3.9 V8 Overheated.. once

On or around Tue, 2 Dec 2003 16:09:00 +1100, "pleasenospam" enlightened us thusly:

coolant gradually buggered off, and then you did something a bit more strenuous than usual...

did it actually get to the cloud of steam stage?

Hi Austin,

No.. didn't see any steam (Not that I was looking!), and there was nothing more strenuous that I can think of.... I'd checked the coolant a few days before and it was fine....Very strange. What is the cloud of steam stage?

Thanks for the reply Pauly

Similar thing happened to my 3.5 Disco. Turned out that one of the hoses to the heater matrix was not as tightly attached to the engine as it should have been. Coolant gradually leaked out from the system over a number of weeks - at the time I was mainly pottering around town so I didn't notice until I made a run down the motorway.

Why? What do you then have to worry about? I got to that stage but my temp sender never went more then half-way. Low and behold I'm replacing the intake manifold gasket.

On or around Tue, 2 Dec 2003 23:43:50 +1100, "pleasenospam" enlightened us thusly:

self-evident... when it gets hot enough to boil and exceed the blow-off pressure in the rad/tank cap, makes a huge cloud of steam.

not recommended practice.

On or around Tue, 02 Dec 2003 20:46:02 GMT, "Jack Kerouac" enlightened us thusly:

if you boil the coolant in a pressurised system, you've got it a fair bit hotter than the manufacturer recommends...

generally, if you shut it off straight away, and leave it stand a bit, and refill it with coolant, it should be OK. If you carry on running it for more than a few minutes, it'll get seriously hot and all sorts of things could fail, or it could seize.

Having said that, I had a 2¼ (petrol) lose a core plug about 3 miles from a suitable garage in heavy traffic... by the time I got to said garage, the engine was smoking-hot, but after fixing the core plug and refilling the system, it never showed any ill-effects. I've never seen one get that hot and survive before though. Bloody sound design, the old 2¼.

if you do boil one, leave it stand for a few minutes before refilling it, less chance of thermal shock cracking things when you put cold water back in it.

Our Range Rover had a really small leak near the top which caused a similar problem. So check your hoses and make sure there isn't a hole in the radiator. The hole on our radiator was at the back and went un-noticed the first time we were looking for a leak.

Our 3.5 Disco' also has a radiator leak. It's coming from the bottom but I can't see exactly where. It might just be a hose clip I suppose but until I take it off I'm going to be none the wiser. It isn't too bad though and so long as we keep an eye on it it's okay.

Cheers Gary

Now somewhere, recently, I read of a mysterious coolant loss which turned out to be a tiny (corrosion) hole in the water-pump (iirc) - coolant evaporated on the hot valley, so no evidence of water loss!

Just a thought.

And the 2.5. I got about 3 miles (of stop/start traffic) in mine between the oil light coming on, and it siezing up and stopping without a sump plug... (bearings wern't too bad either) The oil light might not have come on because of the total loss, but because it had just lost enough to light it up, but it must have been oil-less for a fair while.. (no signs of major oil slicks evident on the road when getting towed home eiher..)

Just noticed this thread after I posted about my 2/14 over heating.

Actually it was not too bad as it was only in the red whilst stuck in traffic, as soon as I got underway the needle settled back into a sensible range, however she was low on water. I guess I shall check all the hoses tommorow when it is light.

Yes, our old Landrover garage told me about that but it isn't the case in ours.

The hole is on the underside of the pump and should be sealed with a rubber plug inside. Apparently this can breakdown with age, hence the leak.

Our leak can be seen as a trickle from under the left side of the radiator.

Cheers Gary