Radical Engine Flushing Experiences?

   / Radical Engine Flushing Experiences? #1  

Gale Hawkins

Super Star Member
Sep 20, 2009
Murray, KY
1948 Allis Chambers Model B 1976 265 MF / 1983 JD 310B Backhoe / 1966 Ford 3000 Diesel / 1980 3600 Diesel
I was wondering if anyone has any radical crank case flushing experiences.

As posted before the 1998 S10 that we bought recently with 524K miles started to having a stuck valve issue that would stick and then free up driving it home. After pushing it hard it now is a complete miss on #5 and the exhaust valve will not completely close but it can be depressed and the spring is not phyically broken. I do not think it is bent because it has started hitting on all 6 six for a brief time since a couple times.

First I plan to drain the oil with the filter left on and pour in a gallon of diesel and fire it up. With the miss the idle will be 400+ RPM.

After doing that (plan to play it by ear) I will drain, change filters and fill with only new ATF (I have a gallon of cheap stuff that has been setting around for a couple years). Will play that by sound but may try it for a few hundred miles.

Friday I got new tires put on the tow dolly so I am ready for what may come I think! :D
   / Radical Engine Flushing Experiences? #2  
I always heard that ATF always works better if it's fresh, not old stuff that's bern sitting around for a couple years.

Wouldn't it be worth a few extra bucks for some fresh ATF if youre going to go to all this trouble anyway?

   / Radical Engine Flushing Experiences?
  • Thread Starter
We are down to running on pure Dex/Merc ATF and it is making about 50 PSI running at a fast idle.

After running for 5 minutes on pure diesel plus what oil was in the filter the lube place owner got nervous. The two guys were standing on either side listening for lack of lube sounds but they never came.

It was making 20 PSI on diesel only in the crank case at 1000 RPM. He caught the tail end of the draining and it was very dark water like but it was free of ANY solids of any kind when I slowly emptied the plastic cup with the drained diesel. Actually the drained oil had 16 oz of Sea Foam and another 16 oz of diesel added some time back.

Well I am going to try and get a few hundred miles on this pure ATF. I had this cheap ATF from when I had a leaking parking brake system on our old Ford F-700 parking brake system so I kind of wanted to use it up some how because now we only keep Dexron VI around the place.

Hence the test of using ATF for in crank case use. Not sure it will help the stuck valve problem but I expect it will be cleaner than before on the inside. :D
   / Radical Engine Flushing Experiences? #4  
I tried just about the same thing with a 99 Saturn. It used oil like crazy after and started leaking hear and there. Only Thing holding that engine tight was the crud in it.

   / Radical Engine Flushing Experiences? #5  
back in the day we used to pour stove fuel thru the carb at a high idle to clean the valves!!
   / Radical Engine Flushing Experiences? #6  
I have, without draining any oil out, added 2 quarts of ATF, start the engine, and only let it idle for 5 minutes, then drained the crankcase, changed the filter, and refilled with clean motor oil, when hydraulic lifters were sticking. I've only done that twice and it cured the problem both times.

But I also once had an experience similar to DiamondPilot. I believe it was 1957 when I bought an old 1937 Plymouth clunker for about $50. I intended to built a hotrod with it and I noticed the crankcase was full, but was probably 90W gear oil and black. So I drained that out, then put in one quart of oil and one gallon of kerosene, started the engine and only let it run about 10 seconds before shutting it off, draining the crankcase, and refilling with motor oil. It was a little hard to start after that with almost no compression.:laughing: Since I intended to replace the engine, I decided to just blow it up. I would wind it up in first gear wide open until it just maxed out and wouldn't rev any higher, step on the clutch, and shift to second without ever letting off the accelerator, then do the same thing going from second to third, and it didn't even have enough compression to throw a rod.:laughing:
   / Radical Engine Flushing Experiences? #7  
back in the day we used to pour stove fuel thru the carb at a high idle to clean the valves!!

