Diesel injector service intervals

[tdi-rick]

I'm specifically concerned with mechanical injection, not high pressure or common rail injectors.
Most diesel specialists advocate servicing/replacement every 60-100 000km, and never to exceed 100 000km.

I can understand this if performance or economy has dropped off or it's blowing black smoke, but what if the truck is literally performing better than ever at 120 000km ?

Am I really playing Russian Roulette?
Will these things just fall over and over fuel the engine ?

I've only used Diesel for the last 2.5 years, so I'm not overly experienced with compression ignition.

Any tips?

Rick

 

[FowVay]

Rick, I don't know what system you're speaking of since your name has TDI in it. TDI's are high pressure systems though not on par with the common rail systems.

Regardless of your system if you disassemble a diesel fuel injection system that is a few years old you will be amazed at how dirty the injectors will be. When you have direct injection it sticks the injector nozzle right inside of the the combustion chamber so all of the heat and soot and dirt and other nasty grimy things get blown all over the injector tip. It is for this reason that routine servicing is recommended. Normally a injector tip will be replaced at 100,000 MILE intervals (162,000KM).

This idea stems to the old IDI days when diesels were completely nasty machines. In a modern electronically controlled diesel engine that is operated on good quality fuel then injector rebuilds should only be a consideration if you're having performance problems. The most notable would be excessive exhaust emissions and poor fuel economy. Otherwise I wouldn't worry about overhauling a perfectly good system.

I have done my own little experiments with fuel additives and have noticed that using them didn't seem to make much difference with regards to nozzle cleanliness. I have a VW TDI and my neighbor also has one. I used Stanadyne additive exclusively for the first 50,000 miles and he used none. We did a comparison of the #1 injector and they looked identical. I now use a additive (SoyShield) for the reassurance that I'm helping to provide better lubrication to my injection pump but I have no evidence that this is taking place.

 

[Shannow]

rick, is that the Nissan 4.2 ?

I think that most of the rebuilders have a "do not exceed 200k km".

 

[Steve S]

tdi, all diesel fuel injectors are high pressure, what does the owners manual recommend?

 

[tdi-rick]

Thanks fella's,
Well, both our vehicles, the Nissan Patrol (4.2l turbo, indirect injection) and the Land Rover Defender (2.5l turbo, direct injection) have exceeded the 100 000km mark.

I remember seeing on a diesel parts site a massive 'WARNING' about exceeding a certain milage on injectors.
Here it is;


Fact Sheets
RECOMMENDED SERVICING - DIESEL FUEL INJECTORS



There is no hard and fast rule regarding servicing of diesel fuel injectors, due to a combination of external factors, such as:
vehicle usage ( city or country, commercial or recreational )
condition of fuel ( possible contaminated source of supply )
vehicle maintenance ( engine condition, filter and water trap maintenance)

Hiflo recommendations for diesel engines fitted with pintle type injectors :


Injectors should be replaced every 60,000 k to 70,000 k, depending on external factors.
Injectors should be replaced in ‘sets’ and not individually.
Injectors must always be serviced when the engine has been reconditioned or rebuilt. Failure to do so may void the engine reconditioner’s warranty.
Important - under no circumstances should injector life exceed 100,000 k.
It should be noted that when injectors are serviced, new nozzles must be fitted as pintle type nozzles cannot be reconditioned.

Possible signs of injectors requiring service are:

Rough idle or pronounced engine knock.
Excessive light coloured smoke on cold start.
Poor or abnormal fuel consumption.
Engine ‘miss’ under load.
Lack of performance.
Engine oil contamination. ( dilution of oil by diesel fuel )

Failure to service injectors as per hiflo recommendations can result in:

Excessive nozzle tip corrosion and erosion.
tip corrosion results from acids formed during the combustion process and tip erosion results from gas turbulence and carbon particles. Both these processes are ongoing and will result in progressive nozzle deterioration and poor engine performance. This is why injector life should never exceed a maximum of 100,000k.
Accelerated engine wear.
Premature engine failure.
Dribbling injector nozzles which cause premature combustion and high pressures, resulting in cracked pistons and cylinder heads.

Hiflo strongly recommends that you also change fuel filters and drain water sedimentors. A diesel engine requires clean good quality fuel plus regular servicing of fuel and air filters and draining of your water sedimentor. Your injectors require servicing at regular intervals.
If you follow this plan your pump should require very little service."


Any comments ?

Rick.

 

[widman]

I believe that if oil analisis shows no contamination of fuel and reasonable soot, no black smoke, and I use a diesel conditioner in EVERY tank, and my mileage is contant, why let some idiot mecanic play with the injectors?
I only have 51,000 Km on my Turbo diesel 4Runner, but 220,000 km on my 95 diesel 4Runner, 210,000 on a Mitsubishi turbo 7 ton, 400,000 km on a 1987 Nissan 3 ton truck, 200,000 km on 97 toyta pickup. All diesels, all with original injectors (although I had pumps replaced until I started useing the diesel conditioner two years ago. Not rebuilt a single pump since.