Thursday, August 6, 2009

Protecting New Turbochargers From Failure Using Cryogenic Treatment

Turbochargers an are expensive components to any vehicle. There are many ways that a turbocharger can fail, leaving the driver stranded. Turbochargers are often not easily repairable, although rebuild kits are widely available. Many mechanics will recommend that new turbochargers be installed rather than rebuilt or repaired units. As a result, the driver can expect to spend over a thousand dollars to get a new turbo and have it installed. Unless of course, the owner is an experienced DIYer that can do it with a little time and sweat utilizing a rebuild kit or brand-new turbo. Cryogenic treatment of a brand-new replacement turbocharger can be well worth the money, especially when considering the amount of time required to remove and replace a turbocharger. If cryogenic treatment is utilized; wear will be greatly reduced, as will fatigue failures. The end result is a turbocharger that will stay in alignment and be able to dissipate heat more efficiently. The bottom line is that cryogenic treatment will lengthen the serviceable life of the turbocharger.

What causes turbo failure? One major problem is oil starvation. Heat soak can cause oil lines to “coke” up at the turbocharger. Over time this oil blocks the passageways in the turbo causing oil starvation. Another way that turbos fail is that the driver will park the car and shut it off after a hard run. This results in the compressor wheel spinning without any lubrication at all. As a result, the bearings inside the turbocharger heat up and begin to wear. In time, this will cause the bearings in your turbo to fail. As a result, the turbo compressor and shaft will run out of alignment causing damage to the turbo housing and the compressor wheel. It’s at this point that it is too late and you are going to spend a significant amount of money to get everything back to normal. But, if you keep driving with a destroyed turbo, your engine can suck in all those small metal parts causing more significant engine damage. If it starts to grind, get it checked, do not keep driving it.

Is turbo failure completely avoidable? It needs to be understood that at some point the turbo will fail because its oil seals will begin to leak, causing significant amounts of blue smoke and oil loss within the turbocharger. I have heard horror stories with old Mercedes 500 turbo diesels from the 1980’s that ended up losing all of their oil through the turbo because the seals failed instantly. I myself had this problem with my old 1999 Saab 9-3 after 217,000 miles. Fortunately, it was just beginning to fail and the seals were only weeping. At start-up and on take-off I would see a large blue smoke cloud. Although synthetic oil is recommended for most turbocharged engines, it can cause some rubber gaskets and seals to weep with age. Normal oil will prevent this problem, but it is much more prone to oil “coking” causing eventual catastrophic turbo failure.

What can be done to avoid turbo failure? The first thing to do is to let your car idle after starting and before shutdown to avoid “coking” up the oil lines. This also ensures that the bearings will receive proper oil lubrication after a hard run. If a turbo is cryogenically treated before it is put back together, the owner can expect much longer life without failure. Unfortunately, the oil seals cannot undergo cryogenic treatment since they are made of rubber. Metals and alloys only react to the transformations of cryogenic treatment.

Cryogenic treatment of the compressor housing will remove any residual stresses from the manufacturing process. This will eliminate fatigue failures that take place in the housing. Additionally, the housing will stay in alignment throughout its lifetime. Thermal properties of the turbocharger will be improved through cryogenic treatment after the molecular structure has converted any retained austenite (RA) to martensite. Heat dissipation properties will be enhanced allowing the turbo to release excess heat into the engine bay. This will help protect the turbo from heat soak and oil “coking”. Cryogenic treatment of the bearings, compressor wheel, and shaft will improve the serviceable life of these components. This will reduce failures, due to the parts’ increased wear resistance after cryogenic treatment. Therefore, the bearings will run smoother and will stay within their critical tolerances. This will keep the shaft and compressor wheel from hitting the turbo housing wall and initiating a complete failure.

When it is time for a new turbocharger, make sure to get cryogenic treatment. For most applications cryogenically treating a turbo is less than $100 dollars. Even if you are going to rebuild the turbocharger yourself using a rebuild kit, it makes perfect sense to cryo treat the bearings to ensure that they do not fail prematurely. For more information on the process email me at rtaylor@nitrofreeze or call us at (800)-739-7949.

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