Sludge underneith oil cap

[>MR2turbo4evr<]

I noticed today that there was some yellowish foamy stuff (just like whip cream, except it was yellow) underneith the oil cap of our 4Runner (4th gen V8). Does anybody have an idea what this stuff is? The truck only has only 7000 miles on it and I've changed the oil 3 times already (mobil 1). Please help.

 

[Koz]

Send a sample out to be analyzed.

http://www.blackstone-labs.com/free_test_kit.html

Koz

 

[Bluto]

How much oil do you put in? Check the level on the dip stick. I know it is a silly question. But eliminate the possibility it has too much oil. Some oils come in 5 qt. jugs, people mistake for a gallon.


Any foam on the dip stick?


It may be some moisture. A friend's corolla had yellow residue on the inside of the oil cap. But they were getting the cheap oil done at the dealer. No problems now, with a good synthetic.

 

[greasefingers]

Many vehicles experience this. I do not know if it is common with our T4R

 

[savagebeast]

that is build up of fumes,additives and detergents, run mobil gas and use mobil1 if it bothers you but it's normal.

 

[windglass]

I noticed today that there was some yellowish foamy stuff (just like whip cream, except it was yellow) underneith the oil cap of our 4Runner (4th gen V8). Does anybody have an idea what this stuff is? The truck only has only 7000 miles on it and I've changed the oil 3 times already (mobil 1). Please help.

I has this problem too! Found it two weeks ago and took pictures last week. I just wonder whether there is some coolant leak, but coolant level is normal. My 05 v6 runner has only 5000 miles and uses Mobile 1. I plan to stop by local dealer to get check this satarday.

 

[>MR2turbo4evr<]

How much oil do you put in? Check the level on the dip stick. I know it is a silly question. But eliminate the possibility it has too much oil. Some oils come in 5 qt. jugs, people mistake for a gallon.


Any foam on the dip stick?


It may be some moisture. A friend's corolla had yellow residue on the inside of the oil cap. But they were getting the cheap oil done at the dealer. No problems now, with a good synthetic.

Thats the first thing I checked, but the oil level was good. I searched around on some different forums and found out that this is normal. Thanks very much for helping out guys.

 

[>MR2turbo4evr<]

Re: Re: Sludge underneith oil cap

I has this problem too! Found it two weeks ago and took pictures last week. I just wonder whether there is some coolant leak, but coolant level is normal. My 05 v6 runner has only 5000 miles and uses Mobile 1. I plan to stop by local dealer to get check this satarday.

Yeah thats what that stuff looked like. Exept there was TONS more on our 4Runner.

 

[windglass]

Re: Re: Re: Sludge underneith oil cap

Yeah thats what that stuff looked like. Exept there was TONS more on our 4Runner.

I don't worry it about much because I usually drive my runner only 7 or 8 miles daily in week days. I think it introduce more moisture condensed in oil at cold engin temperature. So in weekend I always drive my runner more than 20 miles to dry the oil. For this problem I will change oil at 3000 miles interval in cold seasons.

 

[>MR2turbo4evr<]

Re: Re: Re: Re: Sludge underneith oil cap

I don't worry it about much because I usually drive my runner only 7 or 8 miles daily in week days. I think it introduce more moisture condensed in oil at cold engin temperature. So in weekend I always drive my runner more than 20 miles to dry the oil. For this problem I will change oil at 3000 miles interval in cold seasons.

Yeah thats probably the problem. I pretty much only drive in to work and back during the week (4 or 5 miles) and always let it warm up for a couple minutes before I start driving it. I don't think it can be something serious, it is a Toyota after all.

 

[Baba Booey]

I'm not sure about the V8s, but my V6 seems to have a fairly long "filler neck" where you pour the oil into the engine. I remember reading a post about a Jeep 4.7L with this same problem on the "Bob is the Oil Guy" (BITOG) forum, and many knowledgable people seemed to imply that a long filler neck contributed to the problem.

Apparently, the long tube cools down much more quickly than the engine block itself, which allows condensation to form in the filler tube and under the oil cap. Occassional long drives are recommended to burn off this excess moisture.

