Unleaded petrol mixed with Diesel in a Chrysler 2.5CRD

Priming the system could cause severe damage only because the pump could be
turning dry. Petrol is wet but to help it lubricate better then add a pint
or so of engine oil to the tank. There should be absolutely no problem then
and at the concentration suggested by the OP, no problem anyhow.

Huw

 

Yes, just add no more than a pint of engine oil to 15 gallons of fuel mix.
Using ATF would even help clean the injectors.

Huw

 

Priming the system, if not done properly, most certainly can ruin the pump.
However, a bit of petrol will not. Much more than 40% probably would result
in damage even with some lubricating oil added.

Huw

 

But she has driven it home from the petrol station which was about 3 miles.

 

Bugger, that's a bit late then. Oh well, the choice is yours. If you do
decide to take a chance I'd highly recommend selling it soon then, if it
does prove to be the worst, then you are talking a lot to fix it.

 

[Snipped Text]

You're use of 'could' and 'should' is obviously taking a slightly
hesitant stance on this one.

Unless you've actually seen results of either option, then taking the
safest is best IMHO. It's a bloody expensive gamble if you're wrong -
and you are going against the advice of the manufacturers!

 

I wonder how much it takes to prime the system? If you'd just put petrol
into a tank that still contained some diesel, then the system was
primed, is it going to take in significant amounts of petrol? If you
realised your error and waited a bit, would the petrol separate out from
the diesel and float on the top? You could in theory then brim it with
diesel and drive, very carefully, to a garage, or siphon it out.

Mind you, I rarely lock my doors at a petrol station, but I do take the
keys out...usually...

 

I think Andy Hewitt is overstating the case in rather overly-dramatic
terms of imminent car death and immense repair bills. Yes, CRD fuel pumps
require full-time lubrication. Yes, they're intended to pump diesel rather
than petrol. But, it is simply unrealistic and unnecessarily operatic to
assert that the tiniest percentage of petrol will take out the pump,
destroy the engine, necessitate complete replacement of the entire fuel
system, etc.

Work through the maths: The OP has stated the vehicle had 1/4 tank of
diesel when his wife drove onto the forecourt. That is probably an
*indicated* 1/4 tank, which in real volumetric terms equates to more like
1/3 tank (accounting for the reserve quantity of fuel in the tank when the
gauge indicates Empty). He further states his wife put in 11 litres of
petrol followed by 40 litres of diesel.

Working from the 1/4-tank start (worst case), that means 40 litres diesel
plus 11 litres petrol = 51 litres = 0.75 tank volume. Therefore, 11 out of
68 litres are petrol, and 57 out of 68 litres are diesel. Therefore, the
tank contains -- worst case -- 16% petrol.

Working from the 1/3-tank start (best case), that means 40 litres diesel
plus 11 litres petrol = 51 litres = 0.67 tank volume. Therefore, 11 out of
76.5 litres are petrol, and 65.5 out of 76.5 litres are diesel. Therefore,
the tank contains -- best case -- 14% petrol.

Diesel fuel is sold all over the world. With the exception of North
America, so is the CRD PT Cruiser. The diesel fuel sold all over the world
is not the same. Its formula is varied to account for local climatic
conditions. It is thinned considerably for cold regions, otherwise it
would be unusable.

In real terms, therefore, the effect is as if the OP had bought a tankful
of diesel in winter in Norway or Sweden.

Mr. Hewitt, you are making a much bigger, scarier deal out of this than it
almost certainly really is.

 

Priming 'could' I said because it won't if done properly.
'Should' be no problem because nothing is absolute. There should indeed be
no problem.

CR systems are sensitive it has to be said but they are as likely to self
destruct for no good reason as for any particular reason. If perchance the
fuel system does break down in the future as a result of incorrect fuel use
then it is likely that the damage will be covered by the cars insurance
company. It is a valid claim if not specifically excluded.

Huw

 

[Snipped Text]

Not sure on those in particular, but a normal fuel injection system uses
a continuous flow of fuel. You have a feed to the pump, the pump feeds a
common rail at constant pressure, the unused fuel returns to the tank.
Obviously with the high pressures involved here, it's going to go around
rather fast.

Yes, although that's probably not a good idea either!

 

Er...no. Diesel and petrol are completely miscible. No such separation
occurs, no matter how long you wait.

 

[Snipped Text]

My error, I didn't see the 'Priming' bit, sorry about that.

We've had a couple paid for by insurance so far, but my conversation
with the engineers suggest they are planning to close that loophole very
soon.

 

Don't get your knickers in a twist over 'priming'. The fuel system is
permanently primed. The electric lift and circulation pump switches on at an
early stage before cranking though. The system only ever needs a proper
priming if the system has been disturbed or a fuel filter changed and more
carefully after running out of fuel. In essence it is self priming by
switching the electric fuel lift pump on for a while to purge the system of
air by circulating fuel through the pipework and back to the tank. Specific
manufacturers have various means of achieving this and some might need a
further knack on the part of the mechanic.
The main thing is not to crank the engine for more than a few seconds
without having purged the system properly first.

Huw

 

[Snipped Text]

That's OK, you can have your opinion. I'll leave you to do the
experimentation.

 

Now there's a surprise! In the good old days it might cost a hundred to
drain the tank and dispose of the waste - nowadays it's new pump, new
injectors or even head - must cost thousands.

 

Having now heard the evidence from bith the the prosecution and the defence,
I'm leaning towards the side of Andy's argument. It was not a question about
eminent damage, but the longer term implications. Even though the car is of
low value, that doesn't mean that he can just replace the car and be up and
running the next day as if nothing had happened.

 

Imminent, not "eminent". And Andy claimed the damage would be severe and
immediate (i.e., imminent).

Pay attention. It's a recent-model PT Cruiser CRD.

 

Do you have an owners manual?

In every owners manual I have ever seen for diesel engines, it tells you
how much of a percent of gas is allowed in the mix.

Even my Jeep owners manual specify what grade and how much if any
alcohol mix is allowed in my gas. They only allow enough mix to get you
to 'real' gas if you are almost out, then to dilute it as far as
possible, otherwise non at all is allowed.

Your manual should say something about it.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Aug./05 http://www.imagestation.com/album/index.html?id=2120343242
(More Off Road album links at bottom of the view page)

 

<bites tongue>

 

If you read all of my replies you will not find any use of the word
iminent, or any variation thereof. The consequences could indeed be
severe though.

As yet I have no idea of the time scale involved, it's obviously a very
large variable, and could be a matter of days, weeks, months years or
never. All I have said is that it's a gamble if you go against the
advice of the manufacturer. I've not even offered any opinion, just
plain and simple known information.

Let's say that the OP decides to simply run the vehicle based on advice
given here, and in a couple of months the pump does fail. What then?
Who's going to offer to help the OP out of their predicament?