Cleaning Engine Compartment: What to Protect from Water - PeachParts Mercedes-Benz Forum

wcmartin75 · #1 07-13-2010, 05:38 PM

1982 Mercedes-Benz 300 TD (Turbo)

Underneath my hood, the engine is filthy. I want to degrease it and hose it down.

What are those components that I will want to protect from water with zip lock bags or plastic film?

Any other good hints on cleaning the engine compartment?

bustedbenz · #2 07-13-2010, 07:02 PM

Quote:

Originally Posted by wcmartin75

1982 Mercedes-Benz 300 TD (Turbo)

Underneath my hood, the engine is filthy. I want to degrease it and hose it down.

What are those components that I will want to protect from water with zip lock bags or plastic film?

Any other good hints on cleaning the engine compartment?

I do not say this as a recommendation you should take unadvisedly. I do not recommend it at all. I state it purely as fact.

I've degreased and pressure washed mine without protecting anything.

If you blow something up, *it's not my fault.

I just make sure the engine has cooled off enough that I'm not at risk of cracking the exhaust manifold or something more valuable by exposing something that's several hundred degrees to freezing cold water.

But, I've hit everything under there with pressurized water including the fuse box (while closed of course), injection pump (which is the #1 thing people say to protect in these "How do I clean it" threads), air cleaner box (with the covers on), -- pretty much just open the hood and squirt -- and I've never hurt my 300SDL or my 240D doing this, in over 5 years of ownership of the 300.

Your mileage may vary and I'm not giving this as "advice". Just personal experience.

Oh. You want to be careful not to blast the vacuum or electrical lines in two if you have strong pressure. Just try to be conscious of when you're pounding on metal/rubber which can't be hurt, and when you're pounding on vacuum lines that are usually brittle enough to snap, or electrical connectors/wires that could get blasted. That's the #1 thing to look out for in my opinion.

vstech · #3 07-13-2010, 07:35 PM

brake master cylinder.

cjbrown · #4 07-13-2010, 07:45 PM

Discussed in detail here: http://www.peachparts.com/shopforum/showthread.php?t=280424

Wodnek · #5 07-13-2010, 08:33 PM

I have never covered anything on my diesels. I use half of a can of engine degreaser on the engine after I run it 5 minutes to get it warm, not hot.

let it sit between 5 and 10 minutes.

I lay 100 feet of garden hose i the sun a few hours ahead of time so that the first minute of spray is with hot water.

spray with the hot water, and rpeat with the second half of the can after it dries.

I've used this method with my 85 300D, 79 300SD, and both 87 diesels.
On my gassers I do the same but avoid spraying the distributer cap directly.

Stretch · #6 07-14-2010, 03:22 AM

As I live in a "rusty" area I only use brake cleaner as a degreaser and then only very sparingly - partly because it is so expensive but also because I believe there are no quick short cuts for this sort of thing. I wouldn't let a pressure washer any where near my car.

General advice:-

Be very careful not to force water into joints and gaps.

Take your time.

Do it on someone else's drive way!

Ghoti · #7 07-14-2010, 04:16 AM

Quote:

Originally Posted by bustedbenz

I do not say this as a recommendation you should take unadvisedly. I do not recommend it at all. I state it purely as fact.

I've degreased and pressure washed mine without protecting anything.

If you blow something up, *it's not my fault.

I just make sure the engine has cooled off enough that I'm not at risk of cracking the exhaust manifold or something more valuable by exposing something that's several hundred degrees to freezing cold water.

But, I've hit everything under there with pressurized water including the fuse box (while closed of course), injection pump (which is the #1 thing people say to protect in these "How do I clean it" threads), air cleaner box (with the covers on), -- pretty much just open the hood and squirt -- and I've never hurt my 300SDL or my 240D doing this, in over 5 years of ownership of the 300.

Your mileage may vary and I'm not giving this as "advice". Just personal experience.

Oh. You want to be careful not to blast the vacuum or electrical lines in two if you have strong pressure. Just try to be conscious of when you're pounding on metal/rubber which can't be hurt, and when you're pounding on vacuum lines that are usually brittle enough to snap, or electrical connectors/wires that could get blasted. That's the #1 thing to look out for in my opinion.

x2...I pressure washed inside my SD with no problems at all. Just gotta be careful.

I will never wash the inside of my gasser's engine compartment with water again!! The distributor is like a sponge and it took me days to get the 280SLC running right again.

Phil · #8 07-14-2010, 12:29 PM

When I wash the engine in my car I do it in the morning before I start the car that day, that way everything is cold. I spray the engine with something like 409 and wait for a few minutes then rinse with the hose but only with low pressure. I have heard that spraying the IP when it is hot can really mess things up but since I only do this when the engine is cold it is not a problem. The only thing I try not to get real wet is electric connections.

Fattyman · #9 07-14-2010, 12:43 PM

If it's a Diesel spray away. I use simple green and a pressure washer. Works wonders and I have never had any problems. If the engine is real bad it will take at least 2 sessions. Wear clothing that you don't car about!

ROLLGUY · #10 07-14-2010, 01:41 PM

Quote:

Originally Posted by Fattyman

If it's a Diesel spray away. I use simple green and a pressure washer. Works wonders and I have never had any problems. If the engine is real bad it will take at least 2 sessions. Wear clothing that you don't car about!

I have cleaned many Diesel engine bays at my local self serve car wash without any problems. However, almost every time I clean a Gasser I have had to clean out the distributor cap no matter how much protective covering I put on. I don't think there is any part of a Diesel engine that can't handle high pressure soapy water and/or degreaser. That is just my experience, yours or others may vary.

Ghoti · #11 07-14-2010, 01:49 PM

Quote:

Originally Posted by Fattyman

If it's a Diesel spray away. I use simple green and a pressure washer. Works wonders and I have never had any problems. If the engine is real bad it will take at least 2 sessions. Wear clothing that you don't car about!

Good point. I forgot to mention that I use Castrol Super Clean.

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