Who has actually suffered a Vanos failure on E36 M3 EVO?

I have experienced pretty much the same problem as our man Dan did, and fixed the problem when I replaced the o rings on the exhaust solenoids. The car ran fine on the drive, but after moving it into the garage, lumpy idle again. I put this down to faulty wiring on the solenoids, the contact being re-made on the solenoid whilst refitting, only to be shaken loose. The solenoids are in the kitchen for closer inspection, but I may well buy a new pair for the exhaust side of the vanos which will cost around £250 from the dealership.

The dealership wanted to pop a new vanos unit on at the cost of £2500, and re-timed the exhaust cam to the tune of £690 when I took the car in to be diagnosed - note I stipulated diagnosed and not fixed.

I will report back when I get the new solenoids.

Joesnow - It's unbelievable the lack of knowledge BMW Dealers have in their own Vanos unit. You're not the first person I've heard of that has been made to have a 'Re-time!' It's absolutely ridiculous! There is no reason for a re-time to be needed, why would the cam go out of time in the first place?!

The timing is altered by a helical gear being shoved in and out by a piston moved with oil pressure, the results of the cam position change are fed back to the ECU by Cam Position Sensors. If the cam is in the wrong position, it can only point to the pistons not moving in the Vanos, either due to a failed solenoid, or failed piston seals on the actual piston. What is the point of re-timing the cam, when they can do tests to see that the cam's position is not being altered by the Vanos?

Joesnow, you need to test the electrical resistance of your solenoids, they should all be 4 Ohms approx. You may not be as lucky as me, with a physical wire off, it may be that you've got a break in the solenoid coil itself. It's possible to re-wind the coils, but tricky, and you need a lathe to do this. Another test you can do is apply 12Volts (roughly 1 amp if you can limit it, I wouldn't put a battery across the solenoid coil, you may melt it!) to the centre (-ve) and each of the outer pins (+ve) of your suspect solenoid pair. You should hear them clicking. If they work, then your problem may lie in the actual Vanos piston seals. I'll explain below:-

One thing I think I've discussed elsewhere is the vanos piston seals. Basically, the pistons that do the 'shoving and pulling' of the helical gears have double seals made out of an inner of nitrile rubber in an o-ring form, and an outer seal of teflon. The nitrile rubber compound shrinks with the heat over time meaning oil can leak past the piston and it fails to move properly.

There's a guy in America called Rajaie who has thoroughly investigated this problem (Mainly with American E36's and the M52TU, M54, and M56 engines) and reported his findings to BMW (who, incidentally, have closed the case and refuse to do anything more about it! Electing instead to take £2500 off customers and fit a new, still defective vanos!). He has analysed the o-rings and come up with a manufacturer of an improved formulation for these o-rings called 'Viton'. He sells a complete kit of replacement o-rings and the teflon outer seals for about $60.

I was originally considering replacing my seals and o-rings before I found the wire off on my solenoid, however, it does require removal of the vanos which is no easy procedure.

The full information from Rajaie is available at the following link, it makes interesting reading:- http://bimmer.roadfly.com/bmw/forums/e39/8705552-1...

So..... Joesnow, if you find your solenoids are electrically fine (By the way, a diagnostic should also flag up any electrical problem with the solenoids) and your o-rings on the solenoids are fine, then you may find you need to sort out the piston seals. You may be able to find an independent specialist who'll take the vanos off, it's easy to replace the piston o-rings and teflon seals once the unit is off, then get your indy to put the vanos back on again.

One other thing..... There is a company called Dr. Vanos that do re-conditioned units with all the o-rings and seals changed, and carefully selected gears that reduce the noise somewhat. They require your unit in exchange. I considered them because you get a re-conditioned swappable item for only $350! Much less than the crappy unit BMW would give you which would still have the defective Nitrile o-rings in it! However..... I emailed Dr. Vanos weeks ago, and I've had no response, so not sure how good a business they are! Rajaie, on the other hand, is most helpful and I've had many discussions with him about the problem. Link for Dr. Vanos :- http://www.drvanos.com/euro_m3.htm

Anyway..... Good luck, and i hope it's only an electrical problem!

Yes Matt, I would. I managed to get 8 pieces of shim behind each solenoid, that's a thickness of maybe a millimeter. My solenoids definitely showed signs of 'skewing' before (wear on one side of the thin end that pushes into the housing) and this should hopefully address that. What you have to be careful of, though, is not using too much shim, otherwise you may distort, or put too much pressure on the solenoid covers, and solenoids themselves. Also the cover bolts need to be torqued up carefully, (see Mukerji's post for correct torque).

What I did was keep shimming out until the cover just fitted flush without a gasket, then I fitted the cover with the gasket, this gives a little bit of room for heat expansion of the solenoids.

Regards,

Dan.

Hi Dan, Thanks for the offer, I'm in Derby.

The idle problem came on suddenly. In addition, visual inspection showed connected wires on each solenoid, but one of the tabs onto which the wires are soldered was loose. When I applied 12v across the connections, one solenoid popped, the other didn't. I'll be putting in my order with BMW parts in the next couple of days for a new set.

As this is now my second car, sorting this problem has been a bit sporadic!

Useful thread for new or potential Evo owners.

Yeah, you find it on a lot of non-evo adverts

It's just another way of trying to say "Don't buy a newer car, buy mine"

Thats a PTA Joe ,hope you get to the bottom of it soon

So come on, let's run a book on the mileage...

I'm a buyer at 150k.

By MAF, I mean Mass Air Flow Meter.

I changed all my plugs for Denso ones. I can't stand NGK, for historical Motorbike related reasons.

Denso plugs to fit our car are :-

Denso Iridium IXU22

I bought mine from www.sparkplugs.co.uk

They were £7.67 each pre-vat. Delivery was £4.95 pre-vat.

These plugs are very nice indeed, and in my opinion blow the NGK offering out of the water. (I'd put NGK's in a year, and 8000 miles before, and 2 of them showed signs of sparking AROUND the titanium pad on the outer electrode, and had worn the electrode away!)

Thanks for your help Dan, I'll likely be under the bonnet tomorrow.

Mine is on 80,000 and the only Vanos problem has been perished seals.

Aye, I've seen that Dan, I know where there is a welder!

I actually have the idle control valve on my desk at the moment. Because the car ran great for 20mins after my refit of solenoids, icv and maf, and now runs rough, it is the next point of call.

I checked the plugs and coil packs by disconnecting them in turn to see if it made difference to the idle. It didn't, so I can rule that out.

I'll test the icv, and if working i'll go for the diagnostic. Theres a vanos on ebay starting at £450.