New legacy owner question

Hello,

I just recently purchased a 2015 Legacy premium from a non Subaru dealership. I bought this car because of the service history and lower miles (86,000). Looking at the car I knew there was a few maint. issues that I was probably going to have to address. One is a weak battery the other is changing the spark plugs. I've owned Nissans for several years and had good luck with them. On recommendation from my brother, I bought a 2019 Forester sport new and love it so I bought this car to replace my rogue that was totaled.

Looking at the coil packs it doesn't look like they were removed before selling me the car and the 60,00 mile service record doesn't state that the plugs were changed. So I'm going to take care of it since I will already have the battery out. I already bought the plugs and new boots. Looking at the pack connector though I'm unsure of which direction to push or pull the spring clip. I did some research and found a picture that shows pushing the metal spring clip in while pushing the connector out of the pack. is this the correct process? I just don't want to break the connector or the spring clip.

Thanks,

Eric

I love how you put you have a weak battery. News a great time to upgrade to a group 35 battery and get away from that crap group 25 battery. A lot of others will also suggest the group 34 battery which has a tiny bit better ability then the group 35. Reason I am saying group 35 is that is the exact height and length as stock. The group 34 is wider but its lower height wise. Both will fit on the tray no issues once the cardboard cutout is taken off the battery(assuming you still have one).

The only other thing I would check is the head gasket assuming it’s a four cylinder. As far as the plugs I have always had this done at a mechanic/dealer just due to the pain in the ass it is to replace plugs on a boxer engine. Maybe others can chime in on that question.

Good luck!

I did my plugs this summer and I think it was pull the tab out slightly then push the body of the connector off. I wouldn't bet my life on it tho. Try pushing in first because that's less likely to break but I think you'll find pulling the tab out is the way to go. Doesn't take much, go slow and be gentle and you'll be fine.

Edit you should probably get the FSM anyway for torque specs and that will show you. Mine's at home or I'd look it up now.

Parsed-out Spark Plug R&R info (includes Ignition Coils) from my '16 Service Manual. It should be similar, if not identical, to your vehicle.

I've replaced mine three times so far (twice on my '16 and once on my '19).

I remove the battery tray as well to make more room. There are several large bolts holding securing it. One is particularly difficult to remove (wheel well area) and I left it out after the first plug change.

It made the second plug change much easier and there is plenty still holding the battery tray securely.

I was also able to replace the plugs without disconnecting the ignition coils just by manipulating them around a bit. Drivers-side aft plug was the most difficult.

I also recommend a correctly sized magnetic spark plug socket and slightly above average mechanical ability and tooling to get the job done right.

(several different 1/4" extensions & swivels).

I'm editing together a video of the process and may post it this weekend.

2016 SUBARU LEGACY SERVICE MANUAL - Spark Plugs.pdf

The only other thing I would check is the head gasket assuming it’s a four cylinder. Good luck!

I am a little intrigued as to why you mentioned "head gasket" in relation to the OP's 2015 Legacy. According to what I have read, there is no inherent weakness in that model year, or in any Subaru model upward from then.

I think "head gasket problems" were pretty much only restricted to certain year models, and that was over a decade ago.

I love how you put you have a weak battery. News a great time to upgrade to a group 35 battery and get away from that crap group 25 battery. A lot of others will also suggest the group 34 battery which has a tiny bit better ability then the group 35. Reason I am saying group 35 is that is the exact height and length as stock. The group 34 is wider but its lower height wise. Both will fit on the tray no issues once the cardboard cutout is taken off the battery(assuming you still have one).

 

The only other thing I would check is the head gasket assuming it’s a four cylinder. As far as the plugs I have always had this done at a mechanic/dealer just due to the pain in the ass it is to replace plugs on a boxer engine. Maybe others can chime in on that question.

 

Good luck!

Thanks for the tip. Was going to go with the 25 or 35 depending on size. Now I know.

I did my plugs this summer and I think it was pull the tab out slightly then push the body of the connector off. I wouldn't bet my life on it tho. Try pushing in first because that's less likely to break but I think you'll find pulling the tab out is the way to go. Doesn't take much, go slow and be gentle and you'll be fine.

 

Edit you should probably get the FSM anyway for torque specs and that will show you. Mine's at home or I'd look it up now.

I'll probably be getting the FSM soon. I will try both ways unless someone can give a definitive answer.

Parsed-out Spark Plug R&R info (includes Ignition Coils) from my '16 Service Manual. It should be similar, if not identical, to your vehicle.

 

I've replaced mine three times so far (twice on my '16 and once on my '19).

I remove the battery tray as well to make more room. There are several large bolts holding securing it. One is particularly difficult to remove (wheel well area) and I left it out after the first plug change.

It made the second plug change much easier and there is plenty still holding the battery tray securely.

 

I was also able to replace the plugs without disconnecting the ignition coils just by manipulating them around a bit. Drivers-side aft plug was the most difficult.

 

I also recommend a correctly sized magnetic spark plug socket and slightly above average mechanical ability and tooling to get the job done right.

(several different 1/4" extensions & swivels).

 

I'm editing together a video of the process and may post it this weekend.

That is probably going to be my avenue of attack. I was just unsure of the metal springs holding the connector on because my Nissans don't have these style of connections and I plan on replacing the coil boots. I have all the tools needed as I do most the work on all my vehicles as well as other friends and relatives. I also have a medical condition that causes a severe reaction to most shop prices, even though I understand why they do. I just have a hard time spending money on work I can do myself.

thanks

I think "head gasket problems" were pretty much only restricted to certain year models, and that was over a decade ago.

Correct. The FB25 engine, used in all 4-cylinder Gen 6 Legacys, has never had a "head gasket problem."

I'll probably be getting the FSM soon.

Highly recommended. For $35 you can download a legal copy of the FSM (and a whole lot more) direct from the Subaru Technical Information System.

I am a little intrigued as to why you mentioned "head gasket" in relation to the OP's 2015 Legacy. According to what I have read, there is no inherent weakness in that model year, or in any Subaru model upward from then.

 

I think "head gasket problems" were pretty much only restricted to certain year models, and that was over a decade ago.

 

The assumption was based on the EJ25s problems. Honestly I have not even looked at a four cylinder engine when buying a new or used car since 2006 so I rarely delve in the FB25. I mainly stick to H6s, V6s, and V8s. To be fair my 06 SE Fourth Gen has never had a head gasket issue surprisingly.

***update***

Well, got the new 800cca battery in and changed the plugs, coil boots and springs. Not a bad job and saved me almost half a grand to have the dealer do it.

Some takeaways:

I didn't have to loosen the motor mount bolts. I did remove the battery tray which was a pain because of the 2 lower bolts on the tray. I did figure out that it was way easier to remove the plastic undercover in order to remove the bolts. Now that I know it will probably take me a little less than a hour to do again.