Yellow stuff on oil fill cap

Ian_Olivas · Dec 14, 2017

So I changed the oil and saw this. What is all that yellow crap, I have never seen that before and I think I know what it is but I want a different answer lol I'm in denial

Nick@GotExhaust · Dec 14, 2017

Thats moisture build up. Do you take lots of short trips? could be trapped moisture not burning off.

WHen you drained your oil did it look normal? If your oil looked similar to whats on the cap thats a coolant leak. If your oil looked like normal dirty oil you are ok

chrisp2493 · Dec 14, 2017

Mine did that when I was using dirt cheap oil. I had a bad engine I was working on replacing, so I was just using cheap oil since it was burning through it really quickly.

CostaRam · Dec 15, 2017

Ouch, this looks not very healthy.
As said this is humidity buildup and humidity is nothing to be in a engine.
You either drive the truck only a few miles twice a day or you have a coolant leak.
Check the dipstick if there are similar deposits and if the color of the oil is normal.
Check the coolant level and the coolant itself for similar deposits and control your coolant level in the next days.
If the coolant is sinking or contaminated then you have a leak in a oil/coolant passage or a leaking head gasket.
If the coolant and engine oil looks uncontaminated then you should add some miles to your daily trip to heat up your engine well so that this humidity evaporate.
This humidity het sucked in the engine thru the breather hose when tthe engine cools down and
if you just just cruise for a few miles the humidity acumulates in the oil instead of evaporating due the hot oil temp.
Chris

Casper · Dec 15, 2017

CostaRam said:
Ouch, this looks not very healthy.
As said this is humidity buildup and humidity is nothing to be in a engine.
You either drive the truck only a few miles twice a day or you have a coolant leak.
Check the dipstick if there are similar deposits and if the color of the oil is normal.
Check the coolant level and the coolant itself for similar deposits and control your coolant level in the next days.
If the coolant is sinking or contaminated then you have a leak in a oil/coolant passage or a leaking head gasket.
If the coolant and engine oil looks uncontaminated then you should add some miles to your daily trip to heat up your engine well so that this humidity evaporate.
This humidity het sucked in the engine thru the breather hose when tthe engine cools down and
if you just just cruise for a few miles the humidity acumulates in the oil instead of evaporating due the hot oil temp.
Chris

^^^^ This is spot on. 4.7L's from early 2000's are notorious sludge pumpers when driven short distances, especially as the weather cools. The engine oil never gets hot enough to cook the condensation from the engine block cooling off out of the oil. Even if not a head gasket/coolant leak, that sludge accumulates in the engine pan and can eventually cause your oil pump to fail.

So, if you can conclude its not a head gasket, then you need to take some longer drives to cook the moisture out of your crankcase.

You might also want to research whether or not adding some Seafoam to the crankcase just prior to your next oil change is a good or bad option for your circumstances. Some warn is stirs up too much yiltch and spreads it around the oil jacket, and some say it loosens the crap in your pan so that it will drain or be trapped in the filter and removed with the oil change. I'm not going to suggest one way or the other--its your truck.

chrisp2493 · Dec 15, 2017

I drove mine about 14 miles to work each way every day and whatever other daily driving and it did this. I had no coolant leaks, but I had a bunch of blow by due to a worn out engine.

CostaRam · Dec 15, 2017

Well, 14 miles should be enough heat to evaporate and blow the condesation out. Check your oil and water temp to make that sure!
If you have a lot of blow by then you probably want to install a catch can to catch oil fumes and particularly the humidity.
However, i would run a bottle of seafoam in the oil, then change oil and install the catch can to catch this stuff.
Still, the yellow color of the slime on the filler cap looks like yellow antifreeze to me, usually it's white/brownish color.
Chris

Casper · Dec 15, 2017

CostaRam said:
Well, 14 miles should be enough heat to evaporate and blow the condesation out. Check your oil and water temp to make that sure!
If you have a lot of blow by then you probably want to install a catch can to catch oil fumes and particularly the humidity.
However, i would run a bottle of seafoam in the oil, then change oil and install the catch can to catch this stuff.
Still, the yellow color of the slime on the filler cap looks like yellow antifreeze to me, usually it's white/brownish color.
Chris

Actually, No. You need to heat the entire volume of the oil for a longer period of time so that the ability of the water to stay in suspension is decreased, and it effectively converts to vapor and leaves your lubrication system.

To rectify the accumulation the OP has, you need at least a good hour trip at freeway speeds. 14 miles barely gets warmth out of your heater and certainly is not enough to cook out the previous night's condensation.

I don't think its coolant because I had this same issue with an '03 4.7L.

chrisp2493 · Dec 15, 2017

CostaRam said:
Well, 14 miles should be enough heat to evaporate and blow the condesation out. Check your oil and water temp to make that sure!
If you have a lot of blow by then you probably want to install a catch can to catch oil fumes and particularly the humidity.

Haha trust me it wasn’t from a lack of a catch can. Long story, but it was from a damaged cylinder wall. I was running dirt cheap oil from Walmart while my new engine was getting built. I was going through 5 quarts of oil every two weeks so I wasn’t running good stuff. I never had any yellow build up before until I switched oils. And I know for a fact I didn’t have any leaking coolant either

Charger · Dec 15, 2017

If you know that your not getting coolant into the engine, then it looks like a clogged PCV. I had a similar issue with my Grand Cherokee w/the 4.7. They were notorious for clogging up.
You are going to possibly have sludge in the engine. To check you can pull a valve cover off to see . If so, it needs to be cleaned out SLOWLY.
I'd change the oil with a high detergent oil and new filter. after 100 miles change the filter and replace the lost oil. After 500 miles I'd change the oil and filter again . Which is exactly what I did and I have no crud/sludge now. I've changed the PCV every 2 yrs. Hope this helps.

