Adding unleaded to diesel
Submitted: Thursday, Feb 28, 2008 at 13:23
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Ron173
G'day all,
Some time ago I accidentally picked up wrong pump whilst talking and had put $20 unleaded in my diesel tank before I noticed.
Couldnt drain it, so topped right up full so concentration was minimal, it ran a bit lumpy, and I kept topping up every so often to keep diluting it.
End result was no damage and it certainly decoked it a heap, ran like a train after it for ages.
I also spoke to others who did this by accident and they said same, after initial getting rid of petrol, performance great.
Now I wouldnt do it again, not on purpose anyway, but I could do with that bit of a perk up again.
Also talking with mates, apparently its an old truckers trick to put a few ltrs unleaded in with a full tank for a bit extra punch when big loads on.
So my question is....
Is it good to ocassionaly put in a % controlled amount of unleaded to clean out head n pistons?
Anyone do this, if so what dilution and tell us of your results?
I'm kinda thinking a litre in a full tank of 60ltrs couldnt be bad every couple months, and poss be quite good.
Opinions???
Rgds
Ron
Reply By: Member - colin M (NSW) - Thursday, Feb 28, 2008 at 13:38
Thursday, Feb 28, 2008 at 13:38
Made the same mistake in
Broken hill last year but drained the lot out as I was under impression it could explode. When I came back on went on to this
forum and found out that it is apparently standard practice amongst some of the emergency service guys.
However as I am no technical expert I would refer it to your vehicle manufacturer. Most likely you will get plenty of response on this site over next few days
AnswerID:
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Reply By: Member - Davoe (Yalgoo) - Thursday, Feb 28, 2008 at 13:42
Thursday, Feb 28, 2008 at 13:42
Hmm $20 approx 16l
I have done i once with no ill effects but I ould certainly start geting nervous with much more depending on the size of you tank thats about 20-25%
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Follow Up By: stefan P (Penrith NSW) - Thursday, Feb 28, 2008 at 13:46
Thursday, Feb 28, 2008 at 13:46
I am watching this with interest, as it has crossed my mind to chuck maybe around a 3-5 % mix in for a bit of a clean.
Cheers Stefan
FollowupID:
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Follow Up By: Ron173 - Thursday, Feb 28, 2008 at 13:54
Thursday, Feb 28, 2008 at 13:54
Hi Davoe, Stefan
oh yes 25% waaaay too much, couldnt agree more, I just couldnt get it out.
But it ran sweet as afterwards, and I could see the carbon coming out the exhaust while petrol mix was in there.
Never do it again, I was majorly nervous till it came good, but mines an older diesel, new ones it will stuff the pump for sure.
I am very interested though in adding a SMALL amount in a controlled dilution occasionally for cleaning purposes.
Also watching with interest!
Rgds
Ron
FollowupID:
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Reply By: Member - Doug T (FNQ) - Thursday, Feb 28, 2008 at 13:56
Thursday, Feb 28, 2008 at 13:56
Done the same at
Blackall BP 3 years ago , $30 into the nearly empty rear tank, run it out of town a couple Ks on the front tank and dropped the lot into the table drain, and for the greenies reading this ....last I went passed the site the grasses were were thriving.
.
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Follow Up By: Member - barry F (NSW) - Thursday, Feb 28, 2008 at 18:37
Thursday, Feb 28, 2008 at 18:37
Yeah OK but what sort of grass was it!! LOL
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Follow Up By: Member - Doug T (FNQ) - Thursday, Feb 28, 2008 at 18:54
Thursday, Feb 28, 2008 at 18:54
Barry
Never you mind .........secret
.
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Reply By: Russell [SA] - Thursday, Feb 28, 2008 at 13:57
Thursday, Feb 28, 2008 at 13:57
My old diesel Terrano manual indicated a 30% standard petrol diesel mix would not damage the engine. Never tried it mind you.
Russell
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Reply By: Notso - Thursday, Feb 28, 2008 at 14:41
Thursday, Feb 28, 2008 at 14:41
I remember back in the old days, the Mercedes Handbook recommended putting up to 10% in the tank in the winter. But that must have been back in the 60s
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Reply By: Member - Tour Boy- Thursday, Feb 28, 2008 at 14:54
Thursday, Feb 28, 2008 at 14:54
On all of the 2H and 1HZ powered Yotas I have had I used to put 1/2 litre per full tank EVERY tank and never had a problem. I used to get 270,000km + out of a set of injectors and 9.5 to 11 litres per 100km religiously.
