| Recent jobs: radiator and crankcase vent valve (PCV) | |
My car is a 2003 BMW 4.4 V8
On Saturday I installed a new radiator and thermostat. Fairly easy job but Storey's videos on youtube were a big help with the preparation. Had to make a tool to get viscous coupling off but once that was done the rest was relatively simple. Even managed to recycle all of the coolant using an extraction pump and a careful emptying process (which took a bit longer but was worth it).
After the test drive, I picked up a mild smell in the cabin which at first seemed like an exhaust smell. I'd been noticing it for a couple of weeks, always when coming to a standstill, and had meant investigate further. A quick search threw up the old crank case ventilation issue. This is the one where the valve itself sometimes goes, and the pipes degrade as they carry oil vapour and the oem parts are not actually oil pipes - they are just regular rubber pipes.
So I whipped off the plastic engine cover and had a quick look and sure enough there was a split in one of the pipes and some seepage of oil. On closer inspection however, the pipes were so far gone that they had gone all gooey to the extent that I could pull and stretch them until they just gave way. They were already flat instead of round, and inside was a thick oil & water paste. Yuck!
Went down to the main dealer this morning and picked up all the parts needed. I decided to replace the actual valve itself while I was there. Wished I hadn't though once I got into it. Access is a total nightmare and I kept catching my forehead on some plastic fixings where the ventilation filter assembly goes. I have lots of cuts on my forehead now! In total I replaced the plastic valve, the two main pipes, and the short pipe that goes from the air separator down to the sump. I removed the separator and cleaned it up. This took absolutely ages as it was totally blocked with thick black stuff (an oil rubber mix I think). The small pipe at the bottom of the separator had split in half completely.
Apart from sharing my pain about how big a job this apparently small job is, I wanted to mention it because it is very easy to check whether your car has a similar problem. You may catch it early by checking which would make cleaning of the separator a bit easier. I maybe should have just bought a new one as it took ages to do! My car has 75k on it and was quite clearly on the original pipes since the original difficult to remove BMW pipe clips were still in place. Normally these end up being jubilee clips when the job is done as they are easier to install.
So, to check the state of your crankcase vent system, you need a 5mm allen key. Unscrew the allen bolts on the plastic cover about a quarter of a turn and they'll pop upwards. There are four of them. Then just lift the cover away. The pipes in question are at the back of the engine in the middle and they go across from left to right
For some pics, have a look at Storey's video (again, very helpful when doing the job but I have to say it glosses over what a bitch it is to do!!)
Give the pipes a squeeze and if they are collapsed or feel gooey, it needs doing before it gets worse. The reason for this is that if the ventilation system isn't working properly then crankcase pressure goes up and this can blow the oil seals in the engine under high load.
The dumb thing really with all of this is that LR used non-oil rated piping to carry oil vapour. The net result is that as soon as you replace the pipes they start to degrade. The oil literally soaks into them and eats them away from the inside out. Proper oil piping is resistant to the oil and doesn't degrade like this. Unfortunately they are not easily replaceable with proper oil pipes as they are a special shape to go from crankcase to separator and separator to valve.
|
19th Dec 2011 10:28pm
with rain all day and my garage is otherwise occupied 
