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Hi All,

Here I am another few weeks on and still have a problem with air in cooling system. Tried everything, putting car on ramp to raise 30 deg, coolent changes ,looked for bleed valve on rad etc. I collected my car from mechanic on Tuesday having had another coolant change to see if that would do it. I even printed off the proceedures in the ultimate subaru repair manual post for the mechanic to try - didn't work.

 

Assuming all was followed correctly what else may be the problem. My performance is quite good but I can still hear swishing of water and air coming from under dash area - intensifies when reved and when car is cold - almost non existant after a good spin. Could it be possible that air is getting in thru heater core or something.

 

I've done a couple of hundred miles since this problem started first, if my HG was gone/damaged would I know by now?

 

CURRENTLY:-

My coolent is clear

My oil is clear

No vast amounts of white smoke from exhaust

Ticking over smoothly

Still got good response

No strange smells (exhaust or coolant)

 

Any suggestions?

 

Neil

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Don't know nuthin' about your engine, but does the level of coolant in the reservoir rise from day to day? If so, then air is entering the cooling system and displacing the coolant to the reservoir. If not, then the air must be left over after the coolant is filled. Absolutely no leaks anywhere? No overheating?

 

Tom

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Don't know nuthin' about your engine, but does the level of coolant in the reservoir rise from day to day? If so, then air is entering the cooling system and displacing the coolant to the reservoir. If not, then the air must be left over after the coolant is filled. Absolutely no leaks anywhere? No overheating?

 

Tom

The level just rises and drops as normal - never much of an increase or never below min level. Cant see any leeks nor is level noticeably less, no smell of coolant. Needle on gauge rises as normal to just under half way mark (again usual position).

 

Neil

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The level just rises and drops as normal - never much of an increase or never below min level. Cant see any leeks nor is level noticeably less, no smell of coolant. Needle on gauge rises as normal to just under half way mark (again usual position).

 

Neil

You obviously still have air in the cooling system. If all else fails, get a T fitting with cap made by Prestone (other makes also) to flush the cooling system. You splice this in one of the heater core inlet ou outlet hose (you'll find written on the package if it's for the inlet ou outle those) at it's higher point. You can fit a garden hose to this fitting to flush the cooling system but you can also use it to get rid of any trapped air since it's close to the highest point of the cooling system and it's close to the heater. I have one and when I refill the cooling system I unscrew the cap of this T fitting and wait till coolant leaks out of it. If coolant is up tho the top of the radiator but is not leaking from the T fitting I finish by adding some more thru this fitting. Never had a problem with trapped air since.

Hope my description is clear enough.

Good luck!

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I usually install those on my cars for easy flushing the first time I do a coolant change. They are pretty handy.

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It could still be a tiny head gasket leak. Have your mechanic put a smog sniffer up to the coolant reserviour to check for HCs.

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I'm assuming you've already tested or replaced the radiator cap? Have you checked the coolant overflow tank hose for an air leak? The engine coolant expands when warm, forcing coolant into the overflow tank. When it cools (ie parked overnight), the coolant contracts causing coolant from the reservoir tank to be drawn back into the radiator. If the hose connecting the radiator to the coolant tanks has even a small hole, air will be drawn back into the radiator. Check it out and let us know what you find. Phillip

Hi All,

Here I am another few weeks on and still have a problem with air in cooling system. Tried everything, putting car on ramp to raise 30 deg, coolent changes ,looked for bleed valve on rad etc. I collected my car from mechanic on Tuesday having had another coolant change to see if that would do it. I even printed off the proceedures in the ultimate subaru repair manual post for the mechanic to try - didn't work.

 

Assuming all was followed correctly what else may be the problem. My performance is quite good but I can still hear swishing of water and air coming from under dash area - intensifies when reved and when car is cold - almost non existant after a good spin. Could it be possible that air is getting in thru heater core or something.

 

I've done a couple of hundred miles since this problem started first, if my HG was gone/damaged would I know by now?

 

CURRENTLY:-

My coolent is clear

My oil is clear

No vast amounts of white smoke from exhaust

Ticking over smoothly

Still got good response

No strange smells (exhaust or coolant)

 

Any suggestions?

 

Neil

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looked for bleed valve on rad etc.

It's really a plug, and it's on the top of the radiator, just above where the upper hose slides on.

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The most important "secret" to filling coolant into these engines is doing it through the top radiator hose. Disconnect it at the rad, stuff a 10 inch garden hose down though the rad hose, toward the engine. Attach a funnel to the garden hose and fill until coolant comes out of the rad hose.

 

Re-attach, fill radiator to brim. Run the engine for a minute, with the rad cap off. It should burp when you switch off.

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I'm assuming you've already tested or replaced the radiator cap? Have you checked the coolant overflow tank hose for an air leak? The engine coolant expands when warm, forcing coolant into the overflow tank. When it cools (ie parked overnight), the coolant contracts causing coolant from the reservoir tank to be drawn back into the radiator. If the hose connecting the radiator to the coolant tanks has even a small hole, air will be drawn back into the radiator. Check it out and let us know what you find. Phillip

 

Thanks Philip, I'll give it a go tomorrow,

 

Neil

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