rr v8 4.4 nikasil problem???? please help.

[2002hse]

Hello,
if anyone can help me with this problem I will be eternally greatful!! I have a 2002 hse 4.4 range rover, basically the coolant is pressurising I initially thought it was a head gasget( although the car is not overheating at all) but on arrival at my local land rover dealer to pick up my head gasget set, I was flippantly told that they thought it was a Nikasil problem? which has been a problem with bmw engines for a while? I have since been told that the 4.4's put into range rovers shouldn't have this problem becuase there not Nikasil coated? I am faced with a hefty bill either way but i just need some unbiased advise.

Thankyou in advance,

Anthony.
P.S. I do not want to sell this car and pass the problem onto someone else, this has been the most common answer to my problem.

[TerryS]

Firstly, do not confuse me with someone who knows anything. Secondly, assume most service techs at the dealership know less. They can expound greatly on the technical details on some service bulletin they have thus far been completely unable to understand, and the more confusing it is to them, the more an expert they seem to be.

Nikosil * a proprietary trademark, is nothing more, nothing less than a nickel/silicon alloy, flame-sprayed onto any metalic surface for wear resistance. It is no better and no worse than a dozen other alloys used in the metalizing industry, worldwide.

BMW and other manufacturers used it on both aluminum blocks, and cast iron liners, dry inserted in aluminum blocks. One thing I DO NOT KNOW, is if the BMW engine used by Land Rover had liners, or Nikosil directly applied to the aluminum block casting. What I DO KNOW is that, whether the Nikosil overlay has or hasn't broken broken down, the base metal won't be any more or any less porous than it was without an overlay. That being the case, where is the pressure coming from to pressurize your cooling system? My guess is you were on the right track when you suspected your head gaskets. Doing a hydrocarbon test (some call a block test)will deffinately tell you if the origin of the pressure is combustion gasses, but it won't rule out head gasket vs. porosity. I have a hard time believing that porosity can provide a gas path even remotely as large as a head gasket failure, but even more, porosity tends to close up as the meterial (either the block or the liner material, aluminum, or cast iron) rises in temp, but head gasket failures tend to open up as temp goes up. Sounds pretty impressive, huh? Disclaimer: refer to my opening sentence.

[frickjp]

I'm a dealer tech, so I don't know anything. Nikasil problem was an issue on early 4 litre engines in the early 90's. Problem solved by '94-'95 or so. The issue affected the top of the cylinder above the ring ridge, approx. the top 2 or 3mm. BMW blamed it on high sulfur fuels corrroding the top of the cylinder. Eventually, the corrosion would creep down to the surface the ring rides on, and compression loss would result. A rough idle was the most common symptom. Coolant loss was not. I highly doubt your issue can be blamed on an issue corrected 10 years ago. And no, RR 4.4 engines do not have liners.

[Serg]

BMW replaced a ton of Nikasil engines on mid 90's 530i and 540i's for this exact issue..

[Rovin4life]

coolant can leak from a number of places. Did you diagnosis yourself.
What do you mean pressurizing coolant.
and if it pushing coolant out then its getting air. two likely causes are water pump and headgaskets.