Technical Cooling problem

[DucatoGlobecar]

2018 Ducato 2.3-130 Multijet, Factory, Panel Van Conversion (Globecar), 120 miles into journey, very hot day, cooling water blown out of header tank (boiled), limp into lay-by. Allow to cool, top up from kettle (handy breaking down in a camper). Hint from a mate. Start engine with cab heater on full, no heat from heater, he reckons it's the water pump, might be the thermostat. Which is it, water pump of thermostat, what am I facing? Any ideas will be very welcome, with reasoning, if you can spare the time. AND, any ideas where I can get hold of suitable diagrams? Thanks.

 

[Anthony489]

Hi

Sorry to hear of your "boil-up", rather unusual for a new-ish vehicle.
I am more familiar with vehicles from around 2008, many things carried on in the same way in later years but there have been changes for which I have no documentation so bear that in mind.
Any indication from the temp gauge and/or warning lights ?
The presently inoperative heater might just be due to an air lock, sometimes there is a particular procedure to avoid this when refilling. Even something as simple as squeezing the larger hoses (once warmed up) can sometimes clear it. The heater matrix is not controlled by the thermostat, it is always heated and if no cab heat is demanded the airflow is diverted away.
As far as I know the water pump is still a conventional metal impeller type mechanically driven from the timing belt. There's nothing much to stop these from working unless the belt fails, in which case it will be the least of your worries ! I guess it's possible the impeller has come loose on its shaft but this is rare.
If you were stuck in a long traffic jam or slowly climbing a very long hill (i.e. not enough airflow from forward speed) the radiator cooling fan should switch on, so if the fan or its drive is faulty it could be the problem. The fan operation can be checked by a plug-in diagnostic tester. Normally the ECU will control the fans (via high current relays), depending on what it reads from the coolant temperature sensor. I attach schematics for the fans, these are slighly different if aircon is fitted.
A failed thermostat is also possible. They are based on expanding solid/liquid wax in a capsule with a O-ring sealed polished pushrod. If the seal fails some liquid wax leaks out and the thermostat doesn't open so far the next time. This scenario repeats until it doesn't open at all.

 

[DucatoGlobecar]

Hi

Sorry to hear of your "boil-up", rather unusual for a new-ish vehicle.
I am more familiar with vehicles from around 2008, many things carried on in the same way in later years but there have been changes for which I have no documentation so bear that in mind.
Any indication from the temp gauge and/or warning lights ?
The presently inoperative heater might just be due to an air lock, sometimes there is a particular procedure to avoid this when refilling. Even something as simple as squeezing the larger hoses (once warmed up) can sometimes clear it. The heater matrix is not controlled by the thermostat, it is always heated and if no cab heat is demanded the airflow is diverted away.
As far as I know the water pump is still a conventional metal impeller type mechanically driven from the timing belt. There's nothing much to stop these from working unless the belt fails, in which case it will be the least of your worries ! I guess it's possible the impeller has come loose on its shaft but this is rare.
If you were stuck in a long traffic jam or slowly climbing a very long hill (i.e. not enough airflow from forward speed) the radiator cooling fan should switch on, so if the fan or its drive is faulty it could be the problem. The fan operation can be checked by a plug-in diagnostic tester. Normally the ECU will control the fans (via high current relays), depending on what it reads from the coolant temperature sensor. I attach schematics for the fans, these are slighly different if aircon is fitted.
A failed thermostat is also possible. They are based on expanding solid/liquid wax in a capsule with a O-ring sealed polished pushrod. If the seal fails some liquid wax leaks out and the thermostat doesn't open so far the next time. This scenario repeats until it doesn't open at all.

Anthony489,
Thanks for your time and well reasoned reply.

There was indication from the temp gauge and warning light, but it was very fast, a blink or looking out the windscreen and I would have missed it, the light was a very quick 'flash' and the temp gauge was a v quick up and back down.

The comment re the heater not being controlled by the thermostat is useful, with the heater not working it tells me the problem is with the water pump, ie if the thermostat had failed there would still be water circulating to warm the heater. If the water pump had failed there would be no water circulating at all, ie no heat reaching the matrix and no cooling of the engine. Does that logic hold true?

