Change your oil

[L-10_shooter]

I am a mechanic and hate to see cars come in with 5000+ miles on an oil change. I am building a smallblock chevy for a friend and found a perfect example of why you change your oil regularly at 3000ish miles.

This is before I touched it.

This is after I cleaned out most of the gunk out of the lifter valley.

Edited May 13, 2009 by L-10_shooter

[3GunF1Guy]

That looks like WAAAYYY more than 5000 miles between oil changes.

Looks more like Penzoil at 10k

or Valvoline at 50k

Scott

[HSMITH]

I change my oil every 7500-10K and have NO sludge at all. The only sludge I have ever seen like that was LONG change intervals with Penzoil and engines that were running extremely hot back when I wrenched on cars to pay bills. They usually had 3 or 4 bottles of Barrs leak in the radiator, oil changed yearly whether it needed it or not with the Penzoil, and a LOT of other problems.

[j1b]

I go every 6,000 but I use synthetics. Figure that should be better.

Am I mistaken? I don't use a blend either, just full synthetic.

Jack

[38supPat]

I use synth, but stick to a 5000km oil change anyways, you can't over oil change a car. It may cost more at first but you save in the long run, my engine has 325,000km on it and still runs like new. I've done no major work to it, just change oil and the spark plugs once a year.

[gino_aki]

Doesn't look like it got much cooling system service either.

[al503]

There is a big difference in tolerances between a small block and current engines. If you plan on keeping your car for ~4-7 years, follow the owner's manual. If you're planning on keeping the car for an extended period of time, then send a used oil sample to blackstone and get it analyzed. They'll give very good guidelines in terms of how long you can go between changes.

3K miles between changes in a modern engine is usually overkill unless you're driving in very dirty/dusty conditions or driving a taxi in NY.

[L-10_shooter]

Doesn't look like it got much cooling system service either.

Good observation. I found clots of dirt in the cooling jackets.

I change the oil in both of my cars by color not mileage. I have a 93 ford, cough, and an 02 intrepid that get an oil change when I cant see through the oil to the dip stick. The intrepid gets full synthetic and I only use K&N oil filters, they filter down in the 15-20 micron range. I would say they get changed every 2500-3000 miles or so.

Carbon gets past the rings through blow by and builds up in the oil, wait long enough and it starts sticking to the block and heads and building up. Doesnt matter what the clearances are, all internal combustion engines work the same. I have changed the oil on some newer cars that look like and have the viscosity of crude oil, nasty!!!

[colt]

I am a diesel mechanic , They sell filters to add to trucks and say you can change the oil every 100,000 miles . I should send them a thank you card for all the work I got from them . One guy took it a step above that and had 2 filters added to the truck and when I rebuilt that engine the oil was like at 200,000 miles on it. The crank showed it , the sleeve's were all scored lightly , not normal for a engine with the same miles.

Just got done with a truck that had 1,300,000 miles on the engine and they changed the oil . It look good in side of it except for the valve that put a hole in the piston.

Most of these people bought the truck around 600,000 or so on the engine and put this filter on it and tries the 100,000 oil change and next thing they find is it starts using oil and doesn't stop.

I don't have a lot of faith in oil samples . We have sent 2 sample's out of the same oil to different places and they come back one is ok and the other has a problem in the engine. Out of all the one's that came back with a problem only one wanted to tare it down and find it . The rest just worried out about it till it showed up or sold the truck.

Brent

[BigTinVA]

I see that there are not many Penzoil fans here...

[kgunz11]

My 2008 Chevrolet says not to change oil until 5,000 miles. The quality of the oils being produced these days are suppose to support that. In my PowerStroke I only changed the oil every 6,000 miles using Rotella. My Dad is trying to drive the tires off of a 2003 Z-71. He has 283,000 miles and every part on the truck is original except for the tires, breaks, air and oil filters. He changes the oil every 5,000 miles, which is about every 3 months for him. In his defense, he is NOT an aggressive driver.

[L-10_shooter]

To each there own but I do what I can to make them last longer and run better.

Its kinda like what load do you run in your gun, the one that you like.

Edited May 14, 2009 by L-10_shooter

[kgunz11]

What evidence do you have that oil breaks down after 3000 miles? If it's a bad practice to go so far between oil changes I certainly want to change mine more often. I am no mechanic, and it's been about 5 years since I was inside of an engine block, but that would not be a fair comparison as it was a 68 Camaro convertible rescued from the weeds.

[HSMITH]

I run periodic samples, and my little inline 6 holds 3 gallons of oil, so my case isn't exactly the same as most of you. If you do a sampling program it will take time to get enough data to form any conclusions unless the sample is full of coolant or something similar. BUT, when you have 4 or 6 samples to trend you will be able to form a reasonable conclusion from it. If the oil is still good you can extend the interval, if the oil is tired you might want to pull the interval back, if you see silica you might want to look at the air filtration, things like that.

