oil & oil filter

Hi everyone;

I have a 97 SL, 130000 km (81250 mi). I have been having the oil changed every 5000 km (Castrol 5w/30w) Last change I went for Mobil Synthetic. Noticed a smoother run (maybe it is a subjective perception of mine). Question 1: is it advisable to extend to 10000 km the interval of oil changes with synthetic? Question 2: from browsing this site, I learnt that Fram is a no-no in oil filters. Everyone advises against. So, for next change,which filter brand do you think would be better: Quaker State?, Valvoline? or, the Fram Synthetic? The price difference is not an issue, the life of the engine is. Thanks in advance for all your comments and suggestions.

danielR.

How about an AC oil filter? What novel concept. Using what the manufacturer uses.....

And stay away from the $ynthetics. No need.

The use of synthetics is a decision that is the result of variable factors. It isn't necessarily a simple decision.

Ken

What Napalm says. I run Mobil1 in my SC and have in every car I have owned. (I dont need to but I also notice a smoother running engine with less oil burning in a twin cam) I am a firm believer however in changing your oil every 3K miles or 3 months, whichever first, always, no matter what. Nowadays wi newer engines, such as the ecotec which has an oil life indicator, you can go a little further, but never more than 3-4 months to keep a happy engine.

Nothing wrong with the OEM filters, fram is definately a no-no. I use K&N filters, quite expensive, but so are oil related problems, so it's extra peace of mind for me.

marx404

Probably not.

Proper oil drain interval is a function of usage. The most extreme operating condition is infrequent use involving short trips in stop and go city traffic, especially heavily loaded or on hills or in the wintertime. Operating in a 'spirited manner' with high engine speeds makes the former even worse. The engine never gets a chance to boil off the moisture and fuel and combustion by products. In this type of service, synthetic oil will help with the 'spirited' driver but it will become contaminated just as quickly as petroil and the only way to keep the oil contamination and breakdown under control is with more frequent changes. I would suggest 2000 mi/3 months. Heated garages and block heaters will help (but not solve) for cars in this severe usage. Very hot climates can also require shorter drain intervals but I have no experience.

The gentlest usage is daily runs on the highway (steady 2300-2800 rpm) where the engine gets a chance to operate at full operating temp for an extended period of time. The oil (and engine) will last much longer in this type of service. (Block heaters, proper warmup and covering the front of the car in the winter will help to keep the engine at full operating temp.) Saturn approves extended drain intevals up to 6000 mi in this type of light service but in my personal experience and after several oil analysis, I have found that (in my personal service and 160,000 mi engine) the best drain interval seems to be 3500 mi, after this the (good quality premium petroils) seem to suffer from viscosity breakdown and seem to get thick and black.

As oil begins to break down the consumption rate (personal consumption rate ~1300 mi/lt) goes up and you will notice that you need to add the second liter after fewer miles than the first needed addition. I wait until I am down to the add mark (never below) and if I am over 3000 miles I just change all of it. I do notice higher consumption rates with Quaker State premium or other standard quality bargain oils.

I buy both my (good quality premium) oils and (standard quality) filters by the case whenever I find them for sale at a great price. I have no brand preference. Oils are often used as loss leaders at grocery stores and Wal-Mart so when the price is right I buy several cases. I use 5w30 year round.

Filters are usually purchased from automotive jobbers and there is a huge price difference that never has anything to do with quality. Sometimes big box stores have good price but not regularly. I now have a good source for Wix filters which are reviewed very highly but I never pay extra for premium priced filters. I always change the filter at each change and always curse the fool engineer who placed the filter in a location where it is hard to reach and (since the drip gutter is too small) always leaks oil on the halfshaft and the frame. The only solution seems to be rags and cleanup. I save my old filter so that if I have any engine problems I could go back and cut the filter open for inspection, but I do not normally inspect the filter.

IMHO synthetic oils are not cost effective and I prefer to use petroil (buy smart) and change more frequently. The place where synthetics really shine is in extreme low temperature service (as they do not thicken as much as petroils at low temp), especially if it is not possible to plug in an engine block heater.

Just my .02 YUMMY

I like Mobil 1 oil and PureOne Oil filters for my 3800 and I just change my oil and filter every 4000 miles. I could go longer on the oil for sure if I racked up more miles in a shorter amount of time to burn off moisture and gas in the oil. I take 1+ hour trips when ever I can just to burn out contaminants. As oil advances so do filters. If a filter captures more dirt, it clogs up faster. Good filters shouldnt be of much use after 4000 miles.

Thank you very much for all your comments and suggestions. Based on the folowing facts: I live in Toronto, Canada, and operation under cool temperatures is an important factor, Most of the filter brands you mentioned in your replies are well considered in a site dedicated to oil filters comparison :

,but in Toronto I only have access to Fram, Valvoline (designed by Purolator people), and Quaker (Fram disguised under different name).

I will go for Valvoline.

Regarding the type of oil and frequency of changes: I will remain with synthetic. Now, at onset of Spring, will stretch the synthetic I have to 6400Km (4K miles), but in Winter, I believe it will make more sense to change every 3K miles (approx 5000Km).

Thank you all again.

danielR