Yellow gunk on Oil fill cap

[HappyHyundai]

Hey guys. I tried to do a search , but I couldn't find any topics about yellow gunk on Oil fill cap. This is the first time it has happened. I'm using Castrol Syntec 5w30 and AAP oil filter; I don't know if that has to do with anything. Does anyone know what it is? Moisture maybe?

 

[daman]

my friend you have a coolant leak stop running
that motor now!!!

 

[daman]

That's exactly what my 3100 v6 looked like when my intake
gasket failed,,not good...

 

[HappyHyundai]

HAHAHHA DANG. First major casuatly on my engine.. oh boy.

 

[adam123]

Etheir that or condesation build up from cold weather. But for that it looks excessive.

 

[simple_gifts]

I've had frozen condensation under the cap on my 1989 F-150 I6 that looks like peanut butter and there was no coolant leak. I would do a UOA before panicking.

 

[HappyHyundai]

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Etheir that or condesation build up from cold weather. But for that it looks excessive.

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All of this started when the snow came a couple days ago.

 

[HappyHyundai]

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I've had frozen condensation under the cap on my 1989 F-150 I6 that looks like peanut butter and there was no coolant leak. I would do a UOA before panicking.

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Good idea. I'll get it done tommarow.

 

[daman]

Has your coolant level been going down???

 

[Gary Allan]

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Etheir that or condesation build up from cold weather. But for that it looks excessive.

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All of this started when the snow came a couple days ago.

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If it was a coolant leak of that severity, it would have shown up at regular temps too (most likely).

Do you do short trip driving?? Check your PCV system ..and, as was suggested, do a UOA.

 

[Drew99GT]

Wow. My mom drives about 4 miles to work and back ever day, and short trips to the grocery store on weekends. Even with a busted upper intake and leaking lower intake gaskets, the oil cap never looked like that!

However, the Dodge 4.7Ls seem to gunk up just like that without coolent leaks so if it isn't losing coolent and a UOA checks out fine, then just put a blindfold on when you take your oil cap off

 

[dodge1]

That is codsendation build up ,the dodge engines do it when the temp gets really low .The plastic filler tube is cold and lets it build up .When the temp gets around 50f or so it should not be noticable.We call it snot buildup.

 

[HappyHyundai]

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Etheir that or condesation build up from cold weather. But for that it looks excessive.

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All of this started when the snow came a couple days ago.

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If it was a coolant leak of that severity, it would have shown up at regular temps too (most likely).

Do you do short trip driving?? Check your PCV system ..and, as was suggested, do a UOA.

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Thanks for everyones replies.

A couple days ago I replaced my upper coolant hose because Auto Zone parts are garbage. Other than that, my coolant level hasn't been dropping.

 

[Quattro Pete]

How many miles is your commute? If the engine doesn't have time to properly warm up (due to colder ambient temps), that's what you'll see under the cap. It's actually normal. Normally I would say to go on the hwy and put on 75 miles in one go and see if it goes away, but that would be kind of wasteful and may be detrimental to your engine if in fact you do have a coolant leak and not just simple moisture accumulation.

 

[HappyHyundai]

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How many miles is your commute? If the engine doesn't have time to properly warm up (due to colder ambient temps), that's what you'll see under the cap. It's actually normal. Normally I would say to go on the hwy and put on 75 miles in one go and see if it goes away, but that would be kind of wasteful and may be detrimental to your engine if in fact you do have a coolant leak and not just simple moisture accumulation.

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I drive about 600-900 miles a month. It's funny that you mentioned about warm up time; on bitog many people were saying that warm-up and idle was bad for the car.. so now I never warm up the engine and drive off immediatly after driving. I guess that could be a problem. I'm doign an oil change again and see what happens.

 

[HappyHyundai]

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Etheir that or condesation build up from cold weather. But for that it looks excessive.

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All of this started when the snow came a couple days ago.

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If it was a coolant leak of that severity, it would have shown up at regular temps too (most likely).

Do you do short trip driving?? Check your PCV system ..and, as was suggested, do a UOA.

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Gary, I'll check the PCV valve to see if the plug rattles. I haven't checked it since 60,000 miles.

 

[Triple_Se7en]

Warm-up for a minute in cold weather is essential to your engine.

Warm-Up for lengthy spells is not good.

There's a difference! There's also a difference in how hard you accelerate when the engine is cold. Go gently for a block or two - even after that minute warmup.

I very seldom hammer an engine. I very seldom hit passing gear. I never do either before that temperature needle starts moving to warm.

That's what I do anyways.....

 

[ewetho]

That does not look too bad if you are in a cold weather area.

Seen it over and over. In cars that have a fill pipe that leads down to the valve cover it is absolutely normal in cold weather. If the dipstick is clear you are probably just fine and would not use that as an indicator of a problem. If that cap was right over a timing chain and you see stuff down on the chain and on the dipstick then you probably have a problem.

See it in fords all the time during winter in the Chicagoland area that are clear again in summer.

 

[Quattro Pete]

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It's funny that you mentioned about warm up time; on bitog many people were saying that warm-up and idle was bad for the car..

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I didn't mean warm-up while idling. I meant the engine not getting fully warmed up due to short commute. Say your commute is only 5 miles one way (you haven't answered that one

), even though your coolant temp gauge may get up to normal, the oil is still not up to temp and it may not be for another 10 minutes, and for the moisture to burn off it would have to stay warmed up for even longer after that. During summer, the warm-up (again: while driving, not while idling) is quicker. During winter it's slower, and you're slowing it down even more by taking heat away from the engine to warm the cabin.

 

[Chris142]

Taste it. See if it's coolant or water.