Recent Topics
WPA 3 Wireless Security Coming
by StevieC. 09/22/18 01:16 AM
Robo Calls/Telemarketers
by Nick1994. 09/22/18 12:47 AM
What oil should be used!
by BigShug681. 09/22/18 12:28 AM
VW Electronic Parking Brake
by StevieC. 09/21/18 11:48 PM
Leak Sealing and Mould Treatments?
by Ducked. 09/21/18 11:44 PM
UPS / FedEx / USPS
by StevieC. 09/21/18 11:21 PM
puncture repair question
by neo3. 09/21/18 10:55 PM
Can I use a 10 amp extension cord for...
by gregk24. 09/21/18 10:48 PM
In the unlikely event of a crash
by StevieC. 09/21/18 10:09 PM
Craigslist time wasters
by Anduril. 09/21/18 09:41 PM
Who runs a 20wt here?
by StevieC. 09/21/18 07:31 PM
Need help on edit profile
by jetmech1. 09/21/18 06:34 PM
Oil thickness on the dipstick
by Idlewild294. 09/21/18 05:40 PM
Chinese WIX Trans filter bad, let me down..
by jetmech1. 09/21/18 04:47 PM
Gen 8 Accord rear brakes-What tool?
by fdcg27. 09/21/18 04:30 PM
Ammeters?
by buck91. 09/21/18 03:55 PM
Need Help with Double D Knock Out Punch
by user52165. 09/21/18 03:41 PM
Newest Members
JRMFt11, Navyretired, aikwae, ScottRousell, Direct_Rejection
66036 Registered Users
Who's Online Now
25 registered members (chance, DirtyOilGuy, dishdude, Drew99GT, 4 invisible), 748 guests, and 32 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums67
Topics290,810
Posts4,850,740
Members66,036
Most Online3,590
Jan 24th, 2017
Donate to BITOG
Previous Thread
Next Thread
Print Thread
Hop To
Subaru coolant conditioner?? #4651945
01/31/18 11:22 AM
01/31/18 11:22 AM
Joined: Aug 2017
Posts: 538
Nebraska
BJD78 Offline OP
BJD78  Offline OP
Joined: Aug 2017
Posts: 538
Nebraska
I have never owned a subaru before , but our 2002 honda CRV was in an accident and totaled last fall so in Oct 2016 I bought a 2010 Forester with a 2.5 and a 4EAT. Had pretty detailed service records kept by the previous owner, though lots of maintenance was done at a quick lube Shell station here in Lincoln. Anyway Antifreeze tests out fine and service records show it being replaced back in Feb of 2013. I figure when weather warms up I will drain it out since it has been nearly 5 years, flush it with water and put in new coolant. Anyway I was reading the OM and on chap 11-13 it states the following:"Always add genuine SUBARU cooling
system conditioner whenever the coolant
is replaced.
Change the engine coolant and add
genuine SUBARU cooling system conditioner
using the following procedures
according to the maintenance schedule."

I really am no fan of adding after market products to fluids.. seems to me that it is like a stop leak and might clog up the heater core or radiator. I have never really heard of any other vehicle requiring a coolant additive or any additive for that matter. most OM recommend against additives. A bit of research revealed that some Subarus had head gasket issues, but 2010 forester is not on that list. Anyway, I suppose when the weather warms up in a couple of months I will probably do what the owner manual recommends and dump a bottle in there it is a small 4 oz bottle. still dumping that stuff in there makes me a bit nervous, but those design engineers are supposed to have a reason for it. Any Subaru owners on here ever use that stuff(subaru coolant conditioner) or have any issues with it, like a clogged heater or radiator??


2010 Forester:122K
2009 Sonata :189K
2010 Tucson:55K

OCI 5K using the cheapest dino oil I can buy,usually NAPA or TSC Travelers oil.
Re: Subaru coolant conditioner?? [Re: BJD78] #4651955
01/31/18 11:44 AM
01/31/18 11:44 AM
Joined: Sep 2004
Posts: 7,526
Marshfield , MA
andyd Offline
andyd  Offline
Joined: Sep 2004
Posts: 7,526
Marshfield , MA
You've got time to plan the job. Do some research on the interweb. If I owned Subaru, I would be on a forum to gather advice on maintaining it. If its the what-ever and some water pump lube type, that stuff is safe when used as directed.


