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Oil smells like fuel
FR-S manual with 5500miles
Oil smells like fuel. Anyone else? |
I changed mine at 1500 and it smelled strongly of petrol. I don't think I warmed it up like you're supposed to though, if I drove it for 15 minutes I'm sure the PCV or whatever this car has would have taken care of it.
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Brought it to the dealer. Initially two service employees agreed the oil smelled strong of fuel. After they check it out, the mechanic had me smell a jug of new oil compared to my dipstick. My dipstick smelled like gas, jug of new oil didn't but he claimed he couldn't smell gas. I'm going to send some off to get tested.
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How do you have that many miles when you bought your car last Sunday? I'm assuming you bought it used?
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Was the car fully warmed up? From what I understand, cars with direct injection have a little more oil contamination when the car is cold, due to spraying fuel directly into the cylinders. Once the oil gets up to operating temperature the lighter volatiles like gasoline will flash off and go through the PCV system. At least hats the way I understood it.
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Its pretty normal, try to smell some other car's dip stick. I sniffed all of my family's cars and all smiled like gas
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Agreed. I thought this very common.
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Thanks for the replies :thumbsup: |
fuel dilution of oil normal till rings break in
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My first oil change had a tiny bit of fuel in the oil, but the next one didn't. Hope your rings are seated properly.
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All this talk of sniffing dipsticks...and one guy sniffed his whole family's!
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Improper break in procedure to blame? I disagree with the owners manual recommended break in procedure, My opinion it leaves an important step undone. Although I am new here, this isn't my first Rodeo. I've built quite a few engines, mostly high horsepower with stock and aftermarket components. I installed chromoly (hard) rings a few times before giving up on them after having repeated problems getting them to seat. I am careful now to select rings that are cast iron composition, usually the top ring with a chrome surface. When cylinder walls are new, they have a cross hatch texture that is produced by the final honing operation. The purpose of the final hone is to fine tune the cylinder size and to produce the cross hatch finish. The function of the cross hatch finish (which disappears/wears away as the engine breaks in) is to abrade the edges of the top and second rings, this is what is referred to as "seating" these rings. When a new engine with solid base (not roller cam) lifters is started, it must be run for a period of time (about 20 minutes at 2000 rpm) to break in the cam and lifters. With roller cam setups and roller cam followers this step is not required, but a new engine must be run for a few minutes to run the builder/factory quality control procedures. Nonetheless, Neither one of these break in procedures is performed with the engine under load. The break in procedure for piston rings in a new engine is as follows. Take the vehicle on a section of straight road and perform a strong acceleration in a lower gear, 2nd is usually good, lots of torque usually available. At the top of your strong acceleration, allow engine braking to slow the vehicle down to where you would shift to a lower gear. Do this 2-4 times and then proceed with the gentle factory break in procedure. I would say that RPMs at the top end of your strong acceleration runs should reach 5000 on the Tach in this 7450 Redline engine. It won't hurt your engine one bit, Rather it will take advantage of the cross hatch finish's intended function while it is still new and not worn away yet. ask me about new ring and pinion break in. |
remember guys every motor has blow by, this takes place on the compression stroke of the motor as the fuel/air compresses and fuel ignites. A little bit of that pressure gets past the piston rings causing that smell it will get way more potent if you fry your rings. your safe I would say :)
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@Red John knows what he's talking about. My pops was an old school v8 guy and I spent quite a bit of time growing up wrenching and helping him build and machine engines. Most modern import engines and engines in general now have much tighter tolerances than the afformentioned v8s that being said I have seen some newer engines 2afze for example have ring sealing issues causing uneven cylinder wall wear/gouging so it is possible that is could be a ring seating issue. A bit of fuel smell is normal and I have also heard that di tends to dirty the oil a bit quicker but I can't speak from knowledge/experience on that one.
Question for the op is the engine using any oil? I would try driving it a bit and make sure the oil consumption is within spec before you start to panic. -Mike |
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The crosshatch pattern is there for the ring surface to wear to similar to cutting rotors to bed in new brake pads. While it should never completely go away there will and should be a bit if wear to form a proper ring seal. The more common place I have seen wear on newer engines is along the piston skirt.
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Oil smelling like fuel is due to fuel blow by from the direct injection system. High cylinder pressures combined with the direct injection fuel PSI = fuel getting past the rings. Happens on virtually ALL direct injection cars. Audi FSI, Mazda's MZR 2.3, etc. Perfectly normal. Only thing is I recommend oil changes a little sooner. I know that Toyota says you can go like 10k miles, but fuel dilution changes the lubricity a bit and I don't feel comfortable knowing it's in there. That's just a personal preference. I'm coming from a Mazdaspeed 6, and every oil change you get a little buzz from the 93 oct. :P
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^^you are correct, but blow by from a DI motor is significantly higher. Fuel dilution on my MS6, with great compression, has dark brown oil in less than 2k miles. Fuel being injected at 1800psi vs a conventional port injection is going to behave differently in the combustion chamber. It's been covered at nauseum on Audi forums (they've been using DI for a decade now) and people had the same concerns. I had the same concern myself and I was no stranger to turning wrenches. Simple fact is, direct injection causes more blow by, and in turn more nasty crap in the crank case. All I'm saying is that a more frequent oil change regimen vs non-DI systems is advisable, as well as an OCC (oil catch can) and EGR delete. That will measurably reduce the engine contaminants and keep it running like the day you bought it.
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Also, google Motoman's engine break in guide to to understand how to properly break in a fresh motor to get the rings to sit properly.
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