Rav4 T180 - Put petrol into tank should have been diesel

[Jinty]

HELP I put petrol into diesel RAV4 T180 tank , terrible sound like mangled metal.  I had it drained and filters cleaned but the mpg is dropping rapidly, is there anything I can do to reverse this?  Was 34 mpg now 30.4 over a matter of 4 months.  Thank you.

 

[RAV4-D4D]

Never had this problem although I believe if you do misfuel and it causes harm then the damage isn't a gradual thing - I think fairly quickly the fuel pump and/or the injectors give up.

Four months is a long time and it's worth bearing in mind around October time the UK switches to winter diesel and this reduces MPG by a bit. Also, in my experience diesel engines are very sensitive to temperature, I see roughly a 10% difference between driving at temps of 0-5 vs 10-15 degrees; so if you combine that with the falling temperatures from Oct->Jan I would say that's the more likely explanation.

I have a feeling you may be over worrying.

[Mikeyjd]

As above reply. I would say that if any engine damage occurred from the mis-fueling, you would know by now. Maybe try some additive in the fuel?

[Catlover]

Have you not noticed in previous winters that your fuel consumption usually goes up (worse). This is due to winter temperatures dropping. Conversely, come the warmer weather and you should see the fuel consumption lower (better). 

 

[Dippy]

How long/far did you run it with the wrong fuel?

[Mark T180]

On 2/17/2020 at 6:01 PM, Dippy said:

How long/far did you run it with the wrong fuel?

Exactly my question too.

I understand that diesel engine pistons are lubricated by the fuel itself, so putting in petrol would wash the bores clean and rapidly lead to frictional damage like bore scoring etc. 

A very short run and you might be okay, but any significant distance and you would expect damage. 

[Catlover]

In the original post Jinty did say he had tank drained and filters cleaned.

However, Jinty joined the forum 14 Feb, did his original and only post 14 Feb, and not visited the forum since Feb 14.

[philip42h]

In the original post he did also say ...

On 2/14/2020 at 11:46 AM, Jinty said:

...  terrible sound like mangled metal ...

... which made me fear that it was already "too late". But, as others have said, unless and until Jinty comes back with a bit more detail we can only speculate ...

[gjnorthall]

Years ago drivers would add a little petrol to a tank of diesel to minimise waxing in cold weather! However this would be ill advised on modern diesels. Diesel lubricates the fuel pump and injector shuttles and the solvent action of petrol reduces lubrication. The fuel pump is easily damaged without lubrication and shards of metal will be dispersed through the system. It's reckoned that putting up to 5% petrol into diesel won't usually do long term harm. Therefore if you realise when you've dispensed a couple of litres of petrol - you might be able to save the day by then brimming the tank with diesel. If you've actually filled up with petrol, then there's no option but to drain - both switching on the ignition (if there is a primary pump) or starting the engine will cause fairly rapid damage. Unfortunately many drivers don't realise their mistake until the car subsequently grinds to a halt. Fuel companies don't help prevent errors - diesel and petrol nozzles are often in a mixed array on the pump.

[furtula]

You are not reading the whole topic...

This happened over 4 months ago, and his main concern is the MPG drop.

Quote

Was 34 mpg now 30.4 over a matter of 4 months.  Thank you.

It looks to me he had 34 mpg during summer, as he writes that he now has 30.4 in the last 4 months, which are winter months.

We don't know how long he drove, and the mangled metal could be pre ignition once the gas reached the system, after which he quickly turned it off, best case scenario.

 

[gjnorthall]

I infact read the full thread and I'm responding to the general issue of erroneously putting petrol in a diesel tank. A couple of posters were concerned about the after effects of petrol contamination.

[Mark T180]

Regarding garages, I inadvertantly put petrol into my merc diesel and had to have it drained. Had the drain done back at the garage in question and whilst standing around glanced across to the pump in question to see that the petrol pump was actually fitted with a black plastic handle rather than the green it should have been waring. It was my fault, but that mix up in colours removed a final visual check. I wouldn't put it past the garage to have a deal going with the guy who did the fuel drain; he did say he was called out to the garage in question quite freqently! 

I could have had a go at the garage, but I was just happy to survive the incident without engine damage as a drove around the block before realising. Initially thinkig the problem was cheap contaminated fuel. 

 

[Avalon]

Even ignoring that it’s unlikely to have caused a serious issue if run to the point the engine cuts out, such minor differences could be down to fill variation, cold weather, winter fuel package, under inflated tyres, running heater/AC more, change in driving route/style etc. Unless you have a few years of data to compare to, it’s a storm in a tea cup. I say this as the 4.2 I currently run was filled with petrol (not by me) and run to the point it died, that was over 60,000 miles and a decade ago. Tank was drained, filter replaced and fresh fuel flushed through, no related issues since.