We usually did it with Mobil Upper Lube.:laughing: Lots of sweet smelling white smoke.:laughing:
   / Radical Engine Flushing Experiences? #8  
We usually did it with Mobil Upper Lube.:laughing: Lots of sweet smelling white smoke.:laughing:

   / Radical Engine Flushing Experiences?
  • Thread Starter
Bird beat you on trying to throw a rod without trying. :thumbsup:

Interesting flushing cases and a long summary to my experiment.

Well where to fix or replace our 524K mile engine has been made simple by my experiment with pure ATF in the crank case when running and gunning.

Clearly the key to flushing is to keep the engine clean on the inside from new so it never needs flushing. I will keep doing the Sea Foam flush but no more diesel or ATF in the crank case. The experiment as worth it to me to learn for sure what I expected was the case all along and to make the discision to get on with the transplant.

The S10 made it back home but in a cloud of smoke the last 100 foot as things started to let go.
vladen raised a good question as to if it makes practical sense to go to the effort to do a patch job to get it hitting on all cylinders since the entire engine has seen over 1/2 million miles.

If I was into trying to set a record maybe so but with 4.3 engines that have never been opened up out there with 700K-800K miles and still run a record is a mute point.

Weekend before last we found an engine on CL with 119K and the guy had driven the wreck enough to prove the transmission was fully functional before he pulled it and installed it into an Astro and the owner of the wreck gave him the engine in the transmission swap deal.

He was doing some 4.3/5.3L Chevy to Jeep engine swaps so when he pulled the engine he pulled it complete with computer, harness, and the rest of parts that were bolted to the engine like AC compressor, alternator, PS pump and even the MAF all is required to do a transplant into a Jeep. He said everyone started wanting a 5.3L since the cost was about the same as using the 4.3L plus I think money is short for these kinds of project.

Well we will not know for sure until we hear it run but I feel good about the engine especially after meeting the guy. While it cost $100 in gas to go get it. He had just relisted it for $450 down from $650 due to Christmas then tax time and he was moving locations. Locally that complete of engine with 119K miles would be $850 because I have cousins in the car salvage business in two towns nearby and I spoke with both.
With this engine setting on be back of the Nissan it just make no sense to put labor into a 1/2 million mile engine. No question it could have been patched up and lasted a bit longer.

It was bought as a project truck to be my son's first vehicle in less than two years. There was NO way I was going to let him get out on the road with 1/2 million mile engine in his daily driver.

Now I did not expect to get into the project in the dead of winter with no shop but when it started missing on the way home I expected it would be sooner than later. Yes I could wait but the new engine would be better stored under the hood. :)

Before I figured out the miss was valve related we did tune up the old engine and the son did a great job and learned a lot.

The S10 5 speed is more fun than my Blazer so I will make it my daily driver for the next year or so to insure it is ready for him or if we should ditch the project. In the mean time it will serve as his auto shop training lab experiment. :B

We gave $1100 for the truck running and to tag it they wanted me to pay tax on $4900 but even with a sworn statement from the seller I still had to pay taxes on $1400 because the law in KY is unless a salvage title you must pay taxes on no less than 50% of dealer trade in value. The half millions miles did not seem to register with them.

For those who skip to the end do not flush a crank case with pure diesel or pure ATF and I never plan to use either in a crankcase again unless I want the engine to come apart going down the road. Actually did make into the drive way. :B
   / Radical Engine Flushing Experiences? #10  
Just saw this. Diesel doesn't make a very good lubricant for plain bearings. Any sludge broken free would just clog a filter and kill the engine too.

Most engine crud from cheaper old oils are in the top end. Amalie and Pennzoil were notorious in the old days. Most modern oils changed within spec don't make sludge under normal conditions.

I might have recommended taking off the valve cover and using diesel or kerosene and a paint brush, maybe trying to remove buildup. At least you might see why the #5 wasn't working. Compression check, leakdown test, flat cam lobe, scored cylinder. Many a reason for the problem.

You did yourself a favor opting for the fresher engine provided it is in decent condition.