Roadracing7

iTrader: (2)

I went to fill up my car with oil and noticed that the inside of the oil cap and on the dipstick. It smells like oil but it's white. I've been told that it's normal and that it's what happens when there's the least bit of water moister in the oil. I have a new engine and don't think a seal has allowed coolant in. I've noticed it on my 12A and on my friend's FD as well. If anyone could tell me exactly what this is, I'd appreciate it. Thanks.

Richard

RonKMiller

I would do an oil and filter change immediately and see if it happens again within 500 miles. This is not a "normal" condition in any engine. Does it kind of look like cottage cheese?

ROTORROCKET

I get few small pieces of "cottage cheese" around my radiator fill neck. Any thoughts?

Roadracing7

iTrader: (2)

Not cottage cheesish... More like a yellowish white foam. I just changed the oil and none of the residue came out in the oil, and none was in the oil cap this time... My guess is that when I overfilled it on the last oil change that it was being "whipped" up pretty good and just cause some foaming at the top, but the problem is gone. Moral of the story, don't overfill on the oil... Thanks for your help.

Richard

atihun

It IS normal.

Possible that the car wasn't driven enough to evaporate all of the moisture in the engine.

I have 93k on my engine and have seen it occasionally since way back when.....

THe cottage cheese around your radiator fill neck, now that is not normal. I would flush your coolant system, do a back flush if you can, and run a coolant system cleaner through it. While your at it you may want to change your thermostat. Cheap $15 fix, that can save your engine.

luneytune

Yes it can be normal for the white stuff on the oil filler cap but only if the car is not completely warmed up every time its run. The moisture in the oil must be "boiled away" and sucked into the PCV line. Check your PCV check valve is working - blow threw it both ways should work one way only. My car has no white **** but my PCV system is working and I never short trip my FD or if I do short trip I warm it up for 15 minutes first.

rxrotary2_7

actualy it i normal i have seen this before an it is nothing more than moisture. take a scoop of it in your hand, and let it sit....it turns into water

2-Rotor

What's that foamy stuff under the oil fill cap & inside the filler tube?

If you look closely, you probably also see water droplets mixed in or nearby the foam. If you find either, there is probably nothing you can do to permanently get rid of them. Luckily, you don't need to. A change in your driving pattern to include more driving under high load and fully warmed, and less driving of short trips or while the engine is cold, might do the job. Enough of such a change will do the job if your car is totally stock.
What you see is an emulsion, oil mixed with water. Your oil includes emulsifiers as part of the additive package. They cause water to actually mix into and "disappear" within the oil. To a point, they do exactly that, preventing small amounts of water from congregating in any one place that might result in oil starvation in a critical location. As long as the amount of water doesn't exceed the ability ot the emulsifiers to disperse them, no harm is done.

All engines are subject to condensation from the normal heatup and cooldown processes, the same way dew forms on the grass in the morning. The oil filler tube area is subject to very little oil flow, and very little ventilation flow, while at the same time it is one area highly subject to the forming of condensation. The emulsifier in the little bit of oil in the area forms the foam as its limit to absorb the oil is reached. When the engine gets hot enough, long enough, the water will boil off. Whether this will routinely happen with yours simply depends on your driving patterns.


Taken from http://mrmazda.members.atlantic.net/...t.html#OILFOAM

MaxRX7

not a good sign. it could be caused by coolant leaking into and mixing with oil.

Tommy

My old motor as well as the new also had the white residue build up under the oil cap. Actually the one now only has about 2k mi on it and its more of a yellowish white with a hint of gasoline smell in it. I thought the only culpret was not properly warming the engine before shutting it off too but i am noticing it all the time no matter if i drive for an hr or 10 min. It would be my luck that my motor is f'd up

luneytune

Check your Positive Eccentricase Ventilation (PCV) valve and lines are working ok. IMHO.

luneytune

Got any more pictures? Really nice looking ride you have there!