Coolant Leak TD5

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neilbar

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Not having a good run with out Disco. The day before lockdown we picked the car up after a gearbox change. Then I had to pick up the Mrs and get the car recovered after the started when. I fitted a reconditioned on.

Now we have a coolant leak. Mileage is about 180k. At 153k I replaced the large top hose that comes out of the head. At 133k the head gasket was done by a garage. The leak is enough to cause the engine to over heat.

I noticed some red crystized coolant on the outside of the small hose that connects to the head. I've taken off, cleaned, put some sealant on and reattached. There isn't any where else obvious that I can see red coolant but it was losing quite a bit of coolant. I'm waiting for for red coolant to come so I can refill. I have a brake pressure tool which I think I can use to test the system. I watched a vid which said 15 psi then leave for 15 mins and check. I'm guessing that it will be able to fit onto the coolant fill up reservoir but since there is an overflow pipe how can I block that off to testing the system?
 
neilbar said:
Not having a good run with out Disco. The day before lockdown we picked the car up after a gearbox change. Then I had to pick up the Mrs and get the car recovered after the started when. I fitted a reconditioned on.

Now we have a coolant leak. Mileage is about 180k. At 153k I replaced the large top hose that comes out of the head. At 133k the head gasket was done by a garage. The leak is enough to cause the engine to over heat.

I noticed some red crystized coolant on the outside of the small hose that connects to the head. I've taken off, cleaned, put some sealant on and reattached. There isn't any where else obvious that I can see red coolant but it was losing quite a bit of coolant. I'm waiting for for red coolant to come so I can refill. I have a brake pressure tool which I think I can use to test the system. I watched a vid which said 15 psi then leave for 15 mins and check. I'm guessing that it will be able to fit onto the coolant fill up reservoir but since there is an overflow pipe how can I block that off to testing the system?
Click to expand...
Why did you replace the top hose? Had it burst?
Take it for a run, get it up to temperature then switch off and check the top hose. If it feels solid, like a fully inflated bike tyre, then you have overpressure in the cooling system. If you're lucky, it's as simple as a faulty pressure cap. Unfortunately, 9 times out of 10 it's the head gasket or a cracked head.
 
On the other hand, it could be a leaking water pump. It has a little weep hole on the casing. It may appear as a small drip with the engine idling but when revved above about 2500-3000rpm, it will gush out of the little hole. Obviously whilst driving it, that will empty your cooling system pretty quick...
 
sierrafery said:
For the engine to overheat from a leak he tank must go completely empty, so do you say you've got it empty then refilled and drove it untill it got empty again and so on?
Click to expand...
We were driving back at night 40 mins each way when Mrs B was driving. She noted that the temp gauge when to zero. Which on our td5 means it's over heating. The next day I put about 4l into it. Used for for short journeys. Then the Mrs used for a longer journey and the same overheating problem happen.
 
There is a little connecting pipe below the manifold (lhs), difficult to see or get at but thats the point where mine first started to leak.
I then fixed a whole host of things as well from that point on, but make sure its not there because I didn't notice that that was the source until it was proper gone.
 
I had the core plug leaking on the head between cyls 3 and 4 exhaust side, was a right sod to remove and refit/reseal.

Screen Shot 2020-04-25 at 20.46.05.png
 
neilbar said:
We were driving back at night 40 mins each way when Mrs B was driving. She noted that the temp gauge when to zero. Which on our td5 means it's over heating. The next day I put about 4l into it. Used for for short journeys. Then the Mrs used for a longer journey and the same overheating problem happen.
Click to expand...
It doesn't mean it's overheating, it means you have a bad leak and the cooling system has emptied itself, therefore there is no coolant left to measure the temperature of. However this also means some parts of the engine WILL overheat. Fill up the system, get the engine up to temp, then get someone to rev it up to about 3000rpm while you check all hoses, radiator and water pump etc. It should then be fairly obvious where your leak is.
 
Bobdog said:
It doesn't mean it's overheating, it means you have a bad leak and the cooling system has emptied itself, therefore there is no coolant left to measure the temperature of.
Click to expand...
Even if the sensor remains out of coolant the steam within the hose and the head's radiant heat will not let the temperature there to drop below 70*C or maybe if the leak is huge right after start up and the needle just reached the middle(that's at 70*C) the temp doesnt drop below 40*C so the needle eventually goes to the quarter section not to zero as the OP said it did... happened to me, i lost around 5 l of coolant once and the gauge went up to the red zone never dropped below middle. The ECT sensor reacts to temperature not to coolant so the gauge will work even if you heat up the sensor with heat gun
 
Last edited:
The coolant finally arrived and I filled up. I can't find an obvious leak but the coolant level is dropping quickly as the car is rev. I left the car idle then filled up then idled again and filled up to the every top. I have a top bleed screw on a hose so bleed some air. Then I got my daughter to rev the car to 2.5k and checked the hoses and pump. The were come redish drops on the bottom of the car under the battery box but I couldn't see where this was coming from. I wondered if it may of been some dropped from where I overfilled the reservoir? At the start I was right on the correct mark at the end I was about 4 cms below it?

Not sure how to find this?
 
Do not fill reservior bottle to the top, the liquid gets hot and when it gets hot it expands, there should be a level mark on the reservior tank.
 
Found these diagrams I think the leak is coming from the bottom left of the connection to the radiator and coolant is being blown back.

How do I take the bottom panel off so I can see that is going on.
 
If you’ve been running it with 4 litre of coolant missing your cylinder head will be toast in my opinion
 
New hose on. It was a real pain. I've taken for a drive after refilling and bleeding. I'm not losing coolant. I will monitor over the next couple of journeys.

Thank you for the help everyone.

Unfortunately the 3 amigos has now come on :)
 
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