2005 RX8 Automatic/4120 oil/136812 miles/Valv 5W2

[Proteus024]

2005 Mazda Rx8 Rotary
Valvoline Conventional High Milage 5W20

Sorry for the lack of baseline data, but I hadn't heard of oil analysis until a couple of months ago. I've had my RX8 for 7 years now, have tried to keep it well maintained, and have had very few issues with it. Now, at 137,000 miles I'm wondering if I'm better off keeping this vehicle or will I be better off trading it in for a used vehicle with a warranty, etc. If the costs of maintaining my RX8 won't be too high, I'd love to keep it, but if the oil indicates serious impending issues ahead I'd love to know.

Blackstone seems to indicate some alarm at the chrome, iron, and lead content, but I thought I'd crowdsource just how alarmed I should be about this and hopefully learn a lot more about oil analysis in the process.

Thanks for any guidance and expertise!



Code:


MI/HR on Oil = 4,120

MI/HR on Unit = 136,812

Sample Date = 6/5/2011

Make Up Oil Added = 2qts





ALUMINUM = 3

CHROMIUM = 29

IRON = 47

COPPER = 3

LEAD = 19

TIN = 0

MOLYBDENUM = 148

NICKEL = 1

MANGANESE = 0

SILVER = 0

TITANIUM = 0

POTASSIUM = 0

BORON = 48

SILICON = 10

SODIUM = 130

CALCIUM = 2130

MAGNESIUM = 9

PHOSPHORUS = 794

ZINC = 1005

BARIUM = 0



cSt Viscosity @ 100°C = 51.6

SUS Viscosity @ 210°F = 7.77

Flashpoint in °F = 360

Fuel % < 0.5

Antifreeze % = 0.0

Water % = 0.0

Insolubles % = 0.3

 

[Quest]

chrome 29, lead 19, iron 47?

I'll just keep on driving this car and not to loose sleep over it.

Afterall: it's just a UOA on a 6yr old car.

Q.

 

[chubbs1]

What are the universal avgs. they gave you? That is important. I also noticed you had to add two qts of oil in 4120 mi. You may want to think about unloading this car. IMO.

Can you type the universal averages for Chromium, Iron and Lead?

Also, B_S usually writes in their comments what mileage these #'s are based on.

 

[Quest]

Originally Posted By: chubbs1
What are the universal avgs. they gave you? That is important. I also noticed you had to add two qts of oil in 4120 mi. You may want to think about unloading this car. IMO.


LOL! OP has a wankel engine that is known to consume a bit of oil (by design) to lubricate it's apex-seals.

In other words: oil consumption is part of the deal with these engines, not like ordinary 4-cycle reciprocating engine designs.

Q.

 

[INDYMAC]

Looks OK to me. These rotary engines drink oil by design, but 2 qts might be excessive. You should check on a RX8 forum about that. Also, since the drink oil routinely, you have to be careful which oil to feed it. The Valvoline should be OK though.

 

[chubbs1]

Originally Posted By: Quest
Originally Posted By: chubbs1
What are the universal avgs. they gave you? That is important. I also noticed you had to add two qts of oil in 4120 mi. You may want to think about unloading this car. IMO.


LOL! OP has a wankel engine that is known to consume a bit of oil (by design) to lubricate it's apex-seals.

In other words: oil consumption is part of the deal with these engines, not like ordinary 4-cycle reciprocating engine designs.

Q.


"designed" into the rotary or not, it is an expense, plus the car is getting up there in mileage. That much chromium is what would concern me. I think it may be time to get rid of this thing while he can.

Thanks for your impressive knowledge about Wankel Q!

 

[Quest]

Originally Posted By: chubbs1
Originally Posted By: Quest
Originally Posted By: chubbs1
What are the universal avgs. they gave you? That is important. I also noticed you had to add two qts of oil in 4120 mi. You may want to think about unloading this car. IMO.


LOL! OP has a wankel engine that is known to consume a bit of oil (by design) to lubricate it's apex-seals.

In other words: oil consumption is part of the deal with these engines, not like ordinary 4-cycle reciprocating engine designs.

Q.




"designed" into the rotary or not, it is an expense, plus the car is getting up there in mileage. That much chromium is what would concern me. I think it may be time to get rid of this thing while he can.

Thanks for your impressive knowledge about Wankel Q!


You are most welcome.

IMHO based on UOA seen on rotary engines in the past: chrome is not an issue for the inner walls of these wankel engines are chrome plated before additional machining takes place (during engine manufacturing)

It would concerns me a lot when chrome reading goes into the hundreds then it may mean excessive wear on the walls of the engine. If that is the case: the next line of action is to perform compression checks to determine the "health" of the walls and/or the apex seals.