'16 Camry LE STP synth 0w20 and STP filter. the Fridge

1994 Ranger ,the Rat, 5w30 dino, STP filter

'16 Camry SE, Valvoline HM 0w20 and OEM filter
Thick oil is better grin2
Re: Subaru coolant conditioner?? [Re: BJD78] #4651969
01/31/18 12:03 PM
01/31/18 12:03 PM
Joined: Dec 2008
Posts: 3,080
Occupied Virginia
Bottom_Feeder Offline
Bottom_Feeder  Offline
Joined: Dec 2008
Posts: 3,080
Occupied Virginia
The Subaru conditioner is just stop-leak. Subarus from very roughly 2000 to 2010 were prone to head gasket leaks and the 'conditioner' was just a band-aid to help avoid a potential problem but it wouldn't fix one if it was already there. Even regular coolant flushes wouldn't avoid the problem in many cases. The gaskets either ended up leaking or they didn't. My 2001 2.5 RS leaked coolant from the crossover tube and oil from the valve covers (another known Subaru issue) but never coolant from head gaskets that I could see. But then it spun a rod bearing (another known Subaru issue!) at a young 114K miles and these issues no longer mattered. wink

Re: Subaru coolant conditioner?? [Re: BJD78] #4651970
01/31/18 12:04 PM
01/31/18 12:04 PM
Joined: Nov 2006
Posts: 19,915
MA, Mittelfranken.de
Trav Offline
Trav  Offline
Joined: Nov 2006
Posts: 19,915
MA, Mittelfranken.de
It is a ginger root based formula made by Holts, it is the same as GM and Bars Leak tabs. Ginger root does not swell when wet only when wet then exposed to air.it will not plug anything in the cooling system when used in specified amounts (too much of a good thing is almost always bad) it will just roam around the cooling system waiting for a leak/weep.

Highly recommended for some Subaru, Cadillac N* engines and any block prone to porosity. A good product!

Last edited by Trav; 01/31/18 12:05 PM.

ASE L1, Master. Deutsch Meisterbrief.
Re: Subaru coolant conditioner?? [Re: Trav] #4652010
01/31/18 12:49 PM
01/31/18 12:49 PM
Joined: Aug 2017
Posts: 538
Nebraska
BJD78 Offline OP
BJD78  Offline OP
Joined: Aug 2017
Posts: 538
Nebraska
Thanks for the input. From the service records from the Valvoline shop the last change was done using Valvoline Asian blue, but there was no indication that subaru conditioner was added at the last coolant change. I kind of doubt if a quick lube place like valvoline would have added it. So anyones guess if the stuff is in there or not. It is not expensive only about $7.00 from the subaru shop here in town. Cheaper than a blown head gasket. So far I see no leaks of any kind other than a bit of oil seepage around the valve covers which is to be expected on a vehicle with over 120K.


2010 Forester:122K
2009 Sonata :189K
2010 Tucson:55K

OCI 5K using the cheapest dino oil I can buy,usually NAPA or TSC Travelers oil.
Re: Subaru coolant conditioner?? [Re: BJD78] #4652024
01/31/18 01:06 PM
01/31/18 01:06 PM
Joined: Jan 2009
Posts: 6,197
New England
gathermewool Offline
gathermewool  Offline
Joined: Jan 2009
Posts: 6,197
New England
What Trav said. The bottle of coolant conditioner is very small - 4.4 oz - which surprised me when I first used it. I haven't done any research on non-long-life Subaru coolants recently, but I'd make sure the last coolant used is 100% compatible; otherwise, I'd have it flushed for the Subie green stuff. Either way, add the conditioner.


'14 Forester XT FA20DIT (Cobb Stage 1)
Edge 0W-40 + FU filter
'15 Legacy FB25 (OEM Stage, uh, neg. 7?)
Edge 0W-20 + FU filter
Re: Subaru coolant conditioner?? [Re: BJD78] #4652122
01/31/18 02:44 PM
01/31/18 02:44 PM
Joined: Jan 2017
Posts: 296
Ontario, Canada
newbe46 Offline
newbe46  Offline
Joined: Jan 2017
Posts: 296
Ontario, Canada
I have 2004 Impreza, quite a bit older than your 2010 Forester. I did experience the head gasket issue and it wasn't fun. Based on my research and the conversation with my mechanic at the time, my conclusion is that all Subarus need to use whatever coolant that is recommended.

I bought mine used and it had the generic greenish/yellowish coolant you can get from auto parts store. When the head gasket started to give me problems, my mechanic drained the old stuff out and put the Subaru branded coolant after the replaced the head gasket.

I think it has something to do with the corrosion of the metal in the radiator by the generic coolant but I'm not 100% sure.


2003 E46 M3 Convertible
2004 Odyssey EX-L
2004 Impreza TS Wagon
Re: Subaru coolant conditioner?? [Re: BJD78] #4652132
01/31/18 02:55 PM
01/31/18 02:55 PM
Joined: Dec 2002
Posts: 6,568
Huntington Beach, CA
tenderloin Offline
tenderloin  Offline
Joined: Dec 2002
Posts: 6,568
Huntington Beach, CA
Recommended by Subaru...Only a few dollars a bottle. What is there to think about?

Re: Subaru coolant conditioner?? [Re: BJD78] #4652163
01/31/18 03:25 PM
01/31/18 03:25 PM
Joined: May 2012
Posts: 1,349
Winchester, Indiana
SubieRubyRoo Offline
SubieRubyRoo  Offline
Joined: May 2012
Posts: 1,349
Winchester, Indiana
Trav nailed it... and the HG issues did not really last til 2010... I would argue after that after the HG change around 2006 to a coated MLS that any HG failures are likely due to maintenance neglect or another catastrophic failure that caused severe overheating.

