Reader Question: The Ethanol Issue?

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Here’s the latest reader questions, along with my reply!

Dennis asks: You are one of the most intelligent writers that I read on any subject. My question? I am 67 now  and was  about to buy a new  Lexus ES350; but your recent article makes me want to track the very elusive first generation Cadillac Seville without the hidden rust vinyl top. I now have an ’06  Lexus IS 250 with 53,000 or so miles and  could live with it longer; the only downside is spending more bucks on staggered tires (don’t last as long)  and postponement of  putting in new spark plugs  in case of getting another car. What to do?

My reply: You raise an important point – and consideration.  Today’s ethanol-blend fuels can cause deterioration of fuel system parts in older cars not originally designed to withstand alcohol-laced fuels. This applies mainly to cars made before the 1990s – before ethanol-laced fuels became ubiquitous.

The good news is the “fix”is relatively easy and inexpensive. Simply replace the components in the fuel system that weren’t originally made to be compatible with ethanol-laced fuel. The even better news is this has probably already been done by now – unless the car in question is a very low-miles “survivor” that has never been rebuilt or had most of its systems gone through.

By now, almost all cars from the ’50s, ’60s and ’70s have had most if not all of their original  fuel system components (e.g., fuel pump and rubber lines; internal carburetor parts such as gaskets, accelerator pumps, floats, needle and seats, etc.) replaced/rebuilt – and with materials that are ethanol compatible.

But if there is any question, just replace these parts. The new/replacement parts will be ethanol-ok.

You may also need to re-jet the carburetor, if the vehicle you’re dealing with has one, because today’s ethanol–laced gas is leaner than the pure gasoline these cars were designed (and calibrated) to run on. But this, too, is very easy – and very inexpensive.

The one that’s not as easy – and is somewhat expensive – but which I recommend doing if it hasn’t already been done is to replace all the factory steel fuel lines (and the steel gas tank) with stainless lines and a new tank. Ethanol-laced fuels attract water and old school steel lines/tanks are susceptible to rusting out from the inside. The flakes can wreak havoc with the running of your car, too – because they’ll inevitably be drawn upstream, sucked into the carb ad clog up some vital passage.

But even this expense – and hassle – is trivial compared with the expense and hassle of a modern car, with all of its “assists”!

I say, get the Seville!

And, thanks for the kind words!

Got a question about cars – or anything else? Click on the “ask Eric” link and send ’em in!

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  1. Ethanol is compatible with more types of rubbers, plastics, and metals than gasoline and aromatics. It causes no greater damage to Cadillac parts (of any age) than gasoline and aromatics…in fact it would cause fewer problems.

    Ethanol does not “attract” water. It will, however, absorb more water (that might be present in the fuel system due to condensation) than gasoline. This is a good thing, not a bad thing, as it will help to remove the water from the system.

    • “Ethanol is compatible with more types of rubbers, plastics, and metals than gasoline”

      Even if true it is irrelevant except when making new parts and designs. If your car has one that is compatible with gasoline but not ethanol it doesn’t matter what other materials are out there. Like the float for my ’73’s carb. The ethanol slowly dissolved it over the years. There are few NOS parts out there, but that’s it. Doesn’t matter if there is a ethanol compatible material unless someone starts making new ones.

  2. Why would a Seville need staggered tires? The late 70’s to early 80’s large GM sedans almost always had a nearly 50-50 weight ratio over the front and rear axles and the Olds 350 shouldn’t be so powerful as to need larger tires in the rear (it was advertised with 180 hp). It’s not like your drag-racing a ‘Cuda with a 440 hemi and a blower. Additionally, large GM sedans seemed to have much better handling, ride manners, and even handled snow better when fitted with near stock-sized tires on all 4 corners. I believe the tires were GR78-15’s on the Seville; 215-75R15’s would be very close to original sized stock tires.

    • Hi Shoal,

      I think you’re right about that. IIRC, those mid-late ’70s GM sedans rode on steel 15×7 wheels, all the same offset. I am certain about the ’83 Olds my parents hd because I worked on the thing!


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