I have been told the water pump is now a plastic impeller bonded onto the shaft and the failure of the bonding is now more common that it used to be. As for the fans - no problem there, they are LOUD, very warm day, windows open, (in road works - I like to hear as much as I can). Those diagrams are fab - where did you find them, I am looking much more for the cooling water circuit, so I can identify where the thermostat, heater, and pump are in relation to each other - are you aware where I can find a diagram of that?

Thanks again.

 

[Anthony489]

Hi again

About 15 years ago, I had a water pump fail on my Audi A3. The impeller was made of glass reinforced plastic, moulded onto the end of a shaft with cross-hatching. The impeller had split, releasing its tension and allowing it to spin on the shaft, severely reducing its effectiveness. The replacement pump had a "proper" metal impeller.

Maybe the accountants have been allowed to save a few pennies on the Ducato ? I can see how a "plastic" pump could fail rather suddenly in this manner, whereas sudden failure of a thermostat is much less likely. It seems to me that each generation of designers forgets the lessons of the past !

The diagrams are extracted from eLearn, which can be downloaded from the forum if you do a bit of digging. Sometimes I annotate them for extra clarity. There is another smaller document called the Training Academy, which was used to brief technicians before the new shape vans arrived in 2006. This has a diagram of the cooling circuit for the 2.2 engine (the older one, not the current ones) which I reproduce below. It should give you an idea. Be careful with this document as it was produced while the vans were still being designed, so has some anomalies.

 

[Communicator]

Hi again

About 15 years ago, I had a water pump fail on my Audi A3. The impeller was made of glass reinforced plastic, moulded onto the end of a shaft with cross-hatching. The impeller had split, releasing its tension and allowing it to spin on the shaft, severely reducing its effectiveness. The replacement pump had a "proper" metal impeller.

Maybe the accountants have been allowed to save a few pennies on the Ducato ? I can see how a "plastic" pump could fail rather suddenly in this manner, whereas sudden failure of a thermostat is much less likely. It seems to me that each generation of designers forgets the lessons of the past !

The diagrams are extracted from eLearn, which can be downloaded from the forum if you do a bit of digging. Sometimes I annotate them for extra clarity. There is another smaller document called the Training Academy, which was used to brief technicians before the new shape vans arrived in 2006. This has a diagram of the cooling circuit for the 2.2 engine (the older one, not the current ones) which I reproduce below. It should give you an idea. Be careful with this document as it was produced while the vans were still being designed, so has some anomalies.

I would like to add an aside comment, as this reminds me of two comments made, or quoted by my father, who died in 1985, and who was an engineerig designer.

1. "I am afraid that we live in an age of cracked plastics."
2. "Value analysis has been applied such an extent that there is no value left in the item."

 

[DucatoGlobecar]

Hi again

About 15 years ago, I had a water pump fail on my Audi A3. The impeller was made of glass reinforced plastic, moulded onto the end of a shaft with cross-hatching. The impeller had split, releasing its tension and allowing it to spin on the shaft, severely reducing its effectiveness. The replacement pump had a "proper" metal impeller.

Maybe the accountants have been allowed to save a few pennies on the Ducato ? I can see how a "plastic" pump could fail rather suddenly in this manner, whereas sudden failure of a thermostat is much less likely. It seems to me that each generation of designers forgets the lessons of the past !

The diagrams are extracted from eLearn, which can be downloaded from the forum if you do a bit of digging. Sometimes I annotate them for extra clarity. There is another smaller document called the Training Academy, which was used to brief technicians before the new shape vans arrived in 2006. This has a diagram of the cooling circuit for the 2.2 engine (the older one, not the current ones) which I reproduce below. It should give you an idea. Be careful with this document as it was produced while the vans were still being designed, so has some anomalies.

Hi Anthony again,
I found the 'Training Academy Manual' for my year of build, and yes it is the same diagram - all pretty clear to me.
I did do as someone suggested and wrote to the CEO - not much joy, but as expected. Now I'm waiting for a response from the Auto-ombudsman - replay expected in approx six months. So in the meantime, approaching the courts (previously known as the Small Claim Court)

Cheers.