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MG MGB Technical - Castrol Oils


I recently went to purchase my usual bottle or two of Castrol GTX 20-50w only to find there are now TWO versions. The white bottle and now a green one labelled "For High Mileage Cars" 20-50w. The Castrol website lists both and describes the latter as having special additives to deal with aging gaskets and seals. Would it be ok to switch to the newer version for my 78B?

Thank you.
Ted Anderson

http://www.castrolusa.com/products/productpage1.asp?product_category=1&product_id=52

- looks like it couldn't hurt the B engine -

rn

Product Details

Overview
Grades Available
Warranty



Overview
IT'S A FACT...As your engine ages, its performance decreases and oil breaks down faster. Over time, seals deteriorate, gaskets become brittle and oil consumption increases, leading to reduced performance. To combat the aging process, GTX High Mileage:



Utilizes special base oils to provide superior protection against oil burn-off compared to leading oils
Contains seal conditioners that provide added level of protection and help reduce leakage
Contains proprietary additives that provide superior protection from wear and harmful deposits in higher mileage engines
Reduced deposit formation to minimize compression loss and maximize engine performance
Available Grades
SAE 5W-30: provides a higher level of protection against oil burn-off and viscosity breakdown than leading conventional oils. It exceeds API SL and is recommended wherever API SL, SJ, SH, SG and previous API S categories are recommended. It exceeds the engine protection requirements of ILSAC GF-3, GF-2 and GF-1.
SAE 10W-30: provides a higher level of protection against oil burn-off and viscosity breakdown than leading conventional oils in the leading consumer grade. It exceeds API SL and is recommended wherever API SL, SJ, SH, SG and previous API S categories are recommended. It exceeds the engine protection requirements of ILSAC GF-3, GF-2 and GF-1.
SAE 10W-40: delivers maximum viscosity protection and superior protection against oil burn-off in the second most popular consumer grade. It exceeds API SL and is recommended wherever API SL, SJ, SH, SG and previous API S categories are recommended. It exceeds the engine protection requirements of ILSAC GF-3, GF-2 and GF-1.
SAE 20W-50: contains seal conditioners that help reduce leakage. It exceeds API SL and is recommended wherever API SL, SJ, SH, SG and previous API S categories are recommended. It exceeds the engine protection requirements of ILSAC GF-3, GF-2 and GF-1. Use GTX High Mileage 20W-50 when the ambient temperature is above 20 degrees F.
Warranty and Protection Requirements

Exceeds all passenger car and light truck manufacturers' warranty requirements for the protection of gasoline and turbocharged engines where API SL, SJ, SH, SG and previous API S categories are recommended. Exceeds the engine protection requirements of ILSAC GF-3, GF-2, GF-1, GM 6094M, GM 6085M, Ford ESE M2C153G and F, and Daimler Chrysler MS-6395H.



RN Lipow

Ted,

I'm an old time user of the old time Castrol GTX and change it and filter every 3,000 - 4,000 miles on my old time 64 B.

Call me a luddite, but just cause it's "new and improved" isn't reason for me to change from what i feel works well.

After all, it's just motor oil.

glg

glg gimbut

Been using Castrol oil exclusively since I bought an MGB (new) in 1973.
Right at 30 years and I have never had an oil related failure in any of my cars, or engines that I built. Other things have happened, but nothing that could be blamed on lack of lubrication.
I always used 10w/40 GTX in my MGBs and 20w/50 in the Healey.
Nowadays, both my BMW M Rdstrs use Casrtol products. The interval is a little longer, 4500-5000 miles instead of 2500-3000 that the Bs used to get and Castrol Syntec 10w/40 in the 99 (240hp version) and the 01 (315hp version) gets factory specified Castrol RWS 10w/60 (only available at BMW dealers, not distributed by Castrol in the US).
Point is, if it's from Castrol, I'll use it with confidence.
Randy Forbes

In the UK Castrol market two types of various oils, one for 'modern' engines and one for 'conventional' engines. This is in both mineral (GTX) and synthetic (GTX Magnatec) formulations, the mineral being mainly white packaging and the synthetic being manily green. GTX hasn't been 20W/50 for many years here, but 15W/50 which was even better. However a year or two ago it changed to 15W/40 at the same time as it claimed 30% better protection. Anything of lower viscosity should not really be used in our engines with their relatively large clearances, especially after many tens of thousands of miles. I have just given up using it in my V8 as the hot pressure is significantly lower than before. I tried Magnatec which was slightly better but it is a lot more expensive and only contains 4.5L whereas I need 5L for an oil and filter change. I'm trying Halfords 15W/50 at the moment.
Paul Hunt

Paul, I've always been wary of using non-branded oils like Halfords. Don't know why as they seem to meet the usual specifications. I'll be interested to hear of your experience with it.

Mike
Mike Howlett

Mike - me too, but I feel more comfortable with the higher hot oil pressures (at the moment) of the Halfords. It's as runny as 15W/40 when cold so I shouldn't be losing anything there.
Paul Hunt

Ron,

Thanks for the Castrol web site lead. Interestingly, when I keyed into their guide for the correct oil for my car they only list cars back to 1980? Might be interesting to see what they recommend for 1940/50's technology?

I have been using Castro GTX 10W-40 for winter months, and 20W-50 for summer in both 1969 midget, and 1974 B/GT. Cannot see the extra expense for modern formulas after all these years.

Regards,

L.C.
Larry C.

Since they reintroduced it, I've gone back to "tinned" Duckhams "Q" 20/50.
If it was good enough for my father and grandfather, it's good enough for me.... etcetera ad infinitum.
T J C Cuthill

"I have been using Castro GTX 10W-40 for winter months, and 20W-50 for summer in both 1969 Midget, and 1974 B/GT. Cannot see the extra expense for modern formulas after all these years".

Larry,
At the interval you change the oil in your cars, the dino oil is fine. I'll bet that when you drain it, it still looks clean!

The big advantages to synthetic oil are in extended intervals (9k to 15k miles) and the higher operating temperatures of current (refraining from saying "modern") cars.

Something I have been doing for the last twenty years, is having an analysis done when I change the oil. Early warning system, if you will. Great piece of mind and not all that expensive to do.

Randy Forbes

Randy,

Did not get a lot of driving in this past winter with as much snow and ice we had on the roads around here. Typically, with my M.G.'s I'm putting about (2K +/-) miles in six months between changes, and yes it doesn't look that bad. However, I've read that keeping dirty oil in over the winter months when a car isn't to be driven much is not good for the bearings.

My earlier comment I was referring to modern oils (synthetics), and not modern cars. By the way, I still use "dino-base" in all my vehicles, and still change the modern cars between (3&4K). Do you have someone locally with a lab to do your oil analysis, or do you use a kit?

Regards,

L.C.
Larry C.

This thread was discussed between 31/03/2003 and 03/04/2003

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