Then we go from there.

Q.

 

[Bladecutter]

Originally Posted By: chubbs1
"designed" into the rotary or not, it is an expense, plus the car is getting up there in mileage.


My car is 2 months old, has under 4k miles in it, and basically uses 1 quart of oil every 900 miles so far.

It is a completely different engine design than a piston engine, and the engine has no way to scrape oil off of the rotor housing (combustion chamber) that is needed to lubricate the Apex Seals (what would be the upper compression rings in a piston engine) and then reclaim the oil back into the oil pan.

If the original poster isn't already a member of the RX8 Club forums, he should join up, and compare his oil analysis against the ones that are in a combined thread there.

In fact, to save some time, here's the thread:

http://www.rx8club.com/showthread.php?t=184241&highlight=oil+analysis

BC.

 

[Bladecutter]

Originally Posted By: Proteus024

Thanks for any guidance and expertise!


Here's what I would do:

First off, I would buy 2 5 quart containers of conventional 5W-30 oil, doesn't really matter what brand at that many miles, and 1 new oil filter.

Dump out the oil currently in the engine, and remove the oil filter, re-installing the filter after it drains fully. Pour int he new oil from one of the 5 quart containers.

Start the engine, and let it idle for 10 minutes, then shut it off.

Drain the oil, remove the oil filter, install new filter, and pour in the new oil. Drive for 2500 miles, and take a sample for analysis.

The reason for the double drain is because of the fact that the RX8 has oil coolers in the front bumper, and long oil lines that feed them. The oil in these coolers is not drained out during an oil change, so you will still have a large amount of old oil mixing in with your new oil.

This is the Mazda recommended way to flush the oil out of those oil cooler lines, too.

After looking at some of the oil analysis results in the thread I linked above, some chromium is normal, along with high amounts of iron, but your amounts are really high. Your engine also has many more miles on it in comparison to the ones I looked at on the forum.

Has your engine been previously replaced under warranty by Mazda in the time you've owned it? If yes, how many miles are on the current engine?

I would go into more questions, like how quickly does it start, or have you replaced the ignition coils recently, but that's not the question you came in asking.

BC.

 

[jorton]

A while back another member explained why 30hd performed better than multigrade in Mazda rotaries. They don't have a valve train, or the same style oiling system as other engines.

You should try a 30hd that's certified to api sm or sn. Another good choice is Mobil1 10w-30 because it is considered synthetic 30hd.

 

[INDYMAC]

I think Mazda frowns on using synthetics in these engines. Is that true?

 

[Proteus024]

Thanks for all of the insight and guidance, everyone! I'm learning a lot here!

It's extremely valuable to learn about the manufacturing materials and recommended oil flushing techniques.

In response to further inquiries:

The engine was replaced via Mazda warranty with a new engine at 80,000 miles due to a manufacturing problem with the original apex seals in the 2005 model years. So, this engine probably has around 57,000 miles on it. It starts pretty quickly with no noticeable hesitation, but probably is due for new spark plugs, wires, coils, etc.

 

[Bladecutter]

I don't know if you live in an area where you are required to pass a sniffer emissions test, but if you do, then it might be worthwhile to go get the test done, see if it passes of fails, and look at the readings to see what is high and low on the report.

High HC readings points to bad ignition system or low engine compression.
High CO means that the catalytic converter is toast.
High NOx shouldn't be an issue on this engine, but just in case, typically means you're running lean.

You could do a before and after emissions test with regards to the ignition coil, wires and plugs replacement to see how much of a change there is.

BC.

 

[aquariuscsm]

Originally Posted By: INDYMAC
I think Mazda frowns on using synthetics in these engines. Is that true?


That`s what I`ve always heard too,but then I saw this stuff one time:

 

[Gene K]

I dont think most here could tell a good Wankel UOA from a bad one. I know I cant.

 

[ltslimjim]

After reading through the thread, I believe it would be very interesting to see the suggestion of a HD oil used in this engine for 3,000 miles; as suggested already. Of course another UOA to follow.

I found this note on another site's recommendation regarding oil for a 2005 RX-8:

Quote:
Do not use either synthetic or semi-synthetic motor oil.
Otherwise engine starting performance could worsen.
Please review the Tech Service bulletin for details.


So, if the TSB was fixed...what was it? Can synthetic/semi-syn be used at all now or still a no-no? If that is the case, it appears(even with the addition of makeup oil) that a conventional 5w-20 changed every 3,000 miles may be the rule of thumb for this app.

Still, wouldn't hurt to see a conventional HDEO be used. Perhaps 30 is too thick, but I don't know much about what HD oils offer in the way of grades/multi-grade etc. Of course, the goal would be to try to see what a UOA on a non-synthetic oil would be like.