Mazda 6 and CX-5 2.2 Diesel Turbo Repair and Rebuild

This page is for owners of a Mazda 6 or CX-5 2.2 diesel, and for the garages that look after them, when the car has lost boost, gone into limp mode, started smoking or begun to whistle. It covers which of the two 2.2 engines your car has, which turbocharger comes with it, what wears, what each symptom points to, what the choices cost and how we rebuild the unit. Petrol models and the smaller Mazda diesels carry different turbochargers and are dealt with in the FAQ.

MZR-CD or SkyActiv-D? Which 2.2 Diesel You Have

The 2.2 diesels in these cars are two quite different engines, and the trade listings keep them firmly apart. The MZR-CD is the earlier engine, listed against the Mazda 3, Mazda 6 and CX-7 with a single IHI turbocharger. The SkyActiv-D is listed against the Mazda 3, Mazda 6 and CX-5 from 2012, under the engine codes SH01, SHY1, SHY4, SHY6 and SHY8, with a two-stage turbocharger assembly.

Look at which cars sit on which side. The CX-5 appears only on the SkyActiv-D side, and the CX-7 only on the MZR-CD side. The Mazda 6 appears on both, and so does the Mazda 3. If you drive a CX-5 2.2 diesel, the engine question is already answered and you can move on to the next section. If you drive a Mazda 6, it is the first thing to settle.

Why the power output will not settle it

On many diesels, the output shown in kilowatts at section P.2 of the V5C narrows the turbocharger down to one or two candidates. On the Mazda 2.2 it does not. The MZR-CD’s single-turbo listing covers 150 to 180 hp. The SkyActiv-D is listed at 150 and 175 hp in one catalogue and across 150 to 188 hp in another.

Both engines are listed at 150 hp, and their upper outputs overlap as well. A Mazda 6 2.2 diesel at 150 hp could therefore be either engine, with either turbocharger arrangement, and the logbook figure is no help in choosing between them.

What does settle it

• The build year, as a first filter. The SkyActiv-D listings start in 2012. A Mazda 6 2.2 diesel built before then falls outside them. For later cars, use one of the checks below.
• The number of turbochargers. The MZR-CD carries one. The SkyActiv-D carries a two-stage assembly, two turbochargers built together and sold as one part. Once the unit is off the car, the difference is unmistakable.
• The Mazda number on the label. The MZR-CD unit that is listed with its Mazda number carries R2BH13700. The SkyActiv-D listings give SH0113700A, SH0113700B and SH0113700C, which open with the same two letters as the SkyActiv-D engine codes.
• The engine code. If a service record or parts receipt gives it, an SH code puts the car on the SkyActiv-D side.

If none of these is to hand, send the unit as it came off the car. Identification is the first thing that happens to it on our bench, before anything is dismantled or priced.

The Two-Stage Turbo on the SkyActiv-D

On the SkyActiv-D, the turbocharger is an assembly of two. Trade listings describe it as a twin turbo or bi-turbo and sell it as a single part: one catalogue lists it under 810356, 810357 and 810358 references with suffixes from -0001 to -0003, and another lists 810358-0003 for Mazda 3, Mazda 6 and CX-5 applications from 150 to 188 hp.

Two-stage layouts in general pair a smaller turbocharger, which responds quickly at low engine speeds, with a larger one that supplies the flow higher up the rev range, and use control hardware to share the exhaust between them. The listings for this engine do not break the assembly down stage by stage, so we do not publish stage sizes, valve arrangements or which reference belongs to which stage. You do not need any of that to get the unit repaired.

What you do need to know is that each stage is a turbocharger in its own right, with its own shaft, wheels, bearings and seals, and it wears as one. One stage can be worn while the other still measures within limits. That is why we ask for the assembly to be sent as it came off the car, with both stages together: each is measured separately, and you hear which of them needs the work before anything is priced.

The layout also changes what a boost fault means. With two turbochargers and the hardware that shares the work between them, there are more places for boost to go missing than on a single-turbo car, and a fault in that hardware can cost boost while both rotating assemblies are perfectly healthy. A rebuild covers the whole assembly, not just the stage that failed first.

