Jump to content

Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse

- - - - -

Should I Replace the Radiator?

radiator thermostat leak

  • Please log in to reply
6 replies to this topic

#1 manchuscout


    New User

  • Members
  • Pip
  • 6 posts
  • Mill Valley, CA

Posted 16 July 2013 - 11:52 AM

Last September discovered head gasket leak. Tried to plug with "Alumaseal Stopleak." (Stupid idea)! Problem persisted. Three weeks later I flushed cooling system & tried to plug leak with "Bar's Leak Head Gasket Repair." Leak seemed plugged, but 8 months later engine overheated & radiator coolant was discovered to be way too low.  Replaced coolant, kept radiator filled on inspection.


Ten days ago added Subaru Cooling System Conditioner. Coolant began backing up into coolant reservoir, nearly filling it to the top every 75 miles, with
foam floating near the top. Five days ago tried using "BAR'S LEAKS Head Gasket Repair." Looked good! No steam or water exiting tailpipe, and level of water in coolant reservoir remained steady — BUT — was only able to get 4 quarts of fluid into radiator!  Engine now overheats in 15 minutes. Removed thermostat — no change. Top radiator hose hot, bottom hose cold. My guess — I plugged radiator with all the gunk I poured in. Can I flush that crap out with some sort of commercial additive, or should I just get a new radiator?

#2 Legacy777



  • Moderator
  • 12,810 posts
  • Houston, Tx

Posted 16 July 2013 - 04:28 PM

There may be something out there you can use to flush the radiator, but I'm not really sure of anything.


My suggestion, and you probably won't want to hear this is to have the headgaskets fixed, cooling system flushed and put a new radiator in.  The heater core may be plugged or could plug over time.  I highly discourage using those quick fix's in a bottle as they only prolong the inevitable and usually cause more issues in the long run.

#3 manchuscout


    New User

  • Members
  • Pip
  • 6 posts
  • Mill Valley, CA

Posted 16 July 2013 - 08:50 PM

Thanks for your reply.  Sounds like good advice, but the "Too Big To Fail" swine are coming to take my home.  If I can get this car to run for just 2 more months, I won't have to live in a cardboard box under a freeway overpass.


Thanks again!

#4 Fairtax4me



  • Members
  • 13,034 posts
  • Charlottesburg, VA

Posted 18 July 2013 - 05:17 PM

The only "mechanic in a bottle" fix I've ever seen actually work on a head gasket leak is this stuff called Blue Devil. It costs about $65 a bottle but I have seen it work twice on badly leaking head gaskets. One was mixing coolant and oil and burning coolant in the cylinders. I drained almost 4 gallons of sludge (oil and coolant) out of the engine (Ford 351).

I followed the directions on the bottle and let the engine run for just as long as they instructed. I literally watched the steam in the exhaust, and the bubbles in the radiator disappear.

Blue devil is not chunky and I couldn't see any evidence of it leaving deposits in the radiator. After the treatment was done I simply drained and refilled with fresh coolant. As far as I know that engine is still running without trouble almost two years later.

The other time I've seen it used was a friend of mine had a minor head gasket leak on a Chevy 4.3 v6. Told him about Blue Devil, he bought some and used it and it did repair the leak in that engine as well. He sold the vehicle about 3 months later, so I can't say for sure how long it has lasted.

It does sound to me like you need a new radiator. There are some flushes available but they don't work to remove stop leak crud. A radiator repair shop would have the ability to flush it but it may cost as much or more than a new radiator. Someone just suggested Radiatorbarn.com in another post. You might check them out to save over parts chain store prices.

#5 Rooster2


    Subaru Master

  • Members
  • 4,728 posts
  • Indianapolis

Posted 18 July 2013 - 05:53 PM

A couple of years back, I replaced the radiator in my 98 OBW. Cost about $100, bought it on line. Easy to replace. I think I removed the grill to get room to work.


I, too, am not in favor of trying to fix a head gasket with an additive. I have yet to hear of a head gasket repair with an additive to a Subie that ever worked. I read that the 2.5 motor in 96-99 Subies, have pistons that ever so slightly raise above the block at TDC, so Subaru used extra thick head gaskets. This weakness eventually leads to a bad head gasket, where exhaust gas enters the cooling system leading to over heating. Strangely, the HGs never break so coolant contaminates the oil.


Both my 98 and 99 Outbacks blew their head gaskets, one at 155K miles, the other at 195K miles. So, I know all about being a member of the "blown head gasket fraternity."

#6 manchuscout


    New User

  • Members
  • Pip
  • 6 posts
  • Mill Valley, CA

Posted 24 October 2013 - 05:49 PM

Want to thank all who gave advice.  My original question was "Should I replace the radiator."  Can't say for certain whether additives to the cooling system are a good idea.  I used three different products, settling in the end on stuff called "Nanotechnology - Permanent Head Gasket and Block Repair.  It worked well enough to keep my  Subi running for 3 months.  The other stuff did, indeed, plug up my radiator (already 12 years old) enough to make it useless.  The most useful lesson I learned through all this is that there's an ENORMOUS amount of information in the form of videos on Youtube that can enable one to do one's own car repairs and save serious big bucks!  I'm not dumb enough to try replacing my head gaskets on my own, but I saved a bundle replacing my radiator, alternator and AC belts, steering fluid and knock sensor myself. Gonna do my brakes next.  Thank you, Youtube car-repair ninjas!

#7 Blue Whale

Blue Whale

    USMB Regular

  • Members
  • PipPipPip
  • 70 posts
  • Sunnyvale, CA

Posted 25 October 2013 - 03:43 AM

What's dumb about replacing HG's yourself?  If you have the basic tools, and can follow a list of steps, asking questions or looking for accumulated advice on this board or elsewhere on the web when in doubt, you can do it.  I haven't had to do any Subaru HG's, but I've done it on a diesel VW before.  Nothing that most people couldn't do.  You might choose not to do it yourself, though; it does take some time and work, and if saving your time is more important than saving your money, you can of course pay someone else to do it.

Also tagged with one or more of these keywords: radiator, thermostat, leak

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users