Never had probs with frozen diesel or fungus either
But it's up to you.
Regards
Dave
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Reply By: traveller2 - Thursday, Feb 28, 2008 at 15:13
Thursday, Feb 28, 2008 at 15:13
Isn't 'alpine' or winter diesel just got some unleaded added.
I too put 20l in the back tank of the troopy accidentally, ran it for little while, swapped tanks and kept doing that till I had used enough to be able to add diesel to the back tank to get the ratio down. Never seemed to hurt it.
I'd reckon with the older donks you could get away with a few percent mix with no worries, don't know about these new fangled things though.
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Reply By: Member - DOZER- Thursday, Feb 28, 2008 at 15:52
Thursday, Feb 28, 2008 at 15:52
Was talking about this today with a mate who has a 300,000km 1hz. He ran 20 litres of avgas 50/50 in his motor and it has never ran so good afterwards....the avgas had upper cylinder in it as it was ment for a Herkules motor ....
Andrew
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Reply By: Member - Olcoolone (S.A) - Thursday, Feb 28, 2008 at 15:54
Thursday, Feb 28, 2008 at 15:54
Why do you have to clean the tops of your pistons and how do you know they are dirty?
Diesels are surpose to run on diesel and petrol engines on petrol and before someone says "what about LPG" yes both engines can run on LPG.
Regards Richard
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Reply By: Member - Oldplodder (QLD) - Thursday, Feb 28, 2008 at 16:01
Thursday, Feb 28, 2008 at 16:01
Assuming less than 10% petrol in the older model diesels., i.e. not common rail, I would be a little worried about what it did to the fuel injection pump seals?
Any idea what it would do?
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Reply By: Ron173 - Thursday, Feb 28, 2008 at 16:09
Thursday, Feb 28, 2008 at 16:09
Well this ones generated a bit of interest and more to come I suspect.
Someone asked why you would do it.
To decoke your engine without pulling the head off, hence improving efficiency and economy.
The question I'm asking is not so much will it be ok, but what are the positive benefits.
Has someone got better figures after doing it?
Rgds
Ron
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Reply By: Truckster (Vic) - Thursday, Feb 28, 2008 at 16:21
Thursday, Feb 28, 2008 at 16:21
I went close to 50/50 in the GQ once 4-5am after an all day/nighter at work
Almost idled
home from SPringy/FTG road to Langy.. drained the fuel into the back paddock, drove round to servo on what was in the lines, filled up with diesel, and its still going today.
no change of filter or anything.
Wouldnt do it regularly though. not worth the stress levels.
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Reply By: Robin Miller - Thursday, Feb 28, 2008 at 16:30
Thursday, Feb 28, 2008 at 16:30
Hi Ron
A bit of contamination doesn't cause to many dramas, and it is a rough way to do a bit of decoking, but don't make a habit of it as its a bad idea generally.
Remember that your engine needs a certain cetane value in the fuel so it ignites and petrol directly degrades this apart from other issues such as potential to not fire at all.
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Reply By: Member - Bucky (VIC) - Thursday, Feb 28, 2008 at 16:35
Thursday, Feb 28, 2008 at 16:35
Check out this post !
ThreadID: 53646
gr8 reading !
05 Navara still going strong !
Cheers
Bucky
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Reply By: Member - Adam S (SA) - Thursday, Feb 28, 2008 at 16:46
Thursday, Feb 28, 2008 at 16:46
Howdy Ron.
As others have said a small percentage may not hurt,
but the injector pump has only fine tolerances and by substituting diesel with petrol you lose the lubrication of the diesel.
I know of one case where this was an expensive repair.
Cheers,Adam.
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Reply By: Eric Experience - Thursday, Feb 28, 2008 at 21:24
Thursday, Feb 28, 2008 at 21:24
Ron
The Mercedes owners hand book still states that you can use up to 20% petrol in cold conditions.Remember Mercedes made the first Diesel car 100 years ago this
Easter. A lot of car yards use a higher percentage to clean up an old smelly motor. The petrol burns slower it does not provide any extra power, it heats up the piston and valves and will loosen some carbon. Do it when you are not towing or driving hard. Eric.
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Follow Up By: Member - Davidp P (VIC) - Friday, Feb 29, 2008 at 00:08
Friday, Feb 29, 2008 at 00:08
Hi Ron...was that Merc a current state of the art diesel? cheers silverback
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