Mazda MX-6 V6, please help with oil choices

Losiho · Dec 20, 2003

Hi there, I'm a newbie to this site, and I'm just starting to learn about the world of motor oils, so please go easy with me !

I have a 1993 Mazda MX-6 V6 (2.5L KL03 V6, for those who know their Mazdas). I have owned it since new, it has only 81,000km (50,000 miles) on the clock, is driven hard, and mainly over short distances (>25km).

These cars are very oil sensitive, due to the hydraulic lifters (HLAs). For those interested, an owner has an excellent write up regarding oil choices and HLAs :
http://homepage.ntlworld.com/dorothy.bradbury/probemx/p_p7.htm
http://homepage.ntlworld.com/dorothy.bradbury/probemx/p_m2.htm

To give you some background info, my Mazda service dealer originally used Shell Helix Plus 15w50 semi synth in my car before I started buying my own and asking them to use my own oil. The lifters were noisy with the 15w50 oil. I then tried Mobil 1 5w50, which was absolutely shocking in my engine - the lifters were noisy at start up, and got worse when the engine was at operating temp.

Which brings me to the oil I am currently using, Castrol Synthetic R 5w30. Or at least I was until I spoke to Castrol Australia's tech Dept who told me that Synthetic R 5w30 is made from Group 3 Hydrocracked base. Apparently only Synthetic R 0w40 and 10w60 are PAO based. Now, I have to say I've been happy with the way the Synthetic R 5w30 has performed (HLAs are mostly silent), but if the package claims "Synthetic", I expect it to be synthetic !

Group 4 / 5 100% synthetic 5w30 is basically non-existent here in oz, so my choices are Mobil 1 0w40 (PAO), Castrol Synthetic R 0w40 (PAO) or Motul 0w40 or 5w40 (ester). Redline 5w30 syntheic is available, but is hard to get and costs a bomb.

What would you guys suggest ? I'm worried that I may again have noisy lifters when the engine is up to operating temp running a NNw40 oil.

I'll most likely use whatever oil I choose in my other car, a 1999 Subaru Outback 2.5 H4 (79,000km, 2nd owner, much less oil sensitive than the MX-6).

Finally, are there any disadvantages to ester based synthetics ? I've heard mixed reviews, but I'm not sure if they're valid.

Thanks for your time, sorry about the long post !

FWIW, Castrol Synthetic R 10w60 actually has a lower pour point than Synthetic R 5w30 ! Go figure.
http://www.castrol.com.au/products/formular/

theguru · Dec 20, 2003

Probably a good idea to contact Sprintman, I think he has one these.

Personally, I would suggest using the Motul 300v 5w-30. I'm using it in the Nissan 200sx S15 and my son is using it in his modded 180sx turbo.

Patman · Dec 20, 2003

I believe Sprintman's car is a 1989 Turbo Mazda 626 though.

RTexasF · Dec 20, 2003

I had a 96 626 with the same engine. FWIW I would choose one of the 0w40's that you mentioned. I used Castrol 10W30 GTX year round in the Texas climate but that is not available to you. This is a case where 3000 mile oil change intervals ARE necessary. Clean oil is vital to keeping the HLA's clean and operating quietly. You need to be aware that this engine is prone to valve cover (or camshaft cover) leaks. They don't show up as leaking externally, the oil goes into the spark plug tubes. In severe cases a faulty gasket can fill a tube completely.

Losiho · Dec 20, 2003

Yup, already know about the leaking valve cover gaskets, it's a well known issue. Mine were already replaced at 45,000km.

Thanks for the replies, at the moment I'm leaning towards Motul 300V 5w30 or Ester tech 0w40.

theguru · Dec 20, 2003

From my reading it appears the Motul 300v 5w-30 is a high 30 weight. The 40 point spread of the 0-40 concerned me.

I think Sprintman has a Subaru Outback as well. From what I have seen here, they are fairly easy on oil.

[ December 21, 2003, 09:45 AM: Message edited by: theguru ]

sprintman · Dec 21, 2003

Losiho good car and particularly the V6 engine. The Bradbury site which is a mine of information on these cars says oil type and change frequency is critical for the HLA's and I remember when I first discovered that European web site they recommended one oil only and that was Mobil Delvac 1, definitely not SHC. They rec Redlime MT90 for g'box and Redline D4 ATF for power steering all readily available in Melbourne.

Lordy611 · Dec 21, 2003

I have a 94 MX6 with the KL03 engine. My has 70,000 miles, and have recently begun my cleaning with AutoRx. My car has had a strict diet of Mobil 1 synthetic 5w30, but was never particularly quiet. (i am the 2nd owner but got all the service records with the car, so could track the history)
Anyway, I changed the filter and oil to Pennzoil 5w30 and about 100 miles later, the noise from HLAs went away. I am now at about 1000 miles into the 1500 mile treatment and can still report no real noise from HLAs. I dont know if the mineral oil was the reason, or the dirt that the AutoRx cleaned out, but I was not impressed by Mobil 1. Looking into the valve cover oil-add hole, I can see quite a lot of dark brown deposits on non-contact areas that makes me feel good about the fact that AutoRx is in there. We'll see what comes out after the 2000 mile rinse with mineral oil.

