cooling issue, or rather not cooling

[T25vanman]

Hi guys.
I'm trying to identify what the cause is on my 1.6d of water bubbling up and releasing from header tank.
My temp guage needle doesn't work but the red led will flash if no liquid in expansion tank behind the number plate. If that helps at all.
I've not heard the fan kick in recently.
And I have just a couple of days ago fitted a thermostat in the hope that it was that that was causing the problem.
However the old one also worked when I tested it after removal.
There doesn't seem to be any play on the water pump pulley wheel and it turns with the belt and engine running.
I let air out of system until liquid came out of rad bleed bolt. But unsure if system is fully bled as only emptied a little water when I removed thermostat housing. And bled and refilled on my jack jones.
Bottom of radiator is warm.
water inside the header tank drops slightly when revved up.

I am far from a mechanic and am panicking now because I have to use the van to go drive from North Wales to Somerset for Glastonbury in two weeks time.

So time is of the essence as I only have about 4 days spare to diagnose and fix.

I would love to hear your view and thoughts please to help me in what seems to be a nightmare.
I've also taken some pics of the engine bay. Maybe someone could point out what is what thats relevant please.
Also after looking at the back of the dash unit I noticed the circuit next to the right pin (of the 3 pins top centre) is damaged.
And there's some blue tape on a wire too. No idea what the wires for tho. And a flappy circuit bit you'll see near by it on the left. I believe it is normally lay across the other side of the circular circuit.
Please help
I'm so desperate.

[kevtherev]

Hi guys.
I'm trying to identify what the cause is on my 1.6d of water bubbling up and releasing from header tank.
My temp guage needle doesn't work but the red led will flash if no liquid in expansion tank behind the number plate. If that helps at all.
I've not heard the fan kick in recently.

]

oK
Bubbles in the header is bad news.
That could be a head gasket failure.
A combustion gas test would confirm it.

The combustion gas over pressurises the cooling system.

[ghost123uk]

Yes, take it to a garage and ask them to do a "sniff test" in the header tank. Then let us know what they say.

[MidLifeCrisis]

Also after looking at the back of the dash unit I noticed the circuit next to the right pin (of the 3 pins top centre) is damaged.
And there's some blue tape on a wire too. No idea what the wires for tho. And a flappy circuit bit you'll see near by it on the left. I believe it is normally lay across the other side of the circular circuit.
Please help
I'm so desperate.

In the pic below the blue tape looks like it's a connection to your clock (i.e. the clock that tells the time) - looks like a previous owner has made a new wire connection to it after the 'flappy' blue circuit has broken - so not an issue in this case....


In the pic below - these are the three connections that control the temperature gauge (with one connection slightly off the picture to the left) - but I would suggest that if the temp gauge LED flashes when the coolant level is low then that suggests that the gauge is getting a good 10v power and a good ground and that the problem is with the temperature sensor in the engine (or the wire going to it)

If you can find the sensor on the engine and try 'grounding' the sensor wire (touch it to the engine block) and you should see the gauge go to 'hot - this would confirm that the gauge problem is with the sensor (if your sensor has two wires going to it then just ground both wires)
(I'm not sure where the sensor is on a Diesel engine - perhaps someone else can help with this)

[T25vanman]

Hi guys.
I'm trying to identify what the cause is on my 1.6d of water bubbling up and releasing from header tank.
My temp guage needle doesn't work but the red led will flash if no liquid in expansion tank behind the number plate. If that helps at all.
I've not heard the fan kick in recently.

]

oK
Bubbles in the header is bad news.
That could be a head gasket failure.
A combustion gas test would confirm it.

The combustion gas over pressurises the cooling system.

Cheers Kev. That's even more concerning to know.
When I said bubbling I just meant that for some reason the water leaks out of the top of the header tank when heated up. Not sure of it bubbles, just figure of speach.
Should the head gasket be kaput, is it as simple as just replacing it and away I go again?
There' doesn't seem to be white smoke, and the engine runs and drives fine otherwise. I've only noticed during low speed runs of around 800 yards.
If it was bubbling, would that be caused by heat of coolant or air in system?

[MGP]

When you say water leaks out of the header tank where does it actualy leak out of as should go into the top up tank.
Is the system actualy pressurising if so by how much the hoses should be firm but not rock hard.

