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Diesel Fuel In Motor Oil!

RB240Dav

By RB240Dav,
in Engines & Forced Induction

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RB240Dav Enthusiast

RB240Dav

Posted
Posted

I have heard it mentioned on here before, however there isn't a topic discussing its pros and cons.

I have started and ran my rb26 a couple dozen times for a total of maybe 30minutes. This may be the first time the engine has run in years (no history). I'm getting my driveshaft back tomorrow and will be taking the engine and car for it's first spin.

I would like to make sure the motor is free of sludged oil and give it a good flushing. I have heard the 1 quart diesel fuel to 4 quarts standard oil is good. My plan is to drive it 15 miles down the road with the fuel in it and get it changed at the local dealership. (can't wait to see the look on their faces LOL)

Is this safe?

Is it the best way to go?

I have heard that this will help reseat the rings if needed.

Do I have the right fuel to oil ratio?

Will 15 miles (20 minutes) be too long? not long enough?

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https://www.sau.com.au/forums/topic/94323-diesel-fuel-in-motor-oil/
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Beer Baron Grand Master

Beer Baron

Posted
Posted

i wouldn't do it. mainly because i don't fully understand what negative effects it could have. I have previously used wyns oil flush before with good results. but my advice is to crank the engine a little to build some pressure, take it for a 15min drive, come back, drop the oil and change the filter then re-fill with your new oil.

RB240Dav Enthusiast

RB240Dav

Posted
  • Author
Posted

If no one here has tried it, and we're all a little leary about it, what engine flushing products out there do you recommend.

p.s. this is an old timer's trick, my Great Grandfather used mineral oil. Funny thing is, he always went overboard, so if 2 cups was good, then 2 quarts must be better. They let it sit running for 45minutes until they heard *clackity clackity CLUNK* Siezed the motor!! LOL

discopotato03 Grand Master

discopotato03

Posted
Posted

Your choise , I would not put diesel fuel anywhere near the sump . Diesel fuel is exactly that - fuel not lubricating oil so no guarantees it will lubricate . It will thin the oil down thats for sure .

My own experience was to use diesel engine OIL but only because it was a high detergent type used in EMD/GE locomotive diesels .

If I was you I'd run reasonable engine oil in it and change it and the oil frequently for a while . The only way without opening it up to remove gunge is by draining the oil and changing the oil filter .

Cheers A .

ebola Proficient

ebola

Posted
Posted

Plenty of people have done it.

of course, most of those people own diesel vehicles (and usually older ones)

from what I understand blowby of diesel can get into the engine oil.

and it could combust. Ever wondered why even on modern diesel vehicles they have such a short oil change limit?

if you DO decide to try it, remember diesel combusts under pressure. it doesn't need a spark to ignite.

All I can say it, no way in hell I would do it.

Busky2k Veteran

Busky2k

Posted
Posted

Probably the safest way to thin the oil is to use some ATF. Its safe for a flush cos it still has antiwear/seal swelling (etc) additives and yeah, I'd try no more than a 50/50 dilution with normal oil. If you are a tight ass, you could try adding a litre of kerosene but it may screw up your seals...

RB240Dav Enthusiast

RB240Dav

Posted
  • Author
Posted

LOL, tight ass, nah, just looking for some good old proven methods.

hmm, not sure about that one. For example, I know that if you add brake fluid to hydraulic oil (we're talking 2 teaspons to 3 gallons) it'll cause the rubber seals to swell enough to temporarily stop leaks.

I'd be a little over cautious about adding that one, unless ofcourse, somebody has had experience with it.

68charger Apprentice

68charger

Posted
Posted

The problem with "flushing" your engine like that is all the bits of sludge etc that you dislodge end up somewhere, usually blocking fine oil passages etc. I strongly advise you not to do this. If you must try and clean it out you could use an engine oil developed for diesel engines such as castrol rx super(providing the viscosity is correct), diesel engine oils have a very strong detergent content. But I wouldn't even do that.

