Thread: 06 TD5 Defender using WATER

Originally Posted by Blknight.aus

nope your tottaly correct...

the dowels are only there for the initial locating of the head and gasket while you put it all together....

So far Every head fault I've personally seen with the td5 (5 now) Has been easily attributable to either operator error OR dodgy workmanship when the operator has taken it to someone to have the required corrective work done.

The big problem with the dowels is when cheapskate mechanics try to reuse the plastic ones the head can be sat on and the dowels will let it sit off center then engine will work for a while but once the combustion process begins to eat the head gasket failure isnt far off.

I agree with the observation of dodgy workmanship. It would not surprise me if 70% of problems with Land Rovers in general are attributed to this factor. If the owner is unaware of the bad work done he will keep returning to the same mechanic until he sells the vehicle for being unreliable.
I have to pay twice for work done on the timing belt of the Tdi300 because the job was not done correctly in the first time by a "Land Rover especialist"
His work lasted 20000 km and luckily I found the problem when the belt jumped 1 tooth. I just wonder how many Tdi owners have the same problem with this mechanic?
I guess that the TD5 is more sophisticated and require more knowledge person to work on it.

pfaffle...

anyone who wants to do what I can do can do what I can do...

they just have to do what I did...


read books and be prepared to get it wrong a few times then learn from the snafus.

These things come with manuals and those manuals point you to other books on how to do bits that arent explained in the manual...

Originally Posted by Slunnie

There was also a heap of effort put into cooling the engine to keep the heat out of it too.

Here is a really interesting read from LROI that some may be interested in. It's about the development of the TD5. My apologies as the article has been photographed, but if you click on the pics you will get a high res copy.

www.slunnie.com - LROI TD5 article

Getting back to this line of thinking ( thanks for the post Simon very interesting ) if the Td5 is so well cooled why do alot of them keep over-heating? Can't all be down too bad servicing can it?

Leanered tech ones please educate me?

thats simple,

they are made of a heat treated aluminum and the combustion process can generate enough heat to undo the heat treating, so a very high tech coolant system was developed to deal with it...

Lets start out with coolant concentration your doing the right thing, youve noticed the cooling system is a bit low so you top it up with some distilled water. this dilutes the coolant and eventually it will drop below the point where it can deal with the temp range it needs to be able to deal with.

so like all things hi tech its only got to go out of tolerance a little bit and it wont work as effeciently which leads to a bit of heat build up which will slowly start to undo the hardening. This in itself leads to eventual head warpage. But like all complicated things it doesnt stop there As the head is getting hotter the cooling system gets hotter lets face it if it didnt the laws of physics would have gone on holidays but I digress. As the cooling system gets hotter the coolant expands more, more expansion means more pressure which puts things like your hoses and expansion tank at risk more often than not the extra pressure will just squeeze a little bit of coolant out past a hoseclamp untill the pressure is back under control.. So thats not too bad...Untill the hose develops a permanant leak or untill you loose enough coolant that you have the metal inside the cooling system exposed to air and not immersed.

Now when that happens things go very bad very quickly.

Ok lets deal with the wrong coolant

this is easy the wrong coolant will eat the engine parts through a mixture of chemical reation, electrolosys and scouring. last time I checked removing metal from things that deal with pressure isnt such a cool idea.

And finally neglect.

if the radiator becomes clogged (internally or externally) then the coolant doesnt flow or the coolant doesnt get to transfer heat to the atmosphere.. the coolant gets too hot and then bad things happen, again surprisingly quickly. The same applies to water pumps, thermostats heater elements the whole shooting match, if its not up to standard its going to give problems.

and most of that with the exception of cleaning out heat exchangers and radiators is DIY type inspection and repair work....

posts like Dave's make me nervous...did someone say timebomb...

I guess a big part of the problem is that LR crammed five cylinders into a relatively short block and the tolerances of everything seems to be pretty fine..and I presume the block water channels are also small diameter and therefore easily blocked.

I guess, as Dave says, the keys are to maintain cooling systems rigorously and to fit aftermarket temp sensors and coolant alarms...

the cooling jackets are quite roomy for what it is, (more space in there than in a series block at any rate)

ITs only a time bomb if its abused to hard or neglected.... ITs a PC motor you need to give some loving to and it will love you back. Its not like a series 2.25 which is sort of like the village idiot of engines Abuse it and it just comes back for more.

Originally Posted by ak

Getting back to this line of thinking ( thanks for the post Simon very interesting ) if the Td5 is so well cooled why do alot of them keep over-heating? Can't all be down too bad servicing can it?

Leanered tech ones please educate me?

I would like to know the success rate of re-torquing the head bolts at, say, 100k kms, in the same way as some other vehicles. I'd like to do mine as preventative maintenance but dare not unless its already been establised as successful.
Saab used to recommend it but the recommendation stopped when GM bought it and then head gaskets started to leak somewhere aroound 150k kms. But the Saab stretch bolts can be tightened a max of 3 times IIRC whereas LR say only once for the TD5's - ie the original time. In times gone by, Deutz stretch head bolts could be reused as long at their length didn't exceed specified limits, although being air-cooled they don't have the complication of water passages.

Nooooooo...

let me say that again.

Nooooooo..

dont touch the headbolts unless you want to replace them...

they are angle torqued not done up to a torque setting and they are not a very forgiving bolt.... (ask Auke)

However they make great tent pegs so if youre going to redo your head bolts can I have the old ones?

If you wanted to replace the bolts as a preventative measure you might get away with undoing one bolt (eventually all in the correct sequence) and installing the new bolt in that hole to its starting torque then when youve changed all the bolts over to the new ones going in the normal tightening sequence...

But If I was going to do that ID also replace the head gasket.