ATF as Diesel Injector Cleaner.

Myth alert!

Difference in abient temperature when looking at it, it makes a large difference. People considering old oil to new when checking what came out in the tray to whats going in the filler. No-one ever gets the two at the same time and pours them out of the same nozzle at the same temp to see so i guess its partly down to perception. Past that im not sure, ive never experienced Selenia first hand, but i have had countless cars running all sorts of synths and dinos and ive had my current car running everything from 60-quid a fill top-brand synth to costco Chevron (which is Fuchs i believe) to whatever I could grab all of the

10-40 grade and never seen a noticable difference in thin-ness. Going to 5-50 really does look like water compared to syrup at room temp but at the same grade i cant imagine why it would seem thinner at all.

In theory it is difficult to define as the definitions are based on peoples assumptions of what liquid should be, however the thermodynamic evidence against it is a little flimsy from what ive seen.

It is indeed a hotly challenged point but having *seen* with my own eyes an anchient glass window (cant remember how old it was exactly) that had sagged, a hole opened up at the top and the bottom flowed around the lead framework it was in and trapped it there I'll stick with the guys who say it is :) It wasnt ripples from manufacture and it wasnt the frame moving as suggested in your links.

Though that is old glass too, so a very different chemical composition to modern glass.

Well spotted though :)

Care to say where this glass with an hole in is, and how you can show that it wasn't just a manufacturing defect (a thin area that has been blown out by the wind over time, etc? I'm sure there are thousands of Urban Legendkeepers out there who would *love* to see proof, either way. Including professioanl fluid dynamicists.

If you want to see a *genuine really really* viscous fluid, have a look at this:

Only if you've got a new defintion of viscosity.

The message from snipped-for-privacy@italiancar.co.uk (SteveH) contains these words:

That doesn't sound right to me. Viscosity is a measure of how fast an oil will flow out of a small hole!

Anyway, most engine oils have densities that, last time I looked, were very similar.

No. What I mean is that a 0w40 is more viscous when cold than a 15w/40 is when hot.

Huw

Well, for some reason it seems to work like that.

Don't ask me why, the only plausible explanation I can come up with is that it's because the oil is piss thin as it's less dense.

But what do I know? - it's almost half a lifetime since my A-level Physics and Chemistry.

Even a 0w/40 should not leak. Yes it appears thin at room temperature but any 10w40 or 14w/40 etc oil is actually a fair bit less viscous than that when they are at operating temperature.

Huw

Seal compatibility is an integral part of API standards and has been for a couple or three decades. All API approved oils must not let seals harden over a set amount over a set time at a set heat. This standard setting was as a result of early synthetic oils causing seals to harden in an unacceptably shortened time. In summary, all synthetic oils that meet any current or recent past API standard will be fully compatible with all seal types and should not result in leaks in the short or long term.

Huw

You may have had a bad batch or they inaccurately represent the actual viscosity?

Huw

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Huw" saying something like:

Yes, but when cold it's less viscous than the mineral oil that would have been previously used in the engine. This leakage of synth oils in older engines is well known and must have an underlying cause - perhaps marginal crank and cam seals that only seal properly when the shaft has reached running temperature.

Just a speculation; I'd be interested to find out what it is.

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Coyoteboy" saying something like:

Of course. ahahahaaa.... see my reply to Huw up there... that explains it.

If there is a cause, then the varying expansion rate of slack seals and metal parts could be a reason.

I have to say that I have never found a greater leakage from synthetic oil, even in older engines. All engines leak a bit here and there as they age. I've yet to see one that doesn't.

Huw

Though at operating temp the diams of the shafts they seal around are likely to be larger and therefore better sealed. Also at temp the oil pressure will be lower than at cold start for example.

I cant remember where it was, it was an old church. Ive seen its windows in textbooks too, but i dont really have time to search for it. I'm very sure it wasnt wear etc, unless the window had been fitted while the glass was still at full temp lol.

:) thats fascinating :) God im a geek.

About 10 years ago this subject came up in NewScientist. As an experiment, I took an old lightbulb, broke the gas seal, laid it on its side and balanced a brick on it.

It been like that ever since except for the occasions when I check to see if it's still round. Hasn't changed an iota in all that time.

Doesn't seem very liquid to me.

Tim

The rigidity assumed due to length of time for the glass to move would require you to measure the bulb with a very accurate micrometer/set of calipers, in exactly the same location and temperature at the beginning and end of your lifetime to see any variation. Bit hard to do lol.

Possibly true but I would have thought that balancing a brick on top of it would have speeded up the process significantly (i.e. by several million fold).

Tim