Did I give bad advice on what to do when gasoline goes in a diesel tank?

[Eddo Rogue]

My idiot buddy just called me in a panic. He put gasoline in his girlfriends diesel car, its a newer-ish BMW coupe of some kind....asked me what to do.

I asked him how much gas, he said not much...I asked how empty is the tank, he said pretty empty...I told him siphon or disconnect a line and pump out what you can...but just fill the tank to the to w/ diesel and cross your fingers....it should dilute enough to burn through...might trip some sensors along the way.

He's a good guy but a total fiasco. I only bother because I am friends w/ his girlfriend and feel bad for her. Also I was curious what to do if I was in such a dumb situation...if one of my idiot friends, or employees did this to me.

What would you do if someone put gas in your diesel?

I got friends in low places.....idiot friends.

 

[Curious Hound]

"It depends"

How much was "not much"?
How empty was "pretty empty"?

I would likely give the same advice. In fact, if all he did was squeeze the handle for a few seconds before realizing the mistake, I'd be tempted to say "Fill it up full, full, full with diesel and go for it." But, that could be bad advice.

 

[pjtoledo]

back in the day, mid '80s to around 2000 I drove a VW Jetta with a diesel engine.
in the winter during extreme cold I would routinely put 1 or 1.5 gallons of gas in every tank, which was only 11 gallons.
that engine was still running when I retired the car at 274,000 miles.

admittingly this is an old tech engine, purely mechanical in the injection system.

 

[Roert42]

Maybe slight misfire from predetination? Worse case I’m thinking if it wasn’t much.


Diesel engines compression ratios are around 2x the average gas engine right?

 

[fastpakr]

back in the day, mid '80s to around 2000 I drove a VW Jetta with a diesel engine.
in the winter during extreme cold I would routinely put 1 or 1.5 gallons of gas in every tank, which was only 11 gallons.
that engine was still running when I retired the car at 274,000 miles.

admittingly this is an old tech engine, purely mechanical in the injection system.

Yep, a bit of regular unleaded in the winter was really common among Mercedes owners back when I had an old diesel.

 

[pjtoledo]

Maybe slight misfire from predetination? Worse case I’m thinking if it wasn’t much.


Diesel engines compression ratios are around 2x the average gas engine right?

I'm thinking the VW old tech was 17-1 compression. anyway, a compression gauge had to go up to 400 psi
you can't get pre-detonation because fuel is injected right at peak compression in the cycle and instantly burns.


EDIT: VW ratio was around 23:1, big truck diesels were less.

 

[Eddo Rogue]

Well I haven't heard back from him yet...so either he is fine, or castrated, again....deservedly so...I got bigger fish to fry than dealing w/ such avoidable problems...that ain't even mine.

 

[Eddo Rogue]

Maybe slight misfire from predetination? Worse case I’m thinking if it wasn’t much.


Diesel engines compression ratios are around 2x the average gas engine right?

Lol hopefully she pings her way out of it.

 

[scotts90ranger]

The lubricity is more of an issue than anything if ran on straight gas which has almost none compared to diesel... the injectors and injection pump are susceptible to wear. I imagine catching it before running would be fine if dealt with like you told him to...

 

[B964]

With the vague amounts hard to say but....
Newer automotive diesels (2000 ish? and up) are much more at risk of damage from gasoline than older ones.
As mentioned above the lubricity is the big issue then detonation then aftertreatment system damage.
Very small tolerance fuel pumps running with not enough lubricity very quickly self destruct sending fine metal into injection system/injectors.

Did a few of these at VW. Gas in tank and run for a bit till quit. 10-15 k repair back in 2010-2013 ish
Last year 2022 Peterbilt with Cummins filled with gas run till quit. Drain, flush, filters. Good to go.

In your friends case a crap shoot. If it were me I would just never put gas in my diesel. Problem solved.
I look at pump and fuel door labels 3 to 10 times while fueling a Diesel. Standing there doing nothing anyhow.

 

[rusty ol ranger]

It really depends on the quanity.

If it was 2 gallons of gas in a 20 gallon tank....id top it off with diesel and run it.

If it was 7 or 8 gallons id be concerned

 

[19Walt93]

At least he didn't put DPF in the tank. The fact that the pump nozzle was so much smaller than the fill hole didn't tip him off?

 

[Eddo Rogue]

The guy is a real moron...and maybe on some hard drugs.
He's more of a "friend" I feel bad for than an actual friend comrade.

I met him through his girlfriend who I have known a while...then this guy clung to me like a lost puppy. She says he loves me smh. He does that to her too...Last heard they were split up but she cant seem to get him out of her hair lol poor lady.

Anyhoo not sure the outcome but she text messaged me this morning that there is a "burning smell"...Im trying to get details of it smells like electrical or otherwise.

 

[85_Ranger4x4]

At least he didn't put DPF in the tank. The fact that the pump nozzle was so much smaller than the fill hole didn't tip him off?

Our BP uses the same size nozzles for both... and for added fun uses their corporate color (green) for the gas pump.

We had a bunch towed in both ways (gas in a diesel and diesel in a gas) just because of that one filling station.

 

[rusty ol ranger]

The guy is a real moron...and maybe on some hard drugs.
He's more of a "friend" I feel bad for than an actual friend comrade.

I met him through his girlfriend who I have known a while...then this guy clung to me like a lost puppy. She says he loves me smh. He does that to her too...Last heard they were split up but she cant seem to get him out of her hair lol poor lady.

Anyhoo not sure the outcome but she text messaged me this morning that there is a "burning smell"...Im trying to get details of it smells like electrical or otherwise.

Burning smell might be the DPF trying to regen and its running hotter because of gasoline