What Happens When You Don't Change the Oil

We had Cummins "L" series motors that had their oil change every 11k to 14k miles in a heavy stop and go duty cycle. Far worse than anything anybody on this board would subject their vehicle to. We determined this was the limit through an oil analysis program for those engines, popping the valve cover off, it was nice and clean all over the valve train. Never had an issue with gunk/varnish building up on those engines. Once our motors are outside of warranty, we do a rigorous oil analysis program to determine how far we can take the oil change interval out and still have plenty of buffer before the oil is too well used. I'm perfectly fine with my 15k oil change intervals, but warranty keeps me at 6 months (which is anywhere between 5k and 9k miles for me).

Any Particle Quantifier analysis would tell you how big the "Chunks" of material are in your oil, so for those sludged up engines, you'd see it in the analysis. You'd also see plenty of soot. Your base/acid number would also be fairly low and your additive package would be well diminished when compared to new.

dodge guy wrote:
How about something better than an oil analysis?!







2005 Toyota Highlander. oil changed religiously by the OLM. customer just couldn't understand how that could happen. No oil analysis needed!

Change your oil people! an oil change is cheaper than a new engine or a car!

I can guarantee you he didn't change that oil at 6000 mile intervals or the motor wouldn't look like that!!!

oil changed religiously by the OLM

Sure he did. :R

How about something better than an oil analysis?!







2005 Toyota Highlander. oil changed religiously by the OLM. customer just couldn't understand how that could happen. No oil analysis needed!

Change your oil people! an oil change is cheaper than a new engine or a car!

dodge guy wrote:
And yet we have people here that will tell you it`s OK to change your oil at 12-15k miles! Heck......even 6k is pushing it!

Just pay attention to the oil life monitor, and change your oil accordingly. No reason to waste time, money and oil because of being afraid of todays engines and lubricants. It really is OK to believe what your truck is telling you.

I would never go past 4000 miles with my 12 CTD because of regens. The oil level increases over time. Extra diesel being dumped in during regen can't help the oils viscosity. There's a big difference between the older diesels and the newest diesels. Newer ones, at least Rams, allow 6 months or 15,000 miles which ever comes 1st. Mine only gives me 6 months or 7500 miles. DEF extends the OCI.

Can't really lump all motors into the same OCI.

I change the oil in my diesel trucks and gasoline cars every 25k km. The manufacturers of the new farm equipment recommend change intervals every year or 600 hrs of use, whichever comes first. 600 hrs at 50 kph would be 30,000 km. And the engines are often worked hard in very dusty conditions during farm applications.....a 500 HP combine engine might burn 20 - 30 gallons of fuel per hour. So oil changes after 12000 gallons of fuel.

I change oil at 5,000 miles, old habits are hard to break, and send samples off to Blackstone. They usually say the oil is good for more miles, 6,000 miles is hardly "pushing it".

dodge guy wrote:
And yet we have people here that will tell you it`s OK to change your oil at 12-15k miles! Heck......even 6k is pushing it!

Show me an oil analysis that says that.

dodge guy wrote:
And yet we have people here that will tell you it`s OK to change your oil at 12-15k miles! Heck......even 6k is pushing it!

Well Toyota says the wife's highlander is just fine for going 10,000 miles between changes. That is on synthetic.

And they provide a lifetime warranty on the drive train. :h