Oil Weight

[GDawgC220]

hey guys,

just had my oil changed (on top of a few other things)...they put in 20w-50 Castrol GTX this time...I don't think i've ever used this weight before. Usually, it's always 10w-40 Castrol GTX or 10w-30.

Is there any performance difference in using the heavier weight this time around? Is it better for the summer time because of the hotter weather?

Thanks, I'm trying to understand more about this difference between oil weights and climate :)

[Andrew C280]

after phoning mercedes benz canada and talking with a few different techs and engineers, they has emailed me a list of oils that are to be used in my car, my dealer was saying 15W-40 which i had know idea why they would use that long story short i am now running 10W 40 quakerstate thats what they recomended and i think 5w-40 for winter, heres the main reason they said to run 40 weight oils instead of 30 or other is that i can get past the gaskets in the engine which was leading to head gasket failure and some other B.S, sound like the oil there useing in your car is for a disel engine, the oil my dearler was using was for industrail engines and generators tractors and cat equiptment. you can feel the different when you use the correct oils in the profromance of the engine yours might feel like its strugleing when accelerating until the oil get warmed up properly

long story short i wish i could find someone who caries mobil one synthetic in 10W-40 in my area i did run synthetic in the car once since the guy who sold it to me put it in and the engine was much smoother and more powerful.

any ways just my 2 cents call up mbusa and get there oil list

[GDawgC220]

i just called up the dealer to make sure they didn't make a mistake in the oil weight :p

he remembers my car and they run 20w-50 in the summer time for non-syn oil cars.

reason being it's suppose to be better in the summer time with the higher heat, 20w-50 is better for the engine. When winter rolls around, they don't run that.

These guys (independent dealership) have been around for a LONG time and are very knowledgeble about MB...so I think i'm in the OK.

[Andrew C280]

I would still phone or get in contact with MBUSA and get them to send the list of recomened oil becasue those weight wont be on the list. do you have a starmark or other warrenty? because they are very specific when it come to claims with the engine when you dont run the recomemed oil.

[GDawgC220]

nah...my engine is 10 years old with 143k on it :p

headgasket's been done already and everything is in good condition. I'll monitor the car see how it runs and stuff...so far so good.

thanks :)

[Andrew C280]

ah you i did not relize that your car had that much mileage there probally right then using thicker oil, because tolerances have mostlikly worn down

[GDawgC220]

lol, yeah, it's got a bunch of miles but still runs awsome :)

usually they use 10w-40 and it's been fine, no leaks or anything, so i was just questioning the 20w-50.

[fastmayte]

hey, yea 20w50 is good for older engines, but how'z the heat? does the engine heat up more? mine runs at around 100 with teh a/c on and in traffic, 90 on the freeway. sometimes 110 in traffic. nothing over. outside temp is around a 100 too. i wonder if the 20w50 runs cooler than the 10w30 mobile i use. i do get alotta leaks. mostly around the oil pan and a small area ont eh head gasket that i've had for about 17k miles now.

[jlomon]

I run the 20w50 from May to September, and 10w40 for the rest of the year. I can tell you straight up that the car runs cooler in the summer with the 20w50. I especially notice it when I've run the car on the highway for a while, and then get in to stop-and-go city traffic. When I was using the 10w40 in the summer, the engine temperature would creep up faster when I was stuck at a light or in traffic. With the 20w50 the needle moves up, but not as fast.

My C280 is a 1994 model with about 85,000 miles on it. If I was running synthetic, I would be fine running the 10w40 all year round, but I'm not sure I'd want to run the 5w40 or 5w50 synthetic options I've seen. I'd be worried that the thinner synthetic oil would lead to the oil seals wearing out prematurely, especially on an older engine.

Jonathan