DFWmax

sounds like a silly question, but i don't know the answer..... does oil run out when you take off the oil filter? i don't mean the amount in the filter, but like the rest of the oil in the pan?

i have always changed my own oil, but i always drain the pan first. my new driving pattern means i do about 500 miles a week (virtually all hi-way), so at a 5000 mile interval, that means 10 weeks (2.5 months). I have always been running redline, with it being expensive, I am thinking that since I almost exclusively drive the highway, I can push the oil to 7500 miles, with a 3750 oil fileter change.

so i pull the filter at the 3750 interval, will a lot of oil come gushing out of the filter connection? i know i have to top off the amount lost to the filter, but should i expect to lose more than a quart?

on the same topic, anyone have comments on oil bypass filters? what about oil coolers? do i need one since i drive about 100 miles a day at 75+ mph?

thanks for any info.

tommy

breaux124

iTrader: (1)

Some oil will come out, but not that much, because the filter sits relatively high in the oil pan. You should be ok with just changing the filter, but still have a few rags on hand.

Daniel B. Martin

You will get the same amount of "spillage" as after you drain the oil pan. The amount that comes out -- only a few ounces -- is about half the volume of the filter shell plus the volume of the engine oil galleries which are above the filter.

Do the math. Figure the cost over 1500 miles. You are balancing the cost of three oil filters plus three oil fills versus six filters plus two oil fills. I bet you will decide to stay with your 5K oil-and-filter change.

You need an oil cooler if you do most of your driving in mountainous terrain, hot (100+ degree) weather, or towing a trailer.

DFWmax

hmmm, here's my breakdown of the cost. i get redline for $8 a quart, and each oil change is 4 quarts = $32 for oil. I think the filters are about $4 a piece.

extended interval -- 2 oil + 4 filter = $80

regular interval -- 3 oil + 3 filter = $108

so the "savings" is $28. not a trivial amount, but also not a *big* savings... i could put an extra $28 into the car every 2.5 months.

what about if i went to 10,000 mile intervals with filter swaps at 5k?

10k interval cost -- 1.5 oil + 3 filter = $60

daniel, do you think 10k is too long a interval? i know that the manual has two oil schedules - 3k and 7.5 k.

thanks for you comments...

tommy

Daniel B. Martin

Yes, 10K is too long. Engine oil is replaced for two fundamental reasons: breakdown and contamination. A superior oil may last longer before it deteriorates. However, all oils become contaminated at the same rate. A good filter will trap solid particles but the traces of water and acids accumulate with time and mileage. If you are sufficiently pressed to save $28 per 15K miles, just switch back to standard engine oil.

Here's another opportunity for savings. This on-the-napkin analysis assumes fuel costs $1.50 per gallon. If you are now getting 28 mpg, your fuel cost for 15K miles is $803. If you can do anything to improve your fuel efficiency by only 1 mpg, your fuel cost for 15K miles is $775. That's the same $28 saved, without the time and trouble of extra filter changes. Think about it.