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best adding coolant , if you don’t have any a top up with water would be fine , as above check pressured expansion tank when it’s cold to make sure it’s not loosing coolant , keep an eye on your coolant levels
best adding coolant , if you don’t have any a top up with water would be fine , as above check pressured expansion tank when it’s cold to make sure it’s not loosing coolant , keep an eye on your coolant levels
I’d need to top up from header tank and not expansion right?
From cold I would undo the main header tank by the intercooler and top up, replace cap. Undo radiator cap and top up if needed, replace cap. Pop off the plastic cap on the overflow bottle nearest the battery and top up to about half way between the cold and hot lines on the bottle.
After a drive you'll see that the level in the overflow bottle nearest the battery has risen an inch or two. This one or two inches then gets sucked back in to the cooling system whilst the engine is cooling down, and should return to the same level as it was when cold.
From cold I would undo the main header tank by the intercooler and top up, replace cap. Undo radiator cap and top up if needed, replace cap. Pop off the plastic cap on the overflow bottle nearest the battery and top up to about half way between the cold and hot lines on the bottle.
After a drive you'll see that the level in the overflow bottle nearest the battery has risen an inch or two. This one or two inches then gets sucked back in to the cooling system whilst the engine is cooling down, and should return to the same level as it was when cold.
As above , oil and coolant well worth checking regularly , as it’s a turbo and forced induction you are more likely to use oil, when the coolant does not return to normal level from the non pressured expansion tank then that can be your indication of possible HG issues , the reason it’s not returning is where it would return too is full of escaped air from the hg failing , on another note a 10/40 or 10/50 oil works a lot better , not only better lubrication but if you were loosing a bit of oil which is normal a slightly thicker oil reduces the oil loss 👍
As above , oil and coolant well worth checking regularly , as it’s a turbo and forced induction you are more likely to use oil, when the coolant does not return to normal level from the non pressured expansion tank then that can be your indication of possible HG issues , the reason it’s not returning is where it would return too is full of escaped air from the hg failing , on another note a 10/40 or 10/50 oil works a lot better , not only better lubrication but if you were loosing a bit of oil which is normal a slightly thicker oil reduces the oil loss 👍
Thanks man. I’m currently using a 10/50 and oil level is bang on. No problems there. Just coolant is bugging me as I’m not sure what to put in there if it needs a little topping up and where to put it. I’ve been told tap water is fine in the overflow tank to get it up to low line when cold and I’ve heard deionised water is recommended due to no chemicals etc. Don’t know what to believe lol. Header tank next to turbo half an inch below neck level btw.
My last Fsti went to 198k miles , i always used tap water , it’s really nothing to worry about , i still only top up with tap water , if you want to use ionised that’s fine no real need , i’ve never used ionised in any of my cars since 1990, oil is all good 5/? is far too thin , the pressured tank by the turbo that will not be full full it will always be a bit below max , as long as both levels once filled correctly , are staying where they are then that’s good , it’s a valid point about the pressure caps they can fail , a few put on higher pressure caps 1.3 bar v 1 bar or so , i run coolant just below the max mark in the non pressured rad tank , i check oil and coolant three times a month which is about every 300 miles or so , yes it’s over checking but it takes no time , the oil will often go down on any car , as long as it’s bit of oil loss that’s ok , i top up a little oil once every three months or so , again i keep oil at max on dipstick , checking oil ….go for a drive , park up somewhere very flat , leave the car for 10 mins or so , dipstick out , three markers , low level , max level then a marker after max level which is basically the level the oil expands to when hot , so when my oils hot it sits between max and hot oil level 👍
Does your service history show which coolant was last used and when? Is there any information on an invoice perhaps? You could then get a small bottle of the same stuff and use that. Prestone coolant I see in Tesco's says it mixes with all coolants, and I think is ready diluted.
For the amount you need this could work for you....maybe someone can confirm that.
If the coolant is over 3 years old, I'd just get the coolant changed anyway.
Then you have piece of mind that it's all the same coolant, topped up and fresh.
If you go to a Subaru dealer for coolant, don't let them sell you the tiny bottle of coolant conditioner - tell them to get stuffed. It's just Barrs leak stuff that you pour in, a scam they use to try and hide potential HG issues!
I had my coolant system pressure tested as I was losing slow but sure small amounts of coolant earlier this year. It was found dripping under pressure from the coolant line to the turbo, he pushed the hose on a little further and moved the clip round and job done.
