With the introduction of E10 fuel in the UK, should I be concerned about the diaphragm in the standard Ford mechanical fuel pump? If the diaphragm perforates it can leak petrol into the sump, contaminating the oil. If the leak is small and pump pressure still adequate this could continue for some time unnoticed with the potential to cause excessive wear?
I have been using Ethanolmate additive in my fuel since the introduction of E5 petrol but, as I understand it, this additive only protects against corrosion and assists fuel stability, it does not help with so called ‘material incompatibilities’.
I am also concerned about the gasket to sender in the fuel tank. I replaced my tank a few years ago and recall that the replacement alloy tank had a cork gasket and cork is most certainly incompatible with Ethanol.
Any thoughts?
I doubt there are many, if any, synthetic rubber chemists on the forum to answer your question. I would suggest the question is directed to the manufacturer of the products on which you have concerns…
I used to manage a synthetic rubber manufacturing plant does that qualify
You just need to find out what the diaphram is made of and then determining ethanol resistance is easy. Most of the likely candidates have good resistance so I would not worry to much
I don’t know what is used to bind the cork granules in the composite but whatever it is it’s no friend of ethanol either. The granules turned to black mush.
My understanding is that most cork gaskets are bound with nitrile rubber. A quick look at a chemical compatibility chart shows that FKM rubber (Viton)(a DuPont trade name) is comparable with an alcohol/gasoline mixture. Don’t dash out and have a gasket made from this stuff, get a sample and test it first.
I too am not that convinced about the worries regarding Ethanol in fuel.
Looking at one of my reference books regarding material resilience to different chemicals.
Ethanol if classified as Ethyl Alcohol has zero effect on Viton, Neoprene and Buna-N (common sealing materials). In fact stainless steel and Aluminium are slightly less resistant to it (but still good).
Petrol on the other hand is a lot more destructive and will destroy Neoprene and Buna-N.
The only way extra Ethanol would affect anything is if it reacts with the petrol and forms something like an Acetate, Chlorine, Oxide or a Glycol.
Any chemists able to clarify
For those of us in the UK … according to their website, ESSO Synergy Supreme 99 is still ethanol free in most parts of the country although the pumps are required to be labelled as up to 5%.
Thanks your thoughts and info everyone.
My concern over the cork gasket to the fuel tank sender was not an urgent one, I was thinking through areas that I should keep an eye on or upgrade when the opportunity arises in view of the roll out of E10 fuel here in the Uk. Non cork gaskets are available for the fuel tank, so I’ve made a mental note to change the gasket if I have occasion to remove the fuel tank sometime in the future and to keep an eye out for leaks. The E10 roll out has caused me to change the rubber fuel lines on my Alfa and Westfield to ethanol resistant - they were over 10 years old and therefore due for renewal, but I probably would not have thought to do so if the E10 issue had not arisen.
I only use Super grade fuel in my Elan of course, but I’m not confident that Super fuels will remain as readily available in the future as they are now, particularly in rural areas. If sales fall, as they may well with electrification and the ability of all modern cars, even high performance ones, to run on lower octane fuel with only marginal loss or performance, finding Super on most forecourts may well become a thing of the past – it will be a purely commercial decision by the outlets themselves. So I’ve been thinking about how to future proof my older cars. I also think that E5 will be damaging incompatible materials, just more slowly than E10 will. So, as I say, it is about recognising the problem and making the changes to ethanol compatibility, not urgently, but as part of ongoing maintenance. I had heard that some Super fuels are still zero ethanol over much of the UK, but it appears to depend on the refinery that supplies your area not just the petrol brand, and in the South West where I live it all Super appears to be E5.
Thanks again, one and all.
does that qualify 
