# Subaru Outback Overheating **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** outback, subaru\ **Created:** [September 3, 2021, 8:14pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150 "2021-09-03T20:14:02Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Lee\_T](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/lee_t/32/86_2.png) [@Lee\_T](https://community.cartalk.com/u/Lee_T)\ **Post date:** [September 4, 2021, 2:21pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/21 "2021-09-04T14:21:23Z")
Subaru had a few years where you could do everything right to prevent head gasket problems and they would still blow, even after Subarus first try at modifying the head gasket construction. One commenter even used Subaru’s coolant additive that was supposed to help, and it didn’t. ---
**Author:** ![ok4450](https://avatars.discourse-cdn.com/v4/letter/o/e9bcb4/32.png) [@ok4450](https://community.cartalk.com/u/ok4450)\ **Post date:** [September 4, 2021, 3:52pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/22 "2021-09-04T15:52:11Z")
Weepage is not “blowing”. I’m aware of various theories about why those gaskets leak; gasket make, block design, yada, yada. IMO it’s because the head bolts do not go through a retightening and especially so because of the 6 bolt design. Those gasket/block theories have been mentioned by “experts” on a few Subaru forums. Those same experts are also the ones who agreed that a worn ring/pinion gear in the transaxle can cause a rough idle… 🙄 ---
**Author:** ![jdmere](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/jdmere/32/3002_2.png) [@jdmere](https://community.cartalk.com/u/jdmere)\ **Post date:** [September 4, 2021, 4:01pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/23 "2021-09-04T16:01:07Z")
Perhaps, but not the 2011 vintage, and especially not the 6 cylinder models. ---
**Author:** ![casey.wells916\_177044](https://avatars.discourse-cdn.com/v4/letter/c/b19c9b/32.png) [@casey.wells916\_177044](https://community.cartalk.com/u/casey.wells916_177044)\ **Post date:** [September 6, 2021, 7:30pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/24 "2021-09-06T19:30:08Z")
The Subaru dealership replaced the thermostat. The overheating only happens when stopped or moving \<5mph. ---
**Author:** ![casey.wells916\_177044](https://avatars.discourse-cdn.com/v4/letter/c/b19c9b/32.png) [@casey.wells916\_177044](https://community.cartalk.com/u/casey.wells916_177044)\ **Post date:** [September 6, 2021, 7:48pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/25 "2021-09-06T19:48:16Z")
I’ll try to clarify the complaint. The vehicle has presented the flashing red temperature warning light approximately 4 times in the last year. Each time was preceded by \>2hrs of driving at interstate speed, usually with 2-3 occupants in the vehicle and luggage. All but one of those times the AC was on the lowest temp setting and highest fan setting. When the vehicle would be stopped, the AC temp would get warm/hot despite the setting. The first time it had the flashing red light, it was January in Indiana and the vehicle was driven for ~4hrs on the interstate and then was sitting in a parking lot, idling with the heat on. The light started flashing and the radiator began overflowing into the overflow reservoir. After the first instance, I took the car to a Pep Boys to flush the radiator. They said it had a leak and needed replaced. I took the car and brought to a local mechanic would said it wasn’t leaking but the fan was not coming on when it should. He replaced the fan, then the module because it was still not coming on. The flashing light came on twice since this, both after 3+hr interstate drives. I have just recently had the dealership change the thermostat. It came on again while sitting in the parking lot for about 5 minutes after driving on the highway for 2hrs. ---
**Author:** ![weekend-warrior](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/weekend-warrior/32/26122_2.png) [@weekend-warrior](https://community.cartalk.com/u/weekend-warrior)\ **Post date:** [September 6, 2021, 8:23pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/26 "2021-09-06T20:23:19Z")
have you tried replacing the radiator cap? ---
**Author:** ![casey.wells916\_177044](https://avatars.discourse-cdn.com/v4/letter/c/b19c9b/32.png) [@casey.wells916\_177044](https://community.cartalk.com/u/casey.wells916_177044)\ **Post date:** [September 6, 2021, 9:59pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/27 "2021-09-06T21:59:50Z")
I have not. ---
**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\ **Post date:** [September 6, 2021, 10:12pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/28 "2021-09-06T22:12:54Z")
> [@casey.wells916\_177044](#): > > I have just recently had the dealership change the thermostat. Paying the fee to have the dealership properly diagnose the cause would have saved you much frustration over telling them what to do. ---
**Author:** ![casey.wells916\_177044](https://avatars.discourse-cdn.com/v4/letter/c/b19c9b/32.png) [@casey.wells916\_177044](https://community.cartalk.com/u/casey.wells916_177044)\ **Post date:** [September 6, 2021, 10:54pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/29 "2021-09-06T22:54:07Z")
I understand that. I’m not very trusting in that dealership chain as they have improperly diagnosed another vehicle. ---
**Author:** ![ok4450](https://avatars.discourse-cdn.com/v4/letter/o/e9bcb4/32.png) [@ok4450](https://community.cartalk.com/u/ok4450)\ **Post date:** [September 7, 2021, 12:06am UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/30 "2021-09-07T00:06:20Z")
You might try changing the radiator cap. I actually mentioned that a few days ago. With age and heat cycles the spring tension can ease and the gasket can degrade. For myself, I consider a radiator cap a maintenance item and change it every 5 or 6 years on my cars just to avoid a potential problem. Your cap is 10 or 11 years old depending upon the in service date of the car. They can be tested but since caps are cheap and easy it’s easier to just change it out. ---
