How often to change oil with a synthetic blend?

[waxworm09]

I just started using a synthetic blend oil in my Tahoe and was curious how often you have to change the oil? It has 162000 miles right now, and I normally change it every 5000 miles with non synthetic, but I have heard you can go longer with a synthetic blend. Is this true, and if so how often should you change the oil, synthetic blend or non synthetic? Thanks

[Lip_Ripper Guy]

I would keep going with 5k.

[caseymcq]

I've been going every 10K with synthetic blend in my Mazda 3. I have been going to Valvoline for that because it is a little tight under the 3

I use conventional in my truck because it isn't a daily driver, just to tow the boat, hunt, haul junk, pick up wood, etc. My truck tells me when to change the oil so I just do as I am told there

In all of my vehicles I run a quart of Slick 50 every 50K. Every third or so oil change I also run a little Sea Foam through the oil about 200 miles or so before the oil change just to give the system a little "cleaning".

[waxworm09]

My Tahoe also tells me when to change the oil, I wasn't sure how accurate it is but I have 5000 miles on it since my last oil change and the change oil light hasn't lit up yet, that's why I was curious if I should do it every 5000 or wait the the oil light comes on. Ill probably give it about 2000 more miles and if the light doesn't come on by then ill change it anyways and use the valvoline synthetic blend.

[spearchucker]

I've been going every 10K with synthetic blend in my Mazda 3. I have been going to Valvoline for that because it is a little tight under the 3

I use conventional in my truck because it isn't a daily driver, just to tow the boat, hunt, haul junk, pick up wood, etc. My truck tells me when to change the oil so I just do as I am told there

In all of my vehicles I run a quart of Slick 50 every 50K. Every third or so oil change I also run a little Sea Foam through the oil about 200 miles or so before the oil change just to give the system a little "cleaning".

The Slick 50 is snake oil. I didn't know they even made it anymore. The Seafoam should also not be needed if you are running a good oil. Todays oil has lot of detergents in it especially if you are running a synthetic.

As for the oil change interval, every car and driving situation is different. The only way to know for sure is to send a sample of your used oil in for analysis. It is about $20 and they can tell you how much life is left in the oil and what wear metals are in the oil.

[Big Tom]

My Avalanche has 190K and I have always used Mobil 1 and changed at 5K.

[caseymcq]

The Slick 50 is snake oil. I didn't know they even made it anymore...

Don't get out much, huh? ...

You tweaked my interest. So I went on a search engine and looked at Slick 50. There were mixed reviews but seemed like a 4:1 ratio that said it really didn't do much. I have used the Slick 50 in few vehicles. One was a 2003 Impala that my wife drove 100+ miles daily. When we got rid of the car it had over 197K, didn't burn a drop of oil, ran like a top, started in any weather, engine sounded the same as the day she drove it off the lot, and it got 30+ mpg out of a V6 on a mid-size car. If it is merely "snake oil" and the vehicles I have just had coincidental luck so be it. It was a good luck charm worth the $10 After looking into it I am not sure if I will use it again the luck may have run out with the Impala

As far as the Seafoam goes you could be right, but in my experience, no matter what type of oil has been through the engine it still comes out dirty and looking at the cap and inside the valve covers I have still seen a bit of sludge in every vehicle. I use a relatively small amount of Seafoam just before an oil change. It definitely isn't doing any harm.

[muddpuppy]

I only use full synthetic oil I change it every 10,000 miles on the car and add as needed. I might add a total of 1/2 quart in that time. 07 Impalla with 120k no issues

I change the car and the truck at the same time everytime using full synthetic it might have 3000 one time and 7000 the next time. all depends on the time of the year. The car gets driven moore thats all I realy know 03 Silverado 120k no issues

[Jeremy airjer W]

In all of my vehicles I run a quart of Slick 50 every 50K. Every third or so oil change I also run a little Sea Foam through the oil about 200 miles or so before the oil change just to give the system a little "cleaning".

Slick 50 = snake oil

No cleaner of any kind should ever be needed when the oil has been serviced properly. In fact more frequent oil changes will do a much better and safer job of removing engine deposits than any oil system cleaner.

As far as mileage I'm not sold on extended service intervals. 5k is my magic number on the Tundra and that what I go by. To many manufacturers are running into sludgeing issues on there newer vehicles with extended service intervals. Volkswagen 1.8 turbo is the newest member to the club!

Not to mention that the oil leakers/burners usually have a history of anything but routine service. 8k or more between oil changes, engine oil is 3 quarts low, and the insides of the valve covers are caked with deposits.

