90-100deg temps, GC or 5w-40 for Miata.

[JGmazda]

Hi guys...I've read up on German Castrol and Syntec 5w-40. Since I'm dealing a high reving 1.8 engine in 90-100deg temps, what's your opinion on which oil would handle the heat better?

I understand the "0" part (0w-30) means nothing at operating temps. I just know that the two oils are completely different in Composition.

Am I nuts to consider GC in the Phoenix climate?
Thanks!

 

[Nickdfresh]

I'd go 0W-30 GC over the BC (Belgian). I think the German Castrol Syntec numbers are pretty comparable to most synthetics weighted at 10W-30...

 

[JGmazda]

Thanks. I realize that the manual calls for 10w-30. But? I've got 110K on the car... And believe me... It's a furnace under that hood when you drive in the summer. My oil pressure seems to suffer when I don't use a "thicker" oil... I like the fact of using a synthetic due to the small sump and extreme temps...

 

[hominid7]

xxW30 would be best for your mazda. The favorite on miata.net seems to be 10w30 Mobil1 or 5w30 mobil1 if your lifters are noisey at startup.

So far i've had no problems using dino 5w30 in my 1.6 ltr mazda 4 and my 2.5 ltr mazda v6.

 

[mechtech]

Is that Miata a turbo?

 

[Nickdfresh]

quote:

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Originally posted by JGmazda:
Thanks. I realize that the manual calls for 10w-30. But? I've got 110K on the car... And believe me... It's a furnace under that hood when you drive in the summer. My oil pressure seems to suffer when I don't use a "thicker" oil... I like the fact of using a synthetic due to the small sump and extreme temps...

---

Don't I know it! I still have scar on my arm from changing oil on a hot Miata...

 

[JGmazda]

No... It's not a Turbo. Can you imagine that would produce? Yes... I very knowledgeable on my cars requirements for the "correct" viscosity.

After researching (thanks to this site!) I've concluded that GC has a higher Cst. than many xxW-30's on the market. I've run 5W & 10W-30's and feel that the former helped with the infamous lifter tick that these engines have on startup.

On the other hand? Many knowledgeable Miata experts run 15w-50 and even 20w-50 citing that early cars called for those specs before CAFE requirements. Frankly? It can get very confusing.

Oh... yes I know... Burnt arms you say? I do all my own maintenance and decided one day to pull into a "Spiffy Lube" place.(Was on Vacation trip) The "kids" there had half my belly pan shield off and were "searching" for the oil filter... I called the manager over and said I was not happy that a national chain couldn't find the oil filter... He shrugged and finally asked me where it was. I pointed it out and told him the best way to get to it was by turning the wheel slightly and reaching up. I watched him then reach down through the scalding manifold and screamed and cussed as he burnt his forearm reaching for the filter.

That was all I needed to see and I told them enough was enough..."Wrap it up... I'll do it myself!" I shouted and got in my car.

Sorry for the off topic... but the burning flesh part I'll never forget.

 

[JGmazda]

Anyhow.... Back to the subject- I'd like to use a synth in my car and change my Dino now at 3k intervals. Plan on going 5k with a synth. Just have not picked out one yet!

GC? It seems to be very well recommended. I will say that I'm not to happy with Mobil's marketing or oils. I ran Mobil 1 5w-30 and had terrible "Hot tick" after coming off a highway stretch in the heat. Doing maybe 75-80mph for and hour commute. Oil pressure way down.

I just feel their synth is too thin.

 

[hominid7]

Have you thought about giving something like Maxlife valvoline 10w30 or 10w40 a try?

 

[JGmazda]

hominid7- I've thought about going to a 10w-40 dino. I don't know why that feels better to me...? Maybe because I can't get used to the idea of using an -0- weight oil in such high temps. It hardly ever goes below 40deg here!

I'm worried about the shearing and the VII issues. (Yes, we BITOGuy's are just anal about that stuff)

 

[moribundman]

quote:

---

Sorry for the off topic... but the burning flesh part I'll never forget.

---

That was the best part!

 

[GeaugaFletcher]

Mobil 1 5w-40 does pretty well in my '97.

