22 replies to this topic

[zahmad]

Ok guys, I am almost at tearing my hair out stage!

So the car had a leaking headgasket that was replaced June of this year, with new water pump and timing belt. After the headgasket was done, within 2000km, the headgasket had blown and the car overheated. Symptoms prior to overheating was the coolant overflow bottle was bubbling (waterfall behind dash sound), eventually leading to the coolant being spat out and thrown everywhere. This lead to a failure in the headgasket on one side.

 

Took it back to the mechanic who changed the headgasket again, checked everything was running fine. Everything was running fine until earlier this week when suddenly the waterfall sound had returned and upon my inspection, way and behold the coolant overflow bottle was way passed the full mark again.

 

As this was a similar symptoms as earlier, I took it straight back to him to see what the problem was, and everything was fine oncemore. Thermostat tested ok, replaced the radiator cap with a new one. He flushed the whole system of any coolant and put water in and some chemical tite to block any possible cracks in the head that might be causing the issue, bleeding the system properly.

 

All this time, temperature gauge is bang on point.

 

Car was run for more than an hour to test any possible bubbling occuring - nothing, spot on.

Car has done another 150kms since that job yesterday and was fine up until half an hour ago when I started the car and the waterfall sound is back! Open the bonnet and again coolant overflow bottle is way past the full mark. Coolant still there underneath the radiator cap.

 

I am at wits' end as to what the problem is and would appreciate some advice from you guys.

Internet searches tell me it could possibly be my hose or a bad radiator allowing air into the system?

Other searches resulted in something about the aircon condenser hoses being the wrong way around? (possibility as he did have the engine out)

 

When he was checking everything, he did notice the bottom radiator hose never got hot (which is why he tested the thermostat, but that checked out fine).

 

At the moment he does not know what else the problem could be so has me really worried....

[Robert]

Blocked heater core

It's a vital part of the cooling system
With it being blocked, the thermostat won't open.
Try bypassing the heater core for a bit
Rebleed the cooling system at the same time

See how it goes

[Bumpty]

Sorry I cannot help Zahmad, Just here to show my support.

[RX25SE]

Blocked heater core

It's a vital part of the cooling system
With it being blocked, the thermostat won't open.
Try bypassing the heater core for a bit
Rebleed the cooling system at the same time

See how it goes

 

... or blocked radiator?

[Robert]

Thought I read radiator was replaced

Surely any somewhat competent mechanic would have checked that

[duncanm]

Also - presumably he's done a check for hydrocarbons in the coolant (ie: not another HG or crack).

[zahmad]

Blocked heater core

Seems like a plausible reason as its feels worse when the A/C system is on...

 

Thought I read radiator was replaced

Surely any somewhat competent mechanic would have checked that

He did check that I assume.

 

Also - presumably he's done a check for hydrocarbons in the coolant (ie: not another HG or crack).

He did last time, but not this time. I will ask him to perform this test again.

 

Thanks for all your help guys. Will take this suggestions to him to see what happens.

[SubyGarage]

Your mechanic doesnt know how to fit thermostats in Subarus or is using an aftermarket one. The fact that the car has a cold bottom rad hose tells a story. One of no circulation around the cooling system. Subarus have many cooling system issues that most people overlook. I see issues like this weekly from cars that have visited mechanics and have been pushed out the door and no time spend on chasing the issue.. Find another mechanic and Subaru expert .Look on our Facebook page as I have done a write up on a Gen 3 with cooling system issues. I would see one a week on average. More so during the warmer months and a heap of them with heads that have been lifted with the cars having other unsorted issues that come back at a later stage like your car. 

[zahmad]

So an update on the issue. During the day, the bubbling sound cannot be heard during operation as driving the car, everything is normal.

However, on startups at night time, generally 15 degrees, it does the waterfall routine. During this, bottom hose is hot and everything is operating normally. Bubbling is present and coolant overflow is filling up again. The level in the overflow does decrease when the car is left overnight, returning to normal levels.

[zahmad]

Drove the car under heavy load today and it's coming out of the overflow again, going to check the levels of coolant tomorrow after leaving it overnight

[zahmad]

So overnight, nothing went down and its staying that way. Not much left in the radiator, so topped it up.

Thanks to the guys at the monthly meet, i have a few things I want my mechanic to try now.

[surge]

Interested to see how the test for hydrocarbons goes.

Hopefully you have a warranty on the work already done. Sounds like either really bad luck or somebody is not doing their job well at that workshop.

[cameron]

were the heads machined flat?

[zahmad]

No hydrocarbons in the coolant after a test today. Radiator cap has been changed again. Heads were machined flat Cam.

Ben from Ichiban had a quick look at the car today, and suggested that it was the headgasket from the smaller bubbles coming through, but the hydocarbon test obviously negated that.

[zahmad]

So its back again but took a lot longer to fill up the overflow this time.

The overflow happening at specific temperatures has me thinking its either the radiator itself or the heater core.

 

Heater core bypass seems to be the next step...

[Arfreedom]

Your mechanic doesnt know how to fit thermostats in Subarus or is using an aftermarket one. The fact that the car has a cold bottom rad hose tells a story. One of no circulation around the cooling system. Subarus have many cooling system issues that most people overlook. I see issues like this weekly from cars that have visited mechanics and have been pushed out the door and no time spend on chasing the issue.. Find another mechanic and Subaru expert .Look on our Facebook page as I have done a write up on a Gen 3 with cooling system issues. I would see one a week on average. More so during the warmer months and a heap of them with heads that have been lifted with the cars having other unsorted issues that come back at a later stage like your car. 

Post a link to your Facebook page. Thanks


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[Euronymous]

Does your heater still get hot? If so I'd be less inclined to believe its the heater core.
If it happens at higher rpm/load I'd lean towards water pump.
If its erratic in regulating temp, some times gets hot some times its ok, I'd say thermostat.

[zahmad]

Yes, heater still gets hot. Does happen sometimes at higher rpms but not exclusive to...

Temperature stays perfect all the time...

[Euronymous]

Sounding more and more like a head gasket/cracked or warped head.

[Beckers]

Do you know if the heads were pressure tested when they got surfaced ??

If you have the water fall sounds behind the dash, you have air in the cooling system.

If the cooling system is being bleed properly then the air has to be coming from somewhere, most likely the combustion area. ie block/heads or head gaskets.

Never assume something has been done either, always ask the question.