You should just use a high quality engine oil and change it after a thousand kays or so.

If you really are paranoid about sludge or whatever have the engine torn down and cleaned/inspected.

Just my opinion/thoughts.

Graham

Wazz Community Regular

Wazz

Posted
Posted

ok.. was discussin this with a mate the other night.. use the wyns flush stuff let it idle for 10 minutes turn off and usual change oil and filter

a mate put it in and left it in for a couple days the engine devoloped a massive knock and overheated pretty bad (240 farrenheight dunno wat that is in celcuis) that was in a old 308 thats been cained constantly for 8 years since it was built when the oil was dumped it was like water.. not good so yer if you wanna do it let it idle for 10 minutes with the stuff in it than drop it change filter and put new oil in

Wazz

RB240Dav Enthusiast

RB240Dav

Posted
  • Author
Posted

Well thank you, questions answered!!!

I will just go with the normal oil change, just every 500miles a couple times. I'll stick with normal oil as well since synthetic's don't have a lot of detergents in them.

Thanks again.

See you on the flip side.

r33_racer Grand Master

r33_racer

Posted
Posted

your running a fairly high tech multi valve turbocharged motor and your gonna run a mineral oil in it. Mate its not a commo or falcon sorry gm/chev/ford. you wanna give it a good sporting chance by using full synthetic oil or some form with the right viscosity. You may even have to use a slightly thicker grade if the engine is a little old and worn.

RB240Dav Enthusiast

RB240Dav

Posted
  • Author
Posted
LOL synthetics dont have a lot of detergents in them? Seems like you need some re-education :D

Synthetics almost always contain higher amounts of detergents in them compared to mineral oils...

You're right, I don't know what I was thinking. Hence, switching from a mineral based oil in an old engine to straight synthetic can cause chunks of buildup to lift off into the motor. I'm running around here at the shop with an average of 3hrs of sleep a night (often getting online before I head home) getting this car on the road. I won't even bother to explain the super tired line of thought.

I fully plan on using some high grade synthetic!!!!! Just not to flush the motor out. Granted the motor is used, but I want to treat it like a brand new motor which would require a mineral based oil to break in properly. Plus I don't see the need for a good synthetic when I'm going to be dumping it in 500miles anyways.

carl h Proficient

carl h

Posted
Posted

try using a qt of kerosene, its been done before and a national parts chain's engine flush is mostly kerosene.

works well, just dont run the motor under load and change the oil right afterwards but allow for a good draining as you want as much of the kero/oil mix out of the motor.

Busky2k Veteran

Busky2k

Posted
Posted (edited)

Synthetics breaking off 'chunks' of crud in a high mileage motor is nothing but a stupid myth. If anythings gonna do it, its your idea of throwing in kerosene or diesel fuel into your motor. :huh:

The detergents in oil do almost nothing for existing deposits. Rather, they help prevent them instead by keeping the contaminents in suspension. Once they deposit and form varnish or sludge, these detergents cannot do anything about them. Besides, PAO base oil synthetics have a low solubility coefficient and thus dont readily dissolve crud anyway. They're good at not leaving them there in the first place.

Edited by Busky2k
carl h Proficient

carl h

Posted
Posted
try using a qt of kerosene, its been done before and a national parts chain's engine flush is mostly kerosene.

works well, just dont run the motor under load and change the oil right afterwards but allow for a good draining as you want as much of the kero/oil mix out of the motor.

hehe, i didnt reccomend he use it now...... :(

T04GTR Grand Master

T04GTR

Posted
Posted

engine flushes are shit. only good if the motor has low kays.

all the crap that it cleans off ends up bieng jammed i the crankshaft and blocking it. thats why peaple "grub screw the crank" so yoy can remove them and clean the sludge out.

just use a good quality semi or full synthetic.

my 32 gtr has done 160000kms and i use penrite syn 5 (5w-60) and it works a treat.

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