Gas smell in oil

[Skurvy_Pirate]

So I was checking the oil a few days ago and noticed that there was a gas smell when I smelled the oil. I have been looking around and it seems like it could be a number of things from the truck running too rich to bad compression to leaky injectors. I am going to change the oil out asap.

Also, it is no longer being driven as much, just short trips to and from work and randomly around town. It used to be driven about 50 miles per day. Could it be that it is not heating up enough to burn off? Is there anything specific to the 4Runner that is more likely to be the cause of this? It has about 220,000 miles on it.

 

[LittleCaesar]

Any codes? How does it idle?

I try and give all my non daily driven autos an Italian tune up at least once a month. If you can still smell gas, then pull the vacuum line off the regulator and see if you can smell gas there. If no, then it is possibly a slight leak from an injector.

 

[Notoyz]

Little Caesar What's an Italian tuneup?

 

[Skurvy_Pirate]

Any codes? How does it idle?

I try and give all my non daily driven autos an Italian tune up at least once a month. If you can still smell gas, then pull the vacuum line off the regulator and see if you can smell gas there. If no, then it is possibly a slight leak from an injector.

No codes (at least no CEL). It idles fine. After I change the oil I will give it some highway miles and see if the smell comes back.

 

[Skurvy_Pirate]

Little Caesar What's an Italian tuneup?

I think he means just driving it hard, or driving on highway for a while. Just working the engine to clear out buildup.

 

[nevada]

So I was checking the oil a few days ago and noticed that there was a gas smell when I smelled the oil. I have been looking around and it seems like it could be a number of things from the truck running too rich to bad compression to leaky injectors. I am going to change the oil out asap.

Also, it is no longer being driven as much, just short trips to and from work and randomly around town. It used to be driven about 50 miles per day. Could it be that it is not heating up enough to burn off? Is there anything specific to the 4Runner that is more likely to be the cause of this? It has about 220,000 miles on it.

yes, it could cause that.
also, lots of really short trips are about the worst thing you can do.

you may have injectors that leak a tiny bit, but when driven for enough time, its a non-issue.
but, lots of short trips allows it to build up.

 

[etc.]

yes, it could cause that.
also, lots of really short trips are about the worst thing you can do.

you may have injectors that leak a tiny bit, but when driven for enough time, its a non-issue.
but, lots of short trips allows it to build up.

This is true.

 

[Gerdo]

Little Caesar What's an Italian tuneup?

I think he means just driving it hard, or driving on highway for a while. Just working the engine to clear out buildup.

Going for a "Spirited Ride".

 

[mikebontoft]

yes short trips will not allow your pistons to really expand and that could potentially allow some fuel to mix with the oil.

 

[LittleCaesar]

Mikebontoft and Gerdo have it covered as far as what an Italian tune up is. If short trips is the majority of what a motor sees over a period of a month, especially in winter, it is good to really put them through the paces at least once a month for at least 30 minutes. Boat engines are the same way and foul much quicker.

In relevance to the OP, I'd say leaky fuel injector, not enough to cause apparent problems, but might be preparing to bite the farm down the road. Keep an eye out for a possible CEL.

When you have time though, pull the spark plugs to see if any of them seem wet with gas. If so, then time for a compression test (possible worn piston rings).

 

[Skurvy_Pirate]

Thanks for all the replies! I already took it for a "spirited drive" today. I will keep an eye out for any CELs and the oil to see if the smell comes back after a change.

If the top of the piston is wet, couldn't that be a leaky injector as well as a worn piston ring? I will check them next time I get a chance.

 

[LittleCaesar]

Very much so, but with the compression test (both wet and dry), it would pinpoint to whether the ring(s) were not sealing properly. But if the 4runner runs fine, and loses no oil, then I would tend to believe that the bottom end is fine.

Drive 100+ miles, then check the oil. I still would put $$$ on a leaky injector.

 

[Skurvy_Pirate]

I took it in to a mechanic because after an oil change and some long drives (Portland->Seattle and back) there was still a gas smell in the oil. I also needed to get the valve cover gaskets done because they were leaking oil, not bad, but enough to make it smell hot.

It turns out the MAF is bad (or possibly dirty). They recommended MAF, plugs/wires, new air filter, oil change, and a fuel injector flush. I passed on that stuff and just had them go ahead with the valve cover gasket.

They are going to clean the MAF and see if that helps. If not I will be replacing it myself. But I will doing all of the above except the flush either way.

I have a few questions:

1. If the MAF is bad, why doesn't it through a CEL?
2. What readings from ODB II would help tell me the MAF is bad? I assume the mass air flow rate and possibly the air/fuel ratio?
3. Is it worth it to flush out top end after this is resolved? I think they wanted $180

Overall the shop is honest and reputable and I trust them. But I don't want to pay $180 for something that probably isn't needed.

 

[Antznyopantz]

Post Revival

Pirate - what happened with your 4runner? I am at the beginning of this process. Just smelled gas in my oil. 185,000miles - previous owner had let it sit for some time... Hopefully an oil change is the end of it. No codes thrown.

 

[JayRolla]

Running rich from bad O2 sensor is what usually causes this. When running high HP in our e85 cars the oil always has a good ethanol smell to it. But without CEL be hard to find the issue.

 

[zazzomicron]

I'm having a similar issue on my 2000 SR5

I'm throwing a 171 code so will start with an MAF clean. For some reason she ran fine until I filled up with 91 octane. Could be a coincidence.. or not

 

[phattyduck]

A little gas smell is fairly normal.

You can have your oil tested by Blackstone labs or a similar lab and see the fuel dilution levels to KNOW if you have a problem or just a sensitive nose.

-Charlie

 

[zazzomicron]

A little gas smell is fairly normal.

You can have your oil tested by Blackstone labs or a similar lab and see the fuel dilution levels to KNOW if you have a problem or just a sensitive nose.

-Charlie

Good to know. Cleaning the MAF tonight and will change the oil shortly afterwards to see if it has any effect.