15% ethanol in Bolivia’s
gasoline from 1 November:
what it means for your car

Will 15% hurt your engine?

It depends on what you drive. The evidence is strongest for modern cars. The US Department of Energy ran 82 vehicles more than 6 million miles on blends of up to 20%. Ethanol didn’t change how their emission systems wore, and fuel economy fell only in line with the fuel’s lower energy content (ORNL, 2012). That was a test of emission systems, not of engine wear. On that evidence, the US regulator approved 15% for cars and light trucks from model year 2001. It refused 15% for older vehicles, motorcycles, boats and small engines, for lack of test data (EPA).

The evidence isn’t one-sided. Tests funded by the oil and car industries found valve-seat wear in two of eight engine designs at 15–20% ethanol. They also found one fuel-pump model that seized at 15% (CRC engines, CRC fuel pumps). The Department of Energy called their methods flawed (US House hearing record). The fair reading is that particular designs and parts can suffer. It isn’t evidence that 15% wrecks engines in general.

This matters more in Bolivia than in most countries. Motorcycles are the largest group of registered vehicles: 931,205 of 2.67 million at the end of 2025 (La Razón).

Motorcycles are also where the evidence is thinnest. Before Brazil moved from 27% to 30% ethanol in 2025, tests for its energy ministry ran 13 motorcycles on the new fuel. Motorcycle makers said several had trouble starting cold; the testing institute said the differences weren’t a reason to stop (NovaCana, AutoPapo). Those bikes were already built for gasoline with 27% ethanol. A bike built for 10% has much less margin, so a hard start on cold mornings is the first sign to watch.

Where to get gasoline without ethanol

Plain Especial, without the +, has no ethanol by specification. Its quality rules cap oxygen at 0.2% by weight, and ethanol is about a third oxygen, so that leaves room for half a percent of ethanol at most (DS 5619, as amended by DS 5652). It costs the same Bs 6.96 as Especial+.

In the week to 21 October, plain Especial was 19% of the gasoline YPFB delivered to stations: 7.8 of 41.0 million litres, to more than 140 stations. In Sucre and 15 other towns, it was the only gasoline delivered.

In the big cities it arrives in occasional batches, if at all. Santa Cruz: 10 of more than 80 stations, all on 21 October. La Paz and El Alto: 20 of 66 stations, in a single batch on 18–19 October. Cochabamba: none since 8 October. Tarija (9 of 14 stations) and Oruro (15 of 18, in one batch) get more. Potosí looks to be switching: plain Especial was all the gasoline YPFB scheduled for the Potosí district in September, and about 40% over the past two weeks. If Especial+ replaces it elsewhere, the map will change.

In Santa Cruz there’s a second option: Ultra Clean 91, an imported gasoline sold with no added ethanol, the importer said when it launched in October 2025 (Economy). It costs Bs 18.97 a litre at eight stations, all in Santa Cruz department. A 40-litre fill costs Bs 758.80, against Bs 278.40 with Especial: Bs 480.40 more.

Stations that receive plain Especial usually get Especial+ as well. At the pump, ask which one you’re getting.

The cost: a little more fuel

How big the change is depends on what’s in your tank now. Especial+ has carried ethanol since May 2019: 8% at first, then 10% from March 2023 (El Deber). Its specification now allows up to 12% (ANH). YPFB has said up to 12% (Los Tiempos), while in February the mills put the real average at 8.11% (eju.tv). So 15% means 3 to 7 more percentage points of ethanol.

Ethanol has about a third less energy per litre than gasoline (fueleconomy.gov). More of it means slightly more litres for the same distance. Ethanol also raises octane, which protects against knocking, but in most engines that doesn’t add kilometres.

After the switch, a drop of 1–2.5% in kilometres per litre comes from the fuel; it isn’t a fault.

