A green volcano from the radiator.. (possible Subaru head gasket)

I’ve been pretty lucky with my cars right up until this one. But now that the new radiator and hoses have gone into the Subaru Impreza, instead of fixing the problems I’ve been having it’s instead revealed that the issues are coming a little further deeper in the EJ25 engine than first thought.

Or in clearer terms – The infamous EJ25 Subaru head gasket issue strikes again! Damnit.. I was enjoying this car until now..


First it was the knock sensor that died of old age and then I played the fun game of who put in the wrong thermostat backwards previously? Because in all the documentation that came with it, there’s no record of it being changed over with an aftermarket one. I had issues with changing radiator caps that stopped the overflow from being sucked into the radiator until I put the old cap back on and it went back to normal.

Then came a new battery and then a camping trip that caused the heat gauge needle to get excited again and I finally made the time to take it to a radiator shop where it was revealed there was a crack in the 17 old unit (it’d done okay for something that was usually good for roughly a decade) and that the air con needed a regas too before things really heated up.

A week after the new rad went in, I started noticing some more unwanted behaviour creeping back in..


‘Give it a dribble of water tomorrow morning before you go to work and that should be it’ the bloke at the radiator shop suggested when I went to pick it up. And that’s when I noticed the overflow bottle was a little over the full mark, but put it down to probably having slightly more fresh coolant in there from the flush and service than usual.

A couple of days later, that level climbed again. What was going into the overflow was not coming out again. So I manually poured it back into the radiator and tried some of the old radiator caps I had, just in case but no, that didn’t fix it either. That overflow continued to grow.

Here’s a rough photo shop for your amusement.

overflow filling up due to possible Subaru head gasket issue

Which eventually gives you something like this, eventually venting coolant all over the place.

overflow tank full from possible subaru head gasket issue

But since I’d paid for a new radiator and service, I wanted to make sure there wasn’t anything I was missing here like a loose hose or the off chance that all the caps I’d tried were wrong (incredibly doubtful given the fact that one was brand new and the other was a Subaru OEM one) and so I took it back to the radiator shop. Two mechanics came out for a look, tested the cap, looked over the new hoses and then took the keys to try one final thing.

With the car warmed up and the radiator cap off, the senior mechanic started the car and we all grimaced at the the volcano of fresh coolant that suddenly geysered out of the radiator.

‘That’s your head gasket mate. Normally anything in there should be static but the fact that it just got vomitted up when we turned the key shows exhaust gasses are pushing it up and out..’

Well, wasn’t that a kick to the gut? And because the radiator had a crack in it and was obviously faulty, this problem didn’t really make itself known until the sealed system was properly sealed up again and it had nothing to hide behind.

What a learning experience this six months has been then – especially when nine years and about 80,000kms it already had a head gasket change when they replaced the timing belt…


-Spilled coolant from the overflow tank when there’s no obvious problems with the radiator or it’s a new unit.

-Signs of motor oil in your overflow

-Coolant in the overflow being pushed there by venting exhaust gasses but not being sucked back into the radiator as needed

-Overflow coolant smells like fuel

-Your heat gauge goes up randomly but the car does not feel like it’s overheating (this can also be attributed to air bubbles in the system too if it’s not burped properly, another finicky Subi quirk from back then.)

2005 Subaru radiator
Anything more than halfway signals an issue

-Sweet white smoke from exhaust

-Sudden drop in performance

When it doubt, take it to your mechanic for a proper head gasket test before you spend more money on other things trying to chase down issues.


Look, I’d love to tell you ‘another Subaru head gasket goes in and job’s done!’ but even if that happened, I don’t think I’d be able to drive it again without a wary eye on the heat gauge wondering at all times when it might go next. Or what else will suddenly require attention once this is fixed, knowing my luck it’ll probably not be cheap and let’s face it, we’re all out of money at the moment thanks to this insane year. No as much as a hit to the pocket it will be (I dipped into the savings just to get this thing) I think it’s time to sell it in its current state, move onto something a little less quirky and find someone with the time, passion and motivation to keep this thing running because right now with everything going on in the world including more pressing family concerns, that certainly isn’t me.

If you’re interested in it drop me a line, if you’ve got some suggestions on where to find someone keen on an Subaru Impreza RS (outside of Facebook and Gumtree where the idiot factor is right out of control), let me know below.

In the meantime, onwards and upwards in finding something both cheap and reliable – send good vibes or bulletproof Toyotas – both would go alright here right about now.


Ahh to think of how much time and mess I would’ve saved had I bought this earlier – around $20 too so definitely worth having on board if you have to transfer fluid from one part of the car to the other.

Supercheap Auto Fluid Transfer Pump

Fully extended, it looks like this. Given the proximity of the overflow tank to the rad, you really won’t need these extra long hoses but they may come in handy down the track somewhere.

Top hose closest to the pump handle goes into whatever you need to draw from:

Other hose goes into whatever you want the fluid to land. Now I’ve opted for a bottle here because I read on a review on the Supercheap Auto site that the fluid does come out of this hose at a pretty decent rate of knots and since I’m trying to make things as smooth and mess free as possible, the bottle trick works just fine. If you’re going to aim it at the radiator, I’d suggest a large funnel in the opening first just to save yourself getting covered in fast moving coolant.

In no time at all we have an overflow tank back to proper levels and a bottle full of coolant to pop back into the radiator easily.

Previously I’d have to remove the overflow bottle itself, pour things back in and then mop up what went wayward which was usually a bit. (Plus cable tie it back in place because that screw holding it in is long gone.) This way I can have one hand on the funnel with a towel around and control the pour and spillage, burping the upper and lower hose to help draw it through.
It’s nice not having to feed the overflow hose back into the bottle again, that’s also a bonus.

When done, hang the pump up with the hoses angled down and a bottle at the end to grab anything that drips through. Now it’s ready to go again when you are!

So much quicker, so much less mucking about. Like I said, I should have bought something like this ages ago..


If you’re in Australia, try Supercheap Auto (strangely the website says $27 but I bought it a few days for $20, so maybe there was a sale?) or maybe Repco (same sort of hand pump I used to play with at school!)

On Amazon – Affiliate link. Both the Koehler and Pennzoil version look exactly as the unit I used for this. Maybe try one of those first?

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