oil... what's really the right one?

Hello group,

Now that spring has started it's time for my annual oil change on my LeBaron Sedan (known as Saratoga over here in Europe) and so I'm again at the point to decide which oil is the right one...

The situation I'm in is quite difficult since everybody recommends different oil.

The cars manual says that SAE 15W40 would be best, but 10W40 acceptable. My chilton repair manual doesn't even mention 15W40 but recommends 5W30 or 10W30 and reading different sites on the net doesn't help but confuses even more.

Well, 15W40 is quite thick where 5W30 is one of the thinnest I know... 10W40 is somehow the standard oil here in Europe and I have been using it. But now it seems as if my engine gets old and especially the steadily intensifying noise and rattle coming from the crankshaft make me worry. I don't want to buy a rebuilt engine before this one isn't completely worn out and to extend its lifetime I'd like to have your help now for choosing the right oil.

My engine is the Chrysler/Mitsubishi 3.0l V6 and I use to drive about 5000 to 8000km a year, mostly very short distance with cold engine. I know that's not the best thing to do with a car, but I can't help it atm. I reside in an area with normal winters (say -10°C) and warm summers (20 - 30°C). Changing the oil once a year must be enough (changing it all 2500km would be a little overkill I think) and so I'm looking for something that's good for all seasons....

So what would you recommend? Experiences?

By the way, what does the US manuals say regarding the oil?

Do you know the Castrol Magnatec oils?

Best regards,
Matt

My recommendation is Mobile 1 synthetic - in the states, that comes in 10w30 and 15w50. I use the 15w50 and got 180,000 on my 3 litre before it blew a head gasket, and over 200,000 on my S10, still not using oil when I sold it at 225,000 miles. The Chevy 1500 has 195,000 on the same oil. It doesn't burn oil, but the old 350 has the usual rear main seal seep.

I live in a warm climate, north Florida, and I change the oil at 6,000 miles, rather than the 15,000 miles recommended by Mobile.

I started using a 15w-xx oil in the '80s at the recommendation of a mechanic that rebuilt a Nissan engine for me, and have had good sucess. The 15-xx mineral oils have less ash (maybe not an issue with synthetics), and I recently saw another rating showing 15-xx oil as superior.

Only question would be if it's appropriate for a cold climate, especially for protection during warm up on -degree days. Because of my sucess, I would use the 15w50 even if I lived in Alaska, but would maybe do long warmups of 5 minutes or more.

I would never use a 15W-xx oil in cold climates, to take Alaska for example, a 15W-xx oil would be like thick honey in that climate and would take forever to get circulating inside the engine providing it even starts due to the heavy drag from the oil pump trying to force the thick oil through the engine, hence why an engine turns over slower in cold climates. Whereas a 5W-xx or even a 0W-xx oil would be a lot easier to get circulating through the engine on a cold start in cold climates.


As the original poster already admitted that the car never really gets warm, that is the worst thing for an engine, oil really doesn't have good lubricating qualities until it is warmed up, but "warmed up" does not mean the engine coolant is at or close to operating temperature either, the only real way to tell is with an oil pressure gauge, the engine oil is considered warmed up when the gauge lowers closer to it's normal pressure reading when the engine is fully warmed and at idle. Running an engine on short trips and never fully warming it up is considered "severe duty" service and dictates more frequent oil changes than an engine that sees a lot of highway usage. Sludge buildup is also more common in engines that run a lot of short trips compared to engines that see a lot of highway use.

You know what? Oil grades are so confusing. First of all, as we all know, oil gets thinner as it gets hotter, you can't deny that. And W stands for winter, the W number apparently means that an engine can pump it as well as a single grade oil of the same number grade, in winter. And as the grade numbers get higher, the viscosity gets thicker. So 5W-30, this means that in winter, cold engine, this oil can be pumped as well as SAE 5 in winter. And 30 means the viscosity at about 200 degrees F, engine operating temperature. But SAE 5 will be a thin oil, whereas SAE 30 will be a thick oil... so what these SAE fools are trying to say is that oil is thin in the cold and thick in the heat? That doesn't make sense. Sometimes people are just in their own little worlds when they create such common standards. Because an oil would really be like 40W-10, wouldn't that make more sense? Irregardless, I am assuming that 5W-30 and 15W-30 oils will both be about the same viscosity in a warmed up engine, correct? And that 5W-20 and 5W-40 will be about the same viscosity in a cold engine, correct? So, a lower W number means a thinner oil in a cold engine in winter? And a higher second number means a thicker oil in a warm engine? I suppose this confusion comes from the fact that single grade oils are measured at operating temperature, not in cold.

http://en.wikipedia.org/wiki/Engine_oil#Single-grade

Dump 5W-30 in your engine if you plan on not warming up your engine in the cold. Or perhaps 5W-40.

Heya,

Well, thanks for the replies! I decided to go for the valvoline Maxlife 5W40 and want to share my experiences with you:

At first the engine was definitely easier to start - an effect that's nearly gone now, about a month after the oil change. It's not that my engine starts up hard now, but I did recognize a difference.

The next thing is that I had a quite intesive rattling noise from the valves before which didn't disappear, but softened a bit. Unfortunately the whole engine got louder and I guess that's because the oil is a bit thinner than the 10W40 I used before.

With regards to fuel efficiency I cannot say anything yet because I do have a better fuel efficiency now, but I guess that's because I was driving some quite long tours during the last weeks which I did not do before.

So well, all in all I cannot complain, but I also didn't experience any wonders (like special supplements in the oil sealing up my valve covers...

Next time I'll definitely go for Maxlife 10W40 (or maybe even 15W40 if I can get one) HC-Synthetic. I hope this will make my engine run smoother and quieter again.

Regards,
Matt