Detergent Vs Non-Detergent Oil

[studda]

Is there any credibility to the notion that putting detergent oil in an engine that previously only ran non-detergent oil will loosen all the grime and ruin the engine? I know non detergent oil is designed to keep the sediment in suspension whereas non-detergent oils let the sediment to settle out on the surfaces of the engine. If I use detergent oil, will I just have to do a few oil changes in short succession to remove the built up grime that will now be suspended in the oil?

[1project2many]

Yes, there is some truth. It's especially true in an engine that doesn't use an oil filter. Depending on what's in the pan you might be able to do multiple flushes using a solvent based flush and still not get all the garbage out of the pan and crankcase. Best bet is to drain the oil and use a hanger or other tool to scrape some garbage from the pan. If you don't get much you can probably go right to detergent oil. If you find sludge and uglies, you've got to make a decision whether or not you want to switch.

[studda]

Here's another issue. The bladder of my fuel pump busted and fuel leaked into the crankcase. Would the fuel in the oil have been enough to free up the sludge from the inside of my engine?

[463]

Change your fuel pump and change the oil and filter.

[studda]

Originally Posted by 463

Change your fuel pump and change the oil and filter.

I'm already planning that. I'm just trying to figure out whether or not to use detergent oil. I'm not sure whether the previous owners used detergent oil or non-detergent oil. With the fuel in the oil, I'm not sure whether there would still be sludge inside the engine or if the fuel would have broken that down.

[463]

Depending the amount of oil to fuel ratio and run time on the engine the fuel would have broken that down some of the sludge.
The normal method is to do two or three oil changes to clean up a dirty motor.

Seafoam is what I have been using for the last ten years or so with very good results and no after effects.
I use a 1/3 of a can in a V8 5 qt oil pan and run the engine 30 to 60 min drive and the change the oil and filter.
http://seafoamsales.com/

[studda]

I haven't run the motor very much at all (maybe 2-3 minutes). I also don't know how long the gas has been in the oil. I'm assuming the bladder dried out from lack of use and busted when I first started the truck. I need to check in the oil pan to see if there is a build up of sediment. Seafoam is awesome. I swear by that stuff. I'm just afraid if I break all that stuff loose, it's going to go in suspension in the oil and eat out the bearings, babbitt out of the rods, and rings.

[gag1025]

I use Seafoam in every application on all my cars, trucks, motor cycle, tractor, lawn mower, generator, etc. It is some great stuff.

[WIDESIDE72]

I had a snapper mower with a tecumseh engine. I bought it for $100 and mower the rest of the summer. It was running fine but the next spring i decided t do some maintenance. I didnt think when i changed the oil and used detergent oil from my car. Locked up the motor tighter than Dick's hat band. Evidently they were using non detergent oil before as the old time i got it from was a small engine repair man before retirement. Learned a lessonthe hard way. Non detergent only in small engines from there on out.

[storm9c1]

I use detergent oil in everything. Never a problem. I always thought non-detergent oil was for very very old engines, like Model-T old, and I never really understood the logic there either except for the reason of switching since an engine that old didn't have detergent oil way back then. IIRC, detergent oil first appeared in the late '40s, early 50s.

If I had a new engine out of the box, or an engine that I've personally know the history or have torn down, I would certainly run detergent oil. Detergent oils really help break down and suspend byproducts and acids of combustion that are otherwise harmful to the engine. In my opinion, the only place for non-detergent oils is in crankcases that are NOT internal combustion engines, such as compressors and electric motors. There are a few small engine manufacturers that may recommend non-det oils in small engines for special cases, I would do what the manufacturer says. But I wouldn't generalize that. I run 10W30 synthetic blend in several small engines (Kohler, Briggs, Honda) with great results. One is a Generac genset that self-tests every Sunday for 10 years and has been used in all weather and over some power outages. Been using 10W30, it's been working great. Another is a 60 year old push mower. It's older than me, and I've used 10W30 detergent oil in it all my life. Runs great except when the points act up. Next time I'll be adding a solid state module to bypass the points. But I digress.

That being said, if you are certain that non-det oil was used previously, it might be a good idea to run 50/50 for the next few oil changes. See what happens. Then eventually make the full switch to detergent oil. It might not hurt to pull valve covers to see how dirty things are.

[ray_mcavoy]

Originally Posted by storm9c1

I use detergent oil in everything. Never a problem. I always thought non-detergent oil was for very very old engines, like Model-T old ...

Same here.

Originally Posted by storm9c1

In my opinion, the only place for non-detergent oils is in crankcases that are NOT internal combustion engines, such as compressors and electric motors.

I just took a look at the label on a bottle of the non-detergent oil I use in my compressor. Says it's not suitable for use in most gasoline engines built after 1930.

[studda]

I use detergent oil in everything as well. There is no question as to which one is better, that is obvious. I looked inside the valve cover and everything looks pretty clean, so I decided to use standard detergent oil. I ran the motor for a good half hour or longer with no issues. I think it should be fine.

[grs]

I bought a 1948 chevy car 35 years ago. It ran great. I drove it to my dads house about 55 miles. I was going to drive it 600 miles home, so I changed the oil. I put detergent oil in it. I then drove it 8 miles , and a rod started to knock. I gave $300 for the car, and sold it for $150. I buy high, and sell low.

[Gumby]

ran some heavy detergant rotella 15-40 many moons ago in my 200k V6 car and with in 200 miles lost half my oil PSI and would drop danger low at idle suddenly.

as if it cleaned out to much gunk that was keeping oil in.

took several years to come back some and doens't drop at idle. 230K and still going strong.

