First of all - thank you Rajaie for your efforts in analyzing this problem, providing a solution, a product and clear instructions on how to repair the part. Fantastic and much appreciated work.

My father and I each own 2000 528i Automatics. Despite the age and mileage on each, these are fine machines which neither of us is anxious to replace.

We replaced the Vanos seals with the kit you sell on both cars about 3 months ago and are now well beyond the 500 mile break-in period that you recommend.

Background:

Father's: 2000 528iA, Aspen Silver metallic. Purchased by me CPO at 51k, sold to him at about 78k later. The mileage on the car when the job was done was 98k.

Mine: 2000 528iA, Sienna Red metallic. Purchased from a private party at 53k who was the only owner. The mileage on the car when the job was done was 83k.

My father is a very experienced aircraft mechanic and I am a software engineer. I'm pretty meticulous about things, but he's the one with the talent and creativity that allowed us to perform this job without much difficulty.

The symptoms:

Neither of us really noticed a problem with an unsteady idle when the engine was warm. What we both did notice was that when the car was cold, that the RPMs would not descend to the "warm" idle speed evenly as the car was warming up. As you're probably aware, the RPMs at idle on a cold engine are much higher for a bit and eventually as the engine heats up, the computer cuts back on the fuel/air intake and the idle drops to about 750 or 800 RPM. As the engine would warm up on both cars, the RPMs would drop suddenly, causing the engine to stumble. The computer would detect this and boost the RPMs again. This cycle went on for a minute or two until the engine was warm. At its worse, the car would die if the RPMs dropped too suddenly. This happened to each of us and probably on the order of once a week. Neither of us noticed an issue when the RPMs were up because of driving (with the engine cold). It should be noted that both of us live in southern CA where it rarely drops below freezing during the winter... and we still had this annoying problem.

The job:

We found that the seals were completely shot in both Vanos units upon disassembly. The O-rings were brittle like plastic (not soft and rubbery) and had flattened on the outside due to riding against the Vanos cylinder walls. The seals were in such bad condition that the pistons (with the old seals still on them ) dropped like rocks into the Vanos cylinders with a lot of slop. Certainly a sign that they were definitely shot. From what we observed, the benefits of variable-valve timing on our cars couldn't have possibly been working at all.

During both installs only two parts were broken. One part was something that Rajaie mentioned in his instructions. This was the aluminum shield/clip on the back left corner of the engine which holds the wires secure. As Rajaie noted, this piece is not important and is in fact not present on newer model cars. The other part we broke was the small plastic elbow that connects the small hose that runs across the radiator from the reservoir to the top of the radiator on the driver's side. This was an original part on the car which we should have taken more care of when removing the radiator hose which led to the reservoir. Half of the elbow fell into the radiator but that wasn't an issue because this was the return side of the radiator - and there was no way it was going to fit through the small channels in the radiator as the coolant circulated, possible clogging a channel through the engine. When we went to BMW to buy a replacement the guy at the parts counter told us that we'd have to replace the entire radiator. After a few minutes of discussion, he "remembered" that that single elbow piece had recently been added to the parts inventory, but was not in the diagrams or parts catalog. I recall it being about $5.

When replacing the Vanos seals, we each replaced the plugs in our cars which were most likely the original ones. They all had huge gaps. I don't know why manufacturers say that they're good for 100k. I know now for certain that they are definitely not.

Following Rajaie's instructions, we finished the first car in about about 6 hours and the second car (after having learned a few things from the first job) in 4.25 hours. The instructions were easy to understand and for the most part spot-on.

One thing I would note is that we found it much easier to spin the fan back onto the water pump shaft from under the car after dropping both the fan and fan cowling in from the top of the vehicle. Even with average-sized forearms they were too big to squeeze between the fan cowling and engine block to spin the fan on from the top.

The result:

Absolutely no issues as I've described in the "symptoms" section above. The cars purrrr again quite evenly and nicely at idle, even when cold.

Both cars have seen an improvement in fuel economy. Both of us are seeing 33mpg on the flat highways cruising at 70mph, with an overall improved fuel economy of 9-11%!

I can't comment on my parent's car, but I can say that my car certainly performs better - more low-end torque. The throttle is more responsive and the car gets up and goes when you get on the gas. Years ago I lived in the midwest. As best I can describe the before and after performance difference is this: prior to changing the seals, my car felt as through it was accelerating from stop through slush. Now, the slush has been removed from all of the roads.

This by far was the best improvement to my 528i that I've made in my years of ownership.

Thanks again, Rajaie.

• Two successful Vanos seal installs - both on 2000 528iA's - epic528 2008-03-03 01:24:46 (468 views)
  • Part number for plastic elbow - epic528 2008-03-11 00:24:23 (209 views)
  • That's a great story! Do you have any photos of the work involved? (nt) - davidc 2008-03-03 10:25:50 (203 views)
    • Unforntunately I do not... - epic528 2008-03-03 10:57:44 (213 views)