079127026C Right High Pressure Fuel Pump for Audi VW 4.2 V8

The application we stand behind is the 4.2 litre V8 FSI petrol engine in the 4163 cc configuration, across the Audi and Volkswagen models that use it — the 4.2 FSI quattro applications on the Audi side and the 4.2 V8 FSI on the Volkswagen side, and two things carry that application: the cast number on the body of your own unit, and the side it came off. We deliberately do not extend that to a model year range, because the sources we can cite overlap and contradict each other on exactly that point and a value we cannot stand behind twice is worse than no value at all. That is the petrol high pressure pump this engine was built with, and an order that starts from the pump coming off is the one that arrives correct.

Two more identifiers worth having. If the vehicle is still with the customer, the vehicle identification data on the registration document and on the windscreen settles the engine variant faster than any chart, and the engine code on the plate settles which build the vehicle left the factory as. Where the pump is already off the engine, a photograph of the engine code plate and a photograph of the cast number on the pump settle it instead. Any one of those three alongside the engraving is enough for us to confirm in writing; all of them together is what stops a number-range mix-up reaching your workshop.

Why the cast number matters more than the number range. The family this number belongs to carries many suffixed members, and the published sources place different suffixes on different engines and on different sides. That is the clearest possible demonstration that a number-range search is not a fitment check: two suffixes in one family can be a right-hand pump and a left-hand pump of the same engine, and they are not interchangeable in position. The casting tells you which one you are holding. Match it, confirm the side, and order.

What this page is not claiming. We are not saying that another suffixed member of the family fits your engine, that the left-hand pump is included in this line, that the companion seal ships in the box, or that a pump from a different family substitutes. 079.127.026C describes one unit in one position, and the casting on your own pump is what identifies it. Anything beyond those lines is better answered from your own parts data, and we would rather answer it with you than assert it here.

On a petrol direct injection engine the fuel system is split into a low pressure side and a high pressure side. A lift pump in the tank pushes fuel forward at low pressure. The high pressure fuel pump is what comes next, and it decides everything after that point: it raises the fuel to the pressure the rail needs, and the rail feeds the injectors on that bank of the engine. On a V8 petrol engine there are two banks, and on the 4.2 FSI each bank has its own pump. That single fact runs through this entire page, because it decides how many parts the job needs and what else has to be changed while the engine is open.

The second thing worth holding on to is the number itself. It is written in the vehicle group form as 079 127 026 C, and the body in the photographs is cast with the same digits in a three group form, 079.127.026C. That is not a coincidence of formatting; it is the reason a cast number is the most reliable identifier on a part like this. Listings get copied, numbers get transcribed, and a listing that concatenates a pump with a valve and three other makes is exactly the kind of record where the number on the page and the number on the metal drift apart. The metal is the one that settles it.

A V8 splits into two banks of four cylinders, and it is worth saying plainly that the engine runs on four strokes while the fuel system around it does not care which stroke the piston is on. The third thing is the failure mode, and on this engine it is unusual enough to change how you plan the job. The reported failure is an internal seal letting fuel out of the high pressure side and into the crankcase, rather than a pump that simply stops delivering. Fuel in the oil is what turns a pump replacement into an engine repair, because the oil is what the bearings run on. That is why the published guidance on this application is to replace both pumps and change the oil and the oil filter in the same visit, and why the symptoms section below spends more space on the oil than most pump pages do.

What the photographs show is the unit as it comes off the shelf line for this number: a cast body, a spring-loaded plunger assembly in a machined bore, a two-pin electrical connector on the body, a brass male thread port and a brass push-fit hose tail, and a cast mounting base. What we will not claim is what is inside it. No source we can stand behind publishes whether the internal oil and seal set is assembled before dispatch for this number, so that is confirmed against the packing list rather than asserted here, and it is listed as not published in the specifications table below rather than quietly assumed.

Where our supply differs is what arrives rather than how the part works. Original equipment supply comes through the manufacturer’s own channels, and a buyer whose paperwork requires a factory boxed part does need to go there. What we supply is a high pressure pump replacement — a new compatible unit for the same job, sold under the Vidishi Auto brand, cast with the same number, at a five-piece minimum with no core return. That last point matters on this job more than on a routine injector change: nothing has to come back, there is no exchange loop to manage, and the removed pump stays with you for the warranty file.

