Is your S85 V10 Vanos'd ?

Many S85 V10's are at the point where the Vanos systems are starting to fail. Some of the first symptoms of a Vanos problem in these creatures is a knocking noise in the cam hubs when cranking it over. Other signs include jerky power at low RPM and a gentle knocking sound coming from the front of the heads while running. 

A very worthwhile health check such as the one we are going to explain and demonstrate here can potentially save the whole engine from complete failure.

Performing an oil pressure test on the Vanos high pressure system will indicate if there is any pressure loss or strange fluctuations while the engine is running. The two common failing points of this system are:

  1. The high pressure internal lines splitting and bleeding off most of the Vanos oil pressure from getting to the Vanos hubs bolted to the cams. 
  2. The high pressure Vanos pump itself can disintegrate and early signs will show pressure fluctuation before eventual complete failure of the pump itself. 

So it's really quite simple. All we have done here is tap into the high pressure oils system of the Vanos and measure our oil pressure at idle. We are barely getting 180 psi in the system, which is far from the 1000 psi that these Vanos bad boys need in order to operate correctly. 

The easiest and cheapest first step when showing low oil pressure is to remove the internal Vanos high pressure line and perform a simple leak test. We have done this with 5 psi of air pressure with the hose submerged in water and capped at one end to reveal that in this instance the pressure line has failed in a major way bleeding off almost all pressure going through it.


The same test was then performed on a new pressure line to simply show that we could not create any leaks. The line was then installed into the engine and another oil pressure test taken. 

The images here depict the test performed on our recently built E46 M3 V10 swap. 

good gauge.jpg

Although there were technical information releases on proactive replacement on both these parts on earlier models, they can still fail in any S85 V10 engine. So, this is a good, simple test we offer to anyone who would like a check up on their M5 or for those wanting to try and test their own cars at home. 

Check out our video below!