change interval synthetic

   / change interval synthetic #1  

big bubba

Elite Member
Joined
Mar 7, 2007
Messages
2,753
Location
arkansas
Tractor
M8540
i use rotella T6 in all of my 4 cyl vehicles (gas) ranging 15-20 years old, very pleased with it, no issues. oil consumption is minimal, engines in good shape, oil starts to turn dark around 2.5K. my question is frequency of engine oil change. currently do filter/oil change between 5-6K and realize the best answer to my question would be to get an oil analysis, but defer to the forum expertise @ this point. I've read 7-10k for synthetic are more the norm. My question is on smaller 4cyl engines, is it advisable to change more frequently than the std 6-8 cyl engines most americans use. other than oil analysis what is your take, am i overkill? thx in advance
 
   / change interval synthetic #2  
In my opinion 4,6,8 cylinders makes no difference. I've never seen an oil change interval recommendation that differentiates by the number of cylinders in a vehicle. Gasoline engines that I am familiar with recommend 7,500 mile oil changes under normal driving conditions.
Oil color has nothing to do with whether it is still viable oil doing it's job of lubricating properly. That oil color darkness comes from suspended particles in the oil held there by the detergent additives. They are then removed with an oil change instead of settling on parts or the bottom of the oil pan as they can with a non- detergent oil.
If you want to change oil at 5-6K, have at it. Since you use T6, as I do, just use that extra useful mileage as a cushion to change oil at a more convenient time for yourself. Example, You hit 6k but will be putting 1,000 miles on the vehicle in 2 weeks while on vacation. You can feel comfortable waiting until after you get back before changing oil.
For what it's worth, most oil analysis reports that I have seen seem to indicate that at lower milage change intervals, (5-6K) there is still plenty of life left in oil. That is, unless there is something wrong with the vehicle.
 
   / change interval synthetic #3  
I would say follow manufacturers recommendations. MY Ferris mower with Kawasaki engine say to change first oil at 8 hours then ever 100 hours after that or yearly which ever comes first. It requires full synthetic oil which is a first for me for synthetic being required and Mobil 1 was the only oil I found with the required labeling . I use Shell Rotella full synthetic in all my vehicles and due to mileage per year, I have gone 16 months on my truck before changing it and it was still pretty clear with just a bit of brown color. My book says to only change it when the oil life indicator comes on or yearly. When I first got it, I used Dino oil and it would go 7000+ miles before the computer said to change the oil, so I figured with full synthetic it should go longer with no problem. The computer calculates required change based on engine RPM, temperature and other things (not on oil analysis) and it calculates based on using standard dino oil. I wouldnt worry about the color of the oil in the engine just the oil level. You should watch the automatic transmission oil color, if that turns brown, it needs changing.

Most home use small engines like lawnmowers should go a full season without need to change oil. I think I would use the 100 hours or yearly interval if you don't have something else from the manufacturer. I got 8.5 hours on my Ferris which timed to last mowing of the season so I changed the oil prior to putting it away for winter.
I was looking at grand daughter's Kia for oil change interval last time she visited and it said 7500 miles. I had it changed for here before she went to college last Sept and of course the JiffyLube place put a sticker on it to change a XXXX miles which was 3000 mile interval. They love to waste oil. I told here to add 4000 miles to the oil change sticker before changing it so she still has 3000 to go. I topped it up with about half a quart and put the remaining in her trunk for later use.
 
   / change interval synthetic #4  
Other than problems (leaking head gasket, etc.) the other thing that UOA will assess is driving conditions.

5,000 miles of short trip driving in cold temperatures is tough on oil, even a synthetic.

Check your OEM recommendation on change interval for these engines. Certain engines can be harder on oil than ones of similar displacement. Ex. if you read UOA reports for Subaru's boxer 4 cylinder, they tend to shear down (reduce viscosity) pretty fast.

Useage pattern is a major variable. If a salesman is putting on 3,000 miles plus/month, it might make sense to want to stretch the OCI out a bit with synthetic - no problem with the engine getting hot enough there.

For what you can buy T6 for on sale, I'd just stock up and stay with the intervals you have been using.

You didn't mention time. Keep that in mind too. Some vehicles get driven so little that 6,000 miles could be 3 years driving.

Rgds, D.
 
   / change interval synthetic #5  
I do 5000 miles on my trucks because they are working trucks pulling max loads over 50% of the time.

My car holds 7 qts for a 3.0L motor so I go 10,000 miles on it.

Chris
 
   / change interval synthetic #6  
Most newer gasoline engined vehicles go 15,000 miles with synthetics. Diesels go 10,000 miles. That's what I've been using on my VW Jetta TDI now with about 45,000 miles on it. On my Tacoma that sees only about 2,000 miles/yr, I'll go 3 years on it, like I do with my generators (was gas now a diesel). Change my mower engine oil once/season.

I use an oil extractor. Makes life A LOT easier, particularly on engines where oil filter is on top. You never have to go underneath. Much easier on generators (would be on boats, too). I checked all my vehicles initially. Sucked the oil out and then opened the drain plugs. On my tractor, there was nary a drop came out via the drain plug.

Be sure and get a "Mobil 1" type oil filter for engines that offer them. Otherwise, change the filter in between and add a quart of oil to make up.

Ralph
 
   / change interval synthetic
  • Thread Starter
#7  
hey thanks to above responders for the rock solid advice
 
   / change interval synthetic #8  
I bought a new Toyota V6 a few months ago and it has synthetic oil with oil changes ever 10k, I usually change every 5k on other non synthetic vehicles.
 
   / change interval synthetic #9  
I have a mazda that takes 3.5 quarts to fill with filter. I can safely drive 8500 miles b-4 oil changes . This is based on several UOA,S using Amsoil 5w30
 
   / change interval synthetic
  • Thread Starter
#10  
I have a mazda that takes 3.5 quarts to fill with filter. I can safely drive 8500 miles b-4 oil changes . This is based on several UOA,S using Amsoil 5w30

interesting. do you think w/smaller fill capacities, the change interval proportionally goes down too given same driving cond?
 
 
Top