Seeking Advice: Added Diesel Fuel to New Gas Engine...Yikes!

PROBLEM: My grandfather accidentally added 2-3 gallons of diesel fuel to his brand new 2011 Infiniti G25 (V6 engine). He drove the car 2 miles home. He has not been able to re-start the car. This happened 4 days ago.

QUESTION: Can he wait 2 weeks to take the car to his preferred mechanic if the car is just parked? Or does he need to tow his car to the next available mechanic immediately to drain the disel fuel before it causes further damage?

Any advice about this problem would be appreciated! Thank you in advance!

You honestly should be fine if you wait. That’s assuming he doesn’t need to drive it. If the car wont start at all that probably means he has used all of the unleaded and the diesel has made it way through the engine. Diesel is more ‘oily’ than unleaded and has messed the spark plugs up, and since those wont spark, he can’t start the car.

So you need to drain the tank, any lines and the engine of any remaining diesel and either clean or replace the spark plugs. Shouldn’t be too bad.

A diesel fuel pump nozzle will not fit in a 2011 Infiniti…It’s too big, it simply is virtually impossible to do this unless he used a funnel…And two gallons mixed with 15 gallons of gasoline should not cause much trouble. But again, how did he manage to do this?

If he ran out of fuel and used a gas can filled with diesel, that explains it. The car will not start or run on 100% diesel…It will have to be towed to any garage willing to do the job of draining the tank and purging the fuel lines. That should be the extent of it…

Well, it’t better than putting gasoline in a diesel.

“A diesel fuel pump nozzle will not fit in a 2011 Infiniti…It’s too big”

Well it should be, but I have seen many diesel pumps with gasoline size nozzles. I believe that in some areas the size is mandated, but others not.

That said, I have not seen many small diesel nozzles lately. Caddyman’s comments are likely right.

Caddyman – Not sure how my grandfather made this mistake! It happened at a Chevron gas station in San Francisco.

waldoh – Thank you for the assurance that waiting for the preferred mechanic will not result in further damage. Here’s hoping 2 weeks of diesel fuel sitting in the parked car won’t hurt it too much!

Wow…you know this is actually MUCH harder than you might think… Like Caddy said the Diesel nozzle will not fit in a gas car…unless some Jack hole at the station put a gas nozzle on the D pump…that would be cause for some lawsuit methinks.

As for a small amount of Diesel in your system…again I doubt it would cause much trouble…but as you said she doesnt run.

Dont panic really…if you were nearby I’d have you running in a jiffy…and cheaply…not like the reaming they are about to give you. They are going to say this and that about what got RUINED in your cars fuel system…the injectors, filters, tank…everything…ALL TOTAL BS

They need to drain the tank, fill it with gas, pull the needle out of the fuel rail and run the pump till fresh gas comes out…then prime the car and start her up…it’ll be fine after that.

My question to the guys is…If we put some Diesel and some Gas in a glass Jar…would we see any separation? Or would it become a homologous looking substance? I’m trying to understand if the D fuel would float on top…or hide in the bottom…OR NEITHER? If the D fuel went to the bottom…he could just use the fuel pump to pump that out till he got to fresh gas…then just motor…

But if it fully incorporates then you need to drain it…if the vehicle wont run


I would consider that you check with dealer on a recomend injector cleansing as they really don’t like oil. I would think this is where the culprit lies. I would not expect any motor damage other then fuel delivery system problems.

I would strongly recommend keeping the dealer “out of the loop” on this issue.
Why give them an excuse to later deny warranty claims, based on owner negligence/abuse?

I would recommend using only a highly-reputed independent mechanic for the fallout from this mistake.

DO NOT GO TO THE STEALERSHIP…they will SLAP you with a long list of things that you runied…that you really didnt ruin. The D-fuel will not harm your injectors at all…nothing more is needed than to drain the tank and flush the fuel rail… Then drive…like it never even happened…

VDC IS MUCHO CORRECTO… Go to an independent shop and have them drain the tank…or drain it yourself its easy enuf to do


Do as Blackbird suggested and investigate the nozzle issue.

QUOTE "That depends on the amount added and the engine. There are two immediate impacts of diesel fuel mixed with gasoline: the octane is lowered and the fuel vaporization is reduced. The lowered octane may cause the engine to knock. Some engines have knock sensors and the electronic controls will adjust the timing and other engine conditions to try to control the knock. If the knock remains significant it can damage the engine by causing metal fatigue eventually leading to failure of critical parts like pistons, connecting rods, heads. Some very old engines (e.g. 1950’s tractors) can accommodate lower octane, but the ones found in recent autos are normally running close to the knock threshold. The reduced volatility caused by the added diesel will cause hard starting and will probably result in some unburnt hydrocarbons remaining in the exhaust gas from the engine; these may be reacted in the catalytic convertor causing it to overheat. A modern electronic controlled emission system controls the oxygen level in the exhaust gas going to the convertor so the significant increase in hydrocarbons with controlled oxygen may save the convertor, but will likely result in unburnt hydrocarbons exiting the exhaust. This will result in a smell and air pollution.

