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3.0 legacy coolant issue.


mickjo
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Hi there I have read quite a few posts about my problem but there isnt quite one that fits mine so I apologise if its been covered before.

 

Ive got a 2006 legacy estate spec B 3.0 auto 6 pot engine 245BHP.  Great car pulls great no performance issue as far as I'm aware of.  Ive had the car a couple of months covered 2k miles.  its done 128k mostly subaru FSH last couple of services have been basic oil filter service.  

 

note:The temp gauge is always rock solid 50% of the scale, never higher than that.

 

Anyway.  About 1k miles ago I could see the expansion vessel was empty, so topped it up to the fill mark and could see bubbles coming up through the liquid.   My immediate thought was head gasket failure!!  "I've bought a lemon!!"  But then checked the oil cap and no emulsion was evident.   I decided to have the car coolant checked at a garage for contamination.  No contamination was found. OK maybe its just an air lock.  

 

However whilst driving last week:  The ambient temp was about 6 deg C, and I wasn't hammering the car as I had her indoors with me.  I had just completed some 350 miles uneventfuIl miles pulled over to the side of the road to check the satnav, engine running, and the noticed the temp gauge had shot up almost immediately to just short of the red mark.  the engine fans were running like the clappers.  I immediately switched the interior fan onto full blast heat knob to full heat.

.  And within seconds the temperature gauge dropped back to normal 50%.  Strange!!.  I drove on desperate to get to the destination without incident.  Then did exactly the same 10 miles further when we arrived at out destination. Only this time I lifted the bonnet and clocked the expansion vessel had filled almost to the top.

 

The car was left overnight to cool, I lifted the bonnet and expansion vessel was back to normal lever.  I drove home 350 miles and no incident.  Checked everything I could when home and could see bubbles coming from the expansion vessel as I first stated at the beginning.

 

Note:  The cars internal heater control is not good in fact its poor. (Its a digital display) So say I set it at 23degC as its cold inside, the car inside does not warm up, if you steadily increase the temperature there's still no change in heat until you put it to say at 27DegC.  But then its too hot inside.  Now its when the temperature control is turned down to around 23degC the the engine temperature rose.  could this be the cause?   Could there be some blockage in the matrix, a problematic thermostat.  Any ideas.  

 

I know its a long story and any feedback would be appreciated.

 

Mick  

 

 

 

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I've never heard of a car do that before  :o My 1st thoughts was the same as you Head Gasket or Airlock . But I've never heard of coolant being pushed back. Have you drained it all and refilled it with fresh stuff I think that is what I would do. Just to make sure no blockage in the system. But can't explain the return of the coolant :(

 

Oh and Welcome to S.O.C how rude of me :D 

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Cheers Gambit thanks for the warm welcome.

 

Its a weird one, never experienced anything like this before.  I'm going to persevere with the airlock theory, I just don't want to ruin a good engine doing so.

 

Cheers

 

mick

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Wotcha and welcome - by the sounds of it I wouldn't think head gasket - the fluid doesn't come back in that case, airlock yes it could well be, thermostat also and it would be a relatively cheap fix although your car is comparatively new for this type of failure to occur.

 

As Gambit says keep an eye on it and take it from there

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  • 1 month later...

Hi there this persistent issue is starting to get to me.  It seems to happen when the car has been run for a lets say oven an hour/100miles.  The car is warm at 50% of temp gauge.  Then you come to say road works, immediately the gauge goes through the roof to under the red line, you can hear the radiator fans going flat out.  Once we are moving then the temp comes down and no longer an issue untill we are again pulling up to say road works again.  This has never happened around town/shortish journeys.  But on 2 long journeys I was aware that that I had actually lost coolant about 1litre each time.  

My garage chappie who is very well experienced (not with Subaru's though) has said that hes has come across it before on other cars when the water pump loses efficiency.  I have got it booked in to replace this water pump.  I want the car as my main driving car but feel its gonna have to go if I cant resolve this.  

It is a H6 3.0 spec B legacy 130K miles 2006. 

Mick

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It could be that you need to replace the radiator cap and cleaning the hose to the overflow tank has helped others in the past but not everyone. I'd say if it's not the head gasket could be a really badly blocked pipes or radiator if someone's not cleaned it out or added Rad Seal to it in 130K miles is possible. 

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thermostat & rad cap needs ruling out of equation first, & the thermostat is super cheap, could be replaced & a coolant flush done at same time as cheap first step cure/prognosis & rad caps can be tested or just swapped with a friend, cheap one from autofactors or breakers.

Pumps only loose efficiency if get clogged in scale or blades get corroded badly on pump & this is not a trait on subaru but worth evaluating if nothing else shows up.

I would also get the coolant checked again for exhaust gases to rule out headgasket yet again as to be honest it sounds like a sneaky posibilty, you can use exhaust gas analyser to sniff the radiator & if detect high exhaust gas readings you now head gasket problem.

Sounds easy but sometimes at early stages it very minimal thus hard to detect also it may only be leaking at specific high temps & conditions not being reproduced during testing so could unfortunately still be a possibility. also possible you get minor external leak on the head on these & once again only on a hard run & when real hot then by time you cooled it down to look or take it to a garage no super obvious sign & needs a super keen eye & someone familiar on the subaru headgasket issue to pickup on it.

Fingers crossed on the simple options but I wouldn't waste too much money on likes of pump replacement without really checking for minor leaks (only occurring when engine cooling system really hot), thermostat & rad cap etc.

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  • 3 weeks later...

hi there,

Well I changed my garage and the diagnosis is not good its Head Gasket failure.    The mechanic recommends changing both.  So I'm looking at a small fortune. So its time to decide to repair or part ex.

 

Not Good 

 

Mick

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having a conclusion at least allows you to make choices.

My suspicion was gasket & also suspect it mild problem & was present at time of sale & possibly improved with some coolant leak additive.

Good worthy job on head gasket replacement is not cheap, done a few over the years & used Reinz  gaskets when can & along with very good prep of head & deck finish can be better than when new, unfortunately it quite time consuming & can incorporate a few additional jobs/parts thus not a nice repair bill.

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Just spewing at buying a lemon.  The engine sounds good not lumpy at all so heads aren't warped yet, thought of putting radiator additive in for now (seen that Blue devil in but not sure) until I've saved up for a new car or repair.  Ive been warned its about £1700 for the repair.  

 

The other thing I just bought a tow-bar ready to fit,  And some fecker ran a shopping trolley right the way along the wing to the door mirror huge gouge in the paint.  Makes you wanna cry.   

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Not having much luck by sounds of it :-/

I would say both gaskets replaced & heads inspected & surface cleaning/polish if not needing skimming would be about £1,200 all in for a worthwhile repair effort on your 6 pot ... If you shop around you will probably find quotes around £800-900 but a gamble on how well they prep & rebuild unless know their work ...

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Think bigger the space the more they have a run up!!!  

 

 

Anyway been given a name of a mechanic who's very well regarded, apparently the dogs danglers when it comes to subaru boxer engines, used to work for the local Subaru dealer and hes like doing homers/govies/weekend work cash in hand.  So will be seeing him this weekend see what the crack is.

 

Mick

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