Castrol Syntec 5w/20 in my wife's 2005 Miata

double vanos · Jun 27, 2006

I have been using M1 5w/20 oil in the car since new and it sounds like a waring blender (dry, sandy sound) on crank off every morning when my wife leaves for work. Since the car is in warranty, for the moment, I think GC is out of the question. However, as soon as the warranty is out it'll be GC all the way. Anyway, the car is much quieter now on fire off and it seems that the Castrol is hanging in there. The Chevy / Mazda dealer I bought the car from uses only Castrol Syntec in the oil change pit. The service advisor claims they have never had a problem - it comes highly recommended by the dealer. I am aware that Syntec is only a grp III but it seems like this little car really likes it. So what say ye all? The car gets 5k oci's with factory oil filter. I'll keep in touch on how it goes! I wish I knew exactly what this Syntec 5/20 was made up from; grpIII and what else? Can't seem to find out much. Any comments by the oil heads on this board are always appreciated. DV

buster · Jun 27, 2006

Doesn't make any sense what so ever. M1 0w-20 and M1 5w-20 are among the best out there. No noise was ever detected in any of our cars that ran on it. I think something is wrong with your car. That sucks.

TR3-2001SE · Jun 27, 2006

Is that the recomended viscosity for the 2005 Miata? I have the 2001 and it is the same engine unless you have the turbo version. Recomended was 10-30 above 0 degrees F. Sounds like it is too thin for this engine to me. Never had a problem with M1 10w-30 and many UOA's have been done on my engine.

speedtc · Jun 27, 2006

I stopped using m1 and went to syntec 5w20. The M1 was fine for maybe 2-3 thousand then it seemed to get louder. M1 5w20 does ok in the UOA section so i'm sure it's ok.

Rodbuckler · Jun 27, 2006

I am running the Castrol Syntec 5W-20 in my Ford 4.6L Modular Motor. I was looking for a thick 5W-20 with some stickiness to it, and I got it with the Syntec. This is one very smooth running oil.

Castrol's type III/IV?/V blend in the Syntec seems to make for an excellent street oil in terms of smoothness, life, wear, and cleanliness from what I have seen. On a sour note, the M1 10W-30 ran like rocks in this engine.

hominid7 · Jun 27, 2006

5w20 is what is called for in the '05 Miata. Then again, you are in Houston and it's hot as he77 down there.

You may want to try a thicker 5w20, either dino or a semi-synthetic and see if your noises go away. Motorcraft 5w20 has been very popular.

You may even want to try *gasp* a 5w30 and see how that does

Castrol and Motorcraft semi-synthetic oils are a bit thicker than some and may help quieten things down without being *too* thick.

Check out miata.net and see what all the miata'ers are running.

double vanos · Jun 27, 2006

Yes, the cars specs indicate 5w/20 year around. And the car is smooth and quiet with the Syntec in it. There's nothing wrong with the car - it's made 3 trips from Houston to Bisbee Az since we got it last July. I 10 across west Texas sucks for hours on end to I'm sure the wife did not spare the whip. If the engine was bad it would have failed by now. It's late, I'll check back later - many many thanks for your interest in this guys! DV

bighead · Jun 27, 2006

quote:

Originally posted by hominid7:
5w20 is what is called for in the '05 Miata. Then again, you are in Houston and it's hot as he77 down there.

You may want to try a thicker 5w20, either dino or a semi-synthetic and see if your noises go away. Motorcraft 5w20 has been very popular.

You may even want to try *gasp* a 5w30 and see how that does Castrol and Motorcraft semi-synthetic oils are a bit thicker than some and may help quieten things down without being *too* thick.

Check out miata.net and see what all the miata'ers are running.

If I remember reading correctly, Syntec 5w-20 is like, 9 cSt and the 5w-30 is only like, 9.8 or some low number. I maybe wrong but I swear I read that here recently. Now *if* that's the case, then the 5w-30 would be just a hair thicker than the 5w-20. Again, this is only if my memory is serving me correctly lol..

speedtc · Jun 27, 2006

Bighead....Maybe 5w20 and 5w30 are the exact same. Maybe a little playing with #'s by castrol?