Ian_Olivas · Dec 15, 2017

CostaRam said:
Ouch, this looks not very healthy.
As said this is humidity buildup and humidity is nothing to be in a engine.
You either drive the truck only a few miles twice a day or you have a coolant leak.
Check the dipstick if there are similar deposits and if the color of the oil is normal.
Check the coolant level and the coolant itself for similar deposits and control your coolant level in the next days.
If the coolant is sinking or contaminated then you have a leak in a oil/coolant passage or a leaking head gasket.
If the coolant and engine oil looks uncontaminated then you should add some miles to your daily trip to heat up your engine well so that this humidity evaporate.
This humidity het sucked in the engine thru the breather hose when tthe engine cools down and
if you just just cruise for a few miles the humidity acumulates in the oil instead of evaporating due the hot oil temp.
Chris

So I have a heater core leak and my coolant depletes cause it's leaking but I also have a lit of white exhaust smoke that I believe is engine coolant. And I'm thinking it's a blown head gasket because I took the cap off to check it cause I saw a little on it the last oil change and this time it looked like that and I have not drained the oil yet. I tried to start the truck and it instantly dies on me unless I press down on the pedal to keep the rpms up, so I feel like it's a compression loss issue because of the head gasket. And no normally I don't drive short distances and I've been using the same oil for at least 5 years no issues but my engine is up to 223,000miles now. I'll actually drain my oil now and check the dipstick and report back to see if the rest looks the same. And I use that zerox G-05 coolant that is yellow like what I'm seeing on the cap

Ian_Olivas · Dec 15, 2017

Checked the dipstick and the oil looks normal, it's black like it's time to be changed but it's not milky

panoz3 · Dec 15, 2017

I too have a 4.7 with the same issue: regular short trips that don't fully heat the oil to burn off the condensation. So I researched oil catch cans and decided to install one. You can find my write up here:

http://www.ramforum.com/threads/oil-catch-can-on-a-4-7l-write-up-lots-of-pics.110417/

After only 700 miles I was amazed at how much I poured out. Hope this helps.

Lufty · Dec 15, 2017

Op... I’ve had that moisture build up every winter ( summer not so much but still some) since I bought my 04 Dakota new with the 4.7 running 0w-30 amsoil since 6000 miles on it. In the past I’ve had my pcv valve freeze shut because of that crap and not wanna stay running. Maybe yours is gummed up. Something to try for a couple bucks is replace it. I believe the problem is the plastic fill housing holding the pcv valve doesn’t get warm enough, especially in the winter months and short tripping it, to burn that condensation off like others have said.

Cardhu · Dec 16, 2017

The 3.7 has a tsb they implemented in 2007 for exactly this. Go on a run once a week to get the oil hot like above 100 c to cook off moisture. and new PCV valve was mentioned and worth changing.

Cheap or expensive oil will give same issue. Get it hot, drop out of OD, make it work just burn it off. Can also reroute hoses over engine to stay warmer as that was part of the tsb

Ian_Olivas · Dec 16, 2017

Lufty said:
Op... I’ve had that moisture build up every winter ( summer not so much but still some) since I bought my 04 Dakota new with the 4.7 running 0w-30 amsoil since 6000 miles on it. In the past I’ve had my pcv valve freeze shut because of that crap and not wanna stay running. Maybe yours is gummed up. Something to try for a couple bucks is replace it. I believe the problem is the plastic fill housing holding the pcv valve doesn’t get warm enough, especially in the winter months and short tripping it, to burn that condensation off like others have said.

We have owned it since it was new off the lot and this never happened, is it more common in more millage engines? And okay I'll replace that hose and see if I can get it started to burn that off

Lufty · Dec 16, 2017

I’ve had that condensation since it was new also but yes it seems as it has aged it has gotten worse over time. I think it is pretty common in these motors. I would change/reroute that hose and replace the pcv valve and see if that helps. The time the pcv valve froze shut it wouldn’t run at all unless I gave it throttle.

Ian_Olivas · Dec 17, 2017

Lufty said:
I’ve had that condensation since it was new also but yes it seems as it has aged it has gotten worse over time. I think it is pretty common in these motors. I would change/reroute that hose and replace the pcv valve and see if that helps. The time the pcv valve froze shut it wouldn’t run at all unless I gave it throttle.

Yep. That's where I'm at right now. Engine dies unless I'm pressing the accelerator pedal

Ian_Olivas · Dec 17, 2017

panoz3 said:
I too have a 4.7 with the same issue: regular short trips that don't fully heat the oil to burn off the condensation. So I researched oil catch cans and decided to install one. You can find my write up here:

http://www.ramforum.com/threads/oil-catch-can-on-a-4-7l-write-up-lots-of-pics.110417/

After only 700 miles I was amazed at how much I poured out. Hope this helps.

In that write up on installing a catch can you had put the pdf file for a reroute with the pcv system and there was a cap that goes on the resonator airbox. Where can I get a cap like that to use? Or if that's a lot where can I get the kit?

panoz3 · Dec 17, 2017

Ian_Olivas said:
In that write up on installing a catch can you had put the pdf file for a reroute with the pcv system and there was a cap that goes on the resonator airbox. Where can I get a cap like that to use? Or if that's a lot where can I get the kit?

I searched Ebay for the kit and wasn't able to find it. I also checked a few Mopar parts websites and each said it was discontinued. I think a simple hose barb plug from the hardware store would work.

Yellow stuff on oil fill cap

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