Flush before oil and filter change

[karter13]

Hi all

Should I flush the engine before a oil and filter change

[Kahuna]

I have done this on older engines using a quart of Kerosene, letting the engine run at an idle for 5 minutes & then draining, Seems to work well

[Pappy]

You've seen the way hosing parts down with carb cleaner dissolves oil and grease. I could never get comfortable with the idea of putting a solvent like carb cleaner in my engine oil and running it even for just a few minutes. Good oils will keep your engine clean enough if changed at appropriate intervals.

[lefty o]

just run the engine long enough to be warm then do your oil change.

[GARY C]

I did one years ago that I bought used and had a lot of sludge build up in the heads. I used K&W motor flush and then did a cpl of back to back oil changes over 2 weeks or so and then went to the 3 to 5000 range oil change, a cpl years later I did intake gaskets and timing chain and it was near spotless in the engine.

[Krooser]

I've also used a flush a few times in an older engine and they seem to work well... had an '80 302 that was horribly sludged up... three oil changes and three qts of flush really cleaned her out. Not spotless but not bad.

[Amilcar]

This can be more of a harm than good.. IMO
The abrasive dusty on the oil galleries , has no other way out than the bearings, lifters ,etc
Much worse this on the oil system than glued on the engine block.
Watch out for blocked oil pick up

[engineguyBill]

just run the engine long enough to be warm then do your oil change.

^^^^^^^^^^^^^^^^^^^ THIS ^^^^^^^^^^^^^^^^^^^

Flushing the engine before oil change is not necessary if the oil has been changed at regular intervals in the past. However, if the engine has large amounts of sludge inside, add a quart of Diesel fuel once the engine is warmed up and let it idle for 10 or 15 minutes before draining.

[karter13]

Firstly sorry about the spelling but I am doing this the old school way but anyway here goes
A graham bells book says never ever use any type of flushing oil or home brew mix of engine oil and diesel fuel and kerosene to clean sludge out of a neglected engine. Trying to flush out of a running engine will clog the oil filter and course the filter bypass to open, witch then allows contaminated oil to circulate to the bearings. Worse flushing oil can loosen rubbish build up in the oil gallery and block flow to a main bearing and big end, or up to the camshaft or valve gear.
If the engine is semi neglected it may be possiable to get it cleaned up internally by filling with good quality disiel oil for a 1000-1500km oil change period followed by about anouther 2500-3000km period. Oil blended for Diesel engines have more detergent so may succeed in removing build up. However do change the oil filter after the engine is up to temperature and has been in use for the first hour or so. Cut the filter open and if it's clear of rubbish it shouldn't need changing again until the oil is changed at about 1000 km however is there is a lot of trapped material you will need to keep renewing the filter every few hours until there is no everdemce of sludge present.
After a couple of sessions running with disiel oil you should be able to swap to your usual choose of engine oil

[Schurkey]

it may be possiable to get it cleaned up internally by filling with good quality disiel oil for a 1000-1500km oil change period

I about flipped when I thought you were recommending running a thousand KM on Diesel fuel oil.

Took me a moment to realize you're talking about engine oil rated for Diesel engines.

Blood pressure falling to normal range...

[pdq67]

I was divorced at the time and had my three little ones with me one evening.

Had to walk them across town to my ex's Aunt's place, then come back to my car after I put a quart of diesel fuel in my very sludged up old 221 or 260 Ford V-8 one time and tried to drive it home.

Well, the diesel fuel steamed and killed my dizzy! I had to take a spray can of starting fluid to my dizzy top end and then I drained it out ASAP before I could go anywhere. BUT it did desludge the old engine fine! Old engine, you know, the kind with the red oil light blinking at idle OLD!!

Made a hell of an oil spot in the city's gravel parking lot, He, He!!

Drove over to the Aunt's place, got my kids and went to Doc's place in the country. I had my kids that weekend..

The next morning, I changed the oil again as well as the filter but caught the oil for Doc's Ben Franklin wood stove so I didn't make another mess...

Now I would use good old MMO instead of diesel fuel to desludge one...

pdq67

[wwmtlineman]

Id leave the sludge alone. I saw too many sludge clean outs as a mechanic at a Ford dealership. Unless you plan to drop the pan and clean it out you are only causing problems with the oil pump picking up crap and circulating it thru the engine. This causes a lot of lifter problems. Just change the oil & call it good or do it right & drop the pan for a clean out

[engineguyBill]

Well, the diesel fuel steamed and killed my dizzy! I had to take a spray can of starting fluid to my dizzy top end and then I drained it out ASAP before I could go anywhere. BUT it did desludge the old engine fine! Old engine, you know, the kind with the red oil light blinking at idle OLD!!

pdq67

Off the original subject, but

Saw a guy clean the inside of his distributor cap with starting fluid once. Why, I am not sure. As soon as he hit the ignition to start the car the distributor cap blew up into a thousand pieces. Sure was funny . . . . . . . .

[lance flake]

My dad tells story of a fella that had an old buick. It smoked real bad on start up and he was going to pull it and overhaul. Said he put a steam cleaner down in the oil fill hole to wash it before pulling it out. Something cam up he had to go somewhere refilled with oil and drove it for years afterwards no more smoke. Made a big mess on the ground where all the sludge came out the oil pan drain! lol

[BOOT]

Flushing can cause a leak if the sludge was plugging a hole in old gasket FYI. Some say flushing should be done with fresh oil because old oil is already loaded up with contaminates. Some flushes are not really strong enough to do much and just thin your oil, so you deff shouldn't drive on them like some do.