Can turbo charger be repaired?

1. Installing a new or remanufactured unit is probably the safest way to repair a sick turbo. Not only do you avoid the pitfalls of do-it-yourself rebuilding but you also get a warranty. If you do decide to overhaul the turbo yourself, one of the most difficult aspects of the job is getting the inside of the center housing spotless clean. Ordinary engine degreaser won't remove the baked oil deposits but spray-on gasket remover will. Taking the housing to a machine shop to have it "boiled out" in a hot solvent or caustic tank is probably the best way to clean it.

2. One thing the experts recommend NOT doing is having the center housing sand blasted. Besides the possibility of leaving sand residue inside the housing where it could later damage the bearings, sand blasting changes the surface texture which can lead to lubrication problems. The bearing surfaces must be highly polished, not rough, so sand blasting is out. Glass beading is okay provided a fine bead is used and the housing is thoroughly cleaned afterwards. The shaft itself can be cleaned in solvent. If the shaft bearing surfaces are not perfectly smooth, round and blemish free, plan on replacing the

3. shaft and turbine wheel. Dirty turbo wheels can be cleaned with solvent and a wire brush. Avoid using abrasives and don't sand blast. Do not attempt to straighten a bent wheel blade. Doing so will only weaken it further, causing the wheel to explode when the turbo hits high rpm. A bent blade upsets the aerodynamics of the wheel, reducing pumping efficiency, so always replace any wheel that doesn't have perfect blades.

4. If the compressor or turbine wheels are damaged, they must be replaced. There are a few experts who claim they can successfully repair damaged wheels by welding but for the do-it-yourselfer welding is out of the question -- especially when you consider the "downside" risks of what might happen if a patched compressor wheel were to fail and spew shrapnel into your engine. There's also the problem of rebalancing a repaired turbo wheel. A new compressor wheel may cost $80 to $100 or more, while a turbine wheel and shaft may cost over twice as much. Worn turbine shafts can sometimes be repaired by grinding the shaft journal down and installing an oversized shaft bearing, or by building up the worn shaft journal with hard chrome and remachining it back to its original dimensions. Regrinding and using an oversized bearing is cheaper than hard chroming, which if not done correctly, will flake off and cause a repeat failure. If the lip of either turbo wheel has been rubbing against the seal area on the center housing, you may find a groove worn into the housing. If this is the case, plan on buying a new center housing. In many instances, it is cheaper to buy a new "turbo cartridge" (the center housing with both wheels and shaft preassembled) than it is to try to rebuild a damaged unit.