Blown top radiator hose

humph72 · May 8, 2008

Hi

Hope there is a logical answer to this one????

Just picked my p38 4.6 hse up from garage after air suspension problems and driving home i put on the air con and my top radiator hose blew clean of the rad.....

Replaced hose and flushed water through the system but do not dare put the air con on again incase it happens again....

Also i have ordered a new thermostat and expansion cap just as a precaution and would like to know if anyone else has any answers to this problem??

david451 · May 8, 2008

humph72 said:
Hi

Hope there is a logical answer to this one????

Just picked my p38 4.6 hse up from garage after air suspension problems and driving home i put on the air con and my top radiator hose blew clean of the rad.....

Replaced hose and flushed water through the system but do not dare put the air con on again incase it happens again....

Also i have ordered a new thermostat and expansion cap just as a precaution and would like to know if anyone else has any answers to this problem??

The air con as far as I am aware kicks in the pump on the engine, I can only think that the garage left the hose loose,

See if you can determine what they actually did, then go and look, if they don't tell you that they took the hose off, and see if the component is accesable with the hose attached.

v8kenny · May 8, 2008

There is no reason why they would remove the top rad hose when working on the air suspension that I can think of and I can't see how switching the air con on would have any influence on the hose either - it's belt driven from a pulley
When your engine is running does the top hose feel very hard as if there is a lot of pressure in it ?
If so , start to panic.....................................................................

humph72 · May 8, 2008

Thx for replies but the top hose is as soft as s£!t as they say and and temp inside reads normal all that comes to mind is that maybe where it was standing around for a week some muck has clogged or blocked something and now it seems to be fine...

Also there is no oil in the water and is clean im gonna take it for a run tomorrow now she is cleaned out and i will put on the aircon halfway through the journey and see if she blows again

redrenger89 · May 9, 2008

Hi Humph,

As said can't see why aircon would cause hose to come off.
Try this ...
Remove expansion tank cap
Can you see coolant pumped back into expansion tank if not check this thin hose for blockage.
When replacing thermostat only genuine are recommended.
Check coolant after heater has been switched on for a few minuites, and top up with 50/50 and not water only.
Coolant should be clean and not rusty or rad and engine will require flush and refilled with fresh coolant .
I hope it was just a lose hose

Fred

humph72 · May 13, 2008

well well so far my p38 is running ok but and there is a but!!! if i screw the expansion cap down tight it pressures up the top rad hose but if it is on tight but not fully tight if you get wot i mean no problems....could this be a dodgy expansion cap or something worse...

I have flushed the engine and rad completly and no oil in the water or water in the oil so thinking not a head problem...

i have ordered a new thermostat so far and thinking a cap may well do the trick aswell if not could it be a tempramental water pump....clutching at straws here lol

david451 · May 13, 2008

humph72 said:
well well so far my p38 is running ok but and there is a but!!! if i screw the expansion cap down tight it pressures up the top rad hose but if it is on tight but not fully tight if you get wot i mean no problems....could this be a dodgy expansion cap or something worse...

I have flushed the engine and rad completly and no oil in the water or water in the oil so thinking not a head problem...

i have ordered a new thermostat so far and thinking a cap may well do the trick aswell if not could it be a tempramental water pump....clutching at straws here lol

With the cap off does it chuck yer water out with loads of bubbly ****, I think some peeps said to check that. bring the revs up a bit wif it orf and see what it does, also if you watch as it warms you can tell if the thermostat opens, flow into the header tank and the hoses get warm.

The hose will get pressurised a bit that's normal, but what do you mean bulging like it's gona blow orf.

Water pump was fooked it would overheat.

humph72 · May 14, 2008

Hi and well with the cap off it is totaly normal water coming and going as it should no problems... but also noticed that my viscous fans at the front never switched on at all is this normal or are they dead?

david451 · May 14, 2008

humph72 said:
Hi and well with the cap off it is totaly normal water coming and going as it should no problems... but also noticed that my viscous fans at the front never switched on at all is this normal or are they dead?

If two then they are electric fans, and only come on near an overheat condition, run your engine up with the cap back on properly on a fast throttle watching your temp guage, water header tank and fans. Don't take it into the red but some point above normal the fans will come on, should come on.

This is a good test for you to see what's happening under the bonnet, watch the hoses and if they start to blow up excessively, then return to idle and cool dont touch the cap, remember it's normal for the hoses to be firm with pressure. I would change the cap if this was the case.

there is a sensor somewhere which switches them on, check the wiring from the fans, usually on the radiator.

If it looks to getting too hot dont turn it off turn your heaters to hot and turn on the blowers to cool it down on idle.

If it was ok with cap of on fast idle as you say then I would guess the heads are ok, same with the pump and thermostat.

Run that test and lets see what happens, it's going to get much hotter than it would on a normal run, so if it dont throw up a problem it's probably never.

andytlman · May 14, 2008

sorry to thread hijack but I've been having similar issues with my 4.6 it's never overheated or ever gone above the middle on the gauge but keeps on chucking the water out of the expansion tank. Today i have replaced the cap, on my original one all the o'rings had gone square bought a new one from LL for £13. Just took mine out for a 10mile drive then left it on the drive at idle with the new cap the top hose goes quite firm the coolant is perfect and there is no excessive movment of water in the header tank and no sludge in the oil filler cap. Since fitting the cap the water has stayed in the tank. Am i being paranoid? Or should i get it looked at!

david451 · May 14, 2008

andytlman said:
sorry to thread hijack but I've been having similar issues with my 4.6 it's never overheated or ever gone above the middle on the gauge but keeps on chucking the water out of the expansion tank. Today i have replaced the cap, on my original one all the o'rings had gone square bought a new one from LL for £13. Just took mine out for a 10mile drive then left it on the drive at idle with the new cap the top hose goes quite firm the coolant is perfect and there is no excessive movment of water in the header tank and no sludge in the oil filler cap. Since fitting the cap the water has stayed in the tank. Am i being paranoid? Or should i get it looked at!

If it's ok then perhaps you have fixed it with the cap, your cap seemed to be faulty and leaking whereas this guys is not leaking, and he suspects it's pressurizing the system, which I don't think it is.

Blown top radiator hose

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