21 replies to this topic

[Harry88]

Hi guys.

 

Not quite sure where to go with this one so I will get some opinions on this.

 

I have noticed this morning when driving to work in the cold and again this night that after having the heater turned on for a while the temperature gauge will go into the upper 3rd. Once I turn off the heater and fans it seems to go back to normal range. I drove home from work today with no fans or ac/heat on and no issues after a 45 min drive.

 

Any idea where I should start looking with this one or things that I should be checking?

[duncanm]

water level would be #1.

[El_Freddo]

Cold air.

Subarus have a weird setup with the heater circuit used to open the thermostat. The colder it is the more you use your heater the cred the coolant from the radiator is due to a closed thermostat.

It's a tricky one as the thermostat if aftermarket will behave differently to a genuine unit. It could also indicate the early stages of a blown HG (hope not!).

But the above is what I've found while living in the snow - I used to slide a piece of cardboard over half the radiator and ensure I fully warmed up the engine to running temp (and made sure the cab was toasty!). Next trick here is to remember to remove the piece of cardboard when conditions outside warm up

Cheers

Bennie

[duncanm]

Good point -- heater use (cooling the water out of heater core) is probably stopped thermostat from opening.

 

Dodgy thermostat.

 

[Shaz]

Yep, I'd start with replacing the thermostat Hazmat, and also the coolant levels. 

[Robbks]

only use a genuine thermostat
Also increase the size of the hole in the diaphragm to allow more water to flow through it when closed.

i ALWAYS install a heater core bypass in the lines through the fire-wall. the internal bypass doesn't flow enough water to cool the engine properly in the case your heater core gets blocked (very common)

like this.

 

[Harry88]

Yep, I'd start with replacing the thermostat Hazmat, and also the coolant levels. 

 

Checked the level in the light today and the reservoir was past low. Gonna start with a top up and see if I'm getting the same issue then onto the thermostat.

 

Once I get the coolant how long should I leave the car sitting before I can safely remove the radiator cap to top up?

[Reevesy]

 

Checked the level in the light today and the reservoir was past low. Gonna start with a top up and see if I'm getting the same issue then onto the thermostat.

 

Once I get the coolant how long should I leave the car sitting before I can safely remove the radiator cap to top up?

 

 

Honestly you could pull up,grab a towel and crack the cap slowly with the towel protecting your hand/arm.

But if your worried about the steam and burns leave it half hour or so

[Liberty]

+1 on genuine thermostat if it comes to that. It's full-proof and you won't get any issues man.

[Cam.]

Fill the cooling system to full with it dead cold, Then start at bleed it until it's all gee, Then fill the res and monitor the level.

Coolant doesn't just vanish. It either leaks or is being burnt by the engine.

Get the system pressure tested. If it passes you most likely have a slightly leaking head gasket.

Tell tale sign is a smokey/exhaust smell from the overflow bottle. I have also known Subarus to leave a crusty film inside the bottle.

[Harry88]

Filled up the coolant on a cold engine and so far so good. No rising temp gauge like before. Seems to be sticking around its normal level.

 

I have booked her in for a check up on Wednesday to find out what was causing it.

[Harry88]

 
I have booked her in for a check up on Wednesday to find out what was causing it.

.... And it's a head gasket. Booked in to get done next week.

I guess this was inevitable at some point.

[Shaz]

Ouch. 

[El_Freddo]

Bummer. If you got it early enough it's good news in terms of lack of damage to the heads

Also a good time to do the cam belt and water pump if you've not done them in a while. Also ask your mechanic to replace the O rings in the coolant crossover pipe

Cheers

Bennie

[Liberty]

Damn man. Shit timing having just come back from your trip.

[Harry88]

Also a good time to do the cam belt and water pump if you've not done them in a while. Also ask your mechanic to replace the O rings in the coolant crossover pipe
 

 

Ok cool. I'll run it by him.

 

Damn man. Shit timing having just come back from your trip.

 

Yeah bit of a shit go but at least it will be done now and I won't have to worry about it in the future.

[zahmad]

Same boat as me haz, except mine seems to have gone bad after the headgasket change

[Harry88]

No good man. Hope the workshop is looking after you.

[Liberty]

That's it. Exactly man.

[zahmad]

No good man. Hope the workshop is looking after you.

Yeah I hope so too, should be towing it there on Monday...