Aircooled T25 Milky Oil?

[mrbodly]

Hi All

Did an oil and filter change on my 2L air-cooled T25 last weekend. Went to check the dipstick today and discovered a milky paste on the end of the stick, there is also some milky residue under the oil filler cap. I'm really worried. I thought this was only an issue for water-cooled vans?!

Any ideas?

Cheers
Myles

[ghost123uk]

Your right, it is normally watercooled engines that suffer from this issue, however cool temperatures can cause water condensation inside any engine. Minis used to do it inside the rocker cover in cold weather. It is nothing to worry about.

If you get the engine up to working temperature and take it for a good drive, it will "dry" away. Related comment = By the way I know little about the layout of the Aircooled VW engine, does it have a breather from crankcase to air inlet ? If so, make sure that is not blocked or the above mentioned "drying away" won't occur so well.

Also, I know many folk wire their cool air intake flaps fully open if they have a duff thermostat, (or no thermostat, as I understand they are getting hard to find), if yours is wired open the engine will be running cooler than it was designed to and that won't help re this, especially in the now cool and damp weather.

[CovKid]

I have to say John, I've owned numerous Aircooled v-dubs and they all suffered from this but it was due to my only doing relatively short journeys. As you say its because the engine isn't getting chance to get up to full temperature and water inside the crankcase not being evaporated. It builds up.

You may not shift whats in there without first taking it for a good 20 mile run, draining the oil while engine is hot and allowing it plenty of time to fully drain, then replacing with fresh oil, possibly a different brand or type. However, short journeys may well see the return of the emulsified oil residue. You need to let the van 'stretch its legs' more regularly, or go on the bus or walk in the week.

[mrbodly]

Cheers chaps, that's good news!!

That makes sense, I usually cycle to work but can't stop driving the VW, puts such a smile on my face.
It's 5 miles of stop/start traffic, I cycle because I can't stand sitting in traffic but the VW made driving fun again.

Back on the bike it is then. Save the van for holidays and trips to the seaside!

Once again, thanks for your help.

Cheers
Myles

[Mocki]

Keep using the van, it's doing it more good than harm...... Standing kills them !

[ghost123uk]

Myles, are your thermostat and temperature control flaps working ? (or have they been fixed fully open)

[CovKid]

It'll only 'just' be up to working temperature after five miles and on some days (particularly winter), not even that I suspect. My journey into work is 8 miles and its fully hot by then. Mind you, emulsified oil or not, I too would still drive it. You just need to give it a longer stretch at weekends or vary your weekly route?

Ghost is right about thermostat and flaps too. Folk often remove them or wedge them open which means it takes longer for it to get warm.

[mrbodly]

Not sure about the control flaps, will take a look. If the thermostat needs replacing are they still available?

[CovKid]

Yep. I think you'd do well to see if the thermostat is still there. Unfortunately a myth seems to have crept in over the years that getting rid of it somehow helps with improved cooling - it doesn't. The idea of the thermostat on an Aircooled engine is to shut the engine cooling off until a certain temperature is reached (ie the engine has warmed up) at which point the thermostat opens the flaps. This all helps with the warm up in those first few miles.

With the flaps left open (ie in the case of a missing or defunct thermostat)the engine is being over cooled when it doesn't need/want it and it will then struggle to reach operating temperature. Certainly an omission here will contribute to emulsification of the oil in filler neck etc. The problem is compounded in the damp winter months as during the summer the air is drier and the engine warms up more rapidly, evaporating any moisture in the crankcase - if that all makes sense?

[mrbodly]

The thermostat is indeed still there. No idea whether it works, I assume not if it has been disconnected.

Is there supposed to be a cable running from the thermostat to the flap lever in the engine bay because there isn't one.
Also when I try to rotate the lever it doesn't appear to move much. How do people normally secure these in the open position?

I'd like to get this working again, once again thoughts much appreciated.

Cheers

[mrbodly]

Also one further thing.
My tinware all seems to be there although from underneath I can clearly see the pushrods - should these be obscured by tin?

Cheers
Myles

[BOXY]

The bar in the engine bay should be sprung loaded. If the cable or the thermostat fails, the spring holds the cooling flaps open to stop the engine over-heating. The spring pressure should be enough to clang the flaps shut if you try to turn the bar by hand.

You should have tinware covering the push-rods. One side is missing from my van, but this is the other one.



If you come across an extra right-hand side one let me know.

[mrbodly]

As per my photo's it would appear my bottom tin is missing. Also my engine is cold so the expanded thermostat in the picture, I assume is broken.
Does anyone know where I can source some tin and a working thermostat? Can knackered thermostats be repaired?

Cheers
Myles

photo (3).JPG

photo (2).JPG

[CovKid]

Tinware not a problem as its dead easy to make a close copy by cutting and bending ally sheet. You just need tin snips and a hammer to be honest. I always think some owners (not you) get rather precious about missing lower tinware, scouring places for replacements when its more logical (and quicker) to fit something that will do the same job and not go rusty. I haven't looked but to my knowledge you can still get the thermostat yes - just fit a new one.

Worth doing I'd say - it should ensure warmer temperatures for the engine from cold, improve cooling when hot, and alleviate (to some extent) emulsification issues. It will run as intended.

I have to say, problems associated with Aircooled engines are nearly always the result of numerous 'fixes' applied by previous owners such as the wrong distributor (ie a 009), a webber (pig to get right), tinware lost and rubber grommets between spark plugs and upper tinware as well as engine bay seal gone entirely. Collectively it makes for a right troublesome lump that bears little relationship to what VW had in mind. All those seemingly minor points can add up to one right headache.