And yup, I've sent samples to be analyzed.

 

[surfstar]

Check out the specs for Maxlife Synthetic:

Maxlife Syn 10w30
100*C 11.51
40*C 72.28
TBN 10
Flash Pt *C 230
Pour Pt *C -42
Noack 8.31
date 9/2/2004

API SL/SJ, ACEA A3/B3/B4, BMW LL01/98, VW502.00/505.00, MB229.3/229.1

It is a "thicker" 10w30 at 11.51 Cst. Also free after rebate if they haven't reached the 100k rebate limit yet. Maxlife dino is only 10.6 Cst, so if you want thicker, get the syn.

 

[Cutehumor]

quote:

---

Originally posted by surfstar:
Check out the specs for Maxlife Synthetic:

Maxlife Syn 10w30
100*C 11.51
40*C 72.28
TBN 10
Flash Pt *C 230
Pour Pt *C -42
Noack 8.31
date 9/2/2004

API SL/SJ, ACEA A3/B3/B4, BMW LL01/98, VW502.00/505.00, MB229.3/229.1

It is a "thicker" 10w30 at 11.51 Cst. Also free after rebate if they haven't reached the 100k rebate limit yet. Maxlife dino is only 10.6 Cst, so if you want thicker, get the syn.

---

can't wait for the UOAs to roll in on this oil

 

[JGmazda]

moribundman- It was actually very funny later on. I was angry because I allowed myself to think that perhaps they had changed oil on a Miata at one time. I may have well just rolled in there with a Lamborghini or some other exotic!

Surfstar- I've never seen Maxlife Synth or heard of anyone discussing it. (I'm doing a search now)

GeaugaFletcher- Mobil 1 5w-40? You mean their discontinued Truck and SUV formula?

Maxlife Syn looks good on paper... I really need to do a UOA on what I have now which is Castrol GTX. It's amazing to me how many mechanics I talk to have no idea about oil specs and things discussed on this site.

Yes, they follow the manufactures recommendations. But? If it were not for having an addiction to this site, I would never have thought about using a 0w-weight oil in Phoenix!

My Mechanic just skakes his head when I tell him what I'm thinking. I am trying to compare all the data and make a better choice. Like most of you, we want that "edge" so we can have our cars for a long time.

 

[pscholte]

JGm,

I've run GC in a twin-turbo A6 at speed through Nevada in 100ºF temps without issue. Don't know what more I can tell you.

 

[Mitch Alsup]

Do you have an oil temperature guage?

If so, you can answer this question for yourself. If you oil temperature never gets above 265dF then the mazda specified oil is better the vast majority of the time. If the oil gets above 300dF you need an oil cooler (independent of whether you migrate to a thicker oil). In between 265dF and 300dF you should be looking at the HTHS numbers not the SAE grade, look for an HTHS in the 3.6 range.

 

[JGmazda]

pscholte - Do you know what the HTHS is with GC?

I do not have a temp guage. I've been listening to my engine during extreme runs in dry 100deg heat and like I said, was not happy with the "Hot ticking" that Mobil 1 was producing. I never had that problem with Dino 10w-30. Weird.

Actually, an Oil cooler might not be a bad investment. After Mobil 1 experience, I find their oil and marketing plans quite confusing. Wonder why they don't offer a 0W-30?

 

[JimKJSVT]

JGmazda
mobil1 does have a ow-30. I believe its only 2.99 hths. My 4 favorite oils are from lurking on this site all the time are

Schaeffer's 9000 5w-40
GC 0w-30
Esso XD-3 0w-30 (only in Canada)and
Redline 10w-30. I'm afraid to use more than 30% Redline because it is such a potent cleaner.

 

[JGmazda]

JimKJSVT- So what's your opinion on GC? Is it another flavor-of-the-month oil? Or is the chemistry that much better than most oils? I think that sometimes the only way we can decide is to try the oil and do a UOA.

I'm still wary of using a -0- weight in an application that calls for a 10w. I know... I know... read the stats. But? I guess I'm just looking for reassurance. Oil is Oil is Oil... and then you can drive yourself crazy!