Mazda Rotary Club

General => General Technical => Topic started by: Ada7 on November 13, 2005, 06:41:26 PM

Title: White scum in Oil filler neck?
Post by: Ada7 on November 13, 2005, 06:41:26 PM
Went to check the oil in my car today and top it up, and noticed that i had got some white scum around the oil filler neck.
My car has been loosing coolent for a little while now, but i got it looked at and it was coming out of a join where a gasket may of slipped out a little. Didnt consider that water could be going in to the engine as well as out!!  

I do know that water getting in to the engine a piston car can leave a white film around there,  so was just wondering if its the same on rotarys? If so, how bad is it and what is the likely damage.
I only had the engine build last year, so i\'m hoping its not anything to bad :(

Adam
Title: White scum in Oil filler neck?
Post by: Brett on November 13, 2005, 06:53:09 PM
Moving this to the correct section. :)
Title: White scum in Oil filler neck?
Post by: fro on November 13, 2005, 07:00:07 PM
it may well be nothing.. mayo in the filler neck is pretty normal, especially as the weather gets colder.
Cheers

Rob
Title: White scum in Oil filler neck?
Post by: gmogle on November 13, 2005, 07:04:29 PM
Yeah I panicked about this when I got mine first, turned out to be normal.

Gareth
Title: White scum in Oil filler neck?
Post by: Brett on November 13, 2005, 07:05:46 PM
As long as its not showing on the dipstick I would\'nt worry! (Meant to post this when I moved the thread..having an off day...again...) :)
Title: White scum in Oil filler neck?
Post by: gsb876 on November 13, 2005, 07:40:31 PM
if in doubt keep checking your dipstick for signs of water, do so for a few weeks until you are happy everything is ok  :wave
Title: White scum in Oil filler neck?
Post by: Jono FD3 on November 13, 2005, 07:45:52 PM
Quote from: Ada7I do know that water getting in to the engine a piston car can leave a white film around there,  so was just wondering if its the same on rotarys? :(

Adam

I asked the same question last week, and my but cheeks were pukerd waiting for someone to say REBILD TIME!! But more than a few people told me that it was just a winter rotary thing!
More than a bit disconserting tough, I was filling my shorts for weeks thinking rebild, rebild, rebild!!

Jono
Title: White scum in Oil filler neck?
Post by: Ricco_04 on November 13, 2005, 09:11:18 PM
Ooh, just in case you panic - I filled mine up the other day and when I checked the dipstick there was mayo on there but it\'s just what washed thru when I filled her up :)
Title: White scum in Oil filler neck?
Post by: Ada7 on November 14, 2005, 11:06:24 AM
Cheers for the replys guys. Can hopefully breath a big sigh of releaf now then PHEW!!!  :p
Still need to get the coolent leak looked at fully, and will keep a good watch on the dipstick and neck to see if the \'Mayo\' returns

Adam
Title: White scum in Oil filler neck?
Post by: gsb876 on November 14, 2005, 11:21:03 AM
Ada,

If you have a leak somewhere with the coolant system make sure you carry loads of water with you just incase it does run out, do you have means to checking the water temp ?

If not i suggest you regularly check your coolant level, as if the water does run out you have a major temp jump which will lead to a rebuild.

Something to consider: the stock temp gauge will remain in "normal" zone up until 120oC, at which point it is almost too late  :(

Power FC saved me a few years ago when driving on m-way glanced at water temp and it said 105oC when the air intake was like 18oC (Autumn time) pulled over straight away and there was no water left as had leak on the rad.
Title: White scum in Oil filler neck?
Post by: Kieron on November 14, 2005, 11:29:25 AM
Make sure your commander is set to monitor water temp.

Like I said on msn though, its probably nothing to worry about.
Title: White scum in Oil filler neck?
Post by: Ada7 on November 14, 2005, 11:47:41 AM
Quote from: gsb876Ada,

If you have a leak somewhere with the coolant system make sure you carry loads of water with you just incase it does run out, do you have means to checking the water temp ?

If not i suggest you regularly check your coolant level, as if the water does run out you have a major temp jump which will lead to a rebuild.

