Real Weird Heater Problem

[agius]

hey guys

 

basically long story short ill be cruising feeling a bit cold so i turn my heater on

 

real nice hot air will come out for about 3 mins and bam cold air starts coming out

 

pretty much like turning the heater on when the engine is warm but not running

 

if i turn the heater off for 5 mins and turn it back on same thing happens, its like my water isnt flowing fast enough through the heater core..

 

ive checked for blockages and i have none!

 

i took both firewall hoses off the heater core started the car and water is flowing out of both hoses at equal pressure is this normal?

 

(isnt water suposed to come out of only one hose? there for allowing the water to travel in only one direction so it flows?)

 

ive even changed my heater core over to one that i know that 100% works

 

i am running a thermostat

 

the car is a ke30 with a 4k engine

 

its probably the smallest problem but I'm having one of them slow dumb days were using my brain isnt working for me haha

 

thanks in advance guys!

[Crowie55]

This may sound silly but have you tried swapping the two hoses going into the firewall over?

[ke70dave]

have you also tried undoing both the hoses, and shoving your garden hose on one end, make sure the tap is open, and flush your heater core out?

 

though you said you tried another core.....

 

when it goes cold, you could put your hand on both the heater hoses, see if they are still hot.

Edited October 10, 2011 by ke70dave

[philbey]

Off the top of my head, this is the best thing I can suggest for the moment. I'm not sure if it makes any practical sense though:

 

Perhaps check where in the coolant circuit the heater connects to the engine water circuit. One possibility is that you could be drawing coolant from the cold side of the radiator, through the heater core. Conduction/convection could be heating up the static water in the core, then when it opens it may be flushing through colder water. The more I think about this though, the less I think it is likely, would take some strange plumbing to do this.

 

The other option is, perhaps check your head gasket with a compression test. If you have a crook HG, you may be pressurising the water jacket with air/steam and as the heater connections are high in the block it may be forcing the water out of the heater core. A mate's heater core actually ruptured in his KE36 and filled his cab with steam.

[altezzaclub]

Water will come out of both engine-side hoses, for when the engine is running one hose is slightly pressurised and one not.

It sounds like you're not getting flow through those pipes, maybe the water pump is not up to much.You can see the red dotted hose is the hot side off the higher pressure path, and the green dotted one is entering the pump on the low pressure side along with the bottom rad hose.

 

 

Is your setup like that?

 

[agius]

altezzaclub, you may have shed some light into this..

 

on my engine the green dotted hose is conected to the thermostat base housing where you have it blocked off

 

where does your green dotted house connect to?

[agius]

This may sound silly but have you tried swapping the two hoses going into the firewall over?

 

yeah ive tried that :(

[philbey]

Keep in mind that there's a range of different water pumps and thermostat housings for these motors and it's usually the heater outlet that varies; altezzaclub's KE70 could be quite different from the KE30/55 item.

[altezzaclub]

Philbeys right, and on mine the green hose goes into the water pump on the suction side along with the bottom rad hose. Yours is older.

 

That blanked-off brass fitting above it had a temp controlled vacuum valve fitted, it controlled some of the emissions gear.

 

Where is your other (red) hose connected, because there is no pressure difference to pump water just across the thermostat housing. The pump is sucking water in via the bottom rad hose & the green pipe, then pumping into the motor behind itself, and pushing the water up to the thermostat housing so it can go to the radiator & circulate. Hence the pressure is higher at the red hose than the green hose.

 

 

[agius]

true that guys never knew that

 

ke70's have so much more emission gear

 

my (red) hose goes streight to the heater core

 

when i feel the both hoses that connect to the heater core the red dotted hose is hot and theother hose is luke warm

 

from what you say thats how its meant to be

 

i starting to think this may possibly be a water pump issue i thinks its on its way out

 

but its weird because the car is still running at perfect temperature..according to the temp gauge..

[altezzaclub]

Have you tried what Dave said, hosing the heater out?? The hose temperatures you have are correct, but that could be from either the heater dumping the heat into the car to cool the water down, or the heater being full of sludge or the control valve jammed almost closed, so the water hardly circulates.

 

Check that the valve moves right in and right out, and hose the core out if you haven't.

 

 

[Evan G]

I reckon I found the problem, 4k with 3k heater lines

[agius]

i finally fixed the damn thing

 

its like a sauner in there now

 

all i did is, connect a hose from the heater core to the cold side of the pump (green doted hose)

 

and then connected a hose from the spout at the back of the head (which only 3k's are supposed to have) to the right side of the thermostat base where altezzaclub has it blocked off

 

car is still operating at same temperature

 

heater is now burning my skin off.

 

thanks for everyones input, you were all a great help!

[altezzaclub]

lol! just what you need with summer coming up!

 

 

Well done.

 

 

 

[love ke70]

Only in Victoria do people still ask questions about their heaters in October :P