I wonder why GM's are having all the oil consumption issues? could it be the 10k + mileage between oil changes that's actually causing it? Seems like the cars that stick to the 3-5k service rarely see these types of issues!!

[theoilman]

Some comments on Slick 50. What is it? It is a PTFE resin better known as 'teflon.' Many years ago the US Military did a very extensive test on it as an oil additive. About 1/3 of applications saw an improvement in economy, about 1/3 broke even and to everyone's surprise about 1/3 lost economy. Oil analysis wear testing showed an average of increased wear with the teflon.

What is it supposed to do? It is the same product used to coat teflon and silver-stone cookware. But with the cookware the metal is chemically cleaned and etched first, coated, then baked on at over 700 degrees. What part of your engine is cleaned and etched to prep the surface first? NONE! And almost nowhere is it baked on in your engine. Complete testing and teardown analysis reveals it actually does coat and buildup in two areas: 1. on the piston between the first and second compression ring. It builds up so heavy there that it restricts all oil from reaching the top ring to seal it that the top ring then shows accelerated wear along with the upper cylinder walls. 2. It builds up in lubricant passages where they make a junction or hard turn, building up a dam and restricting oil flow from going on to everywhere it is needed.

Another problem they cause, when left in an engine over 2000 or 3000 miles will cause breakdown into an acid which then means damage to all metal surfaces.

So, Slick 50 and every other PTFE oil additive (QMI to name another) are really 'snake oils' and will likely do much more harm than good in the long term.

NASCAR and other super performance engine builders do use it and similar products, but on a very selective basis. Most of what they do is for example clean, coat, and bake it on pistons skirts before engine assembly, and yes it does help them a very small amount.

Every engine oil on the market today is a complex blend of base stocks and additives built to work a certain way. Rust inhibitors, antifoaming agents, extreme pressure additives, friction modifiers, pour point suppressants, viscosity indexers and more all have to be very carefully balanced to work together. Are you a lubricant engineer? When you add something to your oil you are making yourself one. Do you know that the mix you have now put together is all going to work together properly?

[theoilman]

Oil Change Interval with synthetic blends comments. I don't know of any synthetic blend oil that carries an extended drain interval. Actually there are very few full synthetics that carry any extended drain interval. Other than AMSOIL there are two popular ones that do have an extended drain interval and they are very limited:

Mobil1 Extended (the regular Mobil1 is a standard OEM interval only) and Castrol Edge have very severely limited conditions on extended intevals - both say while vehicle is under OEM warranty and any severe driving conditions that you are NOT to use extended intervals with them (actually almost all (over 90% or 95%) of us in all parts of the country under severe driving. Do you do ANY towing? SEVERE! Extended idling? SEVERE! Short trips? SEVERE! Severe hot (over 90deg) or cold conditions? SEVERE!

There are probably some others to add to this group, but these are the 'popular' ones.

AMSOIL original family carries a 1-year / 25,000 mile normal or 15,000 mile severe interval for most vehicles. This is now being reduced in some engines that, as Airjer has pointed out, are known to be sludge problem causing engines, and in most of these the manufacturers have extended the engine warranties.

AMSOIL XL family carries an up to 10,000 mile with a recommended max of 6 months - in a full synthetic; while the newest AMSOIL family OE is a full synthetic with an OEM interval rating.

[theoilman]

Some engines with known sludging problems. (These are some that the vehicle manufacturers have recognized as having problems, there are more I am sure.)

VW/Audi 1.8 turbo 1998-2004

Chrysler/Dodge 2.7 V6 1998-2005

Dodge/Jeep 3.9 V6, 5.2 V8, 5.9 V8 1994-1999

Lexus/Toyota 2.2 1997-2001

Lexus/Toyota 3.0 V6 1997-2003

Saab 2.0 & 2.3 1999-2004

[1968]

The biggest problem with extended intervals is that many people don't even bother to check the level in between changes. Some manufacturers consider a quart of consumption every 1-2k perfectly normal, even on a engine still under warranty. Doesn't leave much in the pan after 5-10k if none was added.

Synthetic, which I fully endorse, only makes it worse as they think that oil is invincible.

[jeffreyd]

One should consult the manual before adding any additives to the oil. I was reviewing the manual for my wifes magnum with the 3.5l and it said do not use slick 50 or any other additive. It called it out just like that. I live in AZ, drive 100 miles a day and change oil every 10k. I run mobil 1 simply because i cant find an amsoil dealer here and dont want to pay for shipping. I converted the complete fire dept gas engine fleet to amsoil and also the police fleet for another city to amsoil. I swear by it. not a dealer just a user when i can find it.

