Boiling water

On my 2.5 dse the temp guage was not working when I bought it so have assumed it was dead as the car seems to run ok.Yesterday after a run I noticed that the water was bubbling away in the header tank actually boiling.There is no apparent contamination of oil in water/water in oil but on checking the car the previous owner had replaced the radiator hoses etc when hot the hoses are not solid but softish.
Does anyone have any idea why the car seems to be boiling away like this someone told me it sounds like a cracked head but there would be water contamination wouldn't there.
Any ideas

Leave it overnight then in the morning when cold open the header tank cap. If theres more than a little hiss as you undo it then you may have a problem with the head/head gasket. Remember a head gasket can fail accross a cylinder/coolan channel so you don't always get oil contamination.

Obviously ultimately you need to get it compression/sniffer tested

Thanks Hackett did the check and absolutely nothing, the overheating seems to have dissapeared but having read other postings I have a feeling it could be the rad which seems to have been replaced at some point.Am going to go through the whole heating/cooling system ie physically check everything. Just as a point of interest does anyone know how I can repair my temp gauge.

Have you changed the Temp Sensor ? good place to start

Hi Mate,

Just had a similar event with my 4.6. After replacing the thermostat, viscous fan it transpired it was a semi blocked Rad. Before you start ripping the heads off, for two hundred quid it might be worth considering.
As far as the temp gauge as stated earlier replace the sender unit first, located on top of the inlet manifold. Bit of a bugger to get too however a good place to start, and cheap as well about twenty quid.

Andy.

corfunightmare said:

Hi Mate,

Just had a similar event with my 4.6. After replacing the thermostat, viscous fan it transpired it was a semi blocked Rad. Before you start ripping the heads off, for two hundred quid it might be worth considering.
As far as the temp gauge as stated earlier replace the sender unit first, located on top of the inlet manifold. Bit of a bugger to get too however a good place to start, and cheap as well about twenty quid.

Andy.

Click to expand...

On a diesel the sender is under the inlet manifold, bit of a pig to get at, but not impossible.

Dont get to carried away ! Try a new expansion bottle cap first. If its not holding pressure the water will boil.

Not sure from your original post if the rad was replaced. I have read on here that some cheap rads for the diesels may not have the baffle fitted which allows the water to bypass the rad completely.

May be worth a look, and I'm sure much more knowledgable peeps on here will shout up if i'm talkin rubbish.

Thanks everybody - got a busy weekend ahead will let you know outcome!!!!!!!!!!!!