At least snow was useful for something - Coolant leak

Since getting my 3.9 V8 Disco 1 I had noticed there was a leak at the front somewhere. When I noticed it I put my finger in it and it wasn't oil, but I wasn't totally sure what it was.

But then today after a week away I went to start the car up, let it run a couple of minutes to try start to clear the windscreen, and after pulling it back a few feet I had a look on the floor and saw this:



So the snow has been useful. It shows that what is leaking is actually blue. So I'm guessing that it is coolant that is leaking.

It is dripping down somewhere right at the very front of the car, somewhere between the middle of the engine bay and the nearside wheel, but I cant tell exactly as I wasnt sure how far over the car was parked before I moved it.

Are there any common faults to develop coolant leaks on these engines so that I have some suggestion on where to look first?

There can be lots of places that they can leak from. Included are perished hoses, of which there are several, pinholes in the rad, bad water pumps, and around the thermostat if the gasket is bad or if the bolts aren't tight enough.

Have a look at your core plugs.

Well the thermostat is on the list of jobs to do as I have a replacement for it with a new gasket, so I can deffo do that.

Core plugs?

Jonabonospen said:

Well the thermostat is on the list of jobs to do as I have a replacement for it with a new gasket, so I can deffo do that.

Core plugs?

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What prompts you to change the thermostat?

West Slope Rover said:

What prompts you to change the thermostat?

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Because the heater in the car doesn't seem to get hot at all, and someone on here suggested that it could perhaps be the thermostat stuck open, and seen as though a new one was only £10 or something I just thought I would replace it.

It could be because you've had a leak all along and air has been trapped in the system.

Refill the coolant to the max, then run it for a bit, driving up and down an incline if possible then recheck the level and add more (you may have to do this two or three times) to get rid of the air bubble. Once the coolant level remains level, then try your heater.

But to do this West Slope Rover, I need to find and fix the leak first? Otherwise it will surely just be getting air back in again yes?

The hardest thing with finding the leak will be that it only seemed to leak when it was first started from cold. After I took it for a little drive to the local shop and back and parked it over some fresh snow to try find the leak, it didn't seem to drip any blue liquid at all. I just guessed that this was probably due to the leak sealing itself up due to expansion once the system had warmed up.

If it's gushing it won't work. But with the info given, I think you should be able to get enough in to clear the air out. It usually gets trapped in the heater lines, thus keeping the heated fluid from passing through the heater matrix.

Some times a slow leak is hard to find after the motor has come up to temp because contact with hot metal causes it to evaporate before it can make it to someplace that you can spot.

Check the little pipes that run into the plenum, especially the bottom one. It's a bit fiddly and gets bypassed in maintenance.

It's definitely not a gusher. More of a trickler

I'd go for the water pump bearings first if it has been doing it for a while, not got any worse and is only trickling out. Hoses, gaskets and the like have a habit of providing quite a lot of water and they tend to get worse quite quickly as they are under pressure.

Its strange. The other day when I started it up, and the snow had gone, it left a little patch of what seemed like dark oil rather than coolant......

At the weekend hopefully, if the weather holds off, then I am going to get the front jacked up before starting the engine from cold, put some cardboard down and fire it up while someone looks up from underneath and someone looks down in to the engine with bonnet up, and see if we can find where / if it is doing it from cold. Then will let it warm up and see if it still looks like its leaking.