**Author:** ![shanonia](https://avatars.discourse-cdn.com/v4/letter/s/9de053/32.png) [@shanonia](https://community.cartalk.com/u/shanonia)\ **Post date:** [September 7, 2021, 1:00am UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/31 "2021-09-07T01:00:26Z")
You can test a rad cap and the whole cooling system for leaks (liquid or air) with a kit from an auto parts place. I borrowed one from O’Reilly’s a couple years ago and overnight it revealed a coolant leak. (Actually, you pay for their loaner tools and get a refund when they are returned.) ---
**Author:** ![casey.wells916\_177044](https://avatars.discourse-cdn.com/v4/letter/c/b19c9b/32.png) [@casey.wells916\_177044](https://community.cartalk.com/u/casey.wells916_177044)\ **Post date:** [September 7, 2021, 12:31pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/32 "2021-09-07T12:31:54Z")
Thanks, I ordered one. Hopefully that’s the fix. ---
**Author:** ![casey.wells916\_177044](https://avatars.discourse-cdn.com/v4/letter/c/b19c9b/32.png) [@casey.wells916\_177044](https://community.cartalk.com/u/casey.wells916_177044)\ **Post date:** [September 27, 2021, 6:18pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/33 "2021-09-27T18:18:06Z")
Just to follow up with the final diagnosis from an official Subaru service center, either the head gasket has failed or the head has a crack. They would need to send it off to a machine shop for final diagnosis but I think I’m going to cut my losses as estimate was ~$5k and then more in the head needs replaced. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [September 27, 2021, 6:22pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/34 "2021-09-27T18:22:57Z")
$5,000 is crazy high for replacing the Subaru head gaskets. I’d expect it somewhere under $2,000. Find some other Subaru-specific shops and get some estimates. ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [September 27, 2021, 7:09pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/35 "2021-09-27T19:09:01Z")
> [@texases](#): > > $5,000 is crazy high for replacing the Subaru head gaskets. I’d expect it somewhere under $2,000. +1 When my old '97 Outback needed the head gaskets replaced @ 115k miles, the dealership charged me ~$400, and the engine was perfect for at least the next 4 years, at which point I gave it away to a young relative. I realize that someone–either the dealership or Subaru of America–came to my assistance with that repair, and that is why I didn’t hesitate to buy two more (trouble-free) Subies over the succeeding years. Most likely a realistic price for that job nowadays is somewhere ~$1,200-1,600, depending on where the OP lives. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [September 27, 2021, 7:23pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/36 "2021-09-27T19:23:47Z")
I forgot that the OP has the 3.6 engine, which normally does not have the head gasket problem. I’d expect head gasket replacement to cost more than the 2.5, but not 3X as much. ---
**Author:** ![keith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/keith/32/5518_2.png) [@keith](https://community.cartalk.com/u/keith)\ **Post date:** [September 27, 2021, 8:50pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/37 "2021-09-27T20:50:44Z")
You never said whether you were losing coolant or not, that would be critical information. If you are loosing some coolant, but not very much, say a cup a week, then I would put in the cooling system conditioner. It does work in this situation. It doesn’t work so good if you are loosing a lot of coolant, like having to add daily or a quart per week. ---
**Author:** ![casey.wells916\_177044](https://avatars.discourse-cdn.com/v4/letter/c/b19c9b/32.png) [@casey.wells916\_177044](https://community.cartalk.com/u/casey.wells916_177044)\ **Post date:** [September 27, 2021, 9:15pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/38 "2021-09-27T21:15:31Z")
I thought I did, sorry. It is not losing any coolant to my knowledge. The radiator is always full. I’m calling a local mechanic to get another quote. ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [September 27, 2021, 9:22pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/39 "2021-09-27T21:22:40Z")
> [@casey.wells916\_177044](#): > > It is not losing any coolant to my knowledge Is there evidence of motor oil in the coolant overflow reservoir? If there is a dark, greasy line in the coolant overflow container, that would indicate seepage of oil into the coolant via a breached head gasket. If it isn’t losing coolant, and if there’s no evidence of oil in the coolant, then I submit that there is scant evidence of a breached head gasket. Did the dealership ever state that they detected combustion gases in the coolant? ---
**Author:** ![casey.wells916\_177044](https://avatars.discourse-cdn.com/v4/letter/c/b19c9b/32.png) [@casey.wells916\_177044](https://community.cartalk.com/u/casey.wells916_177044)\ **Post date:** [September 27, 2021, 9:27pm UTC](https://community.cartalk.com/t/subaru-outback-overheating/179150/40 "2021-09-27T21:27:42Z")
I believe they said they pressure tested the system and determined it’s either a blown gasket or cracked head but I haven’t picked it up yet and don’t have their paperwork in front of me. The quote is $5,817 which includes a $500 sublet to send the heads to a machine shop to test them and the parts list was standard stuff with the only non-head gasket items being spark plugs. They said their rate is $160/hr for engine repairs. This is a Bob Rohrman Subaru in Lafayette, IN btw. [Previous page](https://community.cartalk.com/t/subaru-outback-overheating/179150.md?page=1) [Next page](https://community.cartalk.com/t/subaru-outback-overheating/179150.md?page=3)