@Discorama that is a very valid point. 20 degrees is significant. Did you go with the earlier DII style oil cooler or do something aftermarket?

Does anyone have a firm idea why they stopped using the oil cooler? Purely a cost saving measure?

I can't believe that a higher torque, higher power motor would necessitate removing the oil cooler for any reason since power = heat. Yet, that is what happened. Oil cooler on the 4.0 D2's and not the 4.6's...

 

Added the stock cooler with thermostat sandwich and custom lines : https://landroverforums.com/forum/di...ys-cold-95865/
(oil temps were 240F/220F before/after not 260F/240F, as I wrote in my comment above, had the wrong numbers in my head, sorry for that, but still a 20F difference)

 

@Discorama 240/220 makes a lot more sense. 260 sounded a little high!

thanks for sharing. Sounds like the oil cooler is a worthy mod. 20 degrees is significant.

 

I checked my logs again, and one day I recorded 250F oil temp without cooler. The conditions for 240F/220F are more a standard case for my D2 (fully loaded, freeway, slight hills, A/C on, 95F outside).

 

The deletion of the oil cooler is probably item #1 on my list if I could ask a Disco engineer what the thought process was. I can't imagine it's cost cutting, but who knows.

 

My number #1 question would be WTF were you thinking with the brittle plastic on the bumpers and the cooling system. And them maybe the coils. The plastics he would probably throw the supplier under the bus, but the coils would probably get him an *** kicking.

 

The plastic bumpers are the worst.

Have not had coil issues yet...

On the subject of cracked blocks, I found this on the Aussie LR Forum:

"The short story is that 4.6L blocks are less susceptible to having slipped liners. The long story...

Sand casting is not a highly accurate process, so there are dimensional variations from block to block. The dimensionally critical area for Rover V8s (where many fail) is the thickness of the wall between the cylinder liner and the water passage. When they fail, water seeps into the cylinder from behind the liner and gets worse and worse and worse... and the engine gets a slipped liner.

On A 4.0 / 4.6 block with an ideal cast, this wall should have a thickness of no less than 3.0mm at its thinnest point. In practice a block of wall thickness of between 2.1mm to 3.0mm was deemed acceptable by the factory. All 4.0 / 4.6 blocks were ultrasonically tested at the factory and minimum thicknesses recorded next to where the pushrods and lifters are. Blocks with a minimum measured thickness of 2.5mm or more were sent to the 4.6 production line, while the remainder (2.1 to 2.5mm) to the 4.0 line. They later started grading them as blue, yellow and red (corresponding to minimum thicknesses of 2.2, 2.5 and 2.8mm respectively) instead of writing the minimum thicknesses. Red went to the 4.6 line while Blue went to the 4.0 line. Yellows were used for both the 4.0s and 4.6s when the factory ran out of either blues or reds."

Link to the forum post.

So it sounds like most of the late 4.6's were probably "yellow" blocks and therefore are a crapshoot with cylinder wall thickness.

Also in that forum they mention an ideal max operating coolant temp of 80 degrees C, which is 176 F..... Not the first time I've read that.

 

I'm pretty sure I had a yellow block 4.6 as I got a factory replacement engine under warranty in 2007 which was shipped from the UK. At that point in time it had to be one of the last of the last as I don't think they were holding out the best for last...

That block eventually cracked in the exact location mentioned in the wall between cylinder 5 and the water passage. Misfires gradually increased as did the amount of water entering the chamber as the water was to much to burn off, plug became fouled, etc.

The upshot here is it took that block 172,000 miles to fail...

 

@Dave03S 172k is a good lifespan for a Rover block. Any keys to longevity you wish to share?

I believe the engine in my 04' is a "factory replacement" block as well. I posted on the Rover V8 appreciation page with pictures and the block number and several members said the number was in line with the blocks that were used when a motor had a cracked block under warranty. According to the PO the block was from a P38 (red block), but based on the serial number I think mine is a yellow block like yours.

 

Thanks, but that block wasn't really babied along... It was dealer serviced for the first 45k miles as I had purchased an extended warranty... The dealer put 5w30 in it that whole time before I knew any better... That's what they were putting in the new vehicles at the time. All out of one giant 55 gallon drum of oil. The camshaft wore a lobe off just after the warranty ended (of course) and that's when I started having to learn things for myself... Also the shop that fixed the camshaft turned me on the 15w40 oil... It was a few years later I discovered this forum and read about the 180 degree thermostat, etc.

So being broke in with 5w30 i suspect led to it burning 1 quart of oil every 1000 miles... (!!yes!!) The engine effectively always had fresh oil in it.

I don't know for a fact that it was a yellow block, nor do I have the number off it, but I suspect it to be the case as that is probably what was left in 2007.

No other wisdom on keeping these running other than frequent oil changes and never overheating.