One thing we do not do is dress that up. The 079127026C pump we ship is ours, not a manufacturer’s and not a vehicle maker’s. The part numbers, the reference series and the vehicle group form appear on this page so you can match the pump you are replacing. They are references for fitment and for searching, not a claim about who made the part. Any origin information associated with a reference unit describes that reference unit rather than the goods we supply, which is why no country of manufacture is claimed anywhere above. The buying guides hold the general method for confirming any fuel system part from the unit itself, and the glossary explains the terminology if any of the names above are unfamiliar.

How we label data. Confirmed means a value read directly from the goods we handle, including the number cast into the body and the connector and ports visible in the photography. Reference means a part number, a family designation or a cross reference quoted so your paperwork can be matched, and carrying no claim about origin. Not published means the field is left blank on purpose — a pressure figure, a component number or a fitment list that we cannot source would be worse than an empty cell, because it would end up in somebody’s parts order or somebody’s engine settings.

What is in the box. One right-side high pressure fuel pump: the cast body with its spring-loaded plunger assembly, the two-pin electrical connector, the brass male thread port and the brass push-fit hose tail, and the cast mounting base, as photographed. The companion seal 03H127307A, the left-hand pump, the engine oil and the engine oil filter are not in this line and are named on this page so the whole job can be planned before the vehicle goes onto the ramp. Whether the pump is supplied with its internal oil and seal set assembled is confirmed against the packing list rather than claimed here.

Read the table from the top, because the order matters. The first three rows are the same number written three ways, and all three are the strongest identifiers on the page: the supplier number, the vehicle group form, and the engraving actually on the flank of the body you can see in the photograph. Used as a 079127026c cross reference map, the table settles the part before it settles the price. If those three agree with your own unit, the part is identified. The row that would identify it wrongly is a number that came from a listing rather than from the metal, which is the failure this page is built to prevent.

The HFS853104D row and the four rows beneath it are there for identification the way a catalogue reference is on any parts entry, and they are worth reading with care. They tell a parts clerk which published numbers resolve to this unit, which matters because your own paperwork may carry the reference series rather than the vehicle group form, and a search box that only knows one of the two will tell you the part does not exist. They are not a statement that the unit in our box was made by that manufacturer, because it was not, and the difference matters both legally and practically when a warranty claim has to be settled.

The two rows for the left-hand pump are the half of the mapping that stops people over-reaching, and they are here for a reason. On this engine the two sides are separate units under separate numbers, and the published fitting position for this number is the right-hand side. Quoting the left-hand number where the right-hand unit belongs is not a near miss that a fitter catches at the bench; on a V8 it is a job that comes apart again. That is why both numbers sit in the same table with their positions written next to them.

What the table deliberately does not do is extend itself. It does not say that another suffixed member of the family fits your engine, that the companion seal is in the box, or that a unit from a different family substitutes. The family this number belongs to carries many suffixes, and the published sources place different suffixes on different engines and different sides of the same engine, so reprinting the rest of the family as fitments would be inventing fitments. Those are exactly the assumptions that turn a cheap order into a second removal, and we would rather leave the cells empty than fill them with a guess. Our comparison charts set out the number families we can evidence, and the buying guides cover the general method for confirming any fuel system part from the unit itself.

The practical difference shows up on the second bank. When one side of this engine has failed internally and the other is close behind, the choice is between replacing one pump and finding the second one weeping a month later, or replacing both while the engine is open. Keeping a matched spare on the shelf — correct cast number, correct side — turns a two-visit repair into a single-visit one. That is the case for stocking this line rather than ordering against each failure, and it is why the minimum on this page is a stocking quantity rather than a single unit.

