Thermostat Hob Test: Height Range for 1.9 DG

[ukgoalie32]

Hi all,

My engine has been running cold since I got it. In an effort to solve the issue. I'm planning on fitting a new thermostat (this one: https://www.brickwerks.co.uk/t3-parts/e ... -2-1l.html) this weekend. I was going to test it's operating correctly in a pan on the hob this evening to confirm that it's not a "dud'n" once installed.

Don't suppose anyone knows what the "height" (dimension X in the sketch below) should be when the temp is greater than 87 deg C
I.e. once it's expanded do they?




Cheers,

Benn

[itchyfeet]

put it in a pan and heat it very slowly, at 90deg C you should be able to get a tea spoon through where the rubber seal is by the large diameter part, that's it opening.

[ukgoalie32]

Magic, thanks itchyfeet

[itchyfeet]

Take you old one out first and heat the two together, this will tell you if the old one is different to the new one.

it's possible somebody put an 80 deg stat in.

[Oldiebut goodie]

put it in a pan and heat it very slowly, at 90deg C you should be able to get a tea spoon through where the rubber seal is by the large diameter part, that's it opening.

Don't forget that the other end closes off the block recirculation also so needs to move out.

[petethefeet]

Hi,
The temp stamped on the thermostat is the start to open temperature, this is the temp the valve has moved 0.1-0.2 mm, the fully open temperature will be approx 14C above the start to open temperature. The displacement over the 14C range will be approx 9mm but this will vary depending on manufacturer.
Thermostats normally ' fail' safe by opening early at a lower temperature than the start to open temperature, but this will cause your engine to run colder and the choke to stay on. The failure is caused by a drop of water getting trapped behind pin that is then pushed out by the expanding wax/copper powder mix as it is heated. The water gives an offset to the operating temperature range.
Test the thermostat by heating slowly in a pan on the hob over 5 mins or so monitoring the temperature if you can.

Hope it helps

[ukgoalie32]

Thanks for the assistance all.

Unfortunately, comparison with the existing wasn't possible, as there was no existing thermostat in there! Now makes sense as to why it had been running cool..

Nonetheless, the new stat behaved as expected during the hob test. Just to check, I've fitted it as per the photo below:


Is this the correct way around? I note the JK diagram shows it the other way round (https://i.ibb.co/tHKWLS9/IMG-20190203-130452.jpg) however I couldn't get it to fit in that way around. Am I correct in thinking that the seal sits on top of the thermostat as I have it shown above?

Thanks for all your assistance, there will be a day when my knowledge is such that I can help others!

It has made me think as to whether any damage has been caused by the absence of a thermostat. I've had the van since May last year and I drove it around through the summer before putting it into storage over winter, since which i've just done a few runs here and there. During the summer months, when on a motorway run for example, the temperature gauge would generally read around the red mark on the image below (higher around town). This has reduced to the green mark during the limited runs (two hours on the motorway and a bit around town) since October (again, slightly higher when around town, but not much). Makes sense with the coolant permenantly circulating around the radiator...


However, I don't know for how long and in what conditions PO's may have been driving it without a stat.

I've always thought the van was running a bit rich and this would make sense. I understand the additional fuel being supplied into the barrel has the potential to "wash out" some of the oil and therefore reduce lubrication with associated wear.

Thoughts on the above would be welcomed. I imagine a compression test would be best to confirm what, if any damage has been done?

Cheers,
Benn

[Oldiebut goodie]

The easiest way to check which way round a thermostat goes is look to see where the small disc end should open/close off the orifice for recirculation around the block/casing. No need for pictures then!