Passat PHEV old fuel question

[Wackywoo105]

My Passat PHEV was delivered in Feb 26 and hasn’t visited a petrol station since and it still doesn’t need to. How long will the fuel last, and how will I know if it’s starting to go bad? When I eventually refill, should I add a fuel stabiliser, and if so, which one?

Just to add: I originally posted this in the Other Marques → Audi, Seat, Skoda & VW section, but I don’t think I’m going to get a reply. I’m also not convinced it belongs there, so apologies if this isn’t the right place either.

[ashenfie]

Technology the petrol past its best. I would keep quarter of a tank max if your driving short ranges

[Stevemr]

I regularly leave my motorbikes for 5 months over winter with fuel in them. But I do make sure it’s e5 fuel. Never have a problem.

[larrylamb11]

In a modern fully sealed fuel tank system the fuel will take literally years to go off. Even then, modern fuel injection will still run with fuel that's gone off - it has to be pretty bad before they won't run. Evaporation of the volatiles is what makes fuel go off and the evaporation is limited in modern fuel systems by far bretter breathing and vapour management.
For a modern car like yours, you really won't need to worry about it.

[xx99xx]

larrylamb11 said:

In a modern fully sealed fuel tank system the fuel will take literally years to go off. Even then, modern fuel injection will still run with fuel that's gone off - it has to be pretty bad before they won't run. Evaporation of the volatiles is what makes fuel go off and the evaporation is limited in modern fuel systems by far bretter breathing and vapour management.
For a modern car like yours, you really won't need to worry about it.

I agree.

Had a similar car during lockdown and didn't need to fill up for about 6 months. Even then, my version of filling up is going from half full to full as I never go below half if I can help it.

Old fuel still works. It's not like your on a competitive race track.

[Teflondon]

My Passat did 1800 miles on electric before I put more fuel in. On the tank iits around 400 miles for petrol.

How you finding your Passat? Mines rubbish, brakes are crap, the car jolts when leaving my house within a minute or so quite often. I'm gonna end up early terminating the lease because I can't stand it.

I'll avoid another plug in hybrid with a dsg box.

[xx99xx]

Teflondon said:

My Passat did 1800 miles on electric before I put more fuel in. On the tank iits around 400 miles for petrol.

How you finding your Passat? Mines rubbish, brakes are crap, the car jolts when leaving my house within a minute or so quite often. I'm gonna end up early terminating the lease because I can't stand it.

I'll avoid another plug in hybrid with a dsg box.

If it helps, my 2017 Passat GTE was perfect for the 6 years I had it. Would've been happy to keep it but had to change because of the lease scheme.

Can't really comment on the brakes - they worked. What's not to like.

Jolts - none really. The transition from petrol engine to electric motor was seamless as it should be. DSG has been amazing in all the cars I've had it in.

[hidetheelephants]

What does the manual say on the subject? That's the first place you should look for information on fuel management with a hybrid. AIUI manufacturers of hybrids generally include routines in the ECU software to test-run the engine periodically to keep everything operational even when users are running for long periods solely on battery.

[Smint]

Soon as i realised just how ridculously frugal our PHEV Prius is i decided E5 was the only fuel going in.
If my running doesn't mean it happens automatically i make sure to drive in battery saver mode for half an hour or so every month, keep things running nicely.

[CSR Performance]

If it was me, I’d deliberately run it low once every 6-12 months and then refill with E5 or add a small amount of stabiliser.

I ran a Golf GTE for 4 years and did nearly 100k in it, absolutely loved that car so I am totally a PHEV fan, but it does sound to me like your Passat is possibly not the right car for you?

[Pizzaeatingking]

I reckon it'll be fine. I've left my M3 in the barn for 6 months without issue.

[Wackywoo105]

Thanks everyone. I’ve no idea what fuel is actually in the tank now, but when I eventually fill up I might switch to E5. I try to run the engine once a month because I’m sure the manual recommends it. The only reason I started wondering about aged fuel is that my father‑in‑law’s Volvo warns him when the petrol is getting old and then forces the engine to use it. My previous two PHEVs (Captur and Cupra) had much shorter EV ranges, so with the Passat, even charging only to 80%, I almost never run out of electric range.

Teflondon said:

My Passat did 1800 miles on electric before I put more fuel in. On the tank iits around 400 miles for petrol.

How you finding your Passat? Mines rubbish, brakes are crap, the car jolts when leaving my house within a minute or so quite often. I'm gonna end up early terminating the lease because I can't stand it.

I'll avoid another plug in hybrid with a dsg box.

I actually really like the Passat. I’ve got the 204 version and I'm happy enough with it. I agree the brakes aren't the best. It’s the Black Edition, so it even has massage seats. My only real annoyance is constantly getting a “new user settings” prompt on the display nearly every time I start it. The transition from EV to petrol is seamless. I also like the autopilot which I've missed since handing back my old Volvo V90.

The car I couldn’t stand was my previous Cupra. That thing was an absolute bag of ste. I handed it back six months early just to get the Passat. Maybe that’s why I appreciate the Passat so much. Same parent company, but the Passat actually works, whereas the Cupra absolutely didn’t.

[GRIMSARGH]

Teflondon said:

My Passat did 1800 miles on electric before I put more fuel in. On the tank iits around 400 miles for petrol.How you finding your Passat? Mines rubbish, brakes are crap, the car jolts when leaving my house within a minute or so quite often. I'm gonna end up early terminating the lease because I can't stand it.I'll avoid another plug in hybrid with a dsg box.

I would go the other way and say I am quite enjoying mine. I agree the sensors are quite sharp and that a stray shadow can set them off. Pulling out of a junction I often get a jolt if there is traffic in the other lane. I also always get a message to update the software when I get in. I have tried a hard reset of the screen but it still demands a reset each time. But otherwise the car drives well, and has not missed a beat on long journeys. I love the range of the battery too as bulk of my driving is on pure battery. Phev really does take range anxiety away

[Goatwidcoat]

No science behind this at all but I would use it up every 6 months or so and use E5. Couple of tanks a year isn't too big a cost when you're running on EV the remainder of the time.