[caseymcq]

... Slick 50 = snake oil ...

Not real sure if it was just an echo or if you are the day late and dollar short type...

I already took my flogging for suggesting Slick 50, thank you, may I have another sir. I looked it up and basically said, "Ok, I was wrong, disregard the Slick 50 suggestion. My bad." May I be excused from my duties as red-headed step child now?

[fishersofmen]

Slick 50 = snake oil....

Sorry I couldn't resist.

[Jeremy airjer W]

May I be excused from my duties as red-headed step child now?

Nope, you will now be know as the redheaded step child from now on! lol

[jeffreyd]

I have to admit that it did go from a simple question to beating up the kid that uses the goo! I apologize for my slam on slick50, i prefer stp lol

[mechanico]

Hello Waxworm09, Common wisdom is to change conventional oil every 3k miles, and synth. every 6k. BUT, that seems expensive. Do it anyway! I have had very good luck with just using the manufacturer recomended oil weight and replacing a quart at changes with a quart of RISLONE. I like Valvoline motor oil, but I can't really say if it matters as much as how often you change it. The "sea foam" is a BAD thing. Water is generally what causes that, however some of those additives may do it too. The problem with most additives is that they don't stay suspended in the oil. The Rislone stays suspended completely. It cleans and coats. I don't get sea foam, or any other wierd stuff in the oil of any of my three high mileage cars. I changed the head gaskets in my daughter's '98 Crown Vic at about 160,000 miles (it used to be my wife's) and it was clean as a whistle, except everything had a gold hugh to it...kind of pretty...but really clean. The real bonus is that the Rislone removes about 90-100% of that valve train noise. The oil light guy has a kind of a point. You can tell when the oil needs changed by the sound and subtle performance difference. Although I'm not sure I want to wait for the oil light to come on. You can't always depend on the pressure guage either, as it is rpm and temp. dependant. Just change it at recomended intervals and you'll be fine. If you don't you'll get valve train tapping or rattling and main bearings get sloppy, and pretty soon you'll cut off your mufflers and run straight pipes just to cover up the noise. An engine will run quit a while with loose bearings and valve trains, but they will get smokey and die a horrible death eventually. Remember Rislone.

And have fun with your beast.

[caseymcq]

I have to admit that it did go from a simple question to beating up the kid that uses the goo!

I log on and the first three posts I read just about had my pop squirting through my nose. ... You guys...

I don't mind takin' the whoopin'. If I am wrong, I am wrong and I learned something out of the deal. No more wasting $10 - $15 every 50K for me.

Good thing Santa stopped by my house before he headed south to you guys. He said he had been reading the thread the last couple days and thought you guys were a little mean ... He was going to throw a lump of coal in your stockings but we have three vehicles that are due for an oil change so I gave him something more appropriate he will leave for you...

Merry Christmas! And I hope Santa gets you some good stuff too

[Jeremy airjer W]

Good one!

[deadeye]

I just don't see why people don't want to change their oil at 3-5k. It gives you a chance to give the vehicle a good once over and see if there is anything else going on with it. Brakes, tire issues, air filters, tune up stuff, belts, and tons of other stuff should be checked. If you do that at 3-5k you can usually stay on top of the other stuff better.

IDK I guess I always do the oil changes on a Saturday morning and give myself the rest of the day to take care of stuff I notice going on. If there is nothing else to worry about then I have a bonus day for fishing. PLUS, its really easy to do and doesn't take long, and doing that at a regular interval is so much better for it, even with synthetic.

As far as the additives, take or leave them as you like. I don't usually use them but on occasion with sticky lifters/cam followers I like sea-foam or cd2. I don't really see a reason to use them for any other reason but if it makes you feel better then go for it.

[quickfish6]

i just say change your oil at 3k no matter what kind of oil you run cause oil is cheaper than an ENGINE!

[dougger222]

Last oil change put syn blend rotella in the F350 and rather than running 10K miles on conventional may go to 15K miles. 193K miles

The F250 runs Amsoil and gets new fluid every 25K miles. 294K miles.

The Excursion runs Rotela syn and new fluid every 20K miles. 222K miles.

All are 7.3 and never had any motor work...

[Red Cabin]

I've been using Schaeffer synthetic plus since my 01 Silverado was new, 10-12,000 intervals and no engine problems yet at 195,000 miles!