Rotella T6 5w40/ 5,000mi / 03 Subaru WRX 2.0T

[HJC]

I had a coolant leak 4500 miles into the OCI. Luckily I caught the temperature gauge on HIGH and shut down the car. I let it cool a bit on it's own and went 1/2 mile at a time until I got home.

Any idea about the traces amounts of fuel?

This forum is great. I love the info here.

 

[dparm]

Trace fuel could be from excessive cold idling.

Looks like the Rotella has held up well. Viscosity still within grade. I bet you could run it longer.

 

[stubbakatt]

Insolubles have been consistently low; what oil filter have you been using?

 

[HJC]

Originally Posted By: stubbakatt
Insolubles have been consistently low; what oil filter have you been using?


I use OEM filters.

 

[Errtt]

Trace of fuel doesn't raise any flag to me - in fact the "Comment" section states it's a small amount and considered normal. Looks like it may have dropped the viscosity just a little tad from the previous UOA. I agree it may be cold weather idling.
For having your temp go high, looks like the oil is doing good to me.
I also see the previous you had the TBN done.

 

[ChiTDI]

Originally Posted By: HJC
Originally Posted By: stubbakatt
Insolubles have been consistently low; what oil filter have you been using?


I use OEM filters.

Smart move. They satisfy an unusual bypass psi number and certainly do filter well.

 

[Artem]

not bad i'd say. looks like everything held up great. i would stick with 5k OCIs unless you're looking to extend.

 

[bluesubie]

Nice! As to the fuel, was the car driven to reach operating temp before you took the sample?

-Dennis

 

[HJC]

I took a 5 mile freeway commute back from work. Then waited about an hour to change the oil.

I do drive about 5 miles stop and go before reaching the highway though and it's around 45F during the evening around here so it's not too cold compared to the rest of the country.

Not too concerned, just that it showed up on this analysis and not previous ones.

 

[shpankey]

I don't think I've ever seen a bad UOA on this oil. lol. Tough stuff.

 

[Steve S]

Overheating from a coolant leak doesn't usually effect the motor oil due to the way water cooled engines are built. There is basically a space between the oil and the heat.

 

[HJC]

Regarding the trace amounts of fuel in the UOA:

I am pretty sure I found an exhaust leak pre-AFR sensor. From my research, this can cause air to be sucked into the exhaust stream. Thus, it makes the AFR sensor think I'm running leaner than I really am. As a result, more fuel is injected to compensate. More than is actually needed.

My long term fuel trims are at +7% to +9%.

I am assuming this could be the cause of the trace amounts of fuel? Correct me if I'm wrong in my assumption.

Thanks.