Yellow gunk oil filler cap

[steevo]

Hi Guys,
      Just carried out the usual weekly fluid checks and iv\'e noticed that iv\'e got a build up of bright yellow gunk under the oil filler cap.

Would i be correct in assuming that iv\'e got water leeking into the oil somewhere in the engine.

There\'s no trace of it on the dipstick or in the coolant.

The cars done 45000 miles on the original engine with an average of 7.5 bar compression.

Am i looking at an engine strip or is this normal on an engine of this milage.

CHEERS !  

STEVE.....

[clive]

Hi Steve,

Have you had to add ANY water lately to the car even a very very small amount,

If you haven\'t give it an oil and filter change,wipe out the cap and may be O/K for a while fingers crossed.

Hope this helps.
 
All the best Clive
clive@mazdarotaryclub.com
//www.mazdarotaryclub.com
//www.mazdaRX-8club.com

[steevo]

Thanks Clive,
                 I haven\'t had to add any water to the car for the 4 months iv\'e had it,although it seems to have used a bit just lately.

The oil and filter has only just been done. I put Castrol GTX 10/40 mineral in it,i dont know what had been used previously,could it be a change/mixing of oil causing it.

CHEERS !

STEVE...

[clive]

Thanks Clive,
I haven\'t had to add any water to the car for the 4 months I\'ve had it,although it seems to have used a bit just lately,


Hi Steve,

Real sad to say the seems to have been using a bit lately is the start of a water seal problem that will make a rebuild of the engine necessary.

Sorry to be the bearer of bad news.

All the best Clive
clive@mazdarotaryclub.com
//www.mazdarotaryclub.com
//www.mazdaRX-8club.com

[Andyp]

dunno if it\'s any help but I got this off the US forums for ya under the topic of "yellow gunk under the oil cap"

From Felix Miata\'s FAQ:


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 of 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.

 

[Iwan]

That match exactly what it is. Please don\'t worry about your engine.
It also happens often when you change your oil brand. Like using Mobil1 bofor switching to Castrol. Another oil will "clear" your engine from the rest of another oil. Couse of chemical fusion it will make a mixture of diferent chemical stuff. Thats the reason why you should change the oil after 1000km (650 miles) after you switch to another brand or another oil. It should stop after the oilsystem is clear of "foreign" components.

REgards
Iwan

[Ed_RX7]

Can anyone shed some light on this matter....coz we are still nut sure what the cause is?



Worried!!!!?

[Andyp]

well I got it on mine when I changed oil brands... been told mines running great so I\'m not worried

[Ed_RX7]

Cheers for the reply Andy........ there is hope.....anytime I start thinking rebuild my heart misses a beat!!!!!.....9 well i suppose all RX owners have that:p


But cheers that put me at ease a little bit......

Andy have you had any flooding issues and if so how did you rectify them?

[Andyp]

yeah don\'t worry too much about rebuilds mate, keep an eye on her and make sure she\'s well maintained... I think you\'d know if you needed a rebuild, from what i\'ve read they\'ll let you know alright

Floodings not something that has affected me to be honest. I\'ve only had it once where I went to south mimms for a car meet and didn\'t idle it after a hard drive (I smelt KFC so it\'s understandable)... I just keep trying it without the gas pedal in and she started...

I\'m very precise with my warmup / cooldown routines since though and I don\'t come accross it. However, could be something else... my suggestion if you\'re worried about it is to have a look at the fd USA forums  they have just about experienced every problem that\'s worried me... use thier search and see if anything helps ya... could be a lot of things really...see what they suggest

best of luck with it!

[gyrpere123]

Don\'t want to upset you but mine started with yellow gunk, then the odd start up problem and then after about 1200 miles big overheat and the start of my winter rebuild project. ( take off rad cap and warm up car from cold, watching for bubbles in water which is a good indication of the start of it ) sorry Mark.

[Andyp]

did you do the rebuild yerself mate? how was that?

[gyrpere123]

I am having a go at the rebuild myself as i am lucky enough to have a spare engine as well which also needs a rebuild. So if it goes wrong i will have the other one done by the experts, but i have all winter so i will take my time and see how it goes.
 Cheers Mark

[Ed_RX7]

Thanks for the insight guys

[Andyp]

best of luck with it, i\'d like to do that myself but wouldn\'t know where to start!

Just as a roundoff, just been out to check my fluids and put some locking dust caps on to stop the pikeys nicking them... and thought i\'d check the oil cap and mine seems to be back to normal, so hopefully no more yellow for me for a long time