Engine Flush Question

Status
Not open for further replies.
Joined
Sep 2, 2010
Messages
141
Location
Wauconda, Illinois
My 2007 Prius has 215,000 miles. I was going to use Liqui Moly Engine Flush.
1. I was going to drain and fill with fresh oil, do the Flush, do a fresh filter and oil change
2. I'm running T6 5w40 due to oil consumption with 5w30
3. For the Flush fill and drain, should I use the 5w40? Or a lighter weight oil? Which one would help clean better?

 
The first thought that comes to mind is: Have you verified that the engine in that vehicle is in need of a flush, or are you just doing this as a "preventive measures" sort of thing?

T6 is a pretty darn good oil when it comes to cleaning things up, so I have to wonder if a flush is really even necessary.
 
Originally Posted By: SirTanon
The first thought that comes to mind is: Have you verified that the engine in that vehicle is in need of a flush, or are you just doing this as a "preventive measures" sort of thing?

T6 is a pretty darn good oil when it comes to cleaning things up, so I have to wonder if a flush is really even necessary.


More of a "preventative maintenance" step. I had some long OCI in the past. Read some users on the Prius Chat Forums did the flush with good results. Supposedly there are a couple of oil channels that get clocked up over time. I've had her since new.. i don't mind paying a few dollars for a TLC.

The current fill is only my 2nd fill with T6. Engine seems smoother and no detonation at load. I was using mostly M1 5w30 it's whole life. After 150k, it started consuming oil to the point of almost 2 quarts at 5k OCI. With the 0w40 T6.. i can go the whole OCI without adding oil
smile.gif


The oil consumption is an issue with these engines. Some have had success with removing the spark plugs and soaking the cylinders with Sea Foam or similar. Guess the rings get stuck in one position and freeing them helps tremendously
 
If you use lighter oil, you will consume more oil, you can continue what you are using or use Castrol euro 0/40. That is good with good mfg specs. I wouldn't do a flush if you have changed your oil on a regular basis
 
Never use a flush unless you are sure your engine needs it.This should not be done just because. If you change your oil on schedule then your engine is clean enough.
You can cause more issues.
 
Originally Posted By: Dallas69
Never use a flush unless you are sure your engine needs it.This should not be done just because. If you change your oil on schedule then your engine is clean enough.
You can cause more issues.


Agreed. But you may want to do the Seafoam soak you mentioned.
 
Originally Posted By: Bullwinkle007
If you use lighter oil, you will consume more oil, you can continue what you are using or use Castrol euro 0/40. That is good with good mfg specs. I wouldn't do a flush if you have changed your oil on a regular basis


I have no intentions of using anything other than 0w40. Actually, I have Castrol Euro 0w40 waiting in the garage for the next OCI. I used that in my german cars and it worked great!!!

My question about the lighter weight oil was for the 10-15 min while doing the flush only. But, reading these comments, i'm not sure I should do an engine flush??
 
Originally Posted By: Dallas69
Never use a flush unless you are sure your engine needs it.This should not be done just because. If you change your oil on schedule then your engine is clean enough.
You can cause more issues.


How do you know if "you need it"?? I'm going off of reading some favorable posts on the Prius Chat Forums.

I did 15k OCI back in the day.. once it started consuming oil, I switched to 5k. There was one OCI that went over 20k
frown.gif
I did a UOA and there was still some life in the oil..
 
Last edited:
If the inside of your engine has enough deposits that you need to do an engine flush, you should also plan on pulling the oil pan and cleaning the oil pickup screen afterward. If you're not prepared to do this I would l probably skip the engine flush.
 
Originally Posted By: JamesBond
If the inside of your engine has enough deposits that you need to do an engine flush, you should also plan on pulling the oil pan and cleaning the oil pickup screen afterward. If you're not prepared to do this I would l probably skip the engine flush.


Very true! Just might skip the engine flush and continue using quality oil 👍
 
I used that same product in my old 1990 Toyota Camry 2.0L acouple years ago. That and paired with Mobil One HM 10W40 cut consumption down drastically. Before the engine flush, I was using 10W30 and going through a quart every 1500 miles. LM makes good/reputable products.

Dale
 
The risk is likely not worth it. I have seen more than a few vehicles that dumped in engine flush chemicals and the flush ends up doing more harm than good and they end up replacing main seals and other oil gaskets and clogging up the oil pickup and and they end up with a ride on a wrecker. Not worth the risk IMO. Do a couple of short 2 to 3 K OCI's with the OM recommended weight of oil and change filter each time and that will clean it up without being overly aggressive.
 
Originally Posted By: BAJA_05
I used that same product in my old 1990 Toyota Camry 2.0L acouple years ago. That and paired with Mobil One HM 10W40 cut consumption down drastically. Before the engine flush, I was using 10W30 and going through a quart every 1500 miles. LM makes good/reputable products.

Dale


The oil consumption with the 5w40 has been cut drastically. I was trying to take it one step further with the flush.. However, all these posts have me a little concerned

[/quote]
Originally Posted By: BJD78
The risk is likely not worth it. I have seen more than a few vehicles that dumped in engine flush chemicals and the flush ends up doing more harm than good and they end up replacing main seals and other oil gaskets and clogging up the oil pickup and and they end up with a ride on a wrecker. Not worth the risk IMO. Do a couple of short 2 to 3 K OCI's with the OM recommended weight of oil and change filter each time and that will clean it up without being overly aggressive.


You're probably right.. which oils out there are more aggressive with cleaning?
 
Last edited:
Not the oil that is aggressive, I am referring to the chemical engine flush products. All modern oils have detergents in them as part of their additive make up.One brand is probably as good as another. Even the engineers at Blackstone agree with that The bottom line is that the detergents in oil are not going to be as aggressive as oil flush chemicals. These oil flushes often can over clean and dissolve sludge and create leaks and other issues. At best a flush will remove the sludge with no harm and no foul , but at worst it can cause leaks and more expenses.
 
Originally Posted By: Bullwinkle007
I wouldn't do a flush if you have changed your oil on a regular basis


AGREED

Originally Posted By: Dallas69
Never use a flush unless you are sure your engine needs it. If you change your oil on schedule then your engine is clean enough.


Yes, if you are paranoid,
just run a few short (3,000-4,000) mile OCI on any good dino oil (yes, even SuperTech)
 
Just because you see a clean valvetrain does not mean that none of your oil channels/passages/drain holes are free and clean from small debris. Same applies to piston ring lands.
Do the flush and don't look back. It WILL Crack loose a couple things here and there, and over next couple OCIs 0w40 oils will finish up the cleaning of those tiny openings, thus improving your oil consumption.
 
Status
Not open for further replies.
Back
Top