So if enough diesel is added to produce any of these problems it is a not a good situation. I would consider draining and replacing the fuel or if practical diluting it with fresh gasoline to eliminate the symptoms."

So, if this doesn’t work , you will be on your own…and the independent will offer no warranty help either and he won’t be cheap either…I would still get the dealership involved in conversation early on. I guess others have had different experiences. Mine have all been honest and forthright. I can still go elsewhere for repair later.

Best of luck !

“if this doesn’t work , you will be on your own…and the independent will offer no warranty help either and he won’t be cheap either…I would still get the dealership involved in conversation early on.”

Dagosa–Warranties do not cover either abuse or negligence on the part of the car owner, and this situation clearly falls into the category of owner negligence. Thus, going to the dealership at this point will not yield any free repairs and could actually jeopardize coverage for future repairs.

That is why I advised the OP to avoid the dealership at this point. Why provide them with a ready excuse for denying future warranty claims?

"Thus, going to the dealership at this point will not yield any free repairs and could actually jeopardize coverage for future repairs. "

VDC; I hear where you are coming from but that was not my point. I would NOT expect to get warranty help, but owner negligence contributing to later warranty coverage may not be the case. If as people say, it causes no problems to begin with. The only way to find out…is ASK. I have always gotten forthright info from dealers…even when I inadvertently added gasoline to a diesel engine. No warranty was affected and I was free to proceed with the input from them as well.

It all depends upon the amount and THE NEXT STEP and avoiding the manufacturer is not the right course of action IMO. My relatives own dealerships and cousin who managed service departments for 5 of them had lamented once how owners deal with problems like this by themselves, creating worse later, when simple information from them could have avoided more headaches. I keep thinking of the time a friend dropped a new outboard motor into the water to the bottom of the lake…nothing is destroyed or harmed at the point we retrieved it . It all depends upon what you do next. We got a dealer’s input on that too…it worked out fine for everyone.

BTW, auto dealerships do not look for “ready excuses” to drop warranties. Unlike health insurance providers, they get reimbursed handily for their work by the manufacturer. As one dealer told me. it’s problematic having products that are too reliable and don’t require warranty work as they don’t make enough in repair reimbursement to even pay for their factory require certification of their mechanics…who’d have thunk it ?

If I have learned two things in life either vicariously or directly…ONE would be that the Police are not your friends…and TWO…neither are car dealers.

I am totally with VDC

Boy, I’d hate to think that because I was a cop at one time and live in an extended family of car dealers I would be judged by my employment and relatives. One thing in life I have learned is if I were honest and well informed i can be friendly and deal with anyone. Be uninformed…your right, you can be friendly with no one. No one says you have to be anyone’s buddy. This is a 2011 vehicle. Start doing service on it beyond the basics and you will be looking at warranty coverage problems…that’s my point.

Decided to scratch the negativity from the record…really no use in voicing that sort of stuff here.

But yes to each his own, I wouldn’t go to the dealer…and some would… I just don’t want to see the OP get in trouble or mess up a warranty. I wish them the best


Just to be clear on the main subject at hand. I respect your life experience as I’m sure you do mine. A 2011 car may at some point need warranty work. My post to VDC and all pointed out possible outcomes of using diesel. I personally see no long term damage but, If it were me and should anything occur later as a direct result, and I did not inform the dealer of my negligent practice and involve them in my decisions I will have to practice some form of deceit to receive warranty compensation later.

Like that’s just you, that’s just me and I can’t do or recommend differently. I really don’t care what kind of deceit I think dealers practice, I will and recommend OP be straight with them from the beginning of the problem by at least “involving them in the conversation”. Actual service can be done elsewhere. I tried to address each of VDC’s points including dealer warranty coverage from my experiences.

This will either be your 31st negative attitude experience with a PO or 30 to 1, whichever way you choose to view it.

I think in the long run, OP will benefit from this approach.

My shop is in a small vacation area and this is a normal problem here, not sure how they get the diesel nozzle to work but they are persistent and do. I do quite a few during the course of a season. It has never been a problem. Drain the tank and refill with gasoline, purge all the diesel / gas mix from the fuel rail and clean or drop in a set of fresh sparkplugs. It sitting a bit will not hurt. IMHO