I have read several used oil analyses on BITOG, and I am pretty sure that both the V6 and, especially, the V8 turn in great reports.

I will pose this question on BITOG and see what response I get.

 

[TRD04RUNNER]

same chit on my M3 during the cold month too. it when you drive your car to the gas station and back little trip here and their and not letting the car run longer to evaporate the moister. it call condensation. it like water on your window in your home when its cold outside and warm inside. the inside temperature is not hot enough to evaporate the moister their for leaving a yellowest foam like moister from the oil on your top of your motor.just take the 4R out and drive it for 1/2 an hour or more and its should clear up!.

 

[Captsolo]

I has this problem too! Found it two weeks ago and took pictures last week. I just wonder whether there is some coolant leak, but coolant level is normal. My 05 v6 runner has only 5000 miles and uses Mobile 1. I plan to stop by local dealer to get check this satarday.

I saw the same (dry brown/black) sludge in my filler cap on my 2005 4runner 4.0L.
after the oil was changed recently, and I freaked out a bit, but not concerned after
cleaning it out and running (and researching) a while.. and looking at the dip stick
regularly ...aka checking the oil color regularly too on dip stick and under the filler cap
- which looks like new oil just out of the can after 3000 miles.

The 4runner gets good Valvoline conventional oil changes at 5000 to 7500 miles with
a good filter at a big shop with 6 lifts, and has 140,000 on the od. I'm surprised my mechanics
never cleaned out the cap. On the work done printout receipt they tell me the weight they use
is W5-30.

I scrubbed the cap clean and monitor it for anything "new" in the cap now.
So far... nothing like the 13 year buildup.
I also am doing my own oil changes with a NAPA synthetic blend W5 30
(now every 5000 miles) for older engine.

I looked down the filler neck and there is dried brown color crust from oil just building up
there over the last 13 years (140,000) and drying. Don't hope for shinny
aluminum in this area. It's going to discolor normally IMO.

This 4 runner runs like new. Never ever had an check engine oil lite in 13 years,
except when turning the key to on to start.

Had the dealer change the tranny fluid and filter at 100,000 miles.

I live in a hot climate that never see the temperature below 50F, and usually 85F.
Longest drives on this 4.0 engine was 20 to 40 miles (on this island) at speeds up to 65MPH
(well above the speed limits here). :lasercannon:

Overheat alarm has never come on... on this engine, and the temperature guage always shows on the low side of the
"safe' area when she's at operating temperature.:lock1:

 

[rwh963]

same thing. showed it to toyota service. they said this is normal frothing. i thought it might be coolant, but no. i think the filler neck contributes to this situation. don't worry, drive on!

 

[riceandpho]

its normal for people who do very short trips.

 

[Berty_K]

its normal for people who do very short trips.

Seconded. Engine doesnt have enough time to burn of condensation.

This is especially apparent in colder temps.

 

[4Genner]

I have the oil cap sludge problem to an extreme degree in my 2008 4.0. It only happens in the cooler half of the year. I live in southeastern PA, the winters are variable but not extremely cold. I’ve had the truck for three winters and it’s always done this. A few weeks ago I installed a cheap catch can as an experiment, and after approximately 750 miles of driving I found a horrifying scene in the catch can.

This seems excessive even for an engine with a known tendency to do this. I have no idea why it seems worse on mine than other similar vehicles, but here’s what I know so far:

-A clean oil study with zero coolant detected pretty much ruled out a head gasket leak. Over 75k miles/2.5 years I’ve added maybe a cup of coolant, which I think could be attributed to the weep hole on the water pump or other undetected small external leaks. There are no signs of oil in the coolant, excessive pressure, bubbling, misfires, exhaust smoke, etc.

-Before anyone says “short trips”, I drove it 300 miles on the highway yesterday and didn’t shut it off for 8 hours. It still happened when I was commuting 200 miles round trip every day too.

-I use top tier gas, fill it up at 1/4 tank, and use heet gas treatment in the winter.

