Gear Oil to Remove Sludge and clean out the Inside

[kfxnando]

well maybe someone was just talking smack, however read that adding some gear oil to the engine oil before doing an oil change helps to clean out sludge

will mention why it cought my eye
the fact that the person also mentioned that while cleaning it could couz the motor to smoke a little, as the sludge gets diluted with the rest of the oil

when I bought my Jeep had no idea what oil was in there, so serviced it and used a fully synthetic 5w-40 shell
and after changing oil the vehicle started smoking at the traffic lights only and it started consuming a small amount of oil, witch it did not before the oil change

is there any truth to this

all comments and corrections or my missconception welcomed

 

[Donald]

Whether the sludge gets diluted with the oil or not how is the oil getting where it can be burned and cause smoke?

Whats the condition and mileage of the engine? Jeep 4.0L engine?

An educated guess would be that the synthetic oil cleaned a lot of crud around the valve stem seals and the valve stem seals were not in good shape anyway. They are not that expensive to replace. Pop the valve cover to check. If the synthetic oil cleaned up crud around the ring pack, then you would have better compression and less oil getting by the rings and being burned.

You are running the right oil (I assume the weight is correct) for your Jeep. Leave the gear oil in diffs and manual transmissions.

 

[kfxnando]

thanx very much for the quick reply

yep should of mentioned that its a V8 4.7

milage, huge problem here
the clustrer has been replaced by the previouse owner
and I got the vehicle from a dealer
have very little info on the history of the vehicle
have had the vehicle at the dealers and they have scanned all systems and cant find any thing that indicates the true milage

as for the valve stem seals makes sence
as over 4000km or maybe even 5000km since the last oil change and the motor oil does not look that bad, so yes agree probably not rings
and the exhaust is clean and dry

if its just valve stem seals then it will stay that way for a long time to come

have also been told that once I do another oil change it will get better as the sluge will be gone

on the oil speck, the book say 5w-30, however could not find any at the time, and went with 5w-40

again thanx for the reply, and will skip on the idea

 

[chubbs1]

The whole ATF thing is a practice that has long died out (hopefully). The main reasoning behind using gear oil to "rinse" an engine was because it had a lot of cleaning additives. That may have been true 40 years ago, but it is not true now. Just look at the ATF analysis section. I do think MMO at the recommended dose can help with some problems. You could try some MMO with Maxlife 5w30 or M1 HM 5w30, I would personally try M1 0w40 or Pennzoil Ultra 5w30. There are four great oils at different prices, pick the price and oil that suits your needs.

OH man, I didn't know you lived in SA. What oils do you have easily accessible?

 

[zyxelenator]

If nothing available-- kerosene.

 

[Quest]

LOL! gear oil to rinse/flush engine? That's news to me.

In my 2 decades of dealing with automobile repairs (still actively, but not into it as F/T biz), never heard of this trick.

I've heard (and used before) all kinds of light mineral oil based products as flush: from kerosene, to ATF, to MMO (no longer use it/don't care anymore), to stoddard solvents. Never use gear oil inside a crankcase before.

To OP: you can try some 10-min flush in-a-can (mainly comprised of either kerosene or stoddard solvent of some sort), kreen (from Kano labs), or whatever light mineral oil based stuff.

Just make sure that you do not drive it (put the bearings under load) while flushing it....simply let it run at fast idle or idle til warm..drain and rinse with cheep multigrade motor oil before you perform another of drain-and-fill with your motor oil of choice.

Good luck.

Q.

 

[Ken2]

Neither gear oil nor automatic transmission fluid have detergents to clean an engine. They don't need detergents in their applications. Don't use either.

You did right with a good oil. Stick with that or another good oil. If there is a problem with the engine, no miracle-in-a-bottle will fix it.

 

[mechtech2]

Originally Posted By: Quest
LOL! gear oil to rinse/flush engine? That's news to me.

In my 2 decades of dealing with automobile repairs (still actively, but not into it as F/T biz), never heard of this trick.

I've heard (and used before) all kinds of light mineral oil based products as flush: from kerosene, to ATF, to MMO (no longer use it/don't care anymore), to stoddard solvents. Never use gear oil inside a crankcase before.

To OP: you can try some 10-min flush in-a-can (mainly comprised of either kerosene or stoddard solvent of some sort), kreen (from Kano labs), or whatever light mineral oil based stuff.

Just make sure that you do not drive it (put the bearings under load) while flushing it....simply let it run at fast idle or idle til warm..drain and rinse with cheep multigrade motor oil before you perform another of drain-and-fill with your motor oil of choice.

Good luck.

Q.


Wasn't kerosene in many of the old type pour in a can cleaning additives?

 

[dparm]

Additive packages are totally different in gear oils. No way would I pour that through my motor.

 

[mongo161]

Using Diesel Fuel for an engine flush is another one that I've heard people using for cleaning out sludge from their engines.

I guess any type of fluid with solvents would help to remove some build up inside an engine. The trick is making sure you remove all of the solvent before you start your OCI.

 

[Christian_89LSC_96XJR]

The cleaning effect from ATF might have been due to cetyl palmitate which back then (1950s and 1960s) was a common ingredient.

"Cetyl palmitate is the ester derived from palmitic acid and cetyl alcohol"
cetyl palmitate

This ester may also be a very good solvent. It is available and used in cosmetics and other applications today - but is nowadays derived from Coconut trees and other plant sources.

 

[Michael_P]

Most gear oils are high in sulfur. When these sorts of oils are introduced to an internal combustion engines crankcase even in small quantities, it is not good. The sulfur in the oil reacts with byproducts of combustion along with the engines heat to form sulfuric acid. I have seen UOA's where the TAN is off the charts from people adding gear oil to their crankcase. Add condensation from cool mornings and the most minute amount of coolant in the engine and acid production goes into overdrive. I have put all sorts of weird stuff in my engine just to experiment, but gear lube is not one of them. It is a bad idea.

 

[chubbie]

+1 the sulfuric acid will eat the the main bearings alloy,I have seen the after math of gear lube 80-90 in a manual trans,which called for sincro-mesh.

 

[sullytex]

KREEN!!!!!

 

[kfxnando]

thanx very much for all the answer s

as for what oils are available locally, all the big names are available here
just not every spares place stocks all the fancy oils
as my other vehicles use normal multitudes, had never bothered looking at anything else

have since found where to get the recommended oils, including Castro and Mobil

as to flush the inside of a motor have used diesel fuel as well before, however cuz I read about the gear oil though would ask here, what better place to get such info

thanx again guys for all the great info, have learned a lot from reading here

 

[Need4racin]

gas will clean your sludge out. dump a gallon of that in there.

 

[Vstrom]

Do not use gasoline in your engine oil!

 

[96Cherokee]

Originally Posted By: Need4racin
gas will clean your sludge out. dump a gallon of that in there.


It's comments like this that steer people in the wrong way, joke or not but somebody that don't know anything will try this!

Don't put gear oil or gasoline in your engine!

 

[Garak]

Originally Posted By: Vstrom
Do not use gasoline in your engine oil!


Unless you somehow go back in time 80 years to a northern winter and forget to bring a modern multigrade with you.

 

[mechtech2]

Originally Posted By: Garak
Originally Posted By: Vstrom
Do not use gasoline in your engine oil!


Unless you somehow go back in time 80 years to a northern winter and forget to bring a modern multigrade with you.

Buick and other Mfrs. recommended adding gas to the oil in winter. So did the manual for P47 fighter aircraft.
Modern oils eliminate this technique.