Something to consider: the stock temp gauge will remain in "normal" zone up until 120oC, at which point it is almost too late  :(

Power FC saved me a few years ago when driving on m-way glanced at water temp and it said 105oC when the air intake was like 18oC (Autumn time) pulled over straight away and there was no water left as had leak on the rad.
Ive got a PFC and so far it hasnt gone over 90/95oC on the water temp, but when i get in the car at the end of the day to go home the buzzer goes off.
I carry a bottle of water with me now since its been going on, just to top up the level before i go anywhere. I dont do any longjorneys at the moment anyway. Max of 20 miles and there\'s garages along the way to stop at if things get a bit to hot.
Cheers again

Adam
Title: White scum in Oil filler neck?
Post by: Ada7 on November 14, 2005, 11:49:34 AM
Quote from: KieronMake sure your commander is set to monitor water temp.

Like I said on msn though, its probably nothing to worry about.
Yeh cheers dude. 1 step ahead of you already ;) :cool

Adam
Title: White scum in Oil filler neck?
Post by: Bobfish on November 21, 2005, 07:39:53 AM
adam, sounds like a coolant seals gone - what you will find is that as you drive, the longer you go on the car gets hotter and hotter. Basically when you stop the water forces its way into the rotor chambers, meaning the car is low on water. You fill it up and drive off. As your driving, the combustion gasses pressurise your coolant system and force the coolant out the AST into the overflow tank.  As you go on, the water heats up and expands into the space the ejected water once filled. After a while, so little water is left in your coolant system it starts to boil, but your low coolant warning will not go off till its too late because the water expands.

I recommend you do a champagne test - open the water filler next, and shove an upturned bottle in it with the top cut off (or the bottom, if your looking at it right way up) make sure its sealed around the bottom!

Start the car, wait for the thermostat to open and the car to come up to temp - the bottle will gradually fill with water. If you see a constant stream of bubbles coming to the surface, you have a problem. Engine rebuild or Radweld - i used radweld on mine and its still holding up fine.

See my site:
http://www.face2faces.co.uk/RX7/howto/oring.htm

The reason you MAY have scum in your oil is because the water is getting past the oil seals on the rotors when the engine is cold, but ive not heard of this before.
Title: White scum in Oil filler neck?
Post by: Kieron on November 21, 2005, 09:35:37 AM
Great post Bobfish but I do hope you are wrong, IIRC Adam hasn\'t done alot of miles on that engine, probably only about 1000 on boost after the rebuild and re map.

Adam, if you need a hand give me a shout.
Title: White scum in Oil filler neck?
Post by: Ada7 on November 21, 2005, 10:15:46 AM
Hi Bobfish. Like Kieron said, i hope your wrong as i only had the engine rebuilt last year. I have taken it to a local garage and they seem to think that its coming out of a gap between a gasket somewhere on top of the engine. Have tried some radweld type product, which seemed to help for a while, but its still leaking a bit so will need to get it to a specailist who can have a better look for me. Cheeked the oil filler neck the oter day, and there was no more \'mayo\' there. so i hoe thats a good thing. :)
Thanks anyway

Adam
Title: White scum in Oil filler neck?
Post by: Bobfish on November 21, 2005, 10:16:19 AM
I hope im wrong too, but unfortunately with these stupid rubber seals right next to 1000c heat you can never be too sure.  Even if the seal gets pinched during the build this can cause issue...unfortunately a fresh rebuild does not guarentee good coolant seals and they can go at any time, the only way to tell is to do a champagne test.

Same here adam - if you need any advice feel free to PM me.

out of interest, were your existing end plates used for the rebuild? what prompted you to get a rebuild? Were they checked for warping? The tiniest amount of warping (caused by overheating) can make your coolant seals go very quickly. As can corrosion in the coolant system. (corrodes thorough the retaining grooves of the coolant seals)
Title: White scum in Oil filler neck?
Post by: Bobfish on November 21, 2005, 10:30:15 AM
I recommend you do a champagne test though just to rule it out. You never know - the gunk might jsut be condensation - it might not however.
Title: White scum in Oil filler neck?
Post by: Ada7 on November 21, 2005, 11:02:38 AM
Quote from: BobfishI recommend you do a champagne test though just to rule it out. You never know - the gunk might jsut be condensation - it might not however.
Ok mate. I\'ll give it a go. cheers :cheers

Adam