-I use synthetic oil, usually Mobil 1. I have heard that synthetics may be more prone to causing or worsening this but, again, others seem to use it without having this issue.

-I’ve changed the Pcv valve and vacuum hoses with Toyota parts several times. There are no signs of vacuum leaks anywhere. The pcv clearly opens because stuff is getting into the catch can!

Open to other ideas!

 

[Trumpet]

I have the oil cap sludge problem to an extreme degree in my 2008 4.0. It only happens in the cooler half of the year. I live in southeastern PA, the winters are variable but not extremely cold. I’ve had the truck for three winters and it’s always done this. A few weeks ago I installed a cheap catch can as an experiment, and after approximately 750 miles of driving I found a horrifying scene in the catch can.

This seems excessive even for an engine with a known tendency to do this. I have no idea why it seems worse on mine than other similar vehicles, but here’s what I know so far:

-A clean oil study with zero coolant detected pretty much ruled out a head gasket leak. Over 75k miles/2.5 years I’ve added maybe a cup of coolant, which I think could be attributed to the weep hole on the water pump or other undetected small external leaks. There are no signs of oil in the coolant, excessive pressure, bubbling, misfires, exhaust smoke, etc.

-Before anyone says “short trips”, I drove it 300 miles on the highway yesterday and didn’t shut it off for 8 hours. It still happened when I was commuting 200 miles round trip every day too.

-I use top tier gas, fill it up at 1/4 tank, and use heet gas treatment in the winter.

-I use synthetic oil, usually Mobil 1. I have heard that synthetics may be more prone to causing or worsening this but, again, others seem to use it without having this issue.

-I’ve changed the Pcv valve and vacuum hoses with Toyota parts several times. There are no signs of vacuum leaks anywhere. The pcv clearly opens because stuff is getting into the catch can!

Open to other ideas!

Seeing as our gasoline already has alcohol in it, I'd stop using Heet. Not needed.

Other than that, perhaps check that the thermostat is working properly and the engine is getting up to temp.

 

[UrbanRunner651]

I see you discovered the onboard latte maker..

Jokes aside the froth is normal. Even if you allow the motor to reach normal operating temp, the residual condensation/oil mix from your shorter trips will still remain. That is the can doing its job, by preventing excess moisture and oil vapor from being dumped back into the system.

I have been running a catch on my 08 for a couple years now and have concluded the following:
-In colder temps (<30), you should expect to empty your catch about every 300 mi. (subjective to can size)
-In warmer temps (>30), you can easily get 1k mi or more between empties.

Most users should practice extra caution and empty frequently in the colder months as allowing it to completely fill and dump back into the intake could lead to much bigger problems.
If you are that concerned, pull the can and just hook the line back up directly to the PCV. Plenty of 4runner owners that experience cold weather and never install a catch. The vehicle will run fine either way.

 

[4Genner]

Thanks for the replies. Addressing both points:

-My understanding of Heet is that it’s supposed to help prevent water from building up in the fuel system, which is a problem that’s associated with ethanol in the fuel as well as natural temperature changes and moisture in the air. However, even if you’re right (maybe you are, I’m no chemist), the engine was still making peanut butter before I started using it heet this winter, so I think it’s a red herring.

-As for the catch can, I’m glad it’s working and my hope was that it would do exactly what it’s doing, I’m just shocked by how much gunk the engine puked out in less than 1000 miles. I don’t know if these engines have inadequate pcv systems, or need a windage tray in the oil pan to reduce the oil vapors, or what. But definitely a lot of oil and water vapors are mixing in the atmosphere of the engine. The gunk did not smell of gas.

-I should have included more information about maintenance. The cooling system is in working order, temp needle stays right under the halfway mark no matter what. The engine has 206,000 miles and uses about 1/2 quart of oil per 5000 miles, most of which is apparently going out of the pcv valve! All maintenance/tune-up items are up to date. My fuel trims are +5-10%, so the computer is correcting a perceived lean running condition but it’s not egregiously out of spec. No check engine lights or codes ever. In sum, it’s an old car but it’s not terribly worn out!