White residue under oil cap
 

Hello, I have a 82 rx7 and lately when filling up oil I have been noticing alot of white grease like material building up at the top of the oil cap and shaft. I asked a "mazda rx7 speacialist" and he told me that it was normal. He told me it was condensation in my engine. I am located in canada and for the past year I have been using 20w50. After talking to the speacialist he told me that I was lucky I didnt blow my engine and 20w50 was for racing only. I was having problems starting my car when it was cold so I thought the problem was the oil. I started using 10w30 and I have done 2 oil changes since then and still see a white residue around the oil cap. It looks like bacon grease and is watery. Has anyone reading this post experienced this before? Thanks in advance.

Unless you used 20w50 in subzero conditions, it should not cause harm to your motor. The onlty way it could is if it thickened up in the cold and caused oil starvation to the motor. In the summer, it's the way to go. In the winter, use 10w30 or 5w30 if you're so inclined. As far as the residue goes, I've never seen that before, and I live in Saskatoon, which can get pretty cold and presumably cause condensation. How does the car run? Are there any problems or driveability issues?

Matt
1979 SA22C
"Got Wankel?"

To a point the condensation is normal, but if you still have all the smog stuff, I'd check it out to be sure its working correctly. I didn't get any white buildup until I removed everything.

Condensation is a normal by-product of combustion. Usually it get's burned off once the oil heats up enough and/or get's sucked out through the PCV system.

Make sure all your lines are connected to the nipples on the oil tube, intermediate housing, charcoal canister and PCV valve.

If everything's functioning correctly you can still get a bit of buildup especially during short trips where the oil doesn't get a chance to heat up enough. If it's only a small amount I wouldn't worry about it.

Well, I don't know exactly what's causing it, but I do know the white bacon fat stuff is caused by water in the oil; condensation or whatever. I've never seen it in my '84, so I can't say if it's "normal" or not.

Let me take a wild guess and say your "specialist" is RX-7 Heaven? If so, run away, run far away!!!! Search the Canadian forum for horror story after horror story. Do not, I repeat, do not, let them touch your car.

The advice you received is absolutely wrong, which isn't surprising given the fact that the folks at RX-7 Heaven do more Old Milwaukee guzzling than they do thinking. I've used Castrol GTX 20W50 for 6 years with absolutely no problem. This is the oil that most of us use and have used for years, there is nothing wrong with it. HOWEVER, you should not be running this heavy an oil in colder weather, as others have mentioned.

REVHED's right, sounds like your PCV (positive crankcase ventilation) system is not functioning correctly.

This problem usually occurs when people remove their emissions control equipment, but do not properly allow air to flow through the nipple on the filler neck (best method is a small breather filter).

This is not a "normal" thing. You should fix the problem as fast as you can - it will cause the inside of your oil filler neck to start rusting very quickly.

As REVHED said, run through your PCV system and make sure everything is connected and working properly.

And if you want to talk to people who actually know the first thing about RX-7's, check out the Canadian forum, there are at least a few guys in Ottawa that know their stuff and are more than willing to help out with advice. Leave the drunks at RX-7 Heaven to what they're good at, which is living in the attic above the shop because they lost their licenses from DUI and their wives divorced them.

BTW, if you'd like another hint about their shadyness, how about the fact that the main guy had the Ottawa Citizen publish that he was dead and his teenage daughters ran the shop LOL? Even though when we called the shop to see, he answered the phone. Very, very shady.

White, greasy residues in oil are caused by water/coolant. Normally you should not have this at all. If a piston engine has this problem, it usally means the head gasket is gone. We can all translate that to a rotary, yes? Condensation should not cause this, as this would not contain the stuff that's in coolant. I don't want to frighten anyone, but I would really start thinking "big problem" here. Of course I don't know how bad it all is, but the problem itself is NOT NORMAL. As someone suggested: find another "specialist".
As for the oil: those numbers are refering to the temperature differences the oil can handle. The first being the lower, the second the higher temp. That's outside temperature, not engine. If you use the same oil during winter in Alaska as you use in Mexican summer, you're gonna get in trouble :D
So normally 20W50 shouldn't cause problems.
My advice: test/repair the PCV, if the problems stays you're in trouble.

Naw, I don't think it's necessarily cause for big worry - many of us have had this problem as a result of modifications, and in every instance I've seen it goes away once you make the PCV system work again.

I think you understand what you're trying to say here, but it sounds slightly misleading the way you put it. The numbers on the oil container are NOT "outside temperature" figures.

This should clear it up:

Ooops, been away from school way too long I guess... Kind of ashamed now. Anyway, since I have no clue about fahrenheit, can't say much about it (Celsius is the man overhere). Thanks for the update. Still, I really don't like any residues in the oil...

Celcius over here too:, I love Canada:)

White gunk under an oil cap is not a good thing. Do a pressure test on your water system and see if you have any leaks...

TRUE, but people need to understand where it comes from.

What happens is hot air/hot oil from the bottom of the oil pan comes up the tube, and the tube is naturally cooler than the motor is, it then condensates, and forms water vapor ...

Thanks alot for the responces. I am going to check on my pcv system. As I do alot of stuff to my car it would not surprise me that the pcv system is not functioning. Also btw the rx7 speacialist was not from rx7 heaven. I will have to agree with silverrocket in saying the guy is a complete moron. They drink more beer than fix cars. He will give you a car for a mikey. He is definately not dead. I read that article in the citizen also. lol. I would like to do his daughter and get all the rx7 parts for free :)

Anybody that reads this NEVER GO TO RX7 HEAVEN unless very desperate for a part. Do not get any work done there or buy any engines etc. He will sell you the crapiest part around. The rx7 speacialist I went to was Mazdees in toronto.

No kidding, Mazdees said never to use 20W50? I wonder if they just meant in cold weather? I've never heard anything but good about Mazdees.