2004 WRX ~160k miles - switch to "conventional"?

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It's been through nearly 160k miles, driven in the snow at Tahoe and Yosemite as well as in the heat, but mostly as a commute car and grocery getter. It's been through the weirdest reverse idler gear break where it was rebuilt, but it's about time for a new car. I'm ready to turn it into a garage queen where I'd like to keep it around (maybe trips up in the snow where AWD would come in handy) and I'm not sure what oil to feed it from this point on. I've occasionally neglected the oil changes, but the engine still runs well on a diet of either Mobil 1 5W-30 or 0W-40. It's basically seen nothing but Mobil 1 since I had a run of Mobil conventional 10W-30 back when I got it for about 6000 miles of frequent changes. Also Subaru OEM filters (mostly from a stash of Tokyo Rokis) and assorted aftermarket filters until I found the Wix 57712. The owners manual says 5W-30 preferred and lists 10W-30 or 10W-40 on the basic chart. Of course there are other options for severe duty including 20W-40, 20W-50, 30, 40, etc, but I never go through those conditions. I'm thinking maybe just a basic motor oil - maybe Chevron 5W-30 since the owners manual says that API SJ/SL of the recommended grade is fine. Once I have a new car this is going to be seeing low miles and maybe I'll take it out for old time's sake or just when I feel like it. I get that Subaru back spec'ed a recommendation for only the severe-service OCIs, but I'm not sure if I'm going to be hitting 3750 miles before 4 months at that point. Any input on what I might consider?
 

y_p_w

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It needs a bit more work though. Possibly needs a rebuilt A/C compressor clutch. Don't know exactly why, but when I start A/C I don't get that kick-in of the compressor engaging. So also no A/C for defrost, where I need to wait for heat. Paint is kind of messed up where the clear coat on the roof has a few holes. And the hood scoop is mostly flaked off paint. Maybe I could also get new Subaru center caps on the wheels. Something rattles - maybe needs new engine mounts? But I love this car. I suppose I could just stick with Mobil 1 0W-40 (which is designed for extended drains) and then just change once a year if it's not accumulating more than 5000 miles. I know they've generally recommended frequent changes under all conditions to take care of accumulation of wear metals that blocked the turbo oil screen, but I haven't had any issues.
 
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Originally Posted by JohnnyJohnson
I'd stick with the full synthetic as you admit you are forgetful of your OCI.
This. If you are not driving it as much, just extend your oci. Once a year or so is fine.
 
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7,651
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The Midwest
The old WRX's are definitely an engine where one should run a VW 502 oil, not a energy conserving 5W30. I once owned a WRX and the owners manual stated a thicker oil was necessary for certain conditions. There are stories from people running Mobil1 5W30 and the engine sucking the oil dry and letting go on Subaru boards. Maybe you have good one, I did. Also to note is that the oil pickup tube on older WRX's and STi's are known for cracking and an aftermarket solution is available. You have a what is becoming a classic car, don't cheap out on the oil. The 04' and 05's look good and have become rare where I live.
 
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Ontario, Canada
with the turbo I'd only run a good synthetic. Mobil1 0w40 sounds like a great idea, you probably don't need more than one oil change a year so the cost difference is negligible. That is a great car keep it as long as you can, they don't make them like that anymore, at 160k it doesn't owe you much and has served you well. I just got my first WRX one month ago (2019 Sport), I would love to get 160k out of it lol. With the air conditioner issue it sounds like you just need to refill the system with Freon,, I revived my father in law's van that had the same symptoms with a DIY Freon kit.
 

Patman

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Oakville, Ontario
Stick with M1 0w40, and change it once a year. That'll cost you all of about $30 per year and will give you peace of mind knowing you've got an oil that can properly handle the heat of that turbo. PS, whatever you do hang onto that car! My son has a 2002 WRX and the early models are getting more and more rare (many die due to massive rust on the chassis) My son runs Pennzoil Platinum Euro L 5w30 in his.
 
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Honestly whenever I have a car that's going to sit and kind of be a backup vehicle, I prefer Synthetic because I'm probably only changing the oil once a year and I don't want to worry about the conventional sitting around that long.
 
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the a/c clutch might just need adjusted.. the gap wears too big then it wont engage.. easy fix watch the youtube video. this one seems decent from a glance
 

y_p_w

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Originally Posted by Patman
Stick with M1 0w40, and change it once a year. That'll cost you all of about $30 per year and will give you peace of mind knowing you've got an oil that can properly handle the heat of that turbo. PS, whatever you do hang onto that car! My son has a 2002 WRX and the early models are getting more and more rare (many die due to massive rust on the chassis) My son runs Pennzoil Platinum Euro L 5w30 in his.
No appreciable rust. Maybe the turbo housing, but that's to be expected. I've never taken it outside of California or Nevada, so no salted roads.
 

Patman

Staff member
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Oakville, Ontario
Originally Posted by y_p_w
Originally Posted by Patman
Stick with M1 0w40, and change it once a year. That'll cost you all of about $30 per year and will give you peace of mind knowing you've got an oil that can properly handle the heat of that turbo. PS, whatever you do hang onto that car! My son has a 2002 WRX and the early models are getting more and more rare (many die due to massive rust on the chassis) My son runs Pennzoil Platinum Euro L 5w30 in his.
No appreciable rust. Maybe the turbo housing, but that's to be expected. I've never taken it outside of California or Nevada, so no salted roads.
That's the difference right there. Up here where the roads get heavily salted we see a lot of cars die an earlier death than they should. When my son bought his WRX and took it in for the safety certificate he found out it needed a massive amount of work since the chassis was completely rotted with rust. He decided to save the car instead of giving up on it though, and now it's in great shape and he will be rustproofing it yearly from now on to make sure it stays in good shape. He also wants to put an STi engine and 6 speed trans into it eventually.
 
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ON, Canada eh?
The difference between Synthetic and Conventional is about $10 but it offers excellent protection in return for that $10. I'd keep using the synthetic especially considering you love the car and you aren't going to be driving it that much anyway. Eat out one less time. wink
 
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Originally Posted by StevieC
The difference between Synthetic and Conventional is about $10 but it offers excellent protection in return for that $10. I'd keep using the synthetic especially considering you love the car and you aren't going to be driving it that much anyway. Eat out one less time. wink
You don't have to eat-out less. Your engine will last longer with better efficiency and less wear, using synthetic. Heck, you can probably increase your eating-out now....lol
 
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NJ
Just another vote to stick with synthetic. In addition to requiring your model year to change the oil under the severe service interval, Subaru also recommends that all turbos use synthetic. I'd stick with M1 0W-40 or use M1 HM 10W-30 since there is really no need for a 0W in your region. You manual allows 10W-30 down to -4F. Even after having turbo failure due to a blocked turbo banjo bolt filter, I still occasionally push my intervals to 5-6k miles running Euro or 10W-40. I also needed to get a new a/c clutch.
 
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ON, Canada eh?
Originally Posted by Triple_Se7en
Originally Posted by StevieC
The difference between Synthetic and Conventional is about $10 but it offers excellent protection in return for that $10. I'd keep using the synthetic especially considering you love the car and you aren't going to be driving it that much anyway. Eat out one less time. wink
You don't have to eat-out less. Your engine will last longer with better efficiency and less wear, using synthetic. Heck, you can probably increase your eating-out now....lol
What I meant is that if the $10 is why he wants to switch oils, eating out one less time will find him that $10. I was being a bit cheeky. grin2
 
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