Viscosity debate....

[Alfa-Stu]

So I have heard that running 5W/50 in the summer is good for spiders. I have also heard 10W/40, and 10W/30.

I would like to ask what oils you all use, brand and viscosity, so i can get a better idea.

Cheers.

[mmolto]

I use Castrol GTX 20W-50.

The 20W-50 has been recommended by many people on this board and was also recommened by the previous owner.

[Legomedic]

I have used Castrol GTX 20W50 since 1988. Neither my '74 2000GTV or my '81 Spider have "complained". I have heard the debates about vegetable oils and synthetics and additives and PTFE ad-nauseum, but I am of the school of: "Don't fix what ain't broke". One thing I must point out though is that we don't get any snow or sub-zero temperatures here (we range between 5 - 35 degrees C), I don't know if this may change things.

[conedriver]

I use Mobil 1 15W/50 in both spiders. This is also one of the Mobil 1 oils retaining a high ZDDP level (Zinc equivalent).

Quote:

Originally Posted by Alfa-Stu So I have heard that running 5W/50 in the summer is good for spiders. I have also heard 10W/40, and 10W/30. I would like to ask what oils you all use, brand and viscosity, so i can get a better idea. Cheers.

[lowmileage]

While I've used GTX 20w-50 in the past, it is highly unlikely I will be using it any more. The zinc level in GTX, as in most other "modern" oils, has taken a severe hit. Diesel oils (Delo 400, Rotella) are 15w-40 and, while they are at zinc levels were in regular dino oil, are also going to suffer with the low sulfur emission oils. I've been threatening to take a look at Valvoline Motorcycle (dino) 4 stroke 20w-50. Right now I have the Delo in it. To get rid of my last supply of GTX 20w-50, I'll probably put 6 qts in along with 2-15 oz bottles of red STP.

[bshorey]

Quote:

Originally Posted by Alfa-Stu So I have heard that running 5W/50 in the summer is good for spiders. I have also heard 10W/40, and 10W/30. I would like to ask what oils you all use, brand and viscosity, so i can get a better idea. Cheers.

[Alfa-Stu]

Wow, you guys really know your stuff. Thanks for the insight.

[WopJob]

GTX 20w-50 is good for the summer, but I use 5 - 50 year round because I use my spider well into December (in NJ) I also recently changed the gearbox from spirax to a 75-90 syntetic for the same reason, easier to shift in the winter.
On a previous spider I ised castrol 10-40 year round from 1986 to 1993, I do not recomment 10-40 because I had to have the engine rebuilt at 80K miles.
this is my personal experience, I used to alternate 20-50 in summer and 5-50 in winter but I don't see the point in doing this anymore. I drive the car 6k miler per year and usually a single oil change in the summer with 5-50 is good for the whole year. I have been using Purolator filters.

[lowmileage]

Quote:

Originally Posted by WopJob On a previous spider I used castrol 10-40 year round from 1986 to 1993, I do not recommend 10-40 because I had to have the engine rebuilt at 80K miles.

[rgrimm]

+1 for what lowmileage said. You want to avoid too much of a spread, so I'd stay away from 5W-50 for sure. I've used the Rotella 15W-40 and Mobil 1 15w-50, which has better ZDDP levels than some of their other blends although people still debate whether it's "good enough" for older engines.

Interestingly, I read someone comparing the "spread" in various oils by dividing (50/5-10, 40/15=2.67, 50/15=3.33). Regardless, the less the spread the better. My only other experience is that with very low "cold" numbers (0W-40, 5W-50) I've gotten some nervously-loud valve train noise on older cars until they warm up. So I don't go any lower than I need to for expected temperatures.

[lowmileage]

Quote:

Originally Posted by rgrimm You want to avoid too much of a spread, so I'd stay away from 5W-50 for sure.

[bshorey]

Quote:

Originally Posted by lowmileage I'm not certain but the "spread of the numbers theory" might be different (may not apply as in the case for dino oils) for syn oils. I know it is for M1 5w-30 which in a dino contains more than the ideal mix of VII's but is good in the M1 instance.

[Bob Sacamano]

I'm another user of Mobil 1 15w/50 in all my Alfa's. Some of the newest cars (i.e a friend's '06 BMW) use something much thinner, like a 0w/40, but Mobil 1 15w/50 is probably the closest to matching the original Alfa spec back in the day. I might try something else in winter, if I lived in a colder climate, but 40F is about as cold as it really gets around here.

[the_sicilian]

just to be clear. these guys are not talking about the Mobil1 15w50 EXTENDED, which is the usual one you find. theyre talking about the dark-red-labeled plain 15w50. the only place ive found it consistently is at Wal-Mart, in the large 5quart bottles.

[lowmileage]

Thanks Guido for pointing out the different versions. When I buy my M1 5w-30 (for my DD), I get the plain jane version also and not the "extended - or whatever they call it now" version. And it use to be so simple buying motor oil.