One oil sample analyzed is akin to looking into the toilet and judging how healthy you are.

[el pres]

I work with a certain highline luxury make and our oil changes are schedualed by the vehicle at

roughly every 10,000 miles, depends how you drove the last 10k, only Mobil 1 full synthetic will do.

Now here's the best part, some people get so used to the fact that they dont have to come in

for a service that when the 10k service reminder alarm and visual picture comes on every time they start

the car, they just countinue to ignore it. At around 18 to 22k the engine usually looses a ring

or drops a valve at which time they come to see me for warranty repairs. Punchline comes when they find out

that they have to buy an $8000-30000 engine + labor, (out of pocket) for the vehicle their leasing !!

As a proffesional here's what I have settled on:

Mobil 1- great stuff, run most engines on it 5000-7500. I'm overkill but I run all of mine on Mobil 1 at every 3000-5000...

Castrol GTX - Great conventional stuff, run this every 3000-4500 worry free !!

Edited May 14, 2009 by P.Pres

[KenOrris]

Does anyone remember when Mobile ! synthetic came out? I think it was in the 70's, they claimed you could go 30,000 without an oil change. I bit, but after 10,000 miles I couldn't stomach how dark the oil looked, changed it and went back to the old stuff. I thought with that much contaminets in it, it had to be doing damage. I go by how dark the oil looks on the dipstick.

[SLM]

Man that's just NASTY! I've seen cleaner blocks pulled out of "dead" junk yard cars showing 100K plus on the odo. It's not just Pennzoil that will do that. Quaker State is notorious with the local mechanics. To this day several that I know won't touch the stuff do to the crud it likes to leave behind... and I've seen those.

Modern engines fit tight but they run hot, very HOT. We have the EPA to thank for that. The heat produced by a modern engine will destroy modern conventional oils. In my car that takes less than 2,500 miles freeway and between 1,800 - 2,000 city. I feel sorry for gas engines that people leave the same (conventional) oil in more than 2,500 miles.

We changed the oil and filter in our race car every 25 to 30 miles and that takes 9 quarts!

[L-10_shooter]

Its not that the oil breaks down, which it will eventually. The problem is all the carbon that gets past the rings gets into the oil and acts like sand paper. In that motor I tore down several of the rod bearings had good sized grooves in them. That abrasive is what kills the bearings then rods knock or leave the block, etc. etc. When the oil gets changed, the carbon and such are drained out.

[boz1911]

This thread reminded me it's time to change my oil..

[Sherwyn]

Don't believe you will break down synthetic oil in 5,000 miles (probably a lot more), but the contamination will get you.

I run Mobil 1 to 5k, but change the filter at 2,500 - yes it probably is overkill, but cheap compared to repairs.

Sherwyn

[Fireant]

All I can go by is what has worked for me. In my 1998 Dodge Ram I put Mobil 1 in from the get go. I change the filter at 5K and the oil and filter at 10K When I traded it in 10 years and 175,000 later the engine ran just as smooth, quiet, and cool as the first time I drove it. My 2006 diesel gets the same type of changes. The manual calls for 7500 change interval with conventional oil. I switched to synthetic at 50K and now do the same filter at 5K and oil + filter at 10K. I'll check back in on this thread when I hit 500K

[davidwiz]

A lot of the newer european cars say change the oil every 15k miles (using synthetic like Mobil 1).

[al503]

A lot of the newer european cars say change the oil every 15k miles (using synthetic like Mobil 1).

I think many of those manufacturers (BMW for one) are also providing 'free' maintenance for the first 4/50K miles. Good synthetics could possibly last that long. It's the filter's capacity to go that long that's questionable at best, IMO.

[Carlos]

A lot of the newer european cars say change the oil every 15k miles (using synthetic like Mobil 1).

It was a no-brainer back when I leased a 3 series BMW - the car had sensors that measured the precise interval for the oil change (full synthetic of course). Based on my driving, the correct interval was just over 14,000 miles. I leased for 2 years & did not ever have to bring it in for oil change #2.

BMW has the answer: the interval should be measured individually by each and every car as no two are alike, nor are they driven alike.

[el pres]

A lot of the newer european cars say change the oil every 15k miles (using synthetic like Mobil 1).

I think many of those manufacturers (BMW for one) are also providing 'free' maintenance for the first 4/50K miles. Good synthetics could possibly last that long. It's the filter's capacity to go that long that's questionable at best, IMO.

The filters on these vehicles have been repeadatley updated to a fleece wraped design for just that reason. The 10-15k

oil change is doable but extream and mostly a marketing tool to sell cars. I have seen many engines maintained at 10k

intervals with over 200k on them and no internal repairs. However, many did not fair that well with oil burning being the

#1 problem. The thing with a 10k interval is that it is so close to max that too many variables come into play. Yes, if you use

only Mobil 1, and the special factory filter, and perform the service not one day after the service counter activation, and

you drive on normal roads with normal driving conditions, then everything should be just fine.