Oil Change Fun

Thought I would post a few pics of an oil sludge problem as I’m often at odds with many over what constitutes a proper oil change interval.

The only info I will provide is that the engine is a small block Ford, there are zero problems with the engine mechanically or with the PCV, etc, etc. The oil is Quaker 10W40, non-synthetic.

Feel free to make guesses about the engine mileage, the oil change intervals as to miles, time, etc. Later this weekend I’ll see if anyone gets this close and the winner will receive a virtual tour of McWillie, OK the next time I go through there with the camera.



Have fun with it. :slight_smile:

Wow…no guesses here, just an ignorant question. If there are no mechanical problems with the engine, why is the sludge gray, as though there’s a large quantity of water in it? Is that just water from normal combustion that’s accumulated in the oil because it was changed so infrequently?

I’ll guess that the engine is 10 years old with 100,000 miles and has been routinely changed every 6,000-7,000 miles.

Maybe someone never drained the front of the oil pan.

I had a customer who put castrol gtx racing oil in his F150 302 with the theory it would be needed because he drove so much. He was towing a 27’ box trailer almost daily round trips, Gallup to Albuquerque, for his business inventory. Lots of miles towing lots of weight.
Yet his engine sludged up anyway due to the heavier viscosity of the racing oil.

Normal oil, changed at proper intervals was correct for him.

His sludge-up was not milky like the pictures.
I wonder if you’re leading us into a scenario of 3000m intervals here ?

I’ll elaborate a tiny bit more. It’s a small block Ford pan with the double sump. The rear looked as bad as the front. I just chose two pics as samples.
As to engine condition, it’s guaranteed there are zero mechanical faults. That’s etched in stone.

The engine has 50,000 miles.

The oil was changed every 3-4k miles.

But it looks like condensation has accumulated in the oil from short trips where the engine never came up to full operating temperature.


What temperature thermostat was in the engine?

And how many years did it take to accumulate enough mileage for an oil change?

Thermostat is a 190 and I won’t say anymore. Maybe later tonight or tomorrow I’ll provide the sordid details. :slight_smile:

How many short trips?  Location?  How old is that Ford?  PVC issue?

Never use Quaker State. It just isn’t worth it when Valvoline, Havoline and Castrol are available. I forgot Mobil.

Based on the color of the sludge, it doesn’t look like it’s due to oil that can no longer hold contaminants or from oil being left in after normal “end of life” breakdown.

As Tester noted, I’ll add another vote for excessive moisture from short trips.

The short trip scenario is correct but the mileage is way off. That engine was built by me for someone about 1.5 years ago and only has roughly 1000 (One, no typo) miles on it. (Properly built with everything being vatted, cylinders bored, msin bearing saddles line bored, etc.)
The oil was changed about 200 miles into the break-in and the ensuing 800 or so miles was put on 2 at a time, 5 at a time, etc, etc. and yes the PCV and all hoses are fine and operative.

The oil was not even dark, just more cloudy looking as if it has a little milk in it. This led to removal of the oil cap which had a small trace of crud on it. In turn, this led to loosening both drain plugs and the first thing dripping out of both was dirty water droplets. Since the red flag is up it was decided that it might be best to pop the pan and that’s what you see in the pics.
(The valve covers are easily removed so I popped those loose too. Everything up top is very clean except for a couple of dime sized blots of sludge.)

I suppose the point being here that one could see how quickly engine oil went downhill here based on the way the car was driven. Imagine what this would have looked like if the next oil change had been at 3k miles and keep in mind this would have been the first 3k mile oil change the engine would have gone through.
Carry this on through for say 20 or 30k miles and it would be a disaster.

27000 miles changed every 3000 miles, and over 3 years old. Is there any way, like using an extra long dipstick to check for sludge without removing the pan. I ask because I’ll be looking for a used car for my daughter in spring.

Only 1000 miles! Very interesting.

I wonder if today’s “Oil Minders” would have detected that driving pattern. They have all the information necessary to call for a very early oil change.

Thank you for sharing this.

By the way OK: What ever happened with the Bosch CIS fuel injection problem you were wrestling with a few months back?

You said 80’s model. Probably carb. 2 mile rich running trips. moisture laden dinosaur
Should change every 3 months if not driving enough

“Never use Quaker State.”

The exact advice a highly respected mechanic gave me ~30 years ago. I think he said the base oil is different from all the other brands.

“Valvoline, Havoline and Castrol”

The brands I’ve been using for the last 20 years or so.

1000 miles in 1.5 years! Is this a hobby car that only gets taken out occasionally?

And I thought my 4000 miles a year was light usage…

I wonder how this engine would get along if oil were changed every 6 months like I do.

Yes, it’s a hobby car and from what I gather it has only seen the city limits sign one time.
My personal opinion is that use such as this combined with humidity is the main reason for oil sludging and here in OK the humidity is often similar to what you would find in the Florida Keys.
It’s not uncommon, especially in the fall, to have days so damp that everything around is dripping water. I’ve raised hoods even on my own car and the entire engine compartment looks like it just rolled through a car wash.
Even sealed headlamps will become saturated to the point the light output is halved.

In this case, the murky oil led to drain plug loosening. When the water drops fell out my first thought was trouble. With the oil drained a screwdriver tip stuck in there showed sludge when removed so this led to the pan drop. After popping a few bearing caps loose thankfully the bearings are not damaged.

The car is not running rich at all and the plugs verify that. It’s simply not ever warming the engine up to operating temps, high humidity, and never giving the engine a chance to burn that moisture off.
I’ve got a sister in law in another town who probably suffers the same problem with her cars. She buys a new one ever so often and the vehicles only see the highway about once a year. They’re also used almost daily with the longest trip being about 2 miles. I’d shudder to see what the inside of one of those engines look like.
The people in trouble are the ones who buy those cars after she trades them in.

As to waterboy’s questiona about checking for this that may be hard to do. You could check the inside of the oil filler cap but if someone has cleaned that off then you would still not know what’s going on. Other than that, the simplest way I know would be to drain the oil and fish around inside the pan with a probe of some sort. A car seller may object to that though even if no harm is done.