• A rich mixture code on one or both banks — The published failure mode on this engine is an internal seal letting fuel into the crankcase rather than the pump simply ceasing. That reads as a rich code on a bank, and the giveaway is the oil, not the code.
• Fuel odour at the oil filler — Where the leak is internal, the fuel reaches the oil. Smell at the filler cap and an oil level that has risen are the two checks that separate an internal pump failure from a metering or injector fault.
• Hard starting that is worse when warm — A hot-soaked engine that cranks long and catches reluctantly is a common companion on this application, and it is worth reading alongside the oil check rather than on its own.
• Misfires that follow load — A bank running rich loses combustion stability as the engine is worked, so the misfire count rises with demand rather than sitting constant at idle.
• Long-term fuel trim pushed negative — The control unit trimming fuel hard to correct a mixture that is already too rich is a strong indication that the fault is upstream of the injector, in the high pressure side.
• A pressure-related fault code on the rail — A code reporting fuel rail pressure below target belongs on the list. Read the scan data against target rather than the code name, because a code names a circuit and not always a part.
• Visible fuel at the seal face or the port joint — Weeping at the mounting face or at a port joint after a joint has been opened is a fitting symptom, and it is the one on this list that a new seal and a clean face will actually fix.
• An oil level that climbs between services — On this engine that is the single most important line on the list. If the level rises, stop driving it and check the oil before anything else, because the fuel in the oil is what turns a pump replacement into an engine repair.

The pattern worth holding on to is the one that arrives with the oil. A high pressure fuel pump on this application does not usually fail by stopping; it fails by letting fuel past an internal seal into the crankcase. That is why fuel odour at the filler and a rising oil level sit at the top of this list rather than a warning light, and it is why the oil is the first thing to check on this engine rather than the last. Our fault code guide explains how to read the data behind a code, and we would rather see your scan data and an oil reading than our guess at either.

The second pattern is about the bank rather than the part, and it changes what you do next. Because the engine has one pump per bank, a fault on one side shows up on the cylinders fed by that side and leaves the other bank steady. That single distinction does more diagnostic work on this engine than any code name, and it is what tells you whether you are replacing one pump or two. A rich code and a rich mixture on both banks at once is a different conversation from the same code on one bank, and treating them the same is how a second visit happens.

• Step 1. Read and record the cast number before anything is unbolted
  Photograph the engraved number on the flank and write it down. On this application that number is the whole identification, and it is the one thing you cannot recover once the old unit is in a bin.
• Step 2. Decide whether this is a one-bank or a two-bank job
  The 4.2 V8 carries one pump per bank. If the engine has any sign of fuel in the oil, the answer is both sides, and that decision belongs before the first bolt is turned rather than after the second bank is found to be weeping as well.
• Step 3. Drain, depressurise and mark the drive position
  Let the engine stand, release residual pressure, and before anything is unbolted mark the position of the pump against its mounting face. The mark is the only thing that guarantees the new unit goes back on the same position.
• Step 4. Clean around the pump and the port faces before opening anything
  Wash down, blow the mounting face and both port faces clean, and only then release the bolts. Grit that lands on a machined surface ends up between the two faces and the new pump will weep from its first minute.
• Step 5. Unbolt evenly and support the body
  Work the bolts in sequence rather than freeing one corner at a time, and support the casting as the last one comes out. A body that drops onto its fitting is how a good replacement turns into a second job.
• Step 6. Fit the companion seal rather than reusing the old one
  Three independent listings name 03H127307A as an article required in addition to the pump. A fresh seal under the refitted pump is the cheapest part of the job and the one most often reused by mistake.
• Step 7. Refit square and torque to the engine figure
  Drop the unit into the marked position, bring the mount up evenly and torque to the figure for your engine. The figure belongs to the engine, not to the part, and we do not publish it for this number.
• Step 8. If the old pump leaked internally, change the oil and the filter in the same visit
  On this engine the published failure mode puts fuel in the crankcase. New pump, new seal, fresh oil and a fresh oil filter in one visit is the repair; a new pump on old oil leaves the damage the old pump already did in place. Prime and verify fuel pressure against target at idle and under load before the vehicle goes back to work.

Two notes on what we deliberately do not print. We do not publish the tightening figure for the mount, the delivery pressure, or the drive phasing, because all three belong to the engine application rather than to the part, and a figure copied from a product page into a workshop manual is how a good pump gets damaged on a correct fit. Take them from the engine manual for the vehicle in front of you. And we do not publish a torque figure as a shortcut, because the mount and the two port joints each have their own value and they are not interchangeable. The installation guide covers the surrounding routine, and the glossary defines the terms if any of the above are new to you.

