Oil tank with sight gauge - sticking plunger

[Rollerball]

My oil tank has this kind of Atkinson Tankmaster sight gauge:

http://i.ebayimg.com/00/s/MTYwMFg3Mzg=/z/c14AAOSw14xWPzt4/$_57.JPG

The small plunger at the side that you pull out/push in to get an oil reading on the sight tube often gets stuck, either it's tough to pull out or tough to push in.

I've tried pulling it out and using WD40 but no luck.

Short of replacing the whole gauge is there any way to free up the plunger?

Failing that, how about if I just replaced this valve:

http://www.ebay.co.uk/itm/Atkinson-...139767?hash=item3a7aab2577:g:VyAAAMXQ-3NRkzvP

If I did that, is it just a simple matter of using a spanner to unscrew the old valve and putting in the new one? What would I need to do to prevent oil from gushing out ?


Also, and just out of interest, how hard is it to replace the whole sight gauge if I decided to go down that route? My main concern would be shutting off the oil supply as, besides the sight gauge and the wheel on the front I can't see how I could isolate the oil flow if replacing the actual gauge. Or is the oil from the tank automatically shut off when the gauge is removed?

 

[Burnerman]

Replace the pull to read valve on your Atkinson gauge.....www.heating-parts.co.uk
Atkinson part number is TM4155
Heating parts number is 227082.
Turning the big valve wheel cuts the flow from the tank, and to your pull to read valve. sadly, the oil never shuts off automatically!
John

 

[Rollerball]

Thanks John. I'm assuming that valve is right for my Tankmaster (I can't see a model number on it and it was last replaced about 10 years ago, it does though look exactly the same as the one that I linked to).

I guess that the Tankmaster hasn't really changed over the years.

 

[Burnerman]

I've found the parts interchangeable but I don't know for certain......however, you can just bung the old one back in, so no great panic. The 'O' rings swell on the plunger, causing it to stick.
Its worth putting a new filter in at the same time - its a nylon gauze.
John

 

[Rollerball]

Thanks again for the advice John.

I only noticed the sticking valve before an oil delivery a few days ago (I don't check it that often though). However, since the oil delivery the level in the sight gauge has dropped more than I exptected (only 3 or 4mm, but that seems a lot over a couple of days). Can the Sight Tube sometimes give false readings? Perhaps the sticky valve is affecting the reading? (just a wild guess).

I'm certain there is no visible oil leak (unless it's underground .....).

 

[Burnerman]

I've found with mine its accurate naturally enough, but of course the surface tension of the kero in the pipe has to be accounted for. When mine snaps shut, the level bounces up by a couple of mm.
Any subterranean oil leaks will show up when it rains, never mind the pong......I found that one the hard way but thankfully it wasn't mine
John

 

[Rollerball]

We've had plenty of rain here and no oil smell so I guess that rules out an undergound leak. Must be the sight tube not giving a good reading I suppose.

My float also bounces back up a bit when the valve is pushed back in but it doesn't seem to bounce up as much as it used to, this makes me once again ponder if it's the sticking valve causing a problem with the reading.