KBK · Jun 28, 2006

I had been using M1 5w-20 for many changes also Syntec 5w-20. Last changed, I tried the Syntec 0w30 GC in Honda Civic 04. I did lots of delivery driving in the city. Yes, I do agree that GC reduces engine's noise and promotes smooth acceleration. I drained it out at 5700 miles but I didn't do oil analysis so I don't know what condition was it. But with 5w-20, the noise shouldn't be a big deal as long as the oil filter is not in the bypass mode. I used M1 5w-20 for the whole winter in Chicago.

double vanos · Jun 28, 2006

As soon as this puppy is out of warranty, I plan a steady diet of GC for it. I have heard that some manufacturers are beginning to analyze the oil in warranty engines and are denying warranty on those without the correct weight oil in them. This action of the MFG's was a knee jerk reaction of the Toyota sludge debacle. Chrysler, VW, and Toyota now validate the oil in the failed engine prior to covering it under warranty. So I'll stay with 5w/20 for now. If I don't like the Castrol I'll try the PP next. DV

Rodbuckler · Jun 28, 2006

GC is a very thick oil to run in a 5W-20 engine. You might want to run OCI's with UOA's on both the Syntec 5W-20 and 0W-30 to see which will work better for the long haul. Seat-of-the-pants will probably tell you the 5W-20 is better.

bighead · Jun 28, 2006

5w-20 oils in general work very well for applications that call for it. I'd find a good 5w-20 and stick with it.

Cooper · Jun 28, 2006

I would go with Pennzoil Platinum 5w20. I have heard that it is a very good oil (Group V), and a lot cheaper than using Mobil 1.

Dave H · Jun 28, 2006

Just a thought, but who makes the factory oil filters? I have used some oil filters (Fram) pre-BITOG that had my car sound very rough on first start up of the day. I tried different oil with no effect. When I switched oil filters to a better quality one (in my case either Nissan's, Mobil 1's, PureOne's, and even bosch), the noise went away. I can only assume a better anti-drainback valve was the cure. Makes sense, since more oil would be kept in the top of the engine when it is sitting, thus it is there when you crank it up.
If the Castrol Syntec makes the noise go away, maybe it could be that it clings better, and therefore doesn't drain back to the pan as quickly. If it's working for you, I'd stick with it. But I'd also check out some different quality filters, too. It's possible that Mazda gets cheap filters.
Being in Houston, I think you could get away with using a 5w30 year round with no problems (I'm in Louisiana, so I see the same heat you do). But being under warranty, that's a tough call. You could try to find what your car specs for in Europe, and that would tell you if Mazda USA is spec'ing 5w20 for primarily CAFE reasons. European oil specs are generally higher than US specs even for the same engine. Of course, they don't have CAFE requirements, either.

Dave

mechtech · Jun 28, 2006

When you start the car cold, the oil is ten times thicker than when hot.
I reallly wonder if this oil is the start up noise problem.

double vanos · Jun 28, 2006

Dave H: you are correct about the same engine as our Miata taking a different weight oil in countries other than the USA. And most Miata enthusiasts, on their message boards like 5w/30 in their engines. Soon as that warranty is gone.... Now the filter is a mazda filter and appears to be built like a tank, I think the start up noise is simply a case of noise till she oils up after a cold start - there is much less of it (well actually none) with the Syntec. I'll go with the GC post warranty. BTW does anyone have concrete proof that PP is 100% or near 100% GRP V base oil? If that is the case I'll just switch to that next OC. When it comes right down to plainly saying it is a GRP V oil pennzoils web site is painfully vague...

goodvibes · Jun 28, 2006

quote:

Originally posted by mechtech:
When you start the car cold, the oil is ten times thicker than when hot.
I reallly wonder if this oil is the start up noise problem.

But it drains back when the car is turned off and the motor oil is still hot. M1's just doesn't seem to stick. I don't see it as a problem as it hasn't shown extra wear in UOAs. I also like quieter oils but wouldn't worry about M1 in the pan.

bighead · Jun 29, 2006

As far as filters go, I'm pretty sure you could find a Motorcraft to slap in there...

Castrol Syntec 5w/20 in my wife's 2005 Miata

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