Technical The power of a good oil change

I'm honestly speechless. As a total newbie I thought I understood the importance of a good oil change, but my mind was blown this morning. I have a 6V 1954 Chevy that's been a little testy while turning over. Sounds a little rough at times, and can all together be a little unpredictable. Today was the day I was going to tackle the oil change, and I discovered the oil was BLACK. Threw in some High Durability Quaker State 10w30 along with a brand new WIX filter... And it's a NEW truck. Fires up instantly, has a perfect idle, and run smoooooooth.

I know this is probably obvious to the motorhead but I'm thrilled. Haha learning more everyday.

 

I'm fanatical about maintaining fresh fluids in my old and new(er) cars.
I won't start an old car without changing all of fluids first. And the old fluid, if there is any, gives you an idea of how the car was maintained in the past.

 

Thanks for the message. Yup, that was a first for me, and I'm officially addicted. The difference was staggering.

 

If an oil change made THAT much difference, it must have had the consistency of tar. I would recommend that you consider removing the oil pan and clean it out thoroughly. What you are most likely to find in the oil pan sump is a thick layer of sludge and lead deposits that may well be dangerously close to blocking the oil pickup screen. Being that you have a pickup, dropping the oil pan is fairly easy as you do not have any/many obstructions blocking it's removal.

Not employing scare tactics here, just making this recommendation based on several experiences with old engines that have not been opened up for decades.

 

Oil that has had the viscosity beaten from it doesn't generally make the oil thicker. It's usually the opposite effect. I bought an old Barracuda years ago and the poor little 273 living under the hood was covered in leaves and cigarette butts. When I dropped the (black) oil out of the crankcase, it came out with the consistency of paint thinner.

Fresh oil, new plugs/wires/vacuum lines (the latter were rotten and broken) and I was driving to work in a car that the seller had insisted "needs a valve job, pretty bad". Used up oil will make a motor run badly.

I'd ask why the oil was so black? Is it because the oil has been run well beyond it's service interval? Is it because the truck doesn't get driven very often and it's had one too many shots of fuel down the carb throat to prime at startup?

 

WIX filter is the way to go imo

 

If the oil is THAT OLD.. it could be a straight-weight. Going to a 10W30 or 10W40, it flows immediately and starts better. Dirty oil as others mentioned traps a lot of bad things including moisture.

 

Change it again in 200 miles or so, it'll be black again, you'll be flushing the system. Throw a pint of Marvel Mystery oik in it now. You;ll be amazed what ya see the next time. Just my 2 cents.

 

Viscosity makes the difference.
Too little as in totally worn out oil, gets easily drawn past the valve stems as well as increased friction, too high can also cause different issues.

 

You guys are referring to the effect of permanent shear loss, when polymers in the oil that provide multi-viscosity performance, are sheared due to stresses in use, and can no longer function as intended, the viscosity of the oil decreases and the oil flows easier.

But as oil ages it undergoes a chemical change via oxidation that causes an increase in viscosity. That's due to polymerization of the molecules in the base oil and additives. These polymerized molecules are longer, heavier and are also polar, so they want to attach themselves to the interior surfaces of the engine, this is the varnish and lacquer that you see in dirty engines. Eventually, if the oil remains unchanged, sludge develops.

So, back to your points, yes oil CAN thin out due to shearing of viscosity index improvers, but more common is an increase in viscosity along with varnish and sludge.

 

A 54 pu has nothing under the engine to hinder you from removing the pan and doing a clean up as stated above. Is a pretty ez job with a 1/4" ratchet set with a 7/16" and 1/2" sockets and 12's" of extensions. I've seen some which still has the large pan head slotted screws. U just need a pan gasket set, Prmatex #2, and a putty knife. There should be a clip holding on the oil pump screen which also needs to come off and be cleaned. U can leave the oil pump on and just clean the screen.
Use some vinyl gloves... this is going to be messy..Good Luck

 

Don't you have to remove the timing chain cover to get the pan off on that model?

I agree with dropping the pan and cleaning it out, but if that is not practical changing the oil at 1000 miles a couple of times will clean out most of the sludge.

Older engines with carburetors, road draft tube and filters that aren't very efficient, go through oil faster than a late model, sealed up, fuel injection job. Oil change every 3000 miles or less was par for the course.

Does your truck have an oil filter? They were optional, and bolted onto the intake manifold. If you don't have one you should get one, oil change interval without a filter was 1000 miles.

 

I made the mistake of not changing the oil in this slightly OT International truck I bought last year. The oil on the dipstick looked good, it had a new filter, so I assumed. The guy I got it from was in the process, supposedly, of getting it going for himself, then things came up.....you know the story. I got it running, and it was having some issues, rocker or lifter noise, or maybe rod. I couldn't track it down, so I dropped the pan. Under the good oil, he evidently put in, was about an inch of sludge, and under that was about an inch of nasty, THICK sludge. Had to work to scrape it out. I don't know how it was running at all. Turns out it wasn't a rod, actually still don't know for sure. Runs good, other than the ticking sound. One of these days I'll take it all apart, or maybe just drive it until it won't go anymore, then fix it.

 

You have to drop the pan to tighten two of the timing cover bolts

 

No, it won't.............

^^^^^^^^This is far more often the case

 

Maybe the oil is so old that it's ARCO Graphite oil.

 

I think I may have a can of that in a small collection of old oil cans.

 

Ooh...my brain was not ready for that..lol.

 

Supposedly on the mechanic's vacuum gauge charts an engine with bad oil in the crankcase can show up, and maybe test as poor compression. It won't seal the piston rings quite correctly. It'd have to be pretty toasted oil I'd think, but people do weird shit.

 

Its makes me cringe to see folks on U Tube do first starts on decades setting engines and never change the oil. The pull the dipstick and remark how clean the oil is! wheen all of the dirt and crud has selttled to the bottom of the oil pan. Good oil gets dirty because it holds particles in suspension. that's why you need to change oil regularly. Myself on a old unknown engine I try and pull the oil pan to be certain the pickup screen isn't clogged and make certain the oil pan isn't full of sludge. Quaker state is a black oil and on a engine without a PCV will create sludge. Pennzoil is the same.

 

When I rebuild these Chev or GMC I tap the front main where the bolts once went thru then use header bolts which have a small diameter shoulder and a 3/8" or 7/16" hex...