TD5 Overheating

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FlatbedPilot

FlatbedPilot

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Location
Shetland
2004 TD5 Defender.

I recently had the head off to carry out work on it so the engine has all new gaskets on the top end. Since putting everything back together it's overheated twice. The first time I thought it had lost coolant because I could see that the bottom radiator hose connection was leaking. I took it apart and reseated it and fitted a new clamp then refilled the system. Now it doesn't leak from anywhere but it's now blowing coolant out of the expansion bottle. All the hoses at the top of the engine are hot but the hoses at the bottom are stone cold.

I've tried bleeding the system in case it's an airlock but I still have the same problem.

Has anyone experienced this and is there a trick to bleeding the TD5 coolant system properly or should I be worried that there might be a more serious problem?
 
When filling the cooling system did you do it gradually a bit at a time (with top hose bleed plug removed) pausing for a minute each time to allow air to dissipate, and did you have heater turned to hot to allow those pipes to fill. Did you flush out the radiator before filling the system, they may be sludge in the bottom causing a blockage.
 
It does sound like it's air locked if all the bottom hoses are cold. Have you followed the bleeding procedure with the bleed screw and the heaters at hot etc?

There was a guy local to me a few years ago had a pig of a time getting rid of an airlock in his Td5, I can't remember the exact solution to clear it, but I certainly wouldn't be pulling the head back off or the like until you know you at least have the water circulating the full system.
 
I can't get the bleed screw undone in the top hose so I disconnected the heater hose until water came out there then reconnected it. I used the bleed screw on the line to the fuel cooler and was just getting coolant out there.

I must admit I just filled it up until I had a level in the expansion tank, not slowly and I think the heater may have been on cold.

The radiator has been out as part of the previous work, not flushed, but I did tip coolant out of both ends when emptying it and it all seemed clean and free flowing.

It does sound like I need to bleed it more.
 
Try undoing the expansion tank from its holder and raising it as high as you can, prop it up to keep it there then " very slowly" fill the system, try getting the vent plug out and continue filling until all air out and expansion tank full, run engine and let it settle and bleed again before resecuring expansion tank. The key to filling the system is do it "very slowly" with pauses and get the bleed screw open. When I say slowly I mean really slowly.
 
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So I've now bled the system as specified, very slowly filling it. It's still the same. I've also tried forcing water through the system by connecting the tee off to the heater on the top hose to a tap with a garden hose. I used another hose to route the open end to the floor and just let it run for about ten minutes. No sign of any air coming out, it ran full bore the whole time. Still no joy.
 
is rad getting hot ,hose above thermostat, id want to know thermostat and water pump were working ok if so remove head, as long as system is filled till bleed screw on top hose runs clear and expansion bottle is full ive found no issues with filling a td5
 
The rad gets a little warm above the thermostat. The pipe off the bottom is stone cold. Maybe the thermostat is u/s? I've taken the thermostat housing out with a view to checking the thermostat but can't see how the housing comes apart. Or is this a complete unit that you have to replace as it is? Can't see how I'll be able to check it without getting it out of the housing.
 
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Its a sealed unit. Thats how they are sold. Its looking like thermostat or water pump problem. I am not sure if you can fit thermostat housing two top hoses the wrong way, I cant remember if pipes are different sizes, but worth checking if you have had it off the car.
 
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As I couldn't test the thermostat I just settled for taking all the hoses off it and banging it on the ground to make sure there was no crap lodged in there. I also got my fingers in there and pushed one end of it and it moved easily enough. So I've refitted it, filled and bled the system AGAIN and had a little drive. When I got home I felt all the hoses and this time the bottom ones were warm so it seems to have done the trick. Only a good long drive will really tell though so fingers crossed.
 
Thanks for all the advice from everyone by the way. I'll update the thread when I'm sure it's ok. Or not, as the case may be.
 
I would put a new thermo on before filling up with expensive antifreeze, if your old one is iffy you will end up with more expense.
 
Just starting two weeks of nights and it's only a few miles to work. I shall see how it behaves on the commute. Won't be doing anything until my next shift break. Plenty of time to get one ordered for when I'm off work again.
 
It's not looking promising.

On my first night shift I checked under the bonnet when I got home in the morning. The top hoses felt like there was nothing in them so I took out the top hose bleed screw and topped up the system. It took about five litres of water before coming out of the bleed point.

Checked again this morning and pretty much the same.

If I top the header bottle up to overflowing and watch it while the engine is ticking over it's slowly pulsing and every few seconds a small bubble bursts from the surface. I think the water system is being pressurised by a blow from one or more pistons into the water jacket.

I'm pretty much resigned at this point to taking the head off again. Either the gasket I used has failed already or I've cocked up somewhere refitting the head.
 
Not that I can tell. The oil looks normal. I think the water is just blowing out of the header bottle until a point of equilibrium is reached.
 
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