Castrol Syntec 20w50 for classic cars?

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I may go back to synthetic in the VW. Tried before and it leaked so badly I gave up.
Lately the many small seal leaks - mostly the pushrod tub seals - have gotten bad enough that I put in some Bars Leaks and it stopped leaking.
But I'll probably go back to Mobil 1 15W-50. That made it sound the smoothest and quietest.
 
Autozone replaced the Syntec 5W50 with it awhile back,and now it`s gone and they restocked the 5W50 again.
 
Originally Posted By: aquariuscsm
Autozone replaced the Syntec 5W50 with it awhile back,and now it`s gone and they restocked the 5W50 again.


Well I still see it, I just bought 8 quarts a couple weeks ago
 
Bump for a question. I heard thaat if you shouldnt use this oil on an engine that has Catalytic Converters because it might damage them. Is this true?
 
Originally Posted By: N7Quarian
Bump for a question. I heard thaat if you shouldnt use this oil on an engine that has Catalytic Converters because it might damage them. Is this true?


It's really only a concern if you have OBD11 with an O2 sensor after the cat or have emission testing in your area. Do you have that there? I'm thinking not if your owner's manual recommends 20W50. Excess phophorus only possibly damages the cat in an emissions level sense and not otherwise structurally or functionally.
 
I don't have emmisions testing and I don't see an O2 sensor after the Cat, heck I don't se ANY o2 sensors at all. My engine does have variable Valve timing though and I'm wondering that if this oil might damage my engine because it says that its specifically used for 'Classic vehicles'.
I'm currently using M1 15W50. Is that basically the same thing but M1?
 
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Then you have nothing to worry about. The US ran cats for over 20 years with higher zddp oil and good part of that with pre cat o2 sensors (not that it matters) before anyone was concerned about cat poisoning.

I'm kind of surprised you have FI and VVT and a cat but no precat O2 sensor. Higher phosphorus wear additve oil will not hurt your engine, it offers more protection insurance. and 50W won't harm your VVT. It's a recommended grade.
 
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lol I may be wrong about the o2 sensor but the time i've owned the car I never seen an 02 sensor anywhere. (But then again I havent really tried to look for one lol.) I wouldnt be surprised if there isn't one lol. My automatic transmission doesnt even have a filter lol, just a strainer. Simplicity at its best.

Another quastion. I'm currently using M1 15w50 but the Castrol that they sell here is 5w50 (edge classic vehicles.) Which would be better for hotter climates?

Final question lol. Why would this type of oil affect whats coming out the tail pipe? I'm not burning or using any oil.
 
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Originally Posted By: N7Quarian
Another quastion. I'm currently using M1 15w50 but the Castrol that they sell here is 5w50 (edge classic vehicles.) Which would be better for hotter climates?


In my opinion the 15W50.

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Final question lol. Why would this type of oil affect whats coming out the tail pipe? I'm not burning or using any oil.


It's the concept maybe theory that phosphorus from the oil leaves a thin coating or somehow poisons the catalyst substrate. Of course if your consuming no oil to speak of it wouldn't anway.
 
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