Subaru Coolant Conditioner is Holt's Radweld rebadged for OEM use. You should not need it on any vehicle produced after 2006 IMHO (but it won't hurt anything if you do use it).

I am on my 4th Subaru, with over 217k on my 01 Forester, and no head gasket issues on any of them.

Re: Subaru coolant conditioner?? [Re: SubieRubyRoo] #4652242
01/31/18 04:35 PM
01/31/18 04:35 PM
Joined: Nov 2006
Posts: 19,915
MA, Mittelfranken.de
Trav Offline
Trav  Offline
Joined: Nov 2006
Posts: 19,915
MA, Mittelfranken.de
My old 22ej (awesome scubie engine) doesn't need it either with its closed deck but its in there anyway.


ASE L1, Master. Deutsch Meisterbrief.
Re: Subaru coolant conditioner?? [Re: SubieRubyRoo] #4652962
02/01/18 10:38 AM
02/01/18 10:38 AM
Joined: Aug 2017
Posts: 538
Nebraska
BJD78 Offline OP
BJD78  Offline OP
Joined: Aug 2017
Posts: 538
Nebraska
(You should not need it on any vehicle produced after 2006 IMHO (but it won't hurt anything if you do use it).)

The only reason I found out about it is because I was waiting in the vehicle and decided to take a look at the OM. I was doing a quick scan of coolant and caught that fine print that (coolant coditioner was recommended) Usually I do not find OMs very exiting books to read so I was almost by accident that I even saw the little sentence about it. The only Subaru I have ever owned, but since the 2010 OM states it should be used I will do a drain and fill soon and put some in. Not sure if it has it in now or not as the service records only indicate coolant was changed. I have never been a fan putting extra products or additives in the coolant but these design engineers must have done some sort of testing to require using it. Have heard many horror stories of peoplewho have dumped stop leaks into radiators and ended up clogging up the radiators and heater cores. Apparently this Subaru stuff basically tends to not clog things up. Hopefully a good product and hopefully Subaru fixes their head gasket issues. I can easily change coolant myself, but really do not want to hassle with finding a place that will take the used antifreeze, not many places want to take it anymore. Almost every place will take used oil, but antifreeze... not so much.

(I am on my 4th Subaru, with over 217k on my 01 Forester, and no head gasket issues on any of them) Exactly, No one wants a head gasket issue as they are not cheap to deal with probably at least 1500 to 2k or more to replace. That is kind of why I went with Subaru, most people I know who have them have them for well over 200-300 K and they tend to run like new even with minimal or spotty maintenance.

Re: Subaru coolant conditioner?? [Re: BJD78] #4653060
02/01/18 12:15 PM
02/01/18 12:15 PM
Joined: May 2012
Posts: 1,349
Winchester, Indiana
SubieRubyRoo Offline
SubieRubyRoo  Offline
Joined: May 2012
Posts: 1,349
Winchester, Indiana
BJD, if the used coolant and oil somehow got mixed together... like a "bad head gasket", parts stores have to accept used oil by law. Just sayin' smile

Re: Subaru coolant conditioner?? [Re: SubieRubyRoo] #4653198
02/01/18 02:39 PM
02/01/18 02:39 PM
Joined: Aug 2017
Posts: 538
Nebraska
BJD78 Offline OP
BJD78  Offline OP
Joined: Aug 2017
Posts: 538
Nebraska
Agreed, most any shop or dealer will take used oil. O reilly, napa, carquest, auto zone, I avoid Wall Marts like the plague, but know people who take used oil there as well. My point was here in lincoln very few places take anti freeze. The local Lincoln EPA lists a couple of shops that do, but a couple iof years back I took some used antifreeze there and the owner acted like I was bothering him. Even though they probably get paid to recycle it. The city recyclers do not even take it. At least now days antifreeze is good for 5 years or so so that is nice. So far I have never had a head gasket failure, have had a couple of hose leaks and a radiator cap that went bad and caused overheat, but never a headgasket. I probably should have researched Subaru a bit more as apparently their engines tend to be more prone to it. hopefully the subaru radiator conditioner will prevent it. Have only had the Forester since Oct 2016 and so far so good, but not sure if conditioner is in there so will just have to drain it and a repalce fluid.and add a bottle of the stuff. I drive by a subaru dealer almost every day so will pick some up along with 2 gal of subaru anti freeze. Too cold to mess with right now so will wait till about mid April as my garage tends to be a bit cool.


2010 Forester:122K
2009 Sonata :189K
2010 Tucson:55K

OCI 5K using the cheapest dino oil I can buy,usually NAPA or TSC Travelers oil.

BOB IS THE OIL GUY® Powered by UBB.threads™