Join Date: Sep 2006
Location: Montgomery Co., Pa.
Drives: 09 Cobalt
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Had a break this afternoon so here comes another batch for you to gnaw on.
Everyone is an expert on oil. I’ve read it and heard it a million times. My dad did this, I’m doing it so it must be right. I’ve done this for 30 years and never had a problem. Synthetic oil will blow up your engine. My buddy has a corner shop and does this. If your buddy jumped off a bridge would you follow?
I’ll really get them on the ropes when we get into a discussion about gear oils because very few change gear oils much less understand what they do. Gear oils next to brake & transmission fluids are the most neglected area I’ve seen when it comes to maintenance.
The first thing I’ll admit is until I started doing some serious field testing in the late 70s I too was one of them know it alls. Now with 35 years of data in hand the story is much different.
Again, mis-information is easier to sell then the truth. Look at the politicians.
Here are some notes for anyone making the switch from conventional to synthetic.
Your first oil change should not be extended very far unless the vehicle is rather new, like under 10-15,000 miles. Even here the first cycle should be shortened just a tad, maybe 20% under what is expected.
Remember earlier where I said to avoid blended oils?
We usually shorten the expected range on the first synthetic fill due to the residue left behind from the conventional oil plus odds are there might be a fair amount of gunk & varnish that’ll get cleaned up with the higher detergent in synthetics. Ya ya ya I can hear it already but overall mileage and the type of maintenance previously done will play into the benefit of this.
Many times I’ll suggest the second oil change cycle be slightly shortened depending on the miles and overall condition of the engine. Oh ya’ I can hear the bean counters working here too. You have to look at the big picture, which few can or want to do.
Many times you’ll see talk about running oil checks or analysis to see if extending oil changes is working towards your benefit. After all one of the benefits we’re looking for is lower engine wear or at least to not go backwards.
Running used oil samples is another area I’ve done countless times. From my practical experience I can usually come up with an “out of picture” if you will point of view and make a suggestion without your having to go thru the testing procedure.
I’ll add however, if you’re one to really push things, then doing at least 1 used oil analysis midway thru or after your second synthetic fill is a good idea. Another reason to run an occasional oil sample is I’ve found leaky head gaskets and other issues that weren’t showing up in the way an engine was running.
It’s typical for me to run an oil sample on an engine that is getting close to going out of warranty if the plan is to keep the vehicle for at least 2 more years. This I do regardless of the oil being used and the service intervals seen. Oh yes, I’ve had several discussions with service managers but I usually win when I confront them with the evidence. After all I was a service manager for several years. I generally know what they want to see.
The above and what follows is where the debate with arm chair & shade tree mechanics gets interesting & one I just watch with humor.
“Normally” I’ll suggest to not extending your first oil change more than 50% over what’s suggested by your owner’s manual as long as this is within the confines of the oil manufacturer. If you have an OLM you should be able to run it to zero. This is something I suggest on a case-by-case basis. Again, what I’m mentioning here is just a rule of thumb and other considerations are given for newer vehicles.
Also, it’s not uncommon to hear sounds you never heard before. Synthetics will sometimes allow the transference of engine noises better than conventional. The tighter molecular structure will allow sound to pass even though it’s still giving you the film strength you need. I’ll also add in many cases synthetics will quiet things down.
The sound transference issue varies from oil to oil, even from group to group & it will vary from engine to engine and the application of that engine.
In some cases your oil color will become very dark. This is because the various detergents are doing their job so don’t panic. Color has little to do with the health of oil structure itself. A darker color in what might seem a very short time usually means gunk & varnish is being pulled.
I’ve done several filter experiments while in the middle of an oil change cycle that gets people when I pull it on them. Let’s say a guy is 2,000 miles into a cycle. The oil is getting dark. I’ve taken his filter off and spun on a synthetic based filter. Usually within a couple hundred miles the color will turn clearer or back towards the original color.
Now, I’m sure the armchair and shade tree mechanics will say something like, that’s because the old filter was plugged. That’s proof you can’t run a filter more than 3-4K miles. You added fresh oil making the color clearer.
I can take the same vehicle and spin on your favorite filter under the same circumstances with no add oil & usually not see any change. In fact oil and air filter’s efficiency will go up with usage but there is also that fine line when getting way out there.
The reason a high quality synthetic medium filter can lighten the oil color is due to its higher efficiency. Here again I’ve seen it several times without using add oil but I made sure the oil level was well within safety margins before sending him out for those couple hundred miles.
Before someone chimes in and suggests high efficiency filtration can strip out viscosity improvers I’ll say it isn’t possible with a conventional filtration system. Bypass systems can get into such an issue but again we’re talking about the average motorist.
Not only will efficiency improve flow will too in many applications. This phase of the discussion can get very long winded and not one to be of big concern to the average motorist when it comes to flow so I’ll leave for now.
Finally, whenever I’ve done a service, I’m a firm believer in pre-filling an oil filter as much as possible & when possible rather than screwing it on empty. This comment I’m sure will bring the critics out.
Give me a few days maybe even mid next week to get some business issues tied up and I’ll be back with the most important aspect if I don’t get run over by a reindeer.