Problems after engine wash

[t_marat]

I have a BMW 520i M50 1994.
We washed the engine with a high pressure water used for washing cars. Engine became very clear and worked without problems at first. But after about 30 mis, its sound changed. It started to sound like a car from 1940s. I don't know how to describe that sound. Somebody told me that 1 or 2 cylinders are not working. After driving for a while there was some kind of burnt smell. I could not identify the smell at first. But it seems like the exhaust pipes close to the engine are about to melt!!! I am a complete newbie, but that what it seems to be.

Before the engine wash I changed the oil (15W-40, Mobil), oil filter and the air filter. Drove for about an hour without problems before starting the engine wash. After the oil change car seemed to be more smooth.

Any help will be appreciated.

[uscharalph]

I have a BMW 520i M50 1994.
We washed the engine with a high pressure water used for washing cars. Engine became very clear and worked without problems at first. But after about 30 mis, its sound changed. It started to sound like a car from 1940s. I don't know how to describe that sound. Somebody told me that 1 or 2 cylinders are not working. After driving for a while there was some kind of burnt smell. I could not identify the smell at first. But it seems like the exhaust pipes close to the engine are about to melt!!! I am a complete newbie, but that what it seems to be.

Before the engine wash I changed the oil (15W-40, Mobil), oil filter and the air filter. Drove for about an hour without problems before starting the engine wash. After the oil change car seemed to be more smooth.

Any help will be appreciated.

I'd love to pressure wash my engine bay, but haven't because of stories like this. So I slowly but surely clean different areas by hand and different brushes / rags etc.

[t_marat]

I shouldn't have, but I did and the result is bad.

What could have gone wrong? Why the exhaust pipes are so hot? The smell is coming from front right side of the car.

[Anthony (M5 in Calgary)]

I shouldn't have, but I did and the result is bad.

What could have gone wrong? Why the exhaust pipes are so hot? The smell is coming from front right side of the car.

If a couple of the spark plugs aren't firing (your rough running comment) there will be a lot of un-burned fuel being sent into the exhaust system and burning there. Fix the misfire quick before you kill your catalytic converter.

PS: I would have thought anybody named Marat would avoid baths...
http://www.bc.edu/bc_org/avp/cas/his.../dav_marat.jpg

[SRR2]

Too late for you, but for anyone else considering this, BMW explicitly prohibits pressure washing anything in the engine room. Frankly, I'd expect that common sense would keep people from doing this, considering the damage even a small pressure washer can do to soft materials like insulation, elastomers, vinyl, fiber components, etc.

[632 Regal]

Hopefully it will dry out for you from the heat.

[RobPatt]

....

[nhall22]

If it is running that badly, I would think the check engine light would come on. Did you check for this.

Neil
1995 530i

[Been-Jammin]

Was the engine running hot when you washed it?

Not to cause unnecessary paranoia, but I've seen a few cases where people have taken their car to a wash bay and cracked a cylinder head on a very hot engine. (above normal) If the engine was hot and you heard alot of "pinging" while washing it, there's a remote chance that this may be the case. After all these are aluminum cylinder heads which will expand and contract with heat, which can cause it to crack or break it's seal at the head gasket. A cracked cylinder head or leaking head gasket can cause a number of symptoms including catalytic converter smell, blue or white smoke, oil in the coolant, coolant in the oil (turns into a gray substance and can collect on the filler cap) and spark plug fouling.

On a lighter note;

With V8 models, their is one coil for each spark plug that sits under a plastic cover on the valve cover. I'm sure that with high pressure, water could leak into the valve cover where the exposed coils are. Wet coils would certainly exibit the symptoms you have explained. They are semi-sealed which could trap water within them and take quite some time to completely dry out. Wet coils will not work, the water interferes with the windings inside. (no spark)

However there are a multitude of other possibilities. High pressure water tends to get into tight places, which makes it very effective for cleaning, but can also get into places that aren't designed to handle the water, even destroy rubber seals and displace grommets and connectors. It also conducts electricity, which can short out or alter voltage sensitive feedback from sensors. It can even destroy an alternator.

I would look at the inside of all of the connectors to see if water has collected behind the seals as well as take a peek under the plastic "BMW" covers. Most of all leaving time to let things dry before applying any voltage by starting the car again.
"BMW says high-pressure steam cleaning can force solutions into the engine harness sheath and associated cables, causing unusual problems that would not have occurred otherwise. BMW engine harness multi-plugs and related sealing measures are not designed to be subjected to the discharge velocity and force of typical commercial steam cleaning units. Further, cleaning solutions with the high-pressure discharge can leave conductive and often corrosive residues deep within the harness and cables."

There is definitely a threat to the life of the catalytic converters if there is abnormally high amounts of unburnt fuel passing through them for any reason. It will try to "convert" all of the unburnt fuel and eventually clog up trying and smell really really nasty in the process. From what I know they are efficient and can recover certain extra amounts, but how much and how long, I don't know.

What the spark plug covers/coils look like on an e34 V8:
http://www.bmwe34.net/e34main/Mainte...e/M60plugs.asp

Let's hope it's something simple, like needing time to completely dry, and of course the next time you contemplate pressure washing the engine compartment, save time and money, go to an ATM, take out a few hundred and donate it to your local charity. ;O)

BMW first issued a warning against high-pressure engine steam cleaning on its vehicles in 1989.
Here is a link to what BMW recommends for engine compartment cleaning:
http://www.bmwworld.com/repairs/detailing/engine.htm

Best of luck.

[stx133]

Had a similar problem in my 540 after a friendly mechanic steam cleaned the engine to try and check for oil leaks for the roadworthy. The misfire was much less severe. took off alll the coil caps and sprayed an anti wetting agent, CRC - WD40, worked a treat.