[marlinowner]

I'm going to refer to the tank behind the number plate as the top-up tank and the other one as the header tank.
When the engine is cold ,the header tank should be full to the brim and the top-up tank should have coolant to somewhere around the min/max lines. When the engine warms up then the coolant expands and the cooling system pressurises. If the pressure increases beyond the limit of the cap on the header tank, some coolant will go into the top-up tank. This is normal and it will be sucked back when the engine cools. If coolant is leaking at the header tank, then this needs sorting, cracks in the header tank and leaks around the coolant level sensor are common.
If a lot of coolant is going into the top-up tank then this could be due to a head gasket failure letting gases from the combustion chambers into the coolant, or could be due to a fault with the cap on the header tank. You can test the cap by taking it off and blowing through the outlet on it, you should be able to blow through but not suck through.
If no coolant goes into the top-up tank when the engine gets hot, this could be due to a faulty header tank cap, or a blockage in the pipe between the two tanks. A fault there will over pressurise the system and cause leaks.

PS took too long to type that!

[T25vanman]

Marlinowner and MGP.

I have just been out to check the pipe between the header tank(hot tank) and the expansion tank, (expansion tank being the cold one behind the number plate) and the pipe is clear with no blockages.

The coolant level sensor clip has popped off at one point, maybe the water is releasing from there and not the Blue cap. I changed the blue cap just a couple of days ago, it was originally a black one. they both work in terms of being able to blow through but not suck. maybe the blowing off is through the level sensor??
when It does it leaks down and onto the floor below the header tank (hot tank).

the header tank (hot tank) has water right up to the brim of the blue cap, and the Expansion tank (cold tank) is between the min and max level. Ive not noticed a big change in the cold tank level.

The Big fat pipe which runs from the engine block toward the front of the van feels squishy and when squeezed can hear what sounds like fluid movement.

The smaller pipe that runs from that to the top of the header tank (hot tank) feel more firm. they both get fairly warm.

[kevtherev]

Ok it seems I took you literally
Does the level in the cold tank rise at all?
My sensor leaks through the O ring no matter wut I try.

[T25vanman]

Ok it seems I took you literally
Does the level in the cold tank rise at all?
My sensor leaks through the O ring no matter wut I try.

it doesn't appear to have risen at all Kev.
Does that suggest anything?

if the O'ring on the hot tank leaks and, if that was where the water was escaping from, what effect would that have on the system etc please?

[kevtherev]

Well it should rise a bit.
So it suggests the van is relieving itself elsewhere as suggested.
The effect is you are constantly going to lose coolant.
So the leak must be stopped
I would renew the lot
Sensor
O ring
Tank
I need to do the same, as mine leaks like this.

[T25vanman]

Well it should rise a bit.
So it suggests the van is relieving itself elsewhere as suggested.
The effect is you are constantly going to lose coolant.
So the leak must be stopped
I would renew the lot
Sensor
O ring
Tank
I need to do the same, as mine leaks like this.

funny you should say that, Ive just ordered all three online.

will that eliminate the problem though?

When I squeeze the hoses they feel squishy and sounds like water is moving around. could there be air in that part of the system? and if so how would I remove it?

[MGP]

The cooling system relies on the water expanding and creating about 1 bar of pressure to raise the boiling point of the coolant as the running temp is so close to the boiling point at atmospheric pressure also you need to pressurise the system to bleed it correctly.
In short any leak is going to stop the cooling system from working properly so best to sort the leaks and go from there.

[T25vanman]

The cooling system relies on the water expanding and creating about 1 bar of pressure to raise the boiling point of the coolant as the running temp is so close to the boiling point at atmospheric pressure also you need to pressurise the system to bleed it correctly.
In short any leak is going to stop the cooling system from working properly so best to sort the leaks and go from there.

with this said, if for instance the hot tank water level sensor wasn't leaking and there are no other visible leaks in the system, but the hot tank cap releases water...what would that indicated? what effect would it have? and why?

[MGP]

The water in the coolant expands as its heated and will continue to do so the more its heated. The cap contains the pressure until it reaches the set pressure of the valve inside it.
The system will under normal conditions not push any coolant into the top up tank however when the engine starts to work hard such as a steep hill it will get a little warmer and may push a little coolant out into the top up tank.
If it starts to push a lot of coolant into the top up tank then you have a problem, it could be that the valve in the cap is weak or that the coolant temp is getting too high or that combustion gasses are getting into the coolant which could be head gasket or a crack in the head or block