It was this hose, but I don't know what your model is :
Does your service history show which coolant was last used and when? Is there any information on an invoice perhaps? You could then get a small bottle of the same stuff and use that. Prestone coolant I see in Tesco's says it mixes with all coolants, and I think is ready diluted.
For the amount you need this could work for you....maybe someone can confirm that.
If the coolant is over 3 years old, I'd just get the coolant changed anyway.
Then you have piece of mind that it's all the same coolant, topped up and fresh.
If you go to a Subaru dealer for coolant, don't let them sell you the tiny bottle of coolant conditioner - tell them to get stuffed. It's just Barrs leak stuff that you pour in, a scam they use to try and hide potential HG issues!
I had my coolant system pressure tested as I was losing slow but sure small amounts of coolant earlier this year. It was found dripping under pressure from the coolant line to the turbo, he pushed the hose on a little further and moved the clip round and job done.
It was this hose, but I don't know what your model is :
It’s a 2.5 Hawk STI and it’s been 6 months since rebuild. I’ve contacted the garage who done the work and they use comma blue antifreeze but it’s not labelled when it’s delivered to the garage so I can’t find the specific one from Halfords. They’ve said they can deliver 1 litre of it to me but a drop of tap water is fine as it’s a 50/50 mix and there’s plenty coolant in there. When you spend thousands on an engine, you don’t wanna take chances so I need assurance lol.
Originally Posted by 1509joe
Tap water would depend on whether you live in a hard or soft water location.
I live in a medium water area.
Originally Posted by nicam49
I live in a hard water area, and for what deionised costs, (Tesco is good value as is Asda... 1 litre Carplan) it's not worth quibbling over.
I was looking at this as well but again didn’t wanna put it in until getting assurance on here. It’s down an inch in the overflow from cold low level, so just want to get it up to that level. When the engine is warmed up it’s just above the low level…
It's probably just where your levels of coolant have now found themselves and any trapped air is now out. Quick top up and you'll be fine. Yes, believe me I know how scary it is after a fresh 2.5 build, worrying times!
Hey guys. On cold this morning, I started by topping up (about an inch) and pouring in coolant/antifreeze at the header tank until fill level very slowly. Put the cap back on. Done the same for radiator cap and put the cap back on. Then filled the overflow tank (plastic bottle) until halfway between low and cold. Left the car for an hour. Then started up and left for work. Once warmed up, put the heater on high and low fan. Anyway, I got to work. Let it idle. Fans on and off. Opened overflow cap and seen one or two bubbles just once, when the fan kicked in. Didn’t see any more bubbles.
Might be just pushing out some trapped air as your levels had dropped a bit, monitor it. You can get the odd bubble, but you don't want constant jacuzzi bubbles like mine was....when my block let go at the top of a cylinder liner!
Hopefully your levels will settle / behave. Keep a close eye on them.
Nothing you did above was "wrong" so don't worry, you did everything "right"
Do the same several times ref warm up etc, then when warm pop off the overflow tank yellow plastic cap (plastic bottle by radiator / battery) and look for bubbles whilst running.
One last thing, be sure not to mix up the metal caps - the one with the ears on it is for header tank near turbo, the round one is for the radiator. I've read too many times these get mixed up!
My suspicion is that after a fresh build, the true levels showed up as just a tad low. Now you've topped up, you should be fine,
However, if levels appear to drop again, then speak to the builder etc. Could be a minor leak like what I had on my turbo coolant hose as linked in post #13, if so, only usually pressure testing shows leaks as small as that - but it's enough over time to make levels drop, and can cause concern until found - tell me about it!
Do check once cold - the level in the header tank, replace cap, the level in the radiator, replace cap....you know the drill!
After a run, you'll see the coolant has risen into the plastic overflow tank bottle by an inch or two, this is normal, as long as the level returns to where it started off when everything has completely cooled down overnight.
Last edited by Hawkeye D; 08 July 2021 at 06:16 PM.
Might be just pushing out some trapped air as your levels had dropped a bit, monitor it. You can get the odd bubble, but you don't want constant jacuzzi bubbles like mine was....when my block let go at the top of a cylinder liner!
Hopefully your levels will settle / behave. Keep a close eye on them.
Nothing you did above was "wrong" so don't worry, you did everything "right"
Do the same several times ref warm up etc, then when warm pop off the overflow tank yellow plastic cap (plastic bottle by radiator / battery) and look for bubbles whilst running.
One last thing, be sure not to mix up the metal caps - the one with the ears on it is for header tank near turbo, the round one is for the radiator. I've read too many times these get mixed up!
