Oil---Best to use in 100k+ engine?

TVST*R · Post by **TVST*R** » Fri Aug 18, 2006 10:28 pm

I am posting this question so we can all weigh in and then others
can search it.

My milage is 109K here in SoCal....What is the best oil to run in it?

What are the pros/cons of running staight 30 weight?

How about Castrol 20/50?

10/30?

I don't want to discuss Synthetics here as I am not switching...not
on the Fiat and not on the Mercedes.

Thanks!
T

racydave · Post by **racydave** » Sat Aug 19, 2006 8:20 am

I wish I could go a straight 30, only if I lived in socal. Im usin 5w3o val syn blend to replace all syn used by po. Someone will tell you different, but I would not go to 50w unless my rings were worn. If you are not using oil, stay thin! just my opinion, .....D in I

Mark_vaughn · Post by **Mark_vaughn** » Sat Aug 19, 2006 9:10 am

I am using 15w40. I read somewhere that it was original recommended.

Mark_vaughn · Post by **Mark_vaughn** » Sat Aug 19, 2006 9:10 am

I am using 15w40. I read somewhere that it was original recommended.

racydave · Post by **racydave** » Sat Aug 19, 2006 10:02 am

Multi viscosity oils have a added "modifier" to achieve a viscosity range. My personal view is your basic protection lies in the base oil. 10w 40 (or 15w 40) was a recomended oil in the late 70, early 80s. GM never recomended it. Since then on newer engs it is not a standard. This is just my opinion, education is a ongoing kind of thing. D in I

Jim DeShon · Post by **Jim DeShon** » Sat Aug 19, 2006 10:18 am

In a Fiat, I would say in most cases 10w40 of 15w40. I ran 20w50 in my Fiat for years but, I live in the California desert where it tops 110deg. in the summer and below 20deg. in the winter. I felt I needed a little better hot weather protection than usual. I also commutted 2 hrs. each way in that enviroment so, heat could build up quite a bit. If in doubt, go by what Fiat recommends. I would not use synthetic in this car. The Fiat engine is an older design with loose clearences. It was not designed for that thin oil. Just one opinion. ...J.D.

mdrburchette · Post by **mdrburchette** » Sat Aug 19, 2006 12:16 pm

I use straight 30 in engines with excessive miles and 10-30 in my newer ones. I've never had an oil related issue, but the temperature here hardly ever goes below freezing or above 95 degrees.

Jim DeShon · Post by **Jim DeShon** » Sat Aug 19, 2006 2:24 pm

Any time we deviate from what the factory says, we are in effect saying "I know more than the factory engineers". You are then, on your own. I do it at times but only with caution. With oil, I would err on the safe side i.e. thicker oil. ...J.D.

So Cal Mark · Post by **So Cal Mark** » Sat Aug 19, 2006 3:47 pm

we've all sworn at the factory engineers over the years, I know I do almost every day

Operating temps are an important factor that few people pay attention to. Most new cars recommend 5w-20 oil, until you read the manual and find out that it only applies to temps of no higher than 60F. The manuals also don't take into consideration engine wear. I agree that thicker oil as the engine wears is a good thing

vcg · Post by **vcg** » Sun Aug 20, 2006 5:22 pm

I like 15-50 Mobil 1 full synthetic in Fiats. Also Selenia Racing 10-60. Both are excellent for worn engines (and racing). They are thick, and maintain high viscocity at high temp.

vcg · Post by **vcg** » Sun Aug 20, 2006 5:22 pm

I like 15-50 Mobil 1 full synthetic in Fiats. Also Selenia Racing 10-60. Both are excellent for worn engines (and racing). They are thick, and maintain high viscocity at high temp.

vcg · Post by **vcg** » Sun Aug 20, 2006 5:23 pm

I like 15-50 Mobil 1 full synthetic in Fiats. Also Selenia Racing 10-60. Both are excellent for worn engines (and racing). They are thick, and maintain high viscocity at high temp.

Jim DeShon · Post by **Jim DeShon** » Sun Aug 20, 2006 5:38 pm

The Mobil synthetic you mention would probably work great. Only problem is, I haven't seen the thicker synthetic oils on the market here in the western US. Maybe someone else knows where to get them here ?? ...J.D.