GC - GTX Start Up blend?

[Bob A.]

I've been thinking of mixing 2 qts. of GTX Start Up (the U.S. version of Magnatec) 5W-20 with 3 qts. of GC for winter use in my 2002, 2.5L Outback. (Easy, PScholte . . . easy, Big Fella! . . . easy Elves! ) The result would be a 2W-30 instead of a 0W-37 which is roughly what GC is. The purposes would be: 1) to reduce GC's 37 wgt. to a legitimate 30 wgt.-- since my 2002 Outback calls for an XW-30; and 2) accomplish no. 1 by combining a complementary lighter weight oil with GC (the GTX S.U. having the prospect of adhering to surfaces much like GC coats engine surfaces). Anybody know of a Castrol tech. who could tell me if these two oils are chemically compatible? I want to use the GC in my Outback, but I really don't want a 40 wgt. (almost) oil for the O.B. BTW, do we know if the Gold has the same heavy-30+ wgt. characteristic as the green? Maybe I'm worrying for nothing???? My six qts. are from the M0504 run, making them Gold.

 

[Losiho]

I have Castrol 5w-30 in my Outback. It's a thick 12.2cSt A3 B3 B4 30W. I have no problems at all. GC would be fine on its own.

 

[Bob A.]

Have you used any other 5W-30s with your Outback, Losiho? If so, have you noticed any difference in mileage between the heavy Castrol 5W-30 and the other(s)?

 

[Losiho]

Bob, I haven't had my Outback long enough. When I purchased it, I think the sump was filled with Castrol Magnatec 10W-40 (GTX Startup in the USA). I haven't noticed any difference in fuel economy between the 10W-40 and thick 5W-30. I will run Motul Eco Energy 8100 5W-30 in future, which is a thin 30W like Mobil 1 (simply because there are no other "real" synthetic 30Ws down here apart from M1 and Redline).

 

[MGBV8]

UK Magnatec is likely to be mineral with say 5% ester.

 

[Losiho]

quote:

---

Originally posted by MGBV8: UK Magnatec is likely to be mineral with say 5% ester.

---

Yup, it's the same down here.

 

[pscholte]

quote:

---

Originally posted by Bob A.: I've been thinking of mixing 2 qts. of GTX Start Up (the U.S. version of Magnatec) 5W-20 with 3 qts. of GC for winter use in my 2002, 2.5L Outback. (Easy, PScholte . . . easy, Big Fella! . . . easy Elves!

---

..... ..... ... ..... ..... ... OK, I'm past that, but ONLY WITH GTX STARTUP, OK?

 

[Bob A.]

All kidding aside, PScholte, it's only O.K. if the mixing makes sense! I'm serious about some input. I don't know if the two oils are chemically compatible. The coating quality of GC may be due to some element other than that which creates GTX startup's coating quality. Mixing the two may negate the coating effects of one or both????? Or not????? I dunno. I do like the prospect of reducing the 30+ viscosity grade of GC (at 100 degrees celsius) to a more pure 30 wgt. acting oil at operating temperatures -- because I think my car performs better with an XW-30 than with an XW-40-like oil -- the latter being what GC most closely resembles on paper. But . . . I also look forward to a quieter engine and excellent wear protection from GC. I'm just trying to get it all with my engine oil: great wear protection; quiet operation; high fuel efficiency. Maybe GC can do that by itself, but I think a truer multigrade, XW-30 oil would perform better. ???? I'm just trying to get GC's wear protection and XW-30 fuel efficiency in one oil.

 

[pscholte]

quote:

---

Originally posted by Bob A.: All kidding aside, PScholte, it's only O.K. if the mixing makes sense! I'm serious about some input. I don't know if the two oils are chemically compatible.

---

I think it depends on how seriously you want to talk about chemical compatibility. I DO NOT believe you will harm your engine by mixing them...now at the level of serious chemical assessment it may not be the best move if you want to maximize (or conversely, keep from minimizing) the capabilities and qualities of the GC. Unless Terry or Molakule will wade in, we won't know to that depth of understanding.

 

['00obw]

quote:

---

Originally posted by Bob A.: I dunno. I do like the prospect of reducing the 30+ viscosity grade of GC (at 100 degrees celsius) to a more pure 30 wgt. acting oil at operating temperatures -- because I think my car performs better with an XW-30 than with an XW-40-like oil -- the latter being what GC most closely resembles on paper. But . . . I also look forward to a quieter engine and excellent wear protection from GC. I'm just trying to get it all with my engine oil: great wear protection; quiet operation; high fuel efficiency. Maybe GC can do that by itself, but I think a truer multigrade, XW-30 oil would perform better. ???? I'm just trying to get GC's wear protection and XW-30 fuel efficiency in one oil.

---

I also don't like thick 30wt's in my 2000 Outback...makes it feel sluggish. I'm using a GC mix for pretty much the same reasons as you are. Currently, a 50/50 mix of GC & Mobil 1 0w20, the previous OCI was a 50/50 mix of MC 5w20 & 5w30 which I had a very good UOA. A UOA on the former is due in 2 months which is a 6 month term. So far I'm quite happy with the mixes, mpg was up 1-1.5, car feels peppier and rpm @ 70mph is down. BTW, no oil I've tried has ever silenced or even deaden that infamous Subaru cold start ticking noise.

 

[Bob A.]

