There is allot of talk about oil sludge on here and I was wondering how many of you who have had their oil pan off found none or extremely little sludge. I have had the oil pan off two engines that were in the family since new and found them to be clean. One was on a Chevy 4.3 with about 140,000 miles and on a Ford 3.0 at about 130,000 miles. Both engines were maintained under the guidelines in the manual using whatever name brand oil was on sale and sometimes Pepboys Proline oil. The filters used were all of your commonly available brands. How many of you have had the same experience?

Note: The oil pan came off the Chevy when the drain plug hole became striped and the Ford had a strange leak at the front of the oil pan.

 

I haven't done my own, but I do remember someone who posted over a year ago about rebuilding their engine with 250K miles and being amazed at how clean it was. It had been running the entire time on dino oil. I think the whole "sludge" issue is overplayed. If you change your oil when you're supposed to even the cheaper dino oils will do a decent job keeping the engine clean.

 

I pulled the oil pan on my 1993 Honda Accord awhile back and found the pan to be generally clean, except for one small area on the side of the pan which had what seemed to be grease (a very thin layer) about the size of a playing card. I was able to just wipe it off with a paper towel. The rest of the pan was very clean. I was able to inspect the rotating assembly somewhat and also found that to be clean and sludge free. BTW, the Accord had 159,000 miles on it using 5W-30 Valvoline Durablend. I now have a 1999 Ranger and wish I had a good excuse to pull the oil pan to check for sludge as the previous owner used Valvoline all climate 10W-40 and only changed the oil about every 10K.

 

I had a 79 F100 with a 302. I pulled the pan at 175k and the pan was very clean. I used various brands of 20W-50 and changed it every 5k. The tops of the heads had some gunk when I changed the valve cover gaskets. I sold the truck in 1996 with 197k. I still see it around town. Must have at least 250k by now.

 

Around 65,000 miles my pan ('95 F150 300 I6) was replaced because of rust. Mechanic said the oil pickup was half clogged with sludge. I have the pan and there a dark tar like coating running along the center part of the pan from front to back, like thick nasty oil slowly drained across it. Since I bought it used, the first 58,000 miles are of unknown history. The truck later showed evidence of abuse, likely from grossly overweight towing. I suspect cheap oil, long change intervals, and perhaps running a quart or more low for extended periods. The tough old 300 survived and runs great today at 108,000 miles.

 

i change mine every 10k with mobil 1 full synthetic and last time in my 2000 explorer, i took the pan off there was a little sludge not that much at all. probably from the last owner.

 

I had a 90 that I had to have the oil pan gasket replaced. That was at 140k. The pan itself was clean. 3k oil and filter changes, dino oil.

 

I pulled the pan on my '97 Caravan at around 112k miles. I bought it used in 2000 with 93k miles. It had a sticker on the windshield for the oil change, so I think the previous owner always took it to a service station. When I pulled the pan, I was using Mobil dino oil and Fram filters. I was suprised how clean it was inside. The only problem was the large dent in the front of it from the piece of firewood that my wife thought she could straddle. At least she was being a good samaritan by trying to get it off of the middle of the road!

 

This is pretty much what I expected. On an engine that is maintained and not abused there is very little if any sludge formation in the pan. To me these results takes a chunk out of the concept of using a premium oil to maintain engine cleanliness rather than better bearing and ring protection.

 

Well, to me using a premium oil like Mobil 1 FS is fine for 10k changes. Ive seen some cases where the additives last to 15k and higher but only for peolpe who drive nearly 95% highway miles. Mine is a combination of excessive high engine speeds for very long periods and stop and go traffic. Today when there was an accident and i had to wait for 35 minutes, i just shut the engine off when we were going to sit for more than 1 minute to save the oil life but i was also pushing empty

 

I recently dropped the pan in my '94 Taurus SHO (138k) to change out the rod bearings. Approximately 1000 miles prior to that, I had put a bottle of Auto-Rx in and changed the oil filter in anticipation of the full engine oil drain.

When draining the oil (Castrol GTX) prior to removing the pan, I noticed the oil was quite black. So, because of the miles, it being somewhat of a higher performance engine (for its time, anyway), and because of the the Auto-Rx treatment, I was expecting to find a very dirty and tarnished oil pan. However, I was pleasantly surprised to find only a faint "film" on the bottom of the pan, and nothing more. The bottom end of the motor looked quite clean, as well. The old bearings showed a little bit of wear, but certainly nothing out of the ordinary.

As you might expect, I was gratified to see all of this, as I am not the original owner of the car. But based on that, I think it's safe fo me to assume now that the previous owner changed the oil regularly. And that gives me a great deal of POM.

 

I'm not knocking the use of Mobil 1 and other similar products. They are fine for use especially for high performance and extended drains. I’m taking a shot at the idea that a good portion of our engines are full of sludge. Synthetics primary advantage it not in cleanliness but rather bearing and ring protection.

 

Sludge is basically a thing of the past. Quaker State was the big culprit for years. The oil had a pariffin base additive (wax) that built up inside engines over time. My first engine rebuild (over 20 years ago) was a Ford, heck I can't even remember what size it was. I do recall that the owner was a die-hard Quaker state fan. When I removed the valve covers I could not believe what I was seeing. Then engine had so much build-up in it that I could barely see the tops of the rocker arms.

Oil quality and cleaning detergents have far surpassed the needs of our engines. With regular oil and filter changes engines will remain clean internally.

In my years working in the R&D department of a large engine remanufacturer, the engines being dissassemble (at the time 300-400 per day) very few were full of sludge.

Just my 2...

 

Last time I pulled an oil pan from an old engine that I knew the history of was back in the late 70s with my Datsun Pickup, owned since new.

I ran Valvoline 20W50 Racing oil in that engine(After all that 1800 engine was a high reveing performance engine, right?) I really should have been using all climate since the driving I did probably required a better detergent package than the racing oil had.

I abused the engine and truck horribly, running right up to red line, driving thru blazing desert and steep mountains. BUT I always changed the oil and filter every 3,000 like the manual said.

At about 50K I hit a rock and ran the engine til it froze, stoopid. I replaced the pan laying on my back in the snow, fun. The pan was clean as a whistle but had varnish on it, you know the dark brown stain. Since I scored some of the bearings, I would drop the pan every few 10s of thousands of miles to check and maybe replace some bearings. The crank had some feelable scoring but I guess the forged steel crank was pretty tough. The engine and pan remained clean and ran just fine right to the day I sold it with 180K on the clock.

So even in the 70s, using good dino oil and regular changes, I had a very clean engine. I think the problem with sludge comes in with people who drive short trips and don't change oil often enough or used really cheap oil(Remember Raylube SA rated oil for 10cents a quart? Still have a can, collectors item now, har har)

I think now with the excellent dinos and syns we have available, the only time you will get sludge is from short trips and lack of maintenance.

None of the engines I have owned since 1980 has required me to drop the pan so I can't say if the syn I always used since then has done better than the Valvoline racing dino I used to use.

Just my thougts.

Jim Henderson

 

Another thing that will cause sludge is engine design. The Toyota/Lexus engines from 2001 is an example. Even timely oil changes didn't stop the sludge buildup.