What Fails on Mazda 2.2 Diesel Turbochargers

The MZR-CD’s single IHI unit and each stage of the SkyActiv-D assembly are built around the same core. A compressor wheel and a turbine wheel sit on one shaft, which turns in oil-fed bearings inside a centre housing, with a sealing ring at each end. The ways that core wears are the same on both engines; the SkyActiv-D simply has two of them.

• Bearings and thrust faces. Low oil pressure, a restricted feed or oil left in too long wears them first. Radial play lets the wheels move towards their housings, end float lets the shaft shift along its length, and either one left running ends with a wheel touching its housing.
• Sealing rings. Once the shaft moves more than it should, the rings stop keeping oil inside the centre housing, and it passes into the intake or the exhaust.
• Variable vanes on the MZR-CD. The VJ41 listing describes a variable-geometry turbocharger. When carbon builds up on the vane ring, boost arrives late, erratically or not at all while the rotating assembly is still sound. Our Garrett GT2052V turbo repair page explains how a vane mechanism works and fails; that is a Garrett unit, not the IHI turbocharger on your Mazda, but the principle is the same.
• Boost control. Whatever moves the vanes on the MZR-CD, or shares the work between the stages on the SkyActiv-D, can fail without the turbocharger itself being worn. That is a separate diagnosis, covered in the cost section below.
• Wheel damage. Grit or debris reaching the compressor, or fragments reaching the turbine, chips and bends blades. A damaged wheel is renewed, never straightened.

Most of these failures begin on the car rather than inside the turbocharger: a carboned or cracked oil feed pipe, a return line that drains slowly, a split intake hose that lets grit reach the compressor, or oil changes stretched too far. A rebuild renews what wore. It cannot correct the cause, and a cause left on the car will wear the rebuilt unit in exactly the same way.

Symptoms, and What Each One Narrows Down

No single symptom condemns the turbocharger. Each one narrows the list of suspects, and some point away from the turbo altogether, so it is worth knowing which list you are looking at before anything is unbolted.

• Limp mode, often with P0299 or P0234 stored. This narrows the fault to the boost control loop: the charge pipes, the vane mechanism or the hardware between the stages, whatever moves it, the pressure sensor and the turbocharger. It does not name one of them. If switching off and restarting clears it for a while, the mechanism or its control is a stronger suspect than a worn rotating assembly. Our guide to turbo overboost and underboost codes explains what the two codes can and cannot tell you.
• Boost that goes missing in one part of the rev range. On the SkyActiv-D, note where it happens. With two stages sharing the work, the engine speed at which the pull fades is useful evidence for the bench, although it does not name a stage on its own.
• A whistle or siren that rises with boost. This points at the pressurised path or the rotating assembly: a leaking hose or joint, or bearing wear letting a wheel run out of true. Our guide to diagnosing a turbo whistle separates the noises that come from the unit from those that do not.
• Black smoke under acceleration. The engine is getting too little air for the fuel it is given. That narrows the fault to air supply, a boost leak, sticking vanes or a restricted intake, before a failed turbocharger.
• Blue or grey smoke, or oil use climbing between services. Oil is getting where it should not, often past worn sealing rings. Oil carried over from the crankcase ventilation system can look the same, so rule that out before the turbocharger comes off.

Two cheaper faults imitate turbocharger failure often enough to check first. A split charge hose or a leaking intercooler joint can stay closed at idle and open only under boost, so a loaded road test tells you more than a look under the bonnet. A blocked air filter or intake starves the compressor and can produce the same loss of pull and black smoke as a tired turbocharger.

Once the noise turns metallic or oil smoke is visible, stop driving the car hard. Every loaded mile after that point moves more of the unit from the rebuild column towards the replacement column. Our guide to turbo failure symptoms sorts the signs by where in the unit they start.

Rebuild Your Own Turbo or Fit a Replacement?

On a CX-5, this is a question of cost and condition. On a Mazda 6 it is also a question of identification, because a replacement is ordered by part number, and a part ordered for the wrong one of two engines is the wrong part however good it is.

