Deposit on Dipstick

[Ducked]

GF's finally tracked down the importer (I don't speak or read Mandarin) and got some Loctite 243, apparently "new, improved" replacement for 242.

Unfortunately, seems I could only get a 50ml bottle, which will last me until the heat death of the universe, if it didn't have a 1 year shelf life, maybe 2 years if I keep it in the fridge. I've seen it suggested that, once opened, this stuff should be left open for storage, because it cures anaerobically?

Kind of makes sense, (though it seems to imply that the bottle is topped-off with pure oxygen at the factory, which I don't know for a fact) but I'm not sure I can bring myself to do it.

I might try keeping the bottle in a sealed container with some hydrogen peroxide.

 

[Ducked]

Originally Posted By: Cardenio327
Ducked:

I looked up Delvac MX (silly me, I previously thought MX meant it was a special oil for Mexico and I always ignored it even though it has always been in my sales catalog). It is a high SAPS high speed marine & trucking oil, not friendly to after treatment systems. It has a starting TBN of 12 while Delvac 1300 Super has a TBN of 10.5. It probably has higher zinc levels than just about any other product in Mobil's line. However, it doesn't carry the mixed fleet diesel/gasoline rating like 1300 Super, it seems it is intended for diesel applications only. Delvac MX is probably one of the oils that the poster from Bolivia, Widman, is recommending for flat tappet engines.



That doesn't sound like the same stuff. The Delvac MX 15W/40 I have is CI-4 /CH-4/ but is also labelled SL/SJ. The sole mention of it (in passing) on the Mobil website states its a CI-4 plus oil. The "plus" apparently implies better soot dispersal, which in turn probably implies higher detergency, probably a bad thing in my wee petrol engine, since its likely to be antagonistic to ZDDP action.

I finally found a figure for Zn in Delvac MX here:-

http://g503.com/forums/viewtopic.php?p=518855&highlight=

Its a Jeep forum poster quoting an email from Mobil, so not exactly a primary source but, 4WIW:-

“Mobil Delvac MX 15W40 diesel engine oil is remaining at the previous
CI-4 Plus API level and will have the higher zinc and phosphorus levels
(1200-1500ppm) used in previous years. This is a premium diesel mineral
oil and not synthetic.”

Slightly encouraging, though the forum post is dated Mon Apr 09, 2007 9:50 am. Hopefully they havn't cut the zinc meantime.

It doesn't bother me enough to stop using it since I have an unopened 5L, but once its gone I'll probably change to local SJ oil (if you can still get it) or SG motorcyle stuff

 

[Clevy]

Originally Posted By: Ducked
Cars was standing for a couple of months while I was away.

Checking the oil before starting I noticed that one side of the dipstick was the reassuring honey-colour of clean oil, but the other was dark grey.

The tissue I wiped the dipstick on has a faintly yellow-gold damp patch that I associate with clean oil, but also a slate-grey "skidmark",wiped off the dipstick, that looks metallic.

I guess there were fine metallic wear particles suspended in the oil, and the long stand has allowed them to settle out. Since the dipstick is at an angle, (i.e. not vertical) it can have an upper and a lower side. I wasn't paying enough attention to know if the upper side was the one with the sediment, though thats what I'd expect.

Is this normal (on a very old car: 1986 Daihatsu Skywing)? Havn't seen it before, but I suppose this combination of circumstances might not have occured/been noticed.

I'd have thought suspended metal would visibly discolor the oil, but I suppose the oil film on a dipstick is rather thin.

I suppose I'd better drain the oil, and maybe drop the sump and look for debris. It had an oil and filter change (Mobil Delvac MX 15/40) about 6 months ago. EDIT but had omly done about 300 miles since then. ENDEDIT) Thats a recent spec oil and, from reading, may not have enough zinc for my flat tappets

There was an intermittant tick when I first bought the car but it went away after I [censored] about with water-cleaning the cylinders, so I was tempted to call it pre-ignition. Maybe something loose just got ground away and/or lodged somewhere.


Zinc isn't really relevant in a broken in engine and to be honest its not the zinc that is critical its the phos in zddp that oxidizes to create the anti-wear layer.
No matter.
My guess is that the oil has done a good bit of cleaning and loosening up stuff. Stick with it. Add a can of mos2 if you are truly concerned.

 

[Ducked]

Thanks for your response. I mention above that the engine contained at least one sludge-filled casting void. If there were more, that would make it impossible to assess the current wear rate, so I'm trying not to think about it.

 

[Ducked]

Originally Posted By: morris
i have in laws that are dips.


So do they.