Disco 3 coolant over spilling

Well week 2 with the Disco 3, I didn't think id be back on so quickly.

Got back from a 15 mile trip today not heavy traffic not pushing got probably only got to 60mph once, anyway when i got home i noticed some coolant dropping from the expansion tank side of the engine, left it until it cooled down and topped it up and ran it up to temp again, bled it and waited, it will reach temp and the fan kicks and when I'm driving the heating kicks in when I pull over the heater blows cold (could be a red herring this bit I'll take it for a longer run) photo attached shows lots of bubbles coming into the tank but you cant see in the photo the amount of steam from the area also.

So what made it over spill and are the bubbles normal, from inspection of the expansion tank and surrounding areas it looks like its spewed out more than once as there are signs of coolant splashed on other surfaces. i have checked the oil and ALL seems fine in there, i dont mind running it to the garage for the once over but wanted to know before hand what it may or may not be.

Any suggestions i would be very thankfull.

Cheers

Bubbles in the coolant usually point to a head gasket, but it could be that it's air locked.
Try opening the cab heater to hot and raising the front of the engine up..on stands or facing up hill.
Then add coolant really slowly, when the engine is cold.

Get the coolant sniff tested for combustion gases

Likely to be a failed EGR cooler thermostat or the system has been opened and not vacuum filled / bled properly.
It's very important to bleed the metal coolant pipe at the rear of the engine just under the scuttle, there's a bleed point on it, ideally pressurise with a coolant system pressure tester rather than running the engine, which can actually draw air in.

Firebobby1 said:

Bubbles in the coolant usually point to a head gasket, but it could be that it's air locked.
Try opening the cab heater to hot and raising the front of the engine up..on stands or facing up hill.
Then add coolant really slowly, when the engine is cold.

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My drive is slightly higher at the front will try this tomorrow... Cheers

1988smithy said:

Get the coolant sniff tested for combustion gases

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Just ordered one from Amazon.. really hope it's not this...

Graculus said:

Likely to be a failed EGR cooler thermostat or the system has been opened and not vacuum filled / bled properly.
It's very important to bleed the metal coolant pipe at the rear of the engine just under the scuttle, there's a bleed point on it, ideally pressurise with a coolant system pressure tester rather than running the engine, which can actually draw air in.

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Right then I'm googling this location now many thanks for the help

Check the o ring on the bleed screw on the tank itself.

P7XES said:

Just ordered one from Amazon.. really hope it's not this...

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I'm sure it will be fine but worth testing before you go mad chasing your tail. @Graculus is very knowledgeable on the newer stuff

P7XES said:

Right then I'm googling this location now many thanks for the help

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Hi I can't find this other bleed point... Did they all have them? It's a 2005 HSE

I can't ever remember not seeing one, I've owned 06MY & 07MY - and worked on plenty of others.
There should be a black metal pipe crossing the rear of the engine just under the scuttle, probably under the engine & transmission harness'. You're looking for the same black plastic bleed screw as on the coolant expansion bottle in the centre third of the engine bay.

Bit of an update that may mean something.... The coolant that leaked onto the concrete drive yesterday has dried and it's now black. Obviously when it was wet it just looked pink.

Graculus said:

I can't ever remember not seeing one, I've owned 06MY & 07MY - and worked on plenty of others.
There should be a black metal pipe crossing the rear of the engine just under the scuttle, probably under the engine & transmission harness'. You're looking for the same black plastic bleed screw as on the coolant expansion bottle in the centre third of the engine bay.

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This cap looks similar?

That's the front of the engine, that bleeds the 'T' piece that joins the coolant flow in both cylinder heads together.
The one you're looking for is at the rear of the engine, over the cover for the HP fuel pump drive belt.

Graculus said:

That's the front of the engine, that bleeds the 'T' piece that joins the coolant flow in both cylinder heads together.
The one you're looking for is at the rear of the engine, over the cover for the HP fuel pump drive belt.

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Thank you Graculus, I have lost the light now so will have to look again on Friday (I'm away until then)

P7XES said:

Thank you Graculus, I have lost the light now so will have to look again on Friday (I'm away until then)

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Hi I'm back we have daylight, can anyone pinpoint this second rear of engine bleed point....

The coolant pipe between the EGR coolers is highlighted below, yours appears to not have the bleed screw. Maybe due to it being an early build?


The next stage is to confirm there are no cold spots - especially across that pipe. use the large hose at the front-centre of the 'V' as a reference, ideally using a infra-red thermometer, check the temperature along that pipe and the two hoses to the right of the engine bay that are the heater flow & return. It's unlikely to be thermostat related but could be due to an airlock in the EGR pipework, or possibly - but rarely, a failing coolant pump.
With any complex coolant system, vacuum filling is always the best way - BTW, do you have the rear heating / cooling pack?

Graculus said:

The coolant pipe between the EGR coolers is highlighted below, yours appears to not have the bleed screw. Maybe due to it being an early build?

View attachment 319843
The next stage is to confirm there are no cold spots - especially across that pipe. use the large hose at the front-centre of the 'V' as a reference, ideally using a infra-red thermometer, check the temperature along that pipe and the two hoses to the right of the engine bay that are the heater flow & return. It's unlikely to be thermostat related but could be due to an airlock in the EGR pipework, or possibly - but rarely, a failing coolant pump.
With any complex coolant system, vacuum filling is always the best way - BTW, do you have the rear heating / cooling pack?

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Thank you, yes I have the rear H/C pack I've bought a new EGR stat (just waiting for delivery) and I've bought the sniffer. I was going to swap the stat; flush; bleed and sniff... However I also have an infrared thermometer so will try this now

I've known the rear heating to cause a lot of airlock issues - but not as many as EGR 'stats. Generally the EGR stats can cause your concern (loss of coolant externally & poor heating performance) whereas the rear heating generally only causes repeated low coolant warnings and poor rear heating performance. Because of the way the pipes are routed, unless you fully drain the rear system & vac. fill, often the best way to force air out is to clamp off the hoses to the front heat exchanger and take it for a short but 'spirited' drive to force coolant around the rear circuit. You need heat, to cause stratification in the coolant circuit which helps with circulation - you can't do it properly on a driveway (or workshop) just by revving the engine.

Ok update would it be a suprise if I said I managed to remove the hose to reveal the stat on top of the cooler and there was no stat installed... It's already been removed.... I hope I've removed the right hose ha ha fun and games .. will this make a difference to the cause ?