Disco 2 Overheating again, eh?

Simon Perks · Sep 19, 2022

A d all was going so well, seemed the ATF thing was ok, checked the injector valve things, also ok.
Decided to replace the top hose, as when I did the head gasket it wasn’t here I had reused the old one, oops I have defender one by mistake so refitted the ok’d one again.
Drove around 100km on Friday night and it over heated ?? Weird
Ok lots of loud hissing from the expansion tank, eh? So bought a new one and cap from LR Germany.
Drove home 200km into the journey and up the gauge went, heater was cold eh?
Turned it off and the temp dropped, eh?
Turned it back on … 20km temp up, turned heater off .. down it goes.
No loss of power but left it off.. temp rose but fell and this kept happening, so no idea?
Thermostat? Top hose? Head not tight enough? ( I don’t have the right tool so I guessed those 90deg 180deg turns) but I have since towed trailers and been into the alps and no overheating issues ..

Have to say there is no significant loss of coolant but the top hose is rock hard ..

Anyone any idea ? If I know what the head bolts should be in NM I could check them.

simon

Interceptorxj · Sep 19, 2022

You need to pressure test the coolant system to see if it is losing pressure, if it is check for external leaks, if none then you probably have internal cracked head/injector sleave which can be confirmed with a sniff test.

Simon Perks · Sep 19, 2022

Interceptorxj said:
You need to pressure test the coolant system to see if it is losing pressure, if it is check for external leaks, if none then you probably have internal cracked head/injector sleave which can be confirmed with a sniff test.

I have heard about this but what exactly is a sniff test?

marjon · Sep 19, 2022

Simon Perks said:
I have heard about this but what exactly is a sniff test?

Something like this Combustion leak tester kit head gasket block sniff 50ml DIESEL test fluid | eBay

They can come in many shapes and forms but all do the same thing.

J

Stanleysteamer · Sep 19, 2022

I've heard that on a TD5 the sniff testers cannot be trusted.
If you aren't losing any coolant then you don't have a leak either to the outside of the system or into a cylinder via a cracked head or whatnot.
again, if your bolts weren't done up tight enough and you had a leak you would be losing coolant.
I am wondering if you still have air in the system.
And temp indicators going up or down can depend on whether they have coolant circulating around them or they are sitting in an airlock.
I'd go through the topping up procedure again, remembering to rev the engine to open all valves in the cooling system, and I'd also want to be sure that the thermostat is fitted correctly and working.

Simon Perks · Sep 19, 2022

All of the above actually lads, I have ordered the original LR thermostat and top hose plus i will pull the head bolts down tonight having read on an Ozy forum that a lot of the chaps in the bush don't trust the whole X-deg, then Y-deg, then A-deg tightening and just go for good old 90ftlbs so I'm going to use that as a bench mark (as all i had was a school protractor when i did it)
I cant keep throwing 100 francs of coolant down the drain so I'll go through the raise tank and fill until i get a fountain from the bleed.
I'll also get rid of those horrible LR pipe clips and use good old jubilee ones when the new hose arrives.

Any further tips on really getting all the air out - heater on full, rev the engine a few times, raising the tank and what about the loop that goes the now redundant EGR cooler?

What so bugs me it wasn't doing this before I took the old hose of not realizing the new one was the wrong one (defender)

Simon

sierrafery · Sep 19, 2022

Simon Perks said:
Any further tips on really getting all the air out - heater on full, rev the engine a few times, raising the tank and what about the loop that goes the now redundant EGR cooler?

the 100% correct procedure is here cooling system bleed also try to stop the viscous fan with a rolled up newspaper when the radiator is hot, if you can means it doesnt lock so no cooling from it.

I've seen cases(not one) when the thermostat was fitted the wrong way around cos it can happen then it overheats, one example https://www.aulro.com/afvb/discovery-2-a/212384-thermostat-fitted-reverse.html

Stanleysteamer · Sep 19, 2022

sierrafery said:
I've seen cases(not one) when the thermostat was fitted the wrong way around cos it can happen

totally, absolutely, hence my remark about it being fitted properly.

Simon Perks · Sep 20, 2022

sierrafery said:
the 100% correct procedure is here cooling system bleed also try to stop the viscous fan with a rolled up newspaper when the radiator is hot, if you can means it doesnt lock so no cooling from it.

Thanks I followed that and took it for a drive, seems ok.
Thermostat is right way round.
Can’t stop the viscous fan with a rolled up newspaper- or should I try harder?
didn’t go mad with head bolts, I tested one and it’s around 90nm so I checked them at that and yes had to bring some up until they are all equal.
Drove to the 15km to the station and it seems fine.
However the heater behavior is a bit odd.
It blows cold when standing still but as soon as I drive or raise the revs it blows warm. Is this an air lock?
The real test will be a 100km plus tonight.

simon

sierrafery · Sep 20, 2022

Simon Perks said:
However the heater behavior is a bit odd.

That can be as simple as it's full of gunk, If you want to save the OAT let it out, fill the system with water + liqui moly(or other high quality) radiator cleaner, drive it one day with that then flush the system and refill with OAT or flush the heater core separately

Simon Perks said:
a lot of the chaps in the bush don't trust the whole X-deg, then Y-deg, then A-deg tightening and just go for good old 90ftlbs so I'm going to use that as a bench mark (as all i had was a school protractor when i did it)

Simon Perks said:
didn’t go mad with head bolts, I tested one and it’s around 90nm so I checked them at that and yes had to bring some up until they are all equal.