[imjeff]

I have only used non-detergent oil for break-in. It's actually getting difficult to find. Use detergent oil. I would run it for maybe 1000 miles, then cut the filter apart and see what/how much crud kicked loose. Then take it from there.

[Pyrotechnic]

Generally what happens is that the crud inside the engine loosens up in BIG pieces. Pieces big enough to cover the oil pickup screen and starve the engine for oil. I've read a few stories where this has happened, and seen it first hand when someone used diesel rated oil in an engine that was heavily sludged (diesel oils have more detergents than standard passenger car oils).

The bottom line is, if it's dirty inside then keep using whatever the engine has been run on. It has come this far run on that oil and there's no reason it won't keep going. The only way to get the engine clean at this point is to take it apart and clean it mechanically.

[whitedog76]

My old man, who has been working on Diesel equpment and Gas powered tractors for well over 40 years, uses 15w40 oil in EVERYTHING. Never had any issues, whether it was a 60 year old tractor with 6,000 hours, or a brand new New Holland.

From what I've researched, the detergent oil does more good than harm. In old, sludgey engines it keeps the crud in suspension, rather than breaking down.

If you have an old engine, that is sludged up and you're worring about carbon breaking off and plugging something up. You're already on borrowed time anyhow.

[Pyrotechnic]

Originally Posted by whitedog76

My old man, who has been working on Diesel equpment and Gas powered tractors for well over 40 years, uses 15w40 oil in EVERYTHING. Never had any issues, whether it was a 60 year old tractor with 6,000 hours, or a brand new New Holland.

From what I've researched, the detergent oil does more good than harm. In old, sludgey engines it keeps the crud in suspension, rather than breaking down.

I also use 15W-40 in everything. Never had an issue, but I have a rule that before switching an older engine to this oil, I always pull the valve covers to see how clean things are. If the engine seems to be clean and cared for, then I run the 15W-40.

You are right, the detergents are good for keeping deposits in suspension, so that they can be carried out of the engine with each oil change. If the motor is clean to begin with, it will stay clean all it's life.

However, like I said above if you put 15W-40 into an engine that has been run on regular passenger car motor oil all it's life and at the same time has serious sludge buildup from abuse and infrequent oil changes, then the sludge will come loose and clog the oil passages, oil pickup screen, and send large particles straight to the bearings.

I have a friend who learned this the hard way. He bought a used car and didn't realize how dirty the engine was inside. He ran it on 10W-30 for a few changes, then decided to switch to 15W-40. Very shortly after that oil change, the car lost oil pressure. When we pulled the oil pan, we found a clogged pickup screen and lots of loosened sludge in the pan. Had he kept running it on the standard passenger car oil, the sludge would have stayed clinging to the inside surfaces of the engine and it would have kept on running.

The big thing any time you increase the detergent levels in any engine is to have a look inside the engine. If it was well cared for, the oil was changed often, and it had a working PCV system all it's life then you may find that it is clean inside. You really have to take this on a case by case basis.

[imjeff]

I'm gonna have to side with Whitedog on this. I've never heard of "regular passenger car motor oil" and running 10W-30 vs 15W-40 isn't much of a difference in viscosity. My guess would be that your friend's car would have lost oil pressure regardless of which viscosity he ran. Sediment is trapped by the oil filter prior to entering the oil galleries so it's rare that a motor dies from that unless the filter gets completely clogged and the bypass opens. Most of the motor I've built after oil pressure drops were due to low or no oil. Most of the particulate doing bearing damage comes from disintegrating bearings...due to low or no oil. There are a variety of possible scenarios, but I don't think anyone can say a slight viscosity change made a motor fail. Most older motors are good with either unless you're real hot or real cold.

[68post]

Originally Posted by imjeff

I'm gonna have to side with Whitedog on this. I've never heard of "regular passenger car motor oil" and running 10W-30 vs 15W-40 isn't much of a difference in viscosity. My guess would be that your friend's car would have lost oil pressure regardless of which viscosity he ran. Sediment is trapped by the oil filter prior to entering the oil galleries so it's rare that a motor dies from that unless the filter gets completely clogged and the bypass opens. Most of the motor I've built after oil pressure drops were due to low or no oil. Most of the particulate doing bearing damage comes from disintegrating bearings...due to low or no oil. There are a variety of possible scenarios, but I don't think anyone can say a slight viscosity change made a motor fail. Most older motors are good with either unless you're real hot or real cold.

I'm sure the real difference is that the 15w-40 was a diesel "high detergent" oil, but I'd run regular pcmo 10w-30 and call it good. If it was running on non-detergent it may have stuck rings and varnished valves and be as said "running on borrowed time".

[imjeff]

There aren't typically problems running diesel oil in gasoline motors unless they are new enough to have a cat. My assumption was that we were talking about pre-cat motors. The general rule of thumb is to run non-detergent oil in things that don't have oil filters. It allows the particulate to settle out in the pan. Run detergent oil in motors with oil filters as it suspends the particulate so the filter can filter it out. The amount of detergent isn't really an issue. I've torn motors down with sludge everywhere that had fine oil pressure running detergent oil. Diesel oils have more additives, but aren't a threat to our trucks unless you're running a cat.

[whitedog76]

I found these articles, good reads.

http://www.earlytimeschapter.org/engineoils.html

http://www.sizes.com/materls/engineOil.htm

Seems like the change from detergent to non-detergent oil had to do with the use of insert bearing more than anything. For Chevy, that would've been the 1953 235. An oil filter was optional at that time also. They weren't standard until 1963, and even then by-pass filters were typically used.