Every 079127026C pump is covered by a 12-month warranty against manufacturing defects. That covers a unit that arrives out of specification or fails early because of how it was made. It does not cover damage from contaminated fuel, from a filter changed too late, from incorrect fitting, from a drive coupling torqued beyond its figure, or from a separate fault elsewhere in the fuel circuit. It does not extend to labour, to the engine oil or to the vehicle. It is a supplier warranty from Vidishi Auto and it is not a Hitachi warranty and not an Audi or Volkswagen warranty — we are not a dealer for any of the equipment makers and no cover from any of them travels with this part.

The one question we ask about every time is whether the engine oil was changed when the old pump came out, because on this application that is the single most common reason a replacement is followed by a second visit. An internal seal failure puts fuel in the oil, and a new pump on old oil leaves in place the damage the old one already did. Tell us what was done and we can tell you quickly whether a claim is likely to stand. If you would rather settle that question before you order, the contact page is the fastest route to a written answer.

The minimum order quantity is 5 pieces, and the reasoning is worth stating rather than leaving you to work out. A pump on this engine is not bought against a breakdown on one vehicle; it is bought against a fleet of V8 petrol cars where the same unit fits every one of them, and where the second bank is usually close behind the first. Five pieces covers a workshop with a shelf spare for each side, and a distributor can hold the right-hand unit, the left-hand unit and the companion seal as a standing trio. From there the line scales normally, and mixed fuel system orders travel on the same export paperwork.

What we do not do on this line is pretend the part is something it is not. The unit we ship is a new compatible replacement sold under the Vidishi Auto brand. It is not Hitachi-branded, it is not Audi-branded or Volkswagen-branded, and it is not a factory boxed original. That matters commercially as well as legally: if your incoming goods inspection needs a specific brand on the paperwork, this is not that product, and we would rather tell you now than have a delivery rejected. The help centre covers ordering and documentation questions.

The package size and gross weight in that table are a packing estimate, and we label it that way rather than quietly presenting it as a specification. No source we can stand behind publishes a packaged figure for this number, so we give you a figure we can pack and weigh against rather than a manufacturer specification we cannot evidence. If your freight is calculated on volumetric weight rather than actual weight, tell us the destination and we will confirm the chargeable weight against the carton we actually use. The shipping page sets out the full documentation and delivery terms, and the order tracking page is where to follow a shipment once it has left.

On the protective side, the two areas we watch are the electrical connector and the machined port faces on the body. A connector pin knocked out of alignment is a fault that looks like an electrical problem for weeks afterwards, and grit on a sealing face is a weep that gets blamed on the new unit. Both are packed protected on every pump, and both are worth checking on arrival before the box goes into stores.

A high pressure pump for a V8 petrol engine is a compact precision casting with a running surface inside it, so this line is checked at unit level rather than by sample. Every batch passes an incoming check for the number cast into the flank, a check that the spring-loaded plunger assembly moves freely in its machined bore, a confirm that the two-pin connector and both brass ports are present, undamaged and capped, a check that the port faces and the mounting face are clean and free of obstruction, and a packed-weight confirmation against the documented figure. The supplier shows an ISO 9001 system certification badge on the product photography, which we record as a supplier statement rather than as a certificate we issue.

Rather than publish reviews we cannot verify, we tell you what we will actually put in writing: a written fitment confirmation against the cast number you send us, a written quote against your quantity and destination, and a warranty position on any claim that follows. If you need a supplier who will sign a specific inspection or conformance document with the order, ask before you buy rather than after, because the answer depends on what the document is. The help centre covers the documentation we can provide, and the partner programme page is the route for a standing arrangement that needs more than a one-off order.

Support is not an add-on on this line — it is how most of these orders get placed correctly. It costs nothing before you buy: send the number cast into the flank of the unit you are removing, which bank it came off, the engine code and the vehicle details, and we check the whole set against what we supply before quoting. That last item is the one people skip, and it is the one that matters most here, because the number family this part belongs to carries many suffixed members that the published sources place on different engines and different sides. Two minutes with a photograph of the casting in front of you is cheaper than a pump that arrives and does not settle the fault.

Two things we will not do, whatever the order size. We will not quote a fitment we cannot evidence, and we will not ship a pump matched on a number range when the casting on the old unit is available. If that costs us an order, it is still the right call: a high pressure pump that arrives mismatched costs a workshop a second removal, and that is the failure we exist to prevent. If anything on this page is unclear, the contact page lists every route to us, and a written answer is always better than a guess on a workshop schedule.