G`day Terry
If you ever have the rocker covers off , inbetween the middle 2 rocker post you should find ERC 0216 if the std heads for model .
Generally the liner shift has a couple of main causes or reasons . If the engine is rebored they will sometimes move but sometimes not . The main cause is being overheated and why the cooling system should always be a priority .
With a 3.5 the problem is not as great because there is a larger amount ( thickness ) of alloy around each liner , because of this they don`t have the same problem as the 3.9/4.0/4.6 of cracks and resultant coolant problems .
Liner shift in a 3.5 if making a noise can be sorted but it requires the cyl head of that liner bank to be removed .
Your engine will likely have an engine #prefix 14D , i`ve got a couple in the shed , One has had all 8 liners drop , it made no noises/rattles and unless it was pulled apart and sighted it wouldn`t be known , no coolant problem , this one has been bored oversize , it will live .
Another has had one liner shift but it did make a noise and having it apart it can be see where the liner has hit the cyl head surface and dented it but no coolant problem , this one is well worn and revs and kms killed it .
Another two all these same 14Ds have no liner movement or any sign they want too , both will live .
These ones have better main caps than earlier ones .
Have another last of RR 3.5s but it hasn`t got off the trailer yet and i really should put something together before i pull another apart .
3.5ltrs don`t but it`s a fallacy that only 4.6ltr crack behind the liners all the 94mm bore engines can/will and do crack blocks . I think the reason the 4.6 gets tared with that brush is because of all the Landrover design changes the P38a cooling system went through ( in use ) . These changes caused many over heat problems which in turn caused the cracks .
The overall fault though is with Landrover and the way the liners are fitted . There has also been comment that the torque to yeid head bolts contribute ( could go on about liners/block/bolts but won`t ) . I also don`t abide with the porous block fallacy , i feel this was used as a way of limiting market pressure and giving the impression that the fault wasn`t/isn`t as bad as it is becuase if Landrover had to replace blocks out of warrantee it would probably have sent them to the wall .
I picked up a later block 3.9 last weekend it either has a gasket or liner/block problem but no rush to findout yet .
If you read UK sites you`ll see that they had many 3.9 block failures and the fault was only sort of addressed late in the new block life , around 98 i think it was .
I have one of the so called sorted 98 build 4.0ltr blocks in the shed and it aint sorted also have another one in our 85 RR 2003 build . It runs much higher compression than std for LPG and it hasn`t given any trouble as yet . If was aware of the problem with the blocks 4 yrs ago i may not have spent the money and bought a new crated 4.0ltr short but at the time it was the best option .
The only time i`d consider they may rot in the areas you mention is if there part empty and air is able to mix ( as in not in use ) or if the wrong type of or a mix of different coolants are used .
Any coolant that is recommended for use with alloy is fine , doesn`t matter really what brand , just a type that is easily obtained locally and further afield .
Best stop now .
Cheers
Peter

