Viscosity debate.... - Page 4

GV27 · #46 (**permalink**) 05-18-2008, 07:57 AM

Quote:

Originally Posted by Joe Papa Sr

Seriously, though, Ive heard from a good source, most engine wear occurs at start up. So, with engine cold, oil must be as thin as possible to be pumped through engine as fast as possible, to do its job, which is lubricate. Thick oil, as in the 20w50, etc, vs say, 10-40, flows SLOWER at startup than is desirable. In fact, ideally, cars should be equipped NOT with oil pressure meters, but oil FLOW meters. But why dont our cars have them? Cuz they cost TOO much!! Pressure sensors are way cheaper to equip a car with. better than nothing, is what they really should be referred to.

Startup with thicker oil is NOT better for your engine than otherwise with thinner oil........every morning you start up. Remember this tomorrow when you start your cold (even in summer) engine............

2fci · #47 (**permalink**) 05-20-2008, 10:13 AM

Quote:

Originally Posted by 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.

**lowmileage** · #48 (**permalink**) 05-20-2008, 10:29 AM

6 qts of the GTX plus 2-15 oz. "jugs" of STP red should bump you up to the old zinc levels for a full crankcase. When you're done with your supply of GTX, re-evaluate the then oil's available. I think the 20w-50 GTX now contains only 800ppm zinc vs. the old 1200 ppm. Nice of them to tell us, aye

.

Oh, just see you've highlighted my earlier post!

**ddouglas77** · #49 (**permalink**) 05-20-2008, 11:21 PM

Quote:

Originally Posted by lowmileage

I think the 20w-50 GTX now contains only 800ppm zinc vs. the old 1200 ppm.

**GTV4EVR** · #50 (**permalink**) 05-21-2008, 06:44 AM

Does anyone have an opinion

on Mobile 1 5W50. I can't find 15W50 this year, only the 5W50. Is it a replacement or ???

**ddouglas77** · #51 (**permalink**) 05-21-2008, 09:17 AM

Quote:

Originally Posted by GTV4EVR

Does anyone have an opinion

on Mobile 1 5W50. I can't find 15W50 this year, only the 5W50. Is it a replacement or ???

**Gubi** · #52 (**permalink**) 05-21-2008, 10:04 AM

Quote:

Originally Posted by GTV4EVR

Does anyone have an opinion

on Mobile 1 5W50. I can't find 15W50 this year, only the 5W50. Is it a replacement or ???

**ddouglas77** · #53 (**permalink**) 05-21-2008, 10:10 AM

Quote:

Originally Posted by Gubi

The 5W50 looks like it's only 1000 PPM ZDDP vs. 1200 for the 15W50. Mongo dunno how much of a difference this makes. In my car I'd want the extra zinc, but I don't have to deal with cold weather so 15W50 is fine for me.

http://www.mobiloil.com/USA-English/...duct_Guide.pdf

**lowmileage** · #54 (**permalink**) 05-21-2008, 10:19 AM

and the point

**GTV4EVR** · #55 (**permalink**) 05-21-2008, 10:26 AM

Thanks guys. I don't drive the car in the cold weather, but since I can't find any 15W50, and I bought 10 litres of the 5W50 I'll give it a try. I've used 20W50 GTX in my Alfas for the last 35 years, but when I bought this car from Ed last July he was using the M1, so I'm going to stick with it. It is a bit of a shock paying over $40 for the 5 litre jug versus $15 for the GTX

**ddouglas77** · #56 (**permalink**) 05-21-2008, 10:29 AM

Quote:

Originally Posted by lowmileage

and the point

**ddouglas77** · #57 (**permalink**) 05-21-2008, 10:31 AM

Quote:

Originally Posted by GTV4EVR

Thanks guys. I don't drive the car in the cold weather, but since I can't find any 15W50, and I bought 10 litres of the 5W50 I'll give it a try. I've used 20W50 GTX in my Alfas for the last 35 years, but when I bought this car from Ed last July he was using the M1, so I'm going to stick with it. It is a bit of a shock paying over $40 for the 5 litre jug versus $15 for the GTX

**GTV4EVR** · #58 (**permalink**) 05-21-2008, 11:30 AM

Quote:

Originally Posted by ddouglas77

You could buy the stuff (15W50) online from various vendors in the US.

2fci · #59 (**permalink**) 05-21-2008, 12:53 PM

I have decided to return my two cases of Castrol GTX 20W-50 due to Castrol's own acknowledgement in October 2007 that it no longer recommends this oil for engines with flat tappet cams, like our 4 cylinder Alfas. Castrol now says the only oil they produce with ZDDP levels adequate for older (API SF and SG) high performance engines is Syntec 20w-50, its full synthetic with a .120 ZDDP rating. It has been formulated for "classic high performance cars."

The solution for me: I'm going back to Kendall GT-1 High performance 20w-50 conventional oil with a ZDDP rating of .119. It's produced by Conoco-Phillips and is less that $3 a quart.