2005 Forester XT - RT6 5W-40 - 3572 OCI - 163K

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I have a 2005 Subaru Forester XT. Relatively new to me, I bought it at 156K last year. Been through two OCIs since I've owned it. Both went to Blackstone. I've had high chromium and they flagged the sodium this time. The engine seems fine, no unexplained coolant loss, knocks or CELs indicating problems. Compression was OK at the time of purchase but I haven't checked since then. Will probably do so soon at Blackstone's advice. I've exchanged emails with them and they suggested that along with checking the cylinder walls with a borescope. They said they weren't entirely sure about coolant making it into the oil since my potassium is 0, but it seemed like a likely culprit for the sodium at Shell doesn't use it in RT6. The previous owners used Mobile 1 and Castrol 5W-30 so I'm hoping that it's just leftovers from that instead. I doubt it would have flushed out entirely after just two changes. I've only been using the the Rotella T6.

This car is mostly a town/rural road driver with very few highway miles with me. Lots of stop and go with a ~10 mile one way commute. I've done some lurking on here and it seems some people recommend a thinner oil than a 5W-40 in for that type of use. Thoughts? Perhaps that would cut down on some of the wear? Prep for a rebuild sooner rather than later?

Hopefully this is formatted neatly enough. This is my first post! :p


Code:


MI/HR on Oil 3698 3572

MI/HR on Unit 159847 163420

Sample Date 10/17/14 05/22/15

Oil Added (qts) 0.75 0.875

Oil Type RT6 5W-40 RT6 5W-40

Filter Type NAPA Gold NAPA Gold



ALUMINUM 3 3

CHROMIUM 4 5

IRON 10 14

COPPER 5 3

LEAD 1 1

TIN 0 0

MOLYBDENUM 64 63

NICKEL 1 1

MANGANESE 0 1

SILVER 0 0

TITANIUM 0 0

POTASSIUM 0 0

BORON 36 33

SILICON 9 9

SODIUM 45 47

CALCIUM 926 856

MAGNESIUM 1273 1268

PHOSPHORUS 1052 1036

ZINC 1266 1274

BARIUM 0 0



SUS Viscosity @ 210°F 71.3 68.1

cSt Viscosity @ 100°C 13.3 12.45

Flashpoint in °F 385 385

Fuel %
Antifreeze % ? 0

Water % 0 0

Insolubles % 0.3 0.4
 
I know mobil 1 does NOT use sodium and I don't recall hearing that Castrol uses sodium also. Sodium can show a false positive in a UOA, Potassium is what you should watch instead
 
OK, thanks! I've never done a UOA on Castrol so I didn't know if it had any or not. The M1 and Castrol are just what I have records for. It's entirely possible that they used some other brand of 5W-30 in there at some point too as they had it changed at a shop.

FWIW I sent some oil from my wife's 05 Cobalt in and it also had elevated sodium but no potassium. It's much lower mileage (less than 50K) and as far as I know the 2.2 ecotech isn't known for head gasket issues. It too has seen no coolant loss. I was wondering if the sodium is perhaps something environmental since I have it on two cars? The Cobalt UOA was done with M1 too.
 
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I run M1 5w40 TDT in my 2009 Forester in the Summer....Castrol 0w30 in the winter.

I don't see your Chrome numbers being that bad!! 3-4ppm isn't anything.
 
Thanks! It is a good bit above Blackstone's universal averages of 1 for this car. They seemed concerned about it. But a UOA is just one tool of many in determining an engine's health so I was going to check out a few other things too.
 
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Don't switch to a thinner oil unless it's a lighter 40 grade or a thick (Euro or HDEO) 30 grade. The sodium could be the HG's but it's less common on 04/05 FXT's.

If you get another compression test, you may as well get a leakdown test at the same time. Does it have the original turbo?
 
Yeah I've not seen many turbo Subarus with blown head gaskets. That usually the open deck NA's territory. This Forester is on its second TD04, but the old one didn't catastrophically fail. Seals just went out according to the previous owner's paperwork and it started throwing oil out the down pipe. It has a second hand turbo on it now but it's lower miles and is in good shape. I've replaced the up pipe with the catless model from an STi. The catalyst in the downpipe corroborates what their mechanic said, they had it replaced about 3 months before I bought it.

I'll be doing the compression test myself (I have a garage full of tools and been doing my own work for a while). A leak down is a good idea too.

I still have an old 2.2L Impreza from the 90s too. Those basically never quit running.
 
Originally Posted By: Phishin
I run M1 5w40 TDT in my 2009 Forester in the Summer....Castrol 0w30 in the winter.

I don't see your Chrome numbers being that bad!! 3-4ppm isn't anything.

I disagree..thats very high especially for 3700 miles.
 
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Originally Posted By: BananaStand
Yeah I've not seen many turbo Subarus with blown head gaskets. That usually the open deck NA's territory. This Forester is on its second TD04, but the old one didn't catastrophically fail. Seals just went out according to the previous owner's paperwork and it started throwing oil out the down pipe. It has a second hand turbo on it now but it's lower miles and is in good shape. I've replaced the up pipe with the catless model from an STi. The catalyst in the downpipe corroborates what their mechanic said, they had it replaced about 3 months before I bought it.

I'll be doing the compression test myself (I have a garage full of tools and been doing my own work for a while). A leak down is a good idea too.

I still have an old 2.2L Impreza from the 90s too. Those basically never quit running.

My first Subaru was a 2.2L Impreza Outback. Those 2.2's were great engines!

My first turbo went out due to seals at 60k and that one lasted only 20k likely due to pushing my OCI too far on thin oil. The uoa prior to that failure was normal, except for an uptick in lead to 10 ppm. Chromium was always 1 or 0 even with 7-8k mile intervals.
 
Hey BananaStand, how close are you to the beach? You'll see in my 4Runner post with M1 that I am also in an elevated sodium / zero potassium situation. The coolant I use (Toyota SLLC) contains potassium hydroxide but no sodium, so that sort of rules out the coolant theory for me.

There may be something to the environmental part, because I park the vehicle about three miles from the salty Delaware Bay and drive a few times per month on our ocean beaches for surf fishing. I figured you might be an OBXer and even venture out on the beach in AWD.
 
I actually live in the mountains, but they do salt a bunch up here in the winter. The one UOA I've done on the Cobalt was after we drove it to the OBX and back (that's when it had the sodium). So you may be on to something there. The Forester has never been to the beach at least with me. I haven't lost any coolant, at least none that I didn't know where it went. No mixing from what I can tell either.

The chromium is concerning as that's ring material. Turbo EJs are kind of known to blow those but you usually only see it on modded or flogged WRX/STis. At least that's where I've seen it. It's not burning a whole lot of oil from what I can tell either. The little bit its loosing (~0.5-0.8 quart per OCI) seems to be weeping out the oil cooler gasket. Going to be replacing gasket here soon when I pull apart the cooling system to replace a couple of sketchy looking hoses and the rusted expansion tank up near the turbo. I like to replace that stuff before it becomes a problem. I did the spark plugs maybe 9-10ish months ago and none of them were oil fouled or abnormal looking. It seems if the rings were cracked on a cylinder as the chromium level seems to indicate I'd be having more problems with compression and oil burning. Are there other sources of chromium I may be over looking? Most everything else on that engine is aluminum or steel as far as I know.
 
I don't know these oils but might it be sodium sulphonate friction modifier? Can't think why you would add it to a 5W40 but maybe someone thought it would be a good idea...
 
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