Well, an interesting twist to this thread is that I found out the GTX Start Up doesn't come in a 5W-20. I thought I had seen this wgt. oil in this brand in a local auto parts store, but the Synteque Blend 5W-20 was adjacent to the Start Up. I was racing through the aisles because I was in a hurry to resume a brake job I was doing and caught a glimpse of the Syn.Blend and connected it with the Start UP which was shelved adjacent to it. (Moral: Haste does make waste.) Now the question is . . . is the Syn.Blend 5W-20 good enough to mix with the GC? I have a vague recollection that I've seen posts on BITOG warning folks not to use the Castrol Syn. Blend. I've not done the search yet to see if I can find those posts because I haven't had time to do so yet. '00obw -- Your post reassures me in my quest, though. It supports my own experience. About a month ago my oil was changed by the local Subaru dealer when I was in getting them to put in a part on a recall notice. I hadn't authorized them to change the oil, but once changed, there was no getting back the oil I had installed, so I ran the house brand for awhile. It was one of Quaker State's 5W-30s. With the QS the Outback seemed like it couldn't get out of its own way. I finally dumped the house oil and put in Chevron 5W-30 (which was in the car when they changed it). The Chev.Supreme has the car running really well at the moment . . . peppy with good mileage. I'm still interested in the GC, but I don't want to get into a situation whereby it makes the car feel like its sluggish due to a higher than 30 wgt. viscosity at operating temperatures.

 

[williar]

Certainly GC isn't for every car. Many will perform better and get adequate protection with a lighter oil, such as M1 5w30, 0w30, or 0w20. But if you already have the GC, then mix away!

 

[Bob A.]

I'm inclined to try the mix -- of whatever oil -- with the GC. In saying that, my goal is to find an appropriate Castrol 5W-20 to mix with the GC because I would like to do the mix with oils from the same company. The logic, correct or not, is that because the two oils are from the same source, the chances of them being more compatible would be maximized. ???????? I have not ignored your specific mix, '00obw. The fuel efficiency increase of 1 to 1.5 mpg. is hard to ignore. I also had to laugh at your observation that no oil (or mix of oils) that you've tried has stopped the start-up ticking that the OB engine emits. So far for me . . . so true!

 

['00obw]

quote:

---

Originally posted by Bob A.: I'm inclined to try the mix -- of whatever oil -- with the GC. In saying that, my goal is to find an appropriate Castrol 5W-20 to mix with the GC because I would like to do the mix with oils from the same company. The logic, correct or not, is that because the two oils are from the same source, the chances of them being more compatible would be maximized. ????????

---

Please correct me if I'm wrong, GC is a very special blend of Group IV and V basestocks whereas the Castrol 5w20 synblend is made up of Group II(+) and III basestocks...possibly even Group I. The Castrol 5w20 Syntec is Group III. So, althou you are mixing oils from the same company, you are not mixings oils of similar basestocks. That said, I would think the additives used would remain same being the same company. Since Mobil 1 uses Group IV basestock, mixing in GC just adds abit of Group V.....I think . The problem I see in my mix is, what if Mobil and Castrol uses additives made by different companies.

 

[Bob A.]

Yeah . . . trade-offs galore (different base stocks/different add. pkgs./different sources of additives) . . . the problems with mixing. Castrol's answer to my questions yesterday? "You'll ruin your engine". '00obw, was your mix of MC 5W-20 and 5W-30 with oils of the same base stocks, i.e., of the same family of oils within the MC inventory? What were their operating temperature viscosities (at 100 degrees C) before mixing?

 

['00obw]

quote:

---

Originally posted by Bob A.: '00obw, was your mix of MC 5W-20 and 5W-30 with oils of the same base stocks, i.e., of the same family of oils within the MC inventory? What were their operating temperature viscosities (at 100 degrees C) before mixing?

---

Yes, I believe both oils are made-up with the same basestocks difference mainly I would guess are VII. Here's the VOA's of all three: http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=11;t=000289

 

[Bob A.]

Looks like a good, safe effective mix. I've been looking at a VOA report comparing Castrol's 5W-20s: Syntec, syntec Blend, and GTX. This report was presented at: http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=11;t=000207#000000 I hope that link works. The additive package which most closely resembles the GC looks to me to be the Syntec Blend, with the exception of the moly. The most current VOA of GC that I've found is dated Oct., '04: http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=11;t=000236#000000 Extrapolation produces the following approximate VOA for a Syntec 0W-30 and Syntec 5W-20 mix (3 qts./2 qts.). I've chosen Syntec 5W-20 because its base stock is most similar to GC's.

code:

---

                          Extrapol.
         Syntec   Syntec   3:2 qt.
         OW-30    5W-20     mix

AL         1        1        1
CR         0        0        0
CU         0        0        0
FE         2        1        2
SN         0        0        0
PB         0        0        0
SI         0        0        0
MO         1       44       19
NI         0        0        0
AG         1        0        1
K          1        0        1
NA         2        1        2
BO         1        2        2
BA         0        0        0
CA      3050     1994     2617
MG       135        9       85
MN         0        0        0
P        919      667      818
ZN       986      722      880
VIS
 100    12.2      9.0    10.92

---

Results (albeit extrapolated): 1. By using Syntec 5W-20, the mix maintains similar base stock. 2. The mix does reduce some of the additive package: calcium by 15%; phosphorous by 11%; Zinc by 11%. 3. The mix reduces the viscosity (at 100 degrees C.) of GC from a 37 wgt. to a truer 30 wgt., which was what I was after. I don't think the effects of the proposed mix to the GC additive package are too concerning. Any thoughts?