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IMS Failures Explained

IMS Failure:  A Silent Countdown...

In the Porsche™ M96 and M97 flat-six engines, the Intermediate Shaft (IMS) is located just below the crankshaft, and the IMS Bearing is positioned at the far end of the shaft facing the transmission. The crankshaft drives the Intermediate Shaft, which in turn drives the camshafts in the cylinder heads.

The IMS Bearing is similar to an axle bearing, in that it is a sealed unit housing steel balls and a permanent lubricant. The seals and the lubricant inside the IMS Bearing are intended to last for the life of your engine. However, as the IMS Bearing ages, it has the potential to deteriorate.

First, the grease seals enclosing the unit become compromised, hardening over time and losing their tension. As the seal fails, engine oil is able to enter the bearing housing. As the seals erode further over time, more and more engine oil seeps in and washes out the permanent lubricant inside, surrounding the steel ball bearings.

Next, while the grease seals may still be intact, the permanent lubricant inside the housing has been dissolved. The compromised grease seal now provides a barrier, preventing the seeped-in engine oil from leaving the chamber, but also preventing enough fresh engine oil to enter that might cool and lubricate the bearing surfaces. The engine oil that has replaced the original lubricant also carries combustion by-products, from blow-by entering the crankcase. These combustion by-products can include traces of fuel and moisture that can also contribute to corrosive wear of the ball bearings and the bearing housing's interior.

As inadequate lubrication, extreme heat, and corrosion continue, mechanical deterioration accelerates. The grease seals continue to wear and continue to allow oil to seep inside the housing, but more ominously, the mechanical deterioration inside the compromised bearing begins to release metal debris that is carried throughout the engine via the ciruculation of the oil. As deterioration continues, the seal on the IMS flange will begin leaking due to increased pressures within the bearing. A visible clue to this stage of the deterioration is oil leaking between the engine and transmission, however this can also be caused by a compromised rear main seal (RMS). Without removing the transmission, it is difficult to diagnose an oil leak in this area.

As time and use wears on the engine, the components inside the IMS Bearing disintegrate. In certain circumstances, it may be possible to replace the IMS Bearing after the bearing center support stud breaks. But when the internal ball-bearing separator fails, allowing the expulsion of the balls themselves, it's too late. As there are no outward signs of any of this damage, the vehicle will continue to be operated. At this stage, the IMS Bearing's outer race begins to make contact with the IMS Flange, damaging both the Intermediate Shaft and the flange. This in turn allows the valvetrain timing to be compromised, and valves and pistons collide resulting in metal debris which travels throughout the engine.

At this point, a complete engine rebuild or a replacement engine are the only options.

Until the development of the IMS Guardian™, it was impossible to determine the condition of the IMS Bearing without removing the transmission and associated components from the engine and inspecting it visually. Because of the labor and expense necessary to gain visual access to the bearing, it was most often suggested that the IMS Bearing be replaced as a preventive measure, regardless of it's current condition. Click here for more information about Flat 6 Innovation's IMS RetroFit Kit.

Now, with the innovation of the IMS Guardian™, you have a first line of defense against IMS failure. The IMS Guardian™ will automatically monitor your engine, and will provide advanced warning at the first signs of IMS failure. With easy, low-cost and unobtrusive installation, it will alert you with a clear visual and audio signal at the first signs of engine damage occurring in your vehicle. 

Now you don't have to guess about the condition of your engine's IMS Bearing. With the IMS Guardian™ installed, you'll be alerted to the first signs of damage occurring. At that point, you should turn off the engine immediately to avoid further damage. The transmission should be removed and the IMS Bearing inspected specifically, along with other engine parts to determine the extent of the deterioration and resulting debris spread. Caught early, an IMS RetroFit Kit can replace the compromised IMS Bearing and save your engine.

The IMS Guardian™ and IMS RetroFit Kit offer a complete defensive package for your M96 or M97 engine, more affordably keeping your car on the road for years to come.

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Featured in the

Tech Forum of the
November 2011 issue of
Excellence Magazine!

Don't Be Caught Off-Guard!

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IMS Guardian

IMS RetroFit Kit

Warranty & Legal


IMS Guardian™
$389.95 MSRP 
to monitor your engine

IMS RetroFit Kit $995 MSRP 
to replace stock IMS bearing

- OR - 

Replacement Engine:
$15,000 - $30,000