Losiho · Dec 21, 2003

Sprintman - Do you visit mx6.com or Probetalk ?
Yep, I have Redline MT90 in my MTX right now. I got it from Pascoe's Perfomance parts, A$27 a quart (3 bottles). I don't mind the travel or expense to get Redline once every 75,000km, but for oil changes every 7,500km....

This is getting confusing. From the technical specs of the shortlist of oils on my list, M1 0w40 is the heaviest viscosity, Castrol Synth R 0w40 is lighter, but still heavier than the hdyro-crap Group 3 5w30 I'm using now. The concern over the point spread in multi-viscosity oils I assume is due to the amount of additives that the manufacturer has to add to make it handle hot and cold weather ?

Does anyone know where I could get the tech specs (viscosity, pour point, etc) of Motul oils ? It's not available on their website as far as I can tell, unlike Mobil and Castrol's websites.

I should also mention that the Outback makes the trip to Mount Buller at least once a year, so it needs a fairly light oil to withstand the sub-zero C overnight temps.

theguru · Dec 21, 2003

Try this
Motul Canada TDS

Losiho · Dec 21, 2003

Thanks Guru

sprintman · Dec 21, 2003

I have an Outback too. Using Castrol Formula R 5W30 (12.2cSt so a thickish 30W) for final rinse mode after RX. Then I'll change to BP Visco 5000 5W40 a thinner 40W (13.95 cSt).

smeltjr · Dec 21, 2003

i also believe that Patman has one of these in the family, though it is a ford probe and i do not know if it is a v6. i would check posts for his uoa's as the vehicles shared the same engines.
he likes to try lots of different oils so that might be some good feedback.

Patman · Dec 21, 2003

quote:

Originally posted by smeltjr:
i also believe that Patman has one of these in the family, though it is a ford probe and i do not know if it is a v6. i would check posts for his uoa's as the vehicles shared the same engines.
he likes to try lots of different oils so that might be some good feedback.

True, my mom has a 94 Probe GT with this 2.5L Mazda V6 engine in it, however I only have two UOAs on it so far, one with Mobil 1 10w30 (old SJ TriSynthetic formula) and one with Castrol GTX HM 5w30, neither of these oils would be available in Australia though, so my data wouldn't help him here. I'm now running Walmart 0w30 synthetic in her car (also another oil they wouldn't be able to get there) She's got about 220,000km on the car now.

Losiho · Dec 21, 2003

We do get Mobil 1 10w30 here. Judging by the specs, it's a much lighter 30 weight than the other oils I've mentioned in my shortlist.

Patman · Dec 21, 2003

quote:

Originally posted by Losiho:
We do get Mobil 1 10w30 here. Judging by the specs, it's a much lighter 30 weight than the other oils I've mentioned in my shortlist.

I know you guys do get Mobil 1 there, however the version I tested in my mom's Probe was the older TriSynthetic version, not the newest SuperSyn version which is better.

Losiho · Dec 30, 2003

Thanks for all your help guys, I ended up buying 5 litres of Motul 8100 E-tech 0w40 for both my MX-6 and Outback. I'm not sure if it's the "right" oil

but it seems to have a good rep. locally, and the specs were suitable. I can only try it and see.

Patman · Dec 30, 2003

quote:

Originally posted by Schwinn:

As for Castrol Syntec oils, as you know they are group 3 and have very high ash contents, which further cuase problems to our HLAs. I would stay away from those oils for this reason alone.

I could be wrong, but I thought that the Castrol lineup of synthetic oils in Australia were definitely all group 4&5, that none of them are group 3.

Losiho · Dec 31, 2003

Yeah I know heavier oils are bad for HLAs, I had a bad experience with Mobil 1 5w50, the lifters tapped constantly, both at start up and at operating temp. Motul 8100 0w40 is at the light end of the 40w scale, so I'm hoping it won't be a problem. (We don't get M1 5w30 down here)

The Castrol lineup in Australia is the Synthetic R range. The 0w40 and 10w60 are Group 4 synthetics, the 25w50 is a mineral oil, and the 5w30 which I was using up until now is a Group 3 Hydrocracked oil.

I'm pretty sure ZR1 oil filters aren't available at my local Holden dealer.

Are there any online parts stores in the USA that stock them and ship overseas ?

Schwinn · Dec 31, 2003

I have a 93 MX6 V6 as well (148k miles on her), and have always used Mobil 1 5w30 (bought it used with 34k on it).

You are correct that the HLAs have issues with heavier oils, which is why your 40 and 50 weight oils are causing you so much trouble. Last I checked, the manual calls for 5w30.

As for Castrol Syntec oils, as you know they are group 3 and have very high ash contents, which further cuase problems to our HLAs. I would stay away from those oils for this reason alone.

Incidentally, the MX6 can take a 1991 Corvette ZR1 filter for an oversized direct fit - this si what I use on my car.

Mazda MX-6 V6, please help with oil choices

Similar threads