• What has to be matched. A new or exchange unit has to be the right VJ reference on the MZR-CD, or the right two-stage assembly on the SkyActiv-D. A rebuild returns the unit that came off your car, so there is nothing to match.
• How exchange units are sold. Remanufactured units are often sold on an exchange basis, with a surcharge held until your old turbocharger is returned. The unit you send back is the one that failed, so its identity has to be right twice over.
• How much of the unit survived. When the turbine wheel, shaft and a housing have all failed inspection, little of the original is left to rebuild. In that case a replacement is often the better value, and we tell you so rather than rebuild a unit that should be replaced.
• On the SkyActiv-D, one stage or both. If one stage has worn and the other measures within limits, the work and the price reflect that.
• Whether the cause has been found. A restricted oil feed or a split intake hose will wear a new turbocharger as surely as a rebuilt one.

What a Mazda 6 or CX-5 turbo replacement costs

Rebuilding your own Mazda turbocharger starts from £185 + VAT. Replacement turbochargers from us start from £450. Neither figure includes removing and refitting the unit, which is the same job on the car whichever route you take.

The rebuild price is confirmed once the unit has been stripped and measured, because it depends on how much of it is still within specification. Bearings, thrust parts and sealing rings are renewed on every rebuild; a damaged wheel, a worn shaft or a cracked housing adds to the work. On the SkyActiv-D, the price also depends on whether one stage or both need rebuilding. What moves a rebuild up its range is set out in our guide to turbo repair prices.

Sometimes the turbocharger is sound and the fault lies in the part that controls it. If your unit carries an electronic actuator and the fault proves to be there, electronic actuator repairs start from £100 + VAT, and our electronic turbo actuator repairs page explains that service.

Our Mazda Turbo Rebuild

You, or the garage that looks after the car, remove the turbocharger and send it to us at Unit 102 Reaver House, 12 East Street, Epsom, Surrey, KT17 1HX, United Kingdom. Independent garages and main dealers send units in for their customers’ cars in the same way. Our turbocharger rebuild service runs in this order.

1. Complete the online Repair Form. Give the registration, the model and build year, the engine code if you have it, the power output from the V5C, the mileage, the symptoms and any fault codes. Copy every number from the turbocharger’s label, and on a SkyActiv-D, from every label on the assembly.
2. Remove and pack the unit. Cover every port so nothing can get in, and pack the unit so it cannot move in the box. Send a two-stage assembly whole. Our guide to removing, refitting and priming a turbocharger covers the work on the car, and packing and postage are on our FAQs page.
3. Identification and strip. The unit is identified from its label, or on the bench where the label is unreadable, and on a Mazda 6 we confirm which engine it came from. It is then stripped to component level by turbo specialists who rebuild turbochargers and turbo actuators as their core work.
4. Measurement and renewal. Shafts, wheels, bearing bores and housings are cleaned and measured against original specification, stage by stage on a two-stage assembly. Bearings, thrust parts and sealing rings are renewed with genuine OE or OEM-grade components that meet or exceed the original, and a part with a known design weakness is uprated rather than put back.
5. Boost control. The vane mechanism on the MZR-CD, or the control hardware between the stages on the SkyActiv-D, is cleaned and freed where sound and renewed where worn, so boost control moves as designed.
6. Balanced, bench-tested and returned. Each rotating assembly is balanced, and the unit is set up and run on the bench before it is boxed and sent back, ready to refit.

Bench time is typically one to three working days from arrival, with postage each way on top. Every rebuild carries a lifetime, unlimited-mileage warranty, with no time limit and no mileage cap. When the unit goes back on, renew the oil feed and return lines rather than reusing them, and prime the oil feed before the engine first runs, so the renewed bearings never turn dry.

Mazda 6 and CX-5 Turbo FAQ

Final Thoughts

A CX-5 owner starts this job with one fewer question than a Mazda 6 owner. The CX-5 2.2 diesel is only ever listed with the SkyActiv-D and its two-stage assembly; the Mazda 6 shares that engine with the older MZR-CD, and at 150 hp the two cannot be told apart from the logbook. Everything that follows, from what to order to what to send, depends on getting that one fact right.

It is a fact the car will give you if you look: one turbocharger or two, and the letters on the Mazda number. Settle it before you buy anything, find out why the unit wore before another goes on, and if you send the turbocharger itself, the question is answered on the bench rather than guessed at from a catalogue.