Sulfur on my filler cap

[lelakwoman]

I drive a '99 Ford Expy. 5.4L, V8, 4R100, and 3.73:1. I do a lot of highway driving and my fair share of in town driving. I change my engine oil every 3K (because it starts to use oil after that) which is about every 5-6 weeks for me.

After reading up on this site, i switched my oil from Pennzoil 5w30 to Mobil 1 5000 5W30. I did that 1000 miles ago. When i took my oil filler cap off, it had a very bright yellow film all over it.

I had been using the Pennzoil SUV & Truck oil for about 45K miles and had never seen the yellow film before.

Prior to the Pennzoil i had used one oil change worth of Valvoline High Mileage oil and had major leaks, and that's why i switched to the Pennzoil.

Should I have my current oil (Mobil 1 5000 5W30) tested (it's in use and has 1000 miles on it)? or should i auto-rx my truck again? or both?

 

[BlazerLT]

quote:

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Originally posted by lelakwoman:
I drive a '99 Ford Expy. 5.4L, V8, 4R100, and 3.73:1. I do a lot of highway driving and my fair share of in town driving. I change my engine oil every 3K (because it starts to use oil after that) which is about every 5-6 weeks for me.

After reading up on this site, i switched my oil from Pennzoil 5w30 to Mobil 1 5000 5W30. I did that 1000 miles ago. When i took my oil filler cap off, it had a very bright yellow film all over it.

I had been using the Pennzoil SUV & Truck oil for about 45K miles and had never seen the yellow film before.

Prior to the Pennzoil i had used one oil change worth of Valvoline High Mileage oil and had major leaks, and that's why i switched to the Pennzoil.

Should I have my current oil (Mobil 1 5000 5W30) tested (it's in use and has 1000 miles on it)? or should i auto-rx my truck again? or both?

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Leave it alone, water condensation like that is normal and the new synthetic will clean the engine nicely.

That is not sulphur.

 

[John K]

I think it would be a good idea to check your PCV to make sure it is operating correctly. Also, before checking your filler cap again make sure it has been fully up to temperature to drive off moisture.

 

[lelakwoman]

how do i make sure the PCV is functioning properly? i don't remember off the top of my head, isn't there a small ball/pellet in there?

Note: when i removed the filler cap that last time, i had just shut the engine off. i drove to town and back to get the new oil (approximately 30 miles).

 

[Blue99]

Well, an accumulation of sludgy condensation on the oil cap or in the filler tube is frequently reported during cold weather. The oilcap/filler tube is an interface between the cold outside air and any moisture coming out of the oil.

It's always a good idea to replace the $3-$4 PCV valve, but my question is, if you clean off the yellow accumulation on the filler cap, does it come right back the next day?

 

[tmorris1]

This is normal. It isn't sulphur, it is water condensation. It is worse on the 5.4L Fords because they have a long filler neck that sticks up above the engine quite a bit.

 

[lelakwoman]

Thanks all for the replies. It's snowing here in indiana again. i haven't checked to see if the condensation comes back, but i will start checking to see if i notice a trend.

thanks again...i thought i had a major problem.

 

[MolaKule]

quote:

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it had a very bright yellow film all over it.

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A bright yellow film could also simply be from the dye in the oil. Oil vapor condenses on the cap and any components that are cool(er) than the rest of the engine.