So it's been a while since we had a good old oil discussion, and I'm starting to get lazy these days so I though I'd see what you guys are thinking. Also I may need to get my flame suit on!

I have been using Castrol Edge full synthetic 5W-50 oil in my Coyote for the last few years. Been happy with it. Car sees about 7K miles per year, is stored from November till late March and it is a weekend road course warrior. About 4 track days per year, so 7K miles and 8 total hours or so of sustained high load, high RPM operation at the race tracks.

Last time I changed the oil was November 2016 right before it went into storage. When it came out late March, the oil was still brand new. Since then I have done 4800 miles and 3 track days. I have another track day in 12 days.

The question I'm struggling with is if I should change the oil now, or wait till October/November? I've been using Ford Racing High Performance oil filters (FL820) and Castrol Edge full syn oil. Still under 5000 miles on it. The oil pan holds 8qt, and the oil is starting to look a bit dark, but still you can see through it. I'm sure there is some sheer to a lower weight ... but 8QT!

Many oils these days (like Amsoil) are advertising 25,000 mile intervals (or 15,000 severe duty). The recommendation for my wife's Kia Sporatage is 7,500 on synthetic blend (which means like 10% syn and 90% conventional). There is also Mobil 1 Annual which recommends 15,000 mile drain interval also. Castrol Edge advertises up to 15,000 mile drain interval.The 2014 Mustang manual calls for max drain interval of 10,000 miles.

So what do you guys think? Should I change it now with 4800, or wait another 2 months till I get closer to 6,000?

P.S. Since I'm an automotive engineer so I'm data driven. So I just ordered a kit from Black Stone labs, and whenever I decide to do the oil change, I will get it analyzed. I'll post the results.

 

What's making you think about changing it now? I think I would wait, 4800 on full synthetic isnt very much.

 

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Honestly, it's just the track time. I've had about 6 hours of it on this oil. If it wasn't for that I wouldn't worry about it.

 

If you love your Mustang, I would change it and not worry about it.

 

test the oil before you change it.

 

Hey Glenn, I would but the oil test kit will take 2 weeks to get here, and my track day is sooner than that. Currently leaning towards changing it now. I think I'll get analysis back saying I could have gone further, which will embolden me next time.

 

I would think the IOLM would help here. Make a note of the Oil Life percent before and after your track days and that might give an idea how much oil life gets used up per event. If you have already done three track days this year and it's over 25%, you probably can get through a fourth day. If it's under 25%, then you might expect the CHANGE OIL SOON and OIL CHANGE REQUIRED messages to come during the day. You should change it before the event (saving a sample for when your Blackstone kit does arrive).

Once you have data from your oil analysis report, that might give you an idea how much over the IOLM you might be able to go (using the same oil and filter).

 

Im in the same position. I have around 8000 miles and it is 3 years old. I use it on the weekends and race once in a while. I use the Ford oil because I can get it cheap from the dealer. I change it once a year.. The gauge goes off telling me it time to change base on the year. I would wait till November. Good Luck

 

Thanks for the suggestion! The IOLM is basically set to go off every 10,000 miles or once per year. I forgot to reset it last time I changed the oil. So it thinks I've gone 8600 miles or so, and it currently is reading 14% left.

Nice, glad you get a good deal. I've seen oil analysis on the Ford oil, and it sheers down to a 30 weight pretty fast. Like after 3000 miles. I have not seen Castrol Edge analysis yet which is why I want to get it looked at, but I'm hoping it's better.

I got a good deal on the Castrol at Advance Auto parts. I paid $59 for 8 Quarts. They have good dales on that stuff every so often.

 

My family use to own a Union Oil 76 station and that's the oil I used for all those years. Then I switched to Valvoline. I have a suburban with 325000 knock on wood its like brand new. I wish they made an oil for our mustangs with Fords Spec the only one they do is a 20W 50 racing oil. I called Amalie
oil company since they have a racing program and they told me that they do not make an oil for our Mustangs and they would not recommend using any of their oils even after the warranty. Im lost on these Mustangs...

But for me I only put about 2500 miles on Her a year.

 

Here is a good interview with Lake Speed Jr in a local Mag, not all of it relates to our modern engines but synthetics and how long between changes do get covered...


http://www.themotorhood.com/themotor...breaks-it-down

 

Thanks for posting, good article!

 

So my last scheduled road course outing for the year is tomorrow. Having 5100 miles on the oil I decided to play it safe and change it. Got a sample I'll send to Blackstone, and once I get the analysis I should know if I could have pushed it further.

I opted to get TBN active additive analysis too, which should help make that decision.

 

As promised here is the Blackstone Lab analysis for my oil. Castrol Edge 5W-50 with 5100 miles including 3 track days. I think I'll be able to change it once a year given these result. They recommend longer drain interval. It's good news for sure!

 

Nice, that's good info. Is there any issue with running 5w50 for street use?

 

I don't think so, but there is also no need for it in my opinion. The 50 weight helps by providing a thicker film, which helps protect components in sustained high temp, high RPM operation. It also helps carry more heat from the engine into the oil cooler (TP and Boss cars have one) once warmed up, but this I think is more of a secondary effect.

In street use I don't think you can get the regular 5W-20 warm enough to worry about any of this to be honest.

 

The good news for my extended drain interval quest is the TBN which is the active ingredient count. Brand new synthetic oil has a count of 8 or 9. Being at 4 with over 5000 miles is a good indication my $7-8k miles per year and track use will still be covered with 1 annual oil change.

I will push the current oil till September/October 2018 and do another oil analysis then. I will also share those results.