If it isn't blow by , how is gas getting into the oil on 4xe?

[Slaw32]

I see alot of mention of the 4xe going into form mode , for many different reasons . One of them is gas in the oil . How does that happen if it isn't being caused by blow by , or more simple question , how is gas getting into the oil pan ?​

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[mllcb42]

On cold starts, the piston rings don't tightly seal. As the engine warms up, the piston rings seals. When the oil gets up to temp, the gas evaporates out.

Phevs have lots more cold starts and less time running at temp, so they're more likely to accumulate oil, unless they're forced to run at temperature for a while (jeep does this with form, other manufacturers may approach it differently).

This is typical behavior of all phevs.

 

[Glamisfan]

I read a thread on one in Canada, and I don’t understand it either. It sounded like the motor doesn’t run enough to get to full temperature, so gas and moisture that is normal in oil doesn’t get burned off? The moisture comes from condensation. So the fuel must be from blow by, but in warmer climates it is burned off at full operating temperatures.

 

[The Last Cowboy]

It’s a characteristic of direct injected engines and turbos increase it somewhat. With DI, fuel is injected directly into the combustion chamber, rather than being mixed with air before, a very small amount of that fuel will get by the piston rings. Add boost and the likelihood increases. Use an oil with no less than the factory spec.

On my EcoBoost engines, I only go to about 75% or so on the oil life monitor. They don’t “make oil” (have a higher volume than what amount of oil put) in, but you can smell it. I also recommend a “spirtited” drive at least once a week. A highway run with several wide open throttle (flooring it) runs through the gears. If you don’t do it often, you will see a black cloud of soot as those deposits will be getting cleaned out. It’s also a good way to keep the oil from sludging, which is common with hybrids that see little to no use of the gas engine.

 

[Slaw32]

It’s a characteristic of direct injected engines and turbos increase it somewhat. With DI, fuel is injected directly into the combustion chamber, rather than being mixed with air before, a very small amount of that fuel will get by the piston rings. Add boost and the likelihood increases. Use an oil with no less than the factory spec.

On my EcoBoost engines, I only go to about 75% or so on the oil life monitor. They don’t “make oil” (have a higher volume than what amount of oil put) in, but you can smell it. I also recommend a “spirtited” drive at least once a week. A highway run with several wide open throttle (flooring it) runs through the gears. If you don’t do it often, you will see a black cloud of soot as those deposits will be getting cleaned out. It’s also a good way to keep the oil from sludging, which is common with hybrids that see little to no use of the gas engine.

Great explanation , don't know much about direct injection . Thanks for answering my question .

 

[four low]

A "Catch Can " might be a good add on the PHEVs that don't see drive cycles of an ICE only.

 

[The Last Cowboy]

The gas engine needs to be worked somewhat regularly. There are a lot of older Priuses out there with an engine full of sludge due to short trips over a number of years, and those aren’t even PHEVs.

 

[bossboy302]

+1^
Like many, I've read about this issue too. Several have tried to run their Jeep in electric-only mode as much as possible. The ICE stays at rest, yet allows fuel into the crankcase. Seems as though the very high fuel pressure pump (to the injectors) may be on even when the engine is not. If so, weird.
In any case, our Jeeps aren't electric vehicles. They're hybrid. That means a low-displacement ICE can have its power supplemented by electric torque assist. It isn't designed to be an electric only vehicle. We've had our 4xe almost 5 weeks, and have left it in 'hybrid' drive mode the entire time, charging overnight. So far its performing as designed, and better than we expected. 33.8 mpg indicated. (that's for another discussion). On longer trips the ICE will come on as designed. Point is, I think for the most part it is best to let the thing do what it has been engineered to do.

 

[mllcb42]

The ICE stays at rest, yet allows fuel into the crankcase.

People running it in electric as often as possible doesn't mean that the engine doesn't come on periodically. I wouldn't assume that there's fuel getting into the oil with no engine running at all.

 

[The Last Cowboy]

The fuel pump primes and a small amount is available to the engine for initial start up. If the engine never gets started, there is still always fuel being pressurized in the lines and small amount will get past the injectors, as designed. Use your engine people.

And as a side comment. An engine runs on combustible fuel, a motor runs on electricity.

 

[bossboy302]

+1^. My assumption (2 posts above) stands, thanks.

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