Biodiesel?

[GaryM]

Yes I know this is strictly in the wrong section but is kind of a general question anyhow. Original post here

 

Have a MKIII 1.8 diesel and was wondering is anyone is running thiers on biofuel? The owners guide suggests that a 5% mix is as far as you can go with this which is what tescos sell anyway, I think. The handbook covers this with what seems to be more of a generic "we can't be bothererd" statement rather than there being specific reasons.

 

I'm guessing the MKII's are fine on the stuff as the engines are based on VW\Audi lumps and the Germans normally rate thier kit on this stuff. MKIII are based on Ford's own engines aren't they?

 

With the increasing fuel & tax costs biodiesel is looking more attractive evrey day. In fact if you belive the blurb it is better for you motor anyway. I know that I'd have to change the fuel filter after switch over but wondered if there were specific reasons that a 1.8 would not run with it?

[Willie Krashitt]

I wouldn't. I have seen the damage that high concentrations of Bio can do to the HP fuel pump of common rail injection systems. Failure mode is well known, and would possibly be a reason for rejecting a warranty repair, leaving the costs down to you. (pump is around

[GaryM]

Thanks for the update obviously this may well get technical and down to specific engine configurations. I'm not mechanic but looking under the bonnet of the 1.8 the engine looks more agricultural than others I ones I have seen.

 

I'd guess the guess the score with the Merc is simply down to low temperatures. Even diesel gels just not a soon a BD. In the winter months thing most people use a BD / Straight Diesel mix.

 

As for the type of fuel dare I say it I'm contemplating DIY :huh: . The drive is high mileages, cheap fuel costs, minimal or no fuel duty. I know this is not going to be clear cut and a risk on my part but just thought I sound people out independently of the Bio-diesel forums.

[Willie Krashitt]

The engine may well look agricultural, but the parts that are affected are the injection system components, and these are anything but! Common rail systems are engineered with incredibly fine tolerances, much closer than diesel fuel pumps of old. The clean assembly hall in Dagenham would amaze you.

The CR high pressure pump and injectors, whilst being specific to the 1.8L engine, are made in the same factories (and with the same materials and tolerances) that supply most car companies, from Audi to Volvo, and I think you will find that very few will warrant their systems with more than B10 (10% bio) at the moment.

 

THe only people who are saying it is better for your engine are those who have something to gain from you using it, and it isn't the manufacturers of the cars.

 

As I said, it is your call, but when you offset the cost of the injection system versus what you might save in pence per mile, then running high levels of bio in a CR engine just isn't worth the risk.

 

The Mercedes experience I referred to earlier wasn't due to fuel waxing that occurs in the cold - it was due to the fuel degrading after it had got hot and pressurised.

 

George.