Before 1 November: five checks

1. 01
   Find your limit. In the fuel section of your manual, look for “ethanol”, “gasohol”, “E10” or “oxygenates”. On a car built for Japan, look for the “E10/ETBE22” label near the fuel filler. Without it, the car was built for gasoline with up to 3% ethanol.
2. 02
   Service older vehicles and motorcycles. Replace the fuel filter and have the hoses and seals checked. A carburettor may need its idle and fuel mixture adjusted.
3. 03
   Fix a check-engine light now. A car that already runs lean on today’s fuel is the most likely to show a warning at 15% (codes P0171 or P0174).
4. 04
   Watch the first few tanks. See a mechanic if you notice harder starts, a rough idle, a warning light, a fuel smell, damp hoses or a jumpy fuel gauge.
5. 05
   Don’t store ethanol gasoline. In a generator, an outboard or a motorcycle parked for weeks, use the fuel within about a month.

Whatever you fill up with, check which stations are selling before you leave.

This year’s engine damage wasn’t blamed on ethanol

Drivers have reason to be wary. Early this year, more than 10,000 owners claimed engine damage from bad gasoline (AFP, via La Nación). In February, YPFB announced it would cut the blend to a minimum. A week later it said it wouldn’t (Opinión, El Mundo).

When YPFB closed its investigation on 11 May, ethanol wasn’t among the causes (YPFB). It named four:

• no quality control on imported base gasoline;
• storage tanks run nearly empty from 2023 to 2025, which built up oxidation, gums and sediment;
• a sudden refill from December 2025 that stirred that build-up into the fuel;
• unstable compounds called diolefins in imported gasoline, which form gums that damage injectors.

New quality rules in May tightened the limit on gums and added a test for how quickly gasoline oxidises (DS 5619).

On 20 October, the drivers’ confederation demanded that the new blend be dropped. “What drivers need right now is quality fuel, not the blends that wrecked engines in the past,” said Víctor Tarqui, secretary general of the Confederación Sindical de Choferes de Bolivia (Éxito Noticias).

Demanding quality fuel is right. The risk that grows with ethanol is water. Ethanol absorbs it, and past a limit a layer of water and ethanol separates out. It sinks to the bottom of the tank, where the pump draws fuel (US EPA). That makes keeping water out matter more at every step from the mill to the station tank.

What’s decided, and what isn’t

On Monday 19 October, the government, YPFB, the sugar-ethanol mills and cane growers signed an agreement. It raises ethanol in gasoline to up to 15% from 1 November 2026 and automatically to 18% from 1 April 2027, according to YPFB’s announcement. YPFB and the mills have until 30 October to sign supply contracts. The price YPFB pays for ethanol goes up from 1 November.

The case for it is dollars. Bolivia imports about 60% of its gasoline, mainly from Argentina and Paraguay (YPFB, May 2026). “For every litre of ethanol produced in Bolivia, we stop importing a litre of gasoline,” said YPFB president Sebastián Daroca.

It isn’t a rule yet. YPFB’s announcement makes it conditional on an evaluation “and the issuing of the corresponding regulations”. The rules already allow up to 25% (DS 5135); what’s missing is a resolution raising today’s 12% cap (ANH).

The mills say they have enough ethanol to start (Red Uno), but this year YPFB was slow to collect what it had contracted (El Deber). The date could slip; the plan itself looks settled.

Other questions

Will gasoline cost more? The agreement raises the price YPFB pays the mills for ethanol. It says nothing about the pump price. Especial and Especial+ cost Bs 6.96 a litre.

Is 18% in April certain? YPFB calls it automatic. Unitel reported that step as still subject to study, and Minister Blanco spoke of reaching 18% “by April” (Visión 360). We’ll update this article when the rules are published.

Can I mix Especial and Especial+? Yes. Both are gasoline, and the mix ends up with an ethanol share somewhere in between.

Is Premium an option? Hardly: ANH recorded premium sales at only two stations on 21 October, both in Santa Cruz, after none since 2 October. And Premium+ also allows up to 12% ethanol.