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ThePog implements balance on the Dynafari


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Sounds like its not consistent pulling back from the expansion tank. I would look at the radiator cap seal and any potential for loss of suck from the vent hose when cooling down. 

The first thing i would do is carefully mark the expansion tank level when 100% cooled down and see if it returns to that level after a heat cycle.

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Just now, mjrstar said:

Sounds like its not consistent pulling back from the expansion tank. I would look at the radiator cap seal and any potential for loss of suck from the vent hose when cooling down. 

That's why I wondered if giving it gravity assist would help, with the added bonus of definitely getting any air out.

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I'd say the results of elevating the expansion tank would be negligible. Is the filler neck definitely compatible with the cap?

 

Also when cold there is not really a requirement to have a huge amount of excess coolant in your expansion tank, its possible now that you have a larger volume of coolant you need to either start your expansion tank level off much lower when cold or run a larger expansion vessel.. 

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27 minutes ago, mjrstar said:

I'd say the results of elevating the expansion tank would be negligible. Is the filler neck definitely compatible with the cap?

 

Also when cold there is not really a requirement to have a huge amount of excess coolant in your expansion tank, its possible now that you have a larger volume of coolant you need to either start your expansion tank level off much lower when cold or run a larger expansion vessel.. 

I just checked the cap geometry, it is definitely the right setup. The cap is also definitely the type that allows fluid to be sucked back through.

I just took 500ml out of the expansion tank, it is now just below the full mark.

I'll check the piping too.

I do wonder how the expansion tank levels would cause the issue though?

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14 minutes ago, mjrstar said:

The "full" mark is for when the engine is at operating temp? 

Is the cap on the expansion tank allowing air back in during cool-down to replace the volume of coolant headed back to the radiator? 

Good point. I will run it up to temp and siphon off to the full mark. And check the cap. Maybe the extra volume of coolant needs way more expansion space?

The more I think about it the more it is the coolant not returning correctly due to volume/expansion/siphoning effects. If on a short trip it gets up to pressure, blows it through but it is unable to return it, maybe because the unheated/uncirculated volume of coolant on the rad side of the thermostat interferes somehow. Long trips everything is equalised heat wise, and the cooling down allows proper vacuum to be produced....?

Best theory yet.

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11 minutes ago, Nominal said:

Chur, I will check those out.

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I think I have solved it, it's probably a combo of two things;

The expansion tank had quite a long connecting tube, plus it was quite low relative to the filler. I think that it was just struggling to pull the coolant back.

I did a cheeky mod to check this which allows me to monitor the coolant and give a bit of gravity assist;

CNprAv6.jpg

 

This highlighted the second and possibly more relevant issue. Because I could see what was happening I soon realised that it takes quite a lot of time for the engine to cool enough to suck it all back. I had been waiting half an hour or so to check the levels, but it has taken something like 4-5 hrs to suck most of it back after a 20 min drive today. So actually it was me introducing the air when I cracked the cap. What a dumb cunt.

For some reason I had only ever checked it the day after when I had done a long drive, obviously giving it enough time to suck it back. Clearly this skewed the results and probably created a problem where possibly there wasn't one. Doh!

Anyway with the earlier rad change there is enough room to put the tank just in front of the engine, and a more reasonable distance and height. I reckon I'll do that tomorrow.

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On 22/12/2020 at 11:57, anglia4 said:

Just move back to Taranaki.

We have passive water cooling of all the things pretty much all year round.

 

On 22/12/2020 at 12:10, ThePog said:

My family insists the weather in Hawera is just as good as Nelson's, I laugh in their faces.

 

I was chatting to some visitors from the naki a couple of weeks ago and they too claimed that they have about the same sunshine hours as Nelson! I thought to myself 'hmmmmm- I always thought it rained heaps there'

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8 minutes ago, yoeddynz said:

 

 

I was chatting to some visitors from the naki a couple of weeks ago and they too claimed that they have about the same sunshine hours as Nelson! I thought to myself 'hmmmmm- I always thought it rained heaps there'

They are fucking lying.

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5 minutes ago, fletch said:

Screenshot_20210102-101910_Chrome.thumb.jpg.97d96580f8c236d75cea09f8cb639fc6.jpg

Not far behind....

My family live in Hawera, even by some miracle they get as much sun as Nelson the southerly wind would bring reality crashing in...

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  • ThePog changed the title to ThePog builds a Dynafari - so many usage updates
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