Cylinder Head Gasket Failure?

Hi Guys
I want to share a quick tail with you all, and perhaps ask for an opinion or two?

Our family is pretty big on Landies, We have 4 at our house alone and a number of relations have had/still own one or two.

I’ve just got back from rescuing my dad from what looks like a cylinder head failure, living in yorkshire we have a decent amount of hills to climb around here and the last one on the way home seems to have finished his disco off.

My parents where driving back from a weekend out with the caravan which is around 2 Ton when loaded.

They where climbing a pretty steep hill, when my dad noticed steam from under the bonnet.

Inspection showed a loose water header cap; there was no warning on the temp gauge to say the engine was in danger at this point.

He tightened it up and drove on.

No issues until he approached the final hill towards our house.

They reached the top of the hill and the temp gauge kicked off, it hit red in around 30 seconds; while the steam returned under the bonnet, worse than before.

Finally engine management seemed to have had enough at this point and threw the towel in and cut the engine.

My Aunt and I ran to the rescue, she towed the van back with her landy, while I stayed with my dad and waited for the engine to cool.

We slowly started to feed it with some more water, but discovered that the radiator was leaking; we’d used around 1/2 to 3/4 of a 2 gallon carrier, but the system filled up. While waiting for it to cool we checked the obvious, and there seemed to be no water in the oil and vice versa.

When we started the engine, the engine seemed to be really bad, sounded almost like it was still on the starter, and water was just pouring out of the radiator, at this point my dad admitted defeat and I had to tow him back home with my disco.

All in all quite a bit of fun

My question is, could this just be a simple leak made worse by some heavy driving, or is it a cylinder head gasket failure?

..and the vehicle is?Model?Year?Engine?

Opps

98 Discovery 300TDi ESX

My bad

The obvious amswer is to replace/repair the rad first. If the rad is known to be old then have it reconditioned or fit a new one, it could be clogged up contributing to overheating on the hill climb.

I have found that many head gasket failures are normaly the failing of another part of the system. Sort the rad first then if you have problems start looking deeper.

I would replace the thermostat and rad cap at the same time as the rad, check the fan was being driven ok, i.e. fan belt not slipping, water pump working, hoses not collapsing whilst engine being revved ect.

If no other leaks and you have bled the system and you still have issues then think about the the head gasket, a chemical test can be done on the coolant to look for combustion gasses.

Of course JMHO,

regards

Dave

If it sounded like it was still on the starter like you say, I would say the hg's gone.

Time for a compression test me thinks.

symptoms exactly the same as mine except my rad didn't go a hose did.. thinking back it was the HGF that popped the hose not the other way round.. compression in the water was so bad on it's last journey that it hit the underside of the (raised) bonnet when the aa man took the cap off.. and he'd been venting it for ages before he undid it.. . the pressure will find the weakest point and in mine that was a hose on top of the inlet manifold.. on yours sounds like the rad was on its way out..

mjltigger said:

symptoms exactly the same as mine except my rad didn't go a hose did.. thinking back it was the HGF that popped the hose not the other way round.. compression in the water was so bad on it's last journey that it hit the underside of the (raised) bonnet when the aa man took the cap off.. and he'd been venting it for ages before he undid it.. . the pressure will find the weakest point and in mine that was a hose on top of the inlet manifold.. on yours sounds like the rad was on its way out..

Click to expand...

This is possible but unlikely. A head gasket contains pressures in the region of hundreds of psi, your rad cap should have released pressure at around 13 - 15 psi.

If your cap was faulty then hose bursting ect is also a possibility however, most (automotive) cooling systems hold pressure as stated above. If a head gasket fails (assuming into the water jacket) the pressure in the coolant would be way above the stated pressures in a few seconds.

Radiator/hose or whatever failures due in theory to a head gasket failure must have been worn/weak in the first place IMHO.

Just a note for your AA man, if he vented for ages he should have known that even if 'only' 10 psi was left in the system as soon as he removed the cap (coolant exposed to atmospheric) the remaining water would have boiled straight away leading to the aforementioned 'hitting the bonnet', perhaps a refresher course?

Be safe!!

regards

Dave

it was enough to pop a hose on mine.. the cap was hissing before the fella gave it a 1/4 turn to speed it up so it was venting but not quick enough to stop the pressure building up.. I agree that there was probably a weakness in the pipe when mine went but I wonder if there may alsi have been a weakness in Dark's dad's rad..

Good point, but the failure must have been catastrophic, or your car must have been overheating for quite awhile?

Going back to my original point it is interesting that customers/friends have come to me in early Range Rovers complaining of water loss (they have a light on the dashboard), this is normaly a hose or rad or water pump but never a head gasket.

Early Discovery owners come to me with a head gasket failed which once repaired and the car started a leak will appear from, you got it a hose or rad or water pump.

Without wanting to put on the flame retardent suit I would suggest that many owners do not check the fluids as often as they should. Many cars are very reliable and they just get taken for granted and unless a light comes on the dashboard some people do not open the bonnet between services.

A slowly creeping up temperature gauge is also rarely noted as is the slowly creeping down fuel gauge (V8 owners excepted ) and we know how often people run out of fuel right?

I tend to glance at the gauges when sitting in traffic and when climbing long hills but rarely on a steady run or running around in town, I even fitted my own 'idiot light' to show low water!

I would hazard a bet that there are more head gasket failures caused due to a small leak going unnoticed in the system rather than poor design ect. This applies to other makes/models of vehicles as well.


regards

Dave

possibly a good point.. but I know what casued mine.. rad was full of mud and it was misfiring.. I drove it anyway.. lesson learnt and a lot more learnt besides while I do the gaskets..