core

Never use 2nd hand units, most of them have dried out coolant in them and are prob worse than the one you currently have @!

"Most" units are copper cored and can be rebuilt for bout $280

Alloy core need to be replaced !! Consult dealer and cry as radiator shops can't supply alloy ones! I have checked with many

[Guest boostcut]

you could call A1 radiators... theyre pretty cheep... i just bort a new toyota prado radiator off them for a cobra kit car im building for 180 plus gst....

http://www.a1radiators.net.nz/index.cfm