Taxi cab runs 20w50

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Staff member
May 27, 2002
Guelph, Ontario
I just got back from a business trip to Montreal (beautiful city, beautiful women!) [Smile] and when I grabbed the cab from the airport, I noticed that this Malibu had quite the noisy engine. It was ticking noticeably at idle, and even louder when moving. Being the oil freak that I am I couldn't help but wonder what oil he was running. I got my answer when I arrived at the hotel! When he opened the trunk to get my bag, I saw a bottle of Castrol GTX 20w50! I guess that thick oil isn't so great for engine longevity after all is it? [Wink] In all fairness, I didn't see the mileage on this cab, so who knows, it could have had 500k for all I know.
Actually Patman, I'm starting to get the feeling that viscosity, like oil type, doesn't really seem to matter as much as regular oil changes and having no defective parts from the start. I, personally have seen 5W30 go to high miles and have heard of 20W50 and everything in between doing the same. I've also seen engines pack up in short order on each different type. I'll stick with my middle-of-the-road philosophy and use 10W30 or 0W40.
Of course I'm not in Canada, but in my Quick Lube Facility we put 20w50 in all taxi's. They are imported with over 120,000 km when they no longer pass emissions in Japan, so the average is probably around 200,000 km. Know one knows for sure, because if they actually convert the dashboard to the left side they often leave out the longer speedometer cable.
Patman, more likely than not, the use of the 20-50 you saw was to prevent/offset a quart a day (or so)consumption that that particular cab was seeing....ticking or not...
You're probably right Dr.T. I wonder if the cabs get maintained on a regular basis or if the drivers decide on that?
FWIW, when a TV news magazine did a story on motor oils and thier effect on engines, they used NYC taxis as the test vehicles. It has been mentioned more than once that the test was not a good barometer, as the taxis were always in service. That is, very few cold startups. Could it be that 20w-50 is a good match for such activity?
I still think the 50wt oil is probably too thick for most of those cabs, especially ones like the Malibu I was in, with it's smaller V6 engine. An older cab with Ford's venerable 302 might like 50wt oil though. I'd probably run 15w40 oil if I had a cab company.
I think you'd run the 15w40 until you found your cabs using oil between changes and possibly getting dangerously low between changes, with stupid drivers that don't check the oil regularly. Then you would put in 20w50 to add a measure of security.
Actually something like NYC taxis are good barometers. Potentially there's plenty of them to potentially provide a good statistical basis. Also idling and slow stop and go traffic is among the most grueling environments for oil. It may be counterintuitive (sort of like the hot southwestern US is the hardest on batteries) but that's what I've always understood.
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