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2004 Forester 2.5 XS 4EAT
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15 Posts
Discussion Starter #1
So I tried searching this will little success, after the timing belt and head gaskets my mechanic put Rotella T6 5w 40 in the forester and I noticed white smoke coming from the tail pipe. I didn't think much of it but after a day I threw in some mobile 1 5w 30 and no more smoke. From all the post I have read the Rotella seems to be good oil to run in these cars but what would cause it to smoke like that?
 

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2000 Subaru Forester L Manual
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13 Posts
Not sure if it's true, but I'm in a motorcycle group as well and one guy has been using rotella t6 for years and he said he's been having some problems the past few oil changes and I guess T6 oil has changed is what he was saying. Like I said, not sure if it's true.

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2013 crosstrek, Forester+
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139 Posts
I don't know any pro or con to Rotella oils, but I have used Castrol, Valvoline and Kendall products for many years and more recently Mobil 1 and Castrol full synthetic with good results.
 

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1999 Forester S
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447 Posts
I run Rotella T6 for many 10's of thousands of miles in my WRX. No tailpipe smoke. I'd be more suspect of the HG and TB service, a new brand of oil will not make an engine smoke, but a botched HG job sure will...
 

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2005 Forester Automatic
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495 Posts
Why the heavier oil? 40wt oil is going to pump harder, flow poorer, especially at startup, though both are 5w, so hypothetically the same cold viscosity.

At full temp (100c) the Rotella 5w40 will be decidedly heavier than a 5w30 oil.

I do not understand why people feel the need to mess with the "hot number". Unless you are going to race the Mohave and KNOW that oil temps are going to be wildly high, running a race weight oil in a street care makes little sense most of the time.

As to the smoke, no clue. Need more info. Using oil? Using coolant? Code? None the aforementioned? Well then, live well and prosper on 5w30. (or 0w30 if you are in the northern wastes.....)
 

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2001 Forester
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1,540 Posts
I do not understand why people feel the need to mess with the "hot number". Unless you are going to race the Mohave and KNOW that oil temps are going to be wildly high, running a race weight oil in a street care makes little sense most of the time.
Last time I checked the owners manual, it recommends 10W-40, 10W-50, 20W-50 for high temperatures(40C) or pulling trailers. So for those of us that live in Arizona and Texas where temperatures have been known to hit +40C, you can bet we all run with those weight of oil. So I do not understand why you are implying it's over kill.
 

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2007 Forester Sports XT 4EAT
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38,739 Posts
@kpla51 curious why it would smoke with 5W-40 but not 5W-30? :confused:

@bman400 you are correct. Per the Subaru technical service document:
NOTE:
If the vehicle is used in areas with very high temperatures or for other heavy duty applications, the following viscosity oils may be used: API classification: SL or SJ SAE Viscosity No. 30, 40, 10W-50, 20W-40, 20W-50.
We run Valvoline SYNPower full synthetic 5W-30 in both our Foresters. :wink:

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]
 

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Could there have been water/coolant that may have been burnt off the first day which was no longer present on the second day, when you changed the oil? In my limited experience with head gaskets and white “smoke” at the tailpipe, it was actually water vapor. When I had ring issues, the oil burning produced grey smoke. Either way, I’m wondering if the situation you witnessed was just a result of contaminants during the rebuild.
 

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2001 Forester
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1,540 Posts
White smoke usually signifies water/coolant. Doubt it's oil related.

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2003 Forester XS
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53 Posts
I'm guessing that the car still requires 5w30 Synthetic - why would you use a different viscosity? And synthetic like Mobil 1 is the only way to go even if optional!
 

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1999 "L" - 231,000 mi. AT
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702 Posts
White smoke usually signifies water/coolant. Doubt it's oil related.
Traditional tailpipe smoke signals:
light blue smoke = burning oil
white smoke = burning coolant (HG leak), often with a sweetish smell
black smoke = too rich mixture, excess gasoline doesn't completely burn. Doesn't happen with FI'd engines to my observation, just the old carburated ones
 
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