coolant flow - (follow up to cooling diagram)

[dave_aber]

This might sound obvious, and be indeed what bongonads was on about in the first instance, but why can't you bleed the head cold with this unscrewed?

[teenmal]

This might sound obvious, and be indeed what bongonads was on about in the first instance, but why can't you bleed the head cold with this unscrewed?

Hi Dave,

I cant see any reason why not,the only problem that I can see is that peeps dont like to remove switches etc.

If it was a butterfly type valve it would be perfect.

[widdowson2008]

Do you have a view of where the Temperature Sender fits into the head ? I think its always been on the other side of the photo's as it were;

I didn't, but I do now
This the one you're looking for? If so, it is fitted at roof of the main chamber level.
Have you got some radical theory to share?

That looks like an ideal bleed point..

Theoretically yes, but apparently quite difficult to do in practice due to access. Kirsty tried it when it was originally suggested by bongonads (NZ). She got burned with coolant when trying to re-fit the sensor.
edit: Dave beat me to it!!!!!!!!!!!!!

[widdowson2008]

This might sound obvious, and be indeed what bongonads was on about in the first instance, but why can't you bleed the head cold with this unscrewed?

Bloody good point (but I'll probably get shot down for saying so)

[mikexgough]

This might sound obvious, and be indeed what bongonads was on about in the first instance, but why can't you bleed the head cold with this unscrewed?

You can..... cold that is ..........and that is what Bongonads was suggesting.....he has a Ford Ranger head with no 3 way Tee....

[g8dhe]

I didn't, but I do now
This the one you're looking for? If so, it is fitted at roof of the main chamber level.
Have you got some radical theory to share?

Not directly (seeing as I've a V6 - you don't have one of there heads for slaughter do you ?) but there have been several discussions regarding bleeding the diesel via the Temp Sender hole by removing it and just chocking the wheels up a bit as I recall - some seem to think its the "way", others the way to scald yourself!

[mikexgough]

but there have been several discussions regarding bleeding the diesel via the Temp Sender hole by removing it and just chocking the wheels up a bit as I recall - some seem to think its the "way", others the way to scald yourself!

Bongonads has bled his Freda that way using the ramps after using the temp sensor removal during refilling and more recently a more "radical" way........ but the knowledge of it will probably make me one of the great unwashed......

[widdowson2008]

Bongonads was ace at getting folks back up, mine included, but I have to sort of agree with the logic, especially the 'elevating the front end' bit.
I can also see how this should work on a cold bleed - ie: no engine used at all. The bonus being 'NO SCALDING'.

Would it work in practice? Dunno, and I certainly don't have the bottle to try it, but there is a very easy way try it.
It would need someone who is confident with bleeding the system such that if it failed, then they could bleed it their way.
Is there anyone in or around the Chesterfield area prepared to give it a go? (Ady? I see you are around)

Incidentally, there is another possible drawback and that is the sensor. Is it a delicate unit? If so, could it possiblly get damaged by removing/replacing it?

[Northern Bongolow]

steve,i have no problem in theory with this method,in bleeding the head,but this does not make a bled bongo.when ive experimented with elevating the front end i tend to get air lodged in the front heater,which can be a pig to remove because of its height in relation to the other components,and the outlets to this are low.
always willing to listen though.

[widdowson2008]

Hi Ady
Have sent you a pm

[mikexgough]

Bongonads was ace at getting folks back up, mine included, but I have to sort of agree with the logic, especially the 'elevating the front end' bit.
I can also see how this should work on a cold bleed - ie: no engine used at all. The bonus being 'NO SCALDING'.
I will probably be hated for this BUT....Bongonads was only trying to say what he had experienced, I guess he was thinking that "engineering brains" were engaged to understand his written words but when they were not engaged and understanding what he was trying to say, that is when the thread went sour.....with misunderstandings...and horrid exchanges .........oh well

Incidentally, there is another possible drawback and that is the sensor. Is it a delicate unit? If so, could it possiblly get damaged by removing/replacing it?

The Unit is delicate and to be honest easily broken but if your going to bleed this way then for the cost replace with a new unit and it would be okay to bleed any air out when refilling the system

Didn't want to be the first to mention this but that was the first thing I spotted too. It's a good 10mm BELOW the roof of the main chamber.
AND - to make the situation worse, the bleed hose is 20mm ABOVE that.
ie - Bleed hose is 30mm above the roof of the main chamber.

The top of the radiator connection is at the same level as the roof of the main chamber, suggesting to me that any air trapped in the head has got to leave via this connection - or am I missing something?

Shoot me down in flames but......this is how I interpreted that Bongonads was saying, which then raises questions about the "bleed" tube - the measurements don't fib......and I know you like to deal in the facts Steve...

[widdowson2008]

Back to the crack in the head and what causes it.
Let me run something past you to see if it makes sense.
In the old days of mining, one method of splitting/breaking up large rocks was by heating them up with a fire, then when good and hot, pour water over the rock. Result? rock would break due to shock of cold water.
Applying this to a cylinder head.
Head gets hot (bloody hot) - coolant hits it - result? split?
If the thermostat isn't working correctly by strictly governing the temperature of the coolant, and suddenly dumps some relatively cold liquid, then do we have the 'split rock' analogy?
Waddyathink?
Couple of things to think about:
- Not only does the head have to tolerate the heat, it is subjected to a repeated string of quick detonations.
- The crack seems to occur at the smallest cross section (weakest point?) and also at the hottest point.

Need some input from them that knows.

BTW Mike - I'm not ignoring your input - just don't want to get dragged into a 'bongonads' discussion, even though I think he was correct most of the time and what he said made sense. He just had a communication skills problem.

[Northern Bongolow]

totally agree with your theory steve.
the problems to solve is why/how.obviously the air lock,held somewhere,is fired round the system,and affects the head.
the way i see it is.
the head without water,or little water, superheats, driving the water/steam out to the rad as it expands,and as the stat may be shut or partly shut this water cannot be replaced fast enough,untill the coolant catches up,then it floods the engine head with cooler coolant.
this affect may be worsened by an underperforming stat,or poor flow,like a partly blocked rad.
this is the kettling affect/noise that has been so often heard shortly before the inevitable coolant dump

all the symptoms i have seen seem to me to point to the stat.whether its bulging pipes,split rads,leaking pumps,its all about pressure.
that why im currently building a pressure monitoring device to give an earlier warning of pressure anomolies that can/may develop.

dont know whether any of this is sensible really but it seems ok to me,but its a team game.
carry on the good work guys and girls.

[g8dhe]

Surely the cracks would start at the point of greatest temperature change and spread from there ? In which case the crack on that basis would start inside the water chambers and spread to the inner surfaces of the head ? From the pictures the crack appeared to start inside the valve areas but hadn't spread to the water chambers ?

[g8dhe]

Ah OK I thought it was just a surface crack from previous comments between inlet and outlet ports. I wonder if its possible, Steve, to tell which way the crack had spread? probably not I suspect.

Edit: Doh where did that message go ? Perhaps it was withdrawn ?