A turbo rebuild means taking the turbocharger apart, cleaning every part, renewing the parts that wear, such as the bearings, seals and thrust assembly, and putting it back together with the rotating assembly balanced. The same job is often called turbo reconditioning or turbo repair. GP Turbos rebuilds turbos at its workshop in Scunthorpe, North Lincolnshire.
What a rebuild covers
MAHLE gives speeds of up to 300,000 rpm for the shaft and wheels of small turbos, and Garrett notes that at full load the oil film between the shaft and its bearings can be only a few microns thick. Wear in the bearings or damage to a wheel soon shows as noise, oil leaks or lost boost. A rebuild renews those parts and rebalances the assembly they sit in.
Garrett draws a line between two levels of work. It describes a remanufactured turbo as one that has been completely dismantled, with every part cleaned, anything worn or damaged replaced, the rotating assembly precision balanced and the finished unit tested. It calls a refurbished turbo a lesser job, where only selected repairs are made. Whoever does the work, it is worth asking which of the two you are getting.
GP Turbos can rebuild a turbo to its original specification or, while it is apart, fit uprated parts. Upgrades offered in GP Turbos’ past listings include a 360° thrust bearing, step-gap oil seals and an extended-tip billet compressor wheel. Taken further, a rebuild becomes a hybrid turbo.
Find the cause first
Garrett puts manufacturing defects at fewer than 1% of turbo failures. It attributes more than 90% to oil, either too little reaching the bearings or oil that is dirty, with debris drawn into the turbo as the other common cause. MAHLE makes the same point from the other side: a replacement turbo can fail again quickly unless the original cause is found and removed.
So before a rebuilt turbo goes back on, check the oil feed and drain pipes, the oil and filter, the air filter and intake, and the crankcase breather. Turbo problems and what they mean goes through the symptoms, and the turbo failure guide covers the causes in more depth.
Rebuild or replace?
A rebuild renews the rotating parts, bearings and seals and reuses the housings, so the condition of the housings matters. MAHLE links cracked turbine housings to excessive exhaust temperatures, and a wheel that has rubbed hard against its housing can damage it too. A cracked or badly damaged housing may need replacing, and sometimes a replacement turbo is the better answer. Once the turbo has been stripped and inspected, we will explain which route makes sense and why.
Cars and vans
GP Turbos’ past listings cover diesel and petrol turbos. They included reconditioned turbos for vans such as the Volkswagen Crafter and Transporter and the Mercedes-Benz Sprinter, as well as upgraded turbos for Volkswagen group, BMW, Vauxhall and Porsche cars. If you are unsure whether yours can be rebuilt, contact us with the part number before you take it off.