Engine Water/heater Hoses

[Stardate]

I've just had a top heater hose blow on my T. Only done 70,000ks. Any one else had this problem or is there a fault with hoses and/or over pressure in the cooling system. Its burst out one side (about 50mm split) and has multiple cracks around the inside. I was lucky that I pulled up at an intersection and saw steam from under the bonnet. If I'd been on the open road sure it would of cooked the motor.

[seventytwo]

Might have to check mine.

You wont cook the engine, the ECU in these cars is pretty smart. When it detects overheating it will start shutting down cylinders so heat is controlled. The engine should go into limp mode to save the engine as well.

[Stardate]

Might have to check mine.

You wont cook the engine, the ECU in these cars is pretty smart. When it detects overheating it will start shutting down cylinders so heat is controlled. The engine should go into limp mode to save the engine as well.

Yes the ECU is smart enough to shutdown the engine etc, but the medium for removing heat from the engine head and block internals is water and the ECU measures the water temp. So if you have a major lose of water like a burst hose where all the water is removed in less than 15seconds then the ECU surely has no way of measuring the temp apart from the thermal conductivity of the metal and by the time that happens the temperature around the cylinder sleeves and around the exhaust valves has already reached extremes.

[Ninka]

Yes the ECU is smart enough to shutdown the engine etc, but the medium for removing heat from the engine head and block internals is water and the ECU measures the water temp. So if you have a major lose of water like a burst hose where all the water is removed in less than 15seconds then the ECU surely has no way of measuring the temp apart from the thermal conductivity of the metal and by the time that happens the temperature around the cylinder sleeves and around the exhaust valves has already reached extremes.

Sorry mate, but unless you are on full throttle acceleration (and probably even then), aluminium will conduct heat quickly enough to detect this.

Also you are not correct in respect of the PCM (ECU) measuring the water temperature to determine this, it actually has a sensor directly at the back of the head, and not in the water, so totally independent

As far as your hose cracking, then this has nothing to do with how many k's your car has travelled, but depends on age, mechanical damage, general condition of cooling system etc.

Like drive belts, hoses are worth checking every year or so, and replace if any signs of damage or ageing are found.

Edited 05/07/07 05:24 AM by Ninka

[Stardate]

In respect of the temp sensing on the back of the head, yes that would be more effective means of measuring temp but the parts of an engine that are the hotspots ie, around exhaust valves and cylinder liners where the water is in direct contact with them, so if they lose that water to keep them cool then the rise in temperature to the senser will be delayed by the thermal inertia and mass of the aluminium. Itakes a finite time for the material to heat up and that heat to travel to the sensor. Also you say the sensor is at the back of the head. What about the distance from number1 cylinder/valves to the sensor.

As for the condition of my hoses, from the outside they look perfect, from the inside they look perfect apart from the splits that have appeared. The failure was not a crack but a burst hose. The rubber of the hose is in good condition, no cracks, no perising, nothing. But after inspecting it very closely the reinforcing fibres that are embedded in the rubber appear to have failed and it wasn't until the cooling system got up to operating pressure that the hose blew up like a balloon and burst. The only way to have inspected this hose for this type of fault would of been to have cut it up!!!!!

[Ninka]

In respect of the temp sensing on the back of the head, yes that would be more effective means of measuring temp but the parts of an engine that are the hotspots ie, around exhaust valves and cylinder liners where the water is in direct contact with them, so if they lose that water to keep them cool then the rise in temperature to the senser will be delayed by the thermal inertia and mass of the aluminium. Itakes a finite time for the material to heat up and that heat to travel to the sensor. Also you say the sensor is at the back of the head. What about the distance from number1 cylinder/valves to the sensor.

As for the condition of my hoses, from the outside they look perfect, from the inside they look perfect apart from the splits that have appeared. The failure was not a crack but a burst hose. The rubber of the hose is in good condition, no cracks, no perising, nothing. But after inspecting it very closely the reinforcing fibres that are embedded in the rubber appear to have failed and it wasn't until the cooling system got up to operating pressure that the hose blew up like a balloon and burst. The only way to have inspected this hose for this type of fault would of been to have cut it up!!!!!

On the temperature sensing, I obviously disagree with you, and will only say this in respect of your comment - Why would the heat from cylinder 1 need to travel to the sensor when #6 is right next to it? This would assume there is a major difference between #1 and #6, something which will not the the case unless there is a major failure, in which case loss of water will be the least of your concerns

Comment about your hose is fair enough, I guess sometime you can just be unlucky

[Stardate]

Just been into the local Ford shop to get a new hose, of which they can't understand their parts list @#$&*

Local rep saw the hose and made the comment "that's normal for those, especially when you start to thrash them" hmmmm I had pushed it but not thrashed, just an interesting comment though.