If it’s the same size as a standard tank , the minimum level is about 1.5 to 2 or so inches up from the bottom , the max level is about 3 to 4 inches from the top , it’s not a large tank maybe 1/2 a litre goes into it , nothing obvious on line about capacity , i run mine on the max line when cold , if I do a coolant change i often put more in as the level will go down once the bubbles go

 

if this is low do you think it could cause an issue or not to this extreme? I stupidly didn’t check the level draining but just trying to rule out the obvious.
also should the header tank cap be 0.9 bar or 1.1bar?

 

I personally think if it’s low then no , the low level is very low on the tank any way , as long as it had some i it it should be fine , it’s there to take excess coolant as it expends and gets hot and return when it’s cooling down , the more important is the contents of the rad and the pressured tank , i recently had a re build done , the level was very low after a drive so just topped it up , no issues , even if it was empty then as long as the coolant was where it should be that should be ok , the only issue you get as it cools down you will get air sucked back into the rad and engine , it’s not unusual not to have to top up after a coolant change

 

Hi mate, I was having these issues with my 2.5 WRX, at first I tried the simple stuff like sensors...like the one under the alternator thinking maybe it was faulty, then I fitted a new thermostat still the same...for me sadly it was indeed the headgasket, I'm not saying yours is but I do wish I got a test kit from the start just to rule it out, I bought one of those cheap ones off eBay that detects CO₂, tried it on my daily and the fluid remained blue, tried it on the Scooby and it sadly changed colour to a greeny/yellow, I think they are only about a tenner on eBay but for the sake of ruling out that problem it's worth it.

Fingers crossed it's not the root of your problems, lovely car by the way!

 

Sniff tests don’t always work , it did not on mine 👍

 

The only thing I can think is that the previous owner put in some Holts Radweld to save the hgs it's a Subaru official 'fix' for prefailing head gaskets - they're laminated with the middle sandwich filling being of graphite which leeches out eventually, their 'fix' being a bottle of coolant conditioner which turns out to be Holts Radweld! Anyway, Here's a YouTube video explaining it.
https://youtu.be/J3eHEE--GwQ?si=zKo2eWsGvp8w7gsn

You draining the coolant probably removed or dislodged the Radweld.... don't worry, just buy a bottle from Halfords but only use half the bottle which is twice as large as the Subaru coolant conditioner bottles.
I've been running my Classic Sport MY99 on it for 4 years now, and only had to refresh the Radweld once, till I get 'aroundtuit' to replacing the hgs.

 

Still no joy I’m afraid, slow normal driving for half an hour kept the gauge where it should be, literally as soon as I overtook someone up to 60-70 in third gear it went up to 3/4 😡 I’m about done with this car 😂

 

If you swapped the stat out and it’s another one in there , plus you have a constant stream of bubbles in the non pressured expansion tank then looks like hg issue ☹️

 

No constant stream of bubbles!

 

Hg then , it will push bubbles out till the air is out , if it’s pushing them all the time , hg , 1500 to 2000 to sort but will need studs not bolts and a de tune running a fair bit for a wrx box , if you are giving up and selling then give me a shout I may know someone who is looking for one 👍

 

Ok thanks, I’m open to offers at this point as I also need house deposit money so if your friend wants to make me an offer then I’m open 😉

 

Pm sent 👍

 

nothing received yet mate

 

I have replied mate.

 

So I have read recently that the coolant tank cap by the turbo should be a lower pressure rating that the one on the radiator. Now that I’ve replaced the radiator cap for the correct one, should I change the one on the tank for a 0.9 bar one? Or am I clutching a straws?
I guess it shouldn’t cause overheating…..

 

Perhaps an initial airlock has allowed the engine to get hot enough to warp a head.

 

Pm come through I will have a chat with him 👍

 

I’m open to offers mate

 

Should the bottom radiator hose stay cold all the time? Even when the temp gauge is high?

 

No the stat should open and the fan should come on when it reaches operating temps.

 

Did you try swapping to stat out ? 👍

 

Have tried today, am going to leave overnight with a funnel in overnight for any air to make its way out, then I’ll update you guys

 

So after all that…. It was the thermostat. Replaced, bled and driven properly, all is good

 

Excellent a relatively simple solution 👍😁 got there in the end faith hopfully restored

 

Woopwoop! Great news!
I wonder if your old thermostat was ok as you said you tested it?
I think there is a small hole on the thermostat plate, I think this hole has to be in the upper "12 O'clock" position when fitted so any trapped air can get out as the air will always rise.

Some stats have what's called a jiggle ball attached to the small hole...that said, I could well be (and probably am) talking out of my ar$e hahhaa

 

Yeah I read about the jiggle thing being fitted at 12 o’clock, which I did both times.
I tested the stat in freshly boiled water initially and it opened but I guess maybe it wasn’t opening fully? As I didn’t have another one to compare it to.
Either way, fixed is fixed lol
Thankyou for your replies guys, much appreciated