My suspicion is that after a fresh build, the true levels showed up as just a tad low. Now you've topped up, you should be fine,
However, if levels appear to drop again, then speak to the builder etc. Could be a minor leak like what I had on my turbo coolant hose as linked in post #13, if so, only usually pressure testing shows leaks as small as that - but it's enough over time to make levels drop, and can cause concern until found - tell me about it!
Do check once cold - the level in the header tank, replace cap, the level in the radiator, replace cap....you know the drill!
After a run, you'll see the coolant has risen into the plastic overflow tank bottle by an inch or two, this is normal, as long as the level returns to where it started off when everything has completely cooled down overnight.
Hey. Just went for another run. Warmed up. Cycled heater on and off. Stopped over. Switched heater off. Fans kicked in and I got a few bubbles…
It can't be HG after a fresh build....at least you'd hope not. Monitor for the next few days closely.
A classic giveaway of HG is usually a lot of coolant (4-5 inches or more) being pushed into the plastic overflow bottle and not being sucked back in when cooled down.
If it continues to drop, my money is on a leaking hose / join somewhere. A pressure test should show it up - up in the air with undertray off is how mine got found.
It's also possible the bubbles you're seeing is air being sucked in through a small leak whilst cooling down.
FYI "cycling the heater on and off" does nothing to help remove any trapped air. The heater circuit is a full flow bypass loop (no control valves involved). Temperature is controlled by air mixing flaps NOT water flow.
Last edited by Don Clark; 08 July 2021 at 07:29 PM.
It can't be HG after a fresh build....at least you'd hope not. Monitor for the next few days closely.
A classic giveaway of HG is usually a lot of coolant (4-5 inches or more) being pushed into the plastic overflow bottle and not being sucked back in when cooled down.
If it continues to drop, my money is on a leaking hose / join somewhere. A pressure test should show it up - up in the air with undertray off is how mine got found.
It's also possible the bubbles you're seeing is air being sucked in through a small leak whilst cooling down.
I’ll keep an eye on it. It’s not bubbling at all on idle. It is being sucked back in when cooling down. Heater is working fine at max temp. Fans kicking on and off. No problem. Only concerned about occasional champagne bubble when fans kick in…
i always keep my non pressured tank just below the max line , there could just be a bit of air in the system , top up so engine pressure cap is full , same with rad cap , you know it’s fine when levels are returning back to more or less what they were after it’s cooled down fully after driving it , the only sign i have found of hg issues is the coolant in the non pressured expansion tank ( the one bolted to the top of the rad ) not returning to the engine after it’s fully cooled down after it’s been driven , if levels keep going down then get a pressure test done , but at this time not sure if they are actually going down , there is a metal cross over pipe at the front of the engine which can be a weakness i exhaust wrapped mine after i put a new one on
Went for a glorious run with plenty of boost. Checked overflow on multiple occasions. Not a single bubble and maintained its level after warming up. Praying it’s sorted itself out.
Wicked news! Sounds like the champagne bubbles were just a bit of trapped / cavitated air bleeding out. Monitor, relax, enjoy the car!
Here's a couple of pics of what a bad day looks like..... this is my original 2.5 STi block that let go after 85k miles. On the day I got it trailered for rebuild, I couldn't even start the car, it was completely hydro-locked from coolant getting into cylinder 1.
Fingers crossed it’s all good 👍
a cracked block that’s unlucky , only seen that once before on a cs400 , what power were you running , my hg failures have always made themselves known by blowing into the non pressured tank , not had piston ring failure as it’s a Fsti , and as i found out £££ always get whole engine re built as crank bearings often follow a hg failure
Wicked news! Sounds like the champagne bubbles were just a bit of trapped / cavitated air bleeding out. Monitor, relax, enjoy the car!
Here's a couple of pics of what a bad day looks like..... this is my original 2.5 STi block that let go after 85k miles. On the day I got it trailered for rebuild, I couldn't even start the car, it was completely hydro-locked from coolant getting into cylinder 1.
How on earth would this happen?! Gaskets, studs and tune from factory?
as far as i am aware, it’s not a common failure as most of the time the boost is pushing every thing out of the bores so you don’t get hydra lock , very unlucky ££ ☹️, the cs400 was at subaru4u , same place you are getting or got yours repaired ? , Len is very good , i would make the old block into a coffee table , or find a scrapped v8 block and do the same 👍 as per Top Gears v8 table
25 June 2021, 12:23 AM