IMO you dont have to go mad with them just to follow exactly the procedure from the WSM rather than relying on what some chaps in the bush are saying

Interceptorxj · Sep 20, 2022

Stanleysteamer said:
I've heard that on a TD5 the sniff testers cannot be trusted.
If you aren't losing any coolant then you don't have a leak either to the outside of the system or into a cylinder via a cracked head or whatnot..

I direct you to this; a loss is a loss!

Simon Perks said:
Have to say there is no significant loss of coolant but the top hose is rock hard ..

Simon Perks · Sep 20, 2022

Interceptorxj said:
I direct you to this; a loss is a loss!

When facing the car, bottom left of the radiator the hose clip was loose .. realized that I was loosing fluid from there but when the engine was ticking over you don't see it, however when i touched the hose (to see how hot it was) it leaked, i theorize that whilst driving this would also happen.
We will see, next job flush the heater and radiator, fit thermostat and new top hose then make another 200km test drive.

Simon

Stanleysteamer · Sep 20, 2022

Interceptorxj said:
I direct you to this; a loss is a loss!

Seems from the post below yours that he has in fact found a loss, so he shouldn't have used the word "no" followed by "loss" in any sense!.
But at least he is still checking for stuff!

Stanleysteamer · Sep 20, 2022

Simon Perks said:
Thanks I followed that and took it for a drive, seems ok.
Thermostat is right way round.
Can’t stop the viscous fan with a rolled up newspaper- or should I try harder?
didn’t go mad with head bolts, I tested one and it’s around 90nm so I checked them at that and yes had to bring some up until they are all equal.
Drove to the 15km to the station and it seems fine.
However the heater behavior is a bit odd.
It blows cold when standing still but as soon as I drive or raise the revs it blows warm. Is this an air lock?
The real test will be a 100km plus tonight.

simon

In the old days, before all this angle bollix, whenever you put a head back on, you expected to drive it 100 miles then retorque the head bolts. So what you have found is not surprising at all. and good on you for doing it.

Simon Perks · Sep 20, 2022

Stanleysteamer said:
In the old days, before all this angle bollix, whenever you put a head back on, you expected to drive it 100 miles then retorque the head bolts. So what you have found is not surprising at all. and good on you for doing it.

As I always did on me series landrovers.
I’m very new to the whole TD5 thing.
Thanks for all the advice chaps.
Should have the new genuine LR parts by the weekend.
One thing I still don’t get is why the acceleration using the cruise control button is better than the pedal so I also have a new throttle sensor coming to see if that will make the difference.
simon

Si Click · Sep 20, 2022

Simon Perks said:
A d all was going so well, seemed the ATF thing was ok, checked the injector valve things, also ok.
Have to say there is no significant loss of coolant but the top hose is rock hard ..
simon

Are you quite sure that your system is not replacing coolant with combustion gases? If the top hose is rock hard and vey hot, it could be full of combustion gases. If you open the bleed when it is rock hard do you get coolant or gas out?

Simon Perks · Sep 20, 2022

Si Click said:
Are you quite sure that your system is not replacing coolant with combustion gases? If the top hose is rock hard and vey hot, it could be full of combustion gases. If you open the bleed when it is rock hard do you get coolant or gas out?

I’ll look tomorrow evening after the drive home but after yesterday’s work the coolant level in the expansion tank has not dropped like it did before.
The top hose was not as hard as before and now the radiator is also warm all over whereas yesterday it was cold to the touch.
Simon

Stanleysteamer · Sep 20, 2022

Simon Perks said:
I’ll look tomorrow evening after the drive home but after yesterday’s work the coolant level in the expansion tank has not dropped like it did before.
The top hose was not as hard as before and now the radiator is also warm all over whereas yesterday it was cold to the touch.
Simon

DOES sound like an airlock or two that you are gradually shifting.
OR the rad was at least partially blocked and the blockage has now moved/disssolved.

sierrafery · Sep 20, 2022

Stanleysteamer said:
In the old days, before all this angle bollix, whenever you put a head back on, you expected to drive it 100 miles then retorque the head bolts

Maybe cos the they didnt use TTY bolts back then... I'd not treat a D2 like a Series 1... like i'd not treat a 2020 Discovery sport or RRS like a Td5...and so on

... no offence

Stanleysteamer · Sep 20, 2022

sierrafery said:
Maybe cos the they didnt use TTY bolts back then... I'd not treat a D2 like a Series 1... like i'd not treat a 2020 Discovery sport or RRS like a Td5...and so on ... no offence

Not offended at all. I do realise the reasons behind the modern ways of putting heads on and stretch bolts etc. Just reminiscing about how much easier things were in the old days. But then it meant a trip back to the garage to retighten the bolts/nuts on studs, unless you could do it yourself. Which is possibly part of why they changed the method.

I too wouldn't apply old methods to new style stuff, you have to put it back together the way it is supposed to be done, or else you are asking for trouble.

Disco 2 Overheating again, eh?

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