Thread: 2010 discovery 4 TDv6 reduced performance error

Originally Posted by BradC

If you are not mechanical I'd suggest letting your mechanic source the fuel pump and associate parts. Nothing worse than being asked to fit customer supplied parts and getting into an argument later about warranty.

I bought a new one from United and fitted it myself. By the time I bought the pump, the associated high pressure lines, a new belt & tensioner and the single-use bolts I was up for just north of $1700 from memory. There's a thread here somewhere with the details. The job took me ~9.5 hours, but I'm a Landrover novice.

Honestly, based on the symptoms it's the most likely culprit. Look on the bright side. You have new injectors. As an aside, what did that set you back?

When you changed the HPFP can you remember if the shaft seal was Viton (orangery/light brown colour) or black rubber? Mine seems to have a fuel leak on the back of the engine and an injector expert thought the seal might be rubber which is no good for biodiesel. I doubt it is rubber, as I've run bio in it for ten years now.

I'm afraid I don't recall the seal colour. I have the old pump buried in the garage somewhere, but that'd take the assistance of an archeologist to locate right now.

Originally Posted by RANDLOVER

When you changed the HPFP can you remember if the shaft seal was Viton (orangery/light brown colour) or black rubber? Mine seems to have a fuel leak on the back of the engine and an injector expert thought the seal might be rubber which is no good for biodiesel. I doubt it is rubber, as I've run bio in it for ten years now.

Viton in its natural state is black, so not an indicator…

Originally Posted by Tombie

Viton in its natural state is black, so not an indicator…

Be careful with Viton seals, O rings etc. The better quality manufacturers colour their Viton seals brown to separate them from cheaper seal manufacturers because Viton has the unpleasant property of emitting Fluorine gas (deadly) when heated via an open flame. Be warned gentlemen.

Originally Posted by Chris D

Be careful with Viton seals, O rings etc. The better quality manufacturers colour their Viton seals brown to separate them from cheaper seal manufacturers because Viton has the unpleasant property of emitting Fluorine gas (deadly) when heated via an open flame. Be warned gentlemen.

Not true regarding quality manufacturers.

One of the highest approved manufacturers (mil spec, mil contracts, NASA supplier etc) makes theirs in pure FKM and doesn’t add colour.

It’s not gas that is harmful either, it’s Hydrofluoric Acid created by intense heat as it breaks down.

Originally Posted by Tombie

Not true regarding quality manufacturers.

One of the highest approved manufacturers (mil spec, mil contracts, NASA supplier etc) makes theirs in pure FKM and doesn’t add colour.

It’s not gas that is harmful either, it’s Hydrofluoric Acid created by intense heat as it breaks down.

Thanks for the correction. I should have said Hydrofluoric Acid in its steam phase, I guess it can be called a gas but either way its deadly.
In regards the MILspec seals not being coloured red or dark brown we need to keep in mind that the good old US of A tend to do this to mislead anyone pinching their IP. That was my experience at CR anyway.

As background, the name Viton covers that family of elastomers comprising copolymers of terpolymers of tetrafluoroethylene (TFE), hexafluoropropylene (HFP) and vinylidene fluoride (VDF or VF2), vinylidene fluoride (VDF) and hexafluoropropylene (HFP) as well as perfluoromethylvinylether (PMVE) containing specialty polymers. Viton first came out of DuPont who were the first to market this family of materials, so Viton has become the most commonly associated name with this fluoropolymer family.
There are four families of Viton polymers and the fluorine content of these most popular Viton grades varies between 66 and 70%. The main grades are A (Dipolymers of VF2/HFP), which has a fluorine content of 66%; B (Terpolymers of VF2/HFP/TFE),which commonly used for seals or gaskets and contains 68% fluorine; F (Terpolymers of VF2/HFP/TFE), which is used in oxygenated automotive fuels and has 70% fluorine content; and finally specialty types (such as GLT, GBLT, GFLT& Viton Extreme), which are used in automotive and oil exploration applications. The FKM you mention is a similar material but from a different manufacturer (German I think) and is used in the same applications. The most common application being windscreen wiper blades. An excellent material too.
Cheers