Stainless steel sleeve for marine turbos
Marine turbochargers are exposed to salt air and corrosive exhaust gases. A stainless steel sleeve in acid-resistant steel replaces the inner surface of the turbine housing and stops the corrosion at its source. We recondition Volvo Penta, Yanmar and other marine diesels with a stainless sleeve, new bearings and documented balancing.
Why do marine turbos corrode?
The exhaust side of a marine turbo meets oxygen, salt and water vapour at 600 to 800 degrees. The cast iron in the turbine housing oxidises from the inside out. When the rust flakes off, a gap opens up between the turbine wheel and the housing wall. Boost pressure drops, the engine feels sluggish, and in the worst case the shaft seizes.
Corrosion in the turbine housing is the single most common cause of failure on marine turbos. Standard cast iron simply is not up to long-term running in a saltwater environment.
What is a stainless steel sleeve?
A stainless steel sleeve is a CNC-machined cylinder in acid-resistant stainless steel (type 2348 / 1.4404) fitted inside the turbine housing. The sleeve replaces the inner surface that would otherwise corrode and builds up a layer that no longer rusts.
Acid-resistant stainless steel 2348 / 1.4404
The same material class used in the chemical industry. It does not corrode in a saltwater environment.
CNC-machined for dimensional precision
The sleeve is fitted with the correct clearance to the outer radius of the turbine wheel.
Preserved gas flow
The original radius and flow geometry are retained. Better turbo response and faster planing.
A one-off cost against future corrosion
Once the corrosion problem is gone, there is no reason to replace the housing again.
Volvo Penta models we recondition
Most marine Volvo Penta diesels use a K26 or similar turbocharger from BorgWarner/KKK. Among others, we recondition:
- Volvo Penta 2003T
- Volvo Penta AD31
- Volvo Penta AD41
- Volvo Penta KAD32
- Volvo Penta KAD42
- Volvo Penta KAD43
- Volvo Penta KAD44
- Volvo Penta KAD300
- Volvo Penta TAMD31
- Volvo Penta TAMD40
- Volvo Penta TAMD41
- Volvo Penta AQAD40
- Volvo Penta AQAD41
- Volvo Penta AQD40
- Volvo Penta D3
- Volvo Penta D4
- Volvo Penta D6
Other makes we accept
- Yanmar 4LH-STE
- Yanmar 4JH, 6LP, 6LY
- Mercury, MerCruiser
- Yamaha, Honda Marine, Suzuki
- Perkins marine
- Caterpillar marine
Not sure which turbo is fitted to your boat engine? Send the engine number and photos and we will identify it.
What is included in the reconditioning?
Stripping and cleaning
The unit is fully disassembled. Every component is ultrasonically cleaned.
Inspection of the turbine housing
We measure the corrosion damage and assess whether a sleeve is needed or a standard reconditioning is enough.
Fitting the stainless steel sleeve
The acid-resistant sleeve is fitted with the correct clearance to the outer radius of the turbine wheel.
New bearings and seals
Thrust bearings, journal bearings and oil seals are replaced with OEM quality.
Balancing
The rotating assembly is balanced in a VSR machine at over 100,000 rpm.
Wastegate calibration and function test
The valve is set to the manufacturer's boost pressure specification. Final inspection before delivery.
All the work is done in our Tyresö workshop. You receive a diagnostic report documenting the condition and what was addressed, plus a 12-month warranty.
Reconditioning versus a new turbo
A complete new unit for a Volvo Penta KAD44 often costs 20,000 to 35,000 SEK. A reconditioning with a stainless sleeve typically lands well below that, and you get back the same unit that was in the boat, with documented balancing.
If you are thinking long term, the sleeve is a one-off investment. Once the corrosion problem is gone, there is no reason to replace the housing again. The price is given after inspection of the unit. Request a quote with the engine number and a description of the problem.
Frequently asked questions about the stainless sleeve
Corrosion in your marine turbo?
Describe the symptoms and send the engine number. We reply within 24 hours. Quote after inspection.
Engines whose turbos we often recondition
Turbocharged platforms we see often. Read the guide for your engine - common faults, specifications and prices.