Engine flush vs synthetic oil

[anylettuce]

Saw something the other day and it makes sense but has me wondering about running synthetic

If a vehicle has built up sludge and junk, you run a engine flush treatment the treatment can dislodge the sludge and potentially plug oil passage ways.

This makes sense but synthetic oil also cleans tge engine. Or does synthetic also clean the engine but at a slower pace.

 

[Lapham3]

I've done it both ways OK, but as the sludge builds up slowly over time, I think the safest is removal in the same way with more frequent oil/filter changes. Mechanical removal can help where practical-such as valve covers and also a good way to evaluate all-good luck

 

[FCD]

At least for classics engine flushes are a bad idea if the engine has not been rebuilt.
I have heard of a guy with a Ford Capri like mine that had been run on cheap conventional oil for all of it's life, he did an engine flush and when he started it , all the sludge blocked the oil pickup screen and the tube, the engine lost oil pressure and the engine had to be rebuilt.
this likely won't be the case with a modern engine though

 

[Popsy]

Synthetic (or not) detergent oil will clean, but slower. I did several short OCI with Semi Synthetic diesel oil to clean things a bit, then an engine flush. Wouln't dare an engine flush directly in a neglected engine, but that's just me maybe.

 

[Donald]

First you need to determine if you even have sludge. Pull a valve cover. Is the sludge gooey or crusted on? Synthetic oil will remove the sludge slowly as will Auto-Rx.

In reality, if the sludge is not excessive and not causing engine problems, then you only need to work at removing it slowly or preventing any more.

 

[OneEyeJack]

I've helped a couple of friends with sludged up engines and Auto-RX did the trick, slow and easy.

 

[UltrafanUK]

Originally Posted By: Popsy
Synthetic (or not) detergent oil will clean, but slower. I did several short OCI with Semi Synthetic diesel oil to clean things a bit, then an engine flush. Wouln't dare an engine flush directly in a neglected engine, but that's just me maybe.


Very correct!
If you have seen actual lumps in the oil when drained, OR the oil pressure warning light has just started flickering at hot idle after a fastish run, then it's a real good idea to drop the sump and clean the pan and oil pump intake screen in particular. Easy job with some cars, a real PITA with others as it might involve removing cross beams and then lowering the engine enough to get the pan off.
Always worth checking the HG if an engine that was well maintained has sludged out, as anti freeze reacts with the detergent/dispersant additives and stops them working.

Using a driver around oil scourer like Marvel is only risk if the engine has a turbo that you like to boot into action. The solvents can be too effective with a badly sludged engine and block the oil filter or the turbo oil feed pipe. Not an issue at idle (Idle use flushes are safer to use), but a real potential disaster at redline RPM.

Mobil 1, Penn/Shell Ultra and Amsoil synthetic all have a lot of detergent additives, although top dog of the cleaners is Ultra 0w30 (A3/B4) due to the natural solvency of its GTL (Group 3 plus) base stock.

 

[demarpaint]

My buddy bought his daughter clean 02 Century to go to a summer job and college this fall with. A peek down the fill tube revealed some sludge and varnish, the interior and exterior of the car are much better. He ordered Kreen and I gave him Mobil 1 Turbo Diesel Truck 5w40 to use with it. I could have sworn I loaded all the Mobil 1 Turbo Diesel Truck in the trunk of my 00 Century I shipped to my son. Anyway that seems to be a nice combo. Three thousand miles later the improvement was tremendous. Now he'll run Pennzoil Platinum 5w30 and a Mobil 1 filter. That should finish up where the Kreen left off and keep it clean.

 

[tig1]

The best solution to the sludge problem is use a quality synthetic from the start.

 

[BrocLuno]

Not an option when buying a used car ...

8 oz of Kreen from Kano labs will do the trick in about 5 oil changes. A bit more aggressive than high detergent synthetic HDEO like Rotella T6, but well within safety bounds as long as you do not dump in a whole bottle

 

[vitez]

I've used Amsoil's engine flush every time I've bought a used vehicle, which is most. Never an issue.

The previous formulation was solvent based, and I would use it, put in cheap conventional oil, go for drive, then change it to whichever synthetic I was using. I was concerned about residual solvent. Now with its detergent formula, I just use as directed and install the oil.

I agree though, I wouldn't use an engine flush in a classic car with a non-rebuilt engine. If the engine is still running after decades of conventional oil leave well-enough alone.

 

[GaleHawkins]

The 2006 Ford Five Hundred that we picked up this year w/110K miles has the cleanest looking oil and top side looking down the oil fill hole. It had been owned for the last 10 years by a Ford salesman (it was his wife's car) and he had had it changed ever 5K miles in the Ford shop by the manual.

 

[GaleHawkins]

Originally Posted By: OneEyeJack
I've helped a couple of friends with sludged up engines and Auto-RX did the trick, slow and easy.


We now run Archoil AR9100 additive in all engines which has ester cleaners like Auto-Rx plus a friction modifier. Like Auto-Rx it works faster in non PAO based motor oil. Before I would like to run Seafoam about 20 miles before draining for an oil change. Now I see no need to use any addition flush. The AR9100 claims to leave the metal coated so there are no dry starts ( we have a lot engines that mainly set without starting very often) so I do not not to flush any off of the moving parts with a flushing agent.

 

[SR5]

My car looked OK down the oil fill hole, a few patches of light varnish, no big problems.

I used some GTL Shell Helix Ultra recently and changed it out early at about 4,000KM (2,500 mi). When I looked down the oil fill again I was amazed at the difference, it was all gleaming inside.

I thought this Pennzoil / Shell Ultra cleaning talk was marketing hype. I stand corrected.

 

[Doog]

Skip all of the snake oil AutoRX garbage....go to Walmart and get some PP and start using that. Over time it will clean your engine.

 

[alcyon]

Originally Posted By: SR5
My car looked OK down the oil fill hole, a few patches of light varnish, no big problems.

I used some GTL Shell Helix Ultra recently and changed it out early at about 4,000KM (2,500 mi). When I looked down the oil fill again I was amazed at the difference, it was all gleaming inside.

I thought this Pennzoil / Shell Ultra cleaning talk was marketing hype. I stand corrected.

I have been using grp 3 synthetics since 11 years back. Never had varnish, slugde, hard starts, clogged PCVs, clogged carb .
MPG is as good as it was 11 years ago too. Clean engine does keep an engine running great. No noticeable oil consumption too. I am sold on grp 3 synthetics.