Diesel in a petrol engine

Not done very often but worth a mention anyways.

These are a much more difficult job to deal with than a petrol in diesel scenario, firstly diesel fuel lines are very easy to access, but petrol fuel lines are armoured for obvious reasons and do not have easy access for clipping onto for a fuel drain.

Further a petrol engine flooded with diesel hates starting.

But the real danger here is from an oil level increase which may sound odd since we are talking about fuel and not oil.

Back in the day we used to run our vans which were petrol  on fuel we had recovered from diesel cars, take for instance a diesel land rover discovery that  inhaled 98 litres of petrol and needed draining, we would pump that straight into our VW transporter 5 cylinder petrol and run on it.

Sure it smoked a bit, and gunged up the cat and o2 sensor, but we bypassed that, free fuel was worth the hassle.

The only downside was that the diesel that was in the petrol did not always burn off in the piston, what happens next is the diesel in the piston slides past the piston rings into the oil sump, and it raises the oil level, also diluting the oil with diesel – which is much thinner than oil should be.

The way round this was to suck out the oil every time we filled up with fuel, it was a bit of a messy old set up but it went like this, fill up with contaminated petrol and remove oil with vacuum kit until it was a bollock hair above minimum, on the next fill up it would be 2 litres over maximum, at which point we would suck out all the oil (thru the dipstick pipe) and put in 3 litres of clean engine oil which was the minimum mark, sounds like allot of work but it reduced our fuel bill by 400 pounds a week and it was well worth the hassle, meanwhile the oil we bought in bulk cost less than fuel per litre, thus 3 litres of wasted fuel for every second fill up was a drop in the ocean.

Like i said it did ruin the Cat, and the O2 sensor, and it never performed fantastically but over the 6 months we trialled it we did save over 10k.

When the transporter finally died we decided to be grown ups and buy a brand new diesel van and it only gets fuel from the pumps, the recycling man now gets our mixed fuel and our days of sucking out oil are but a memory.

for anyone who has put diesel in a petrol motor, you should monitor your oil level closely, it will rise, and left unchecked it can cause very serious harm above a certain level.

I suggest you monitor it and get an oil change very soon after, and keep an eye on it, 2 or 3 oil changes in quick succession is a lot cheaper than wrecking the engine.



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