prep for engine bay powerwash

[stayalert]

Next weekend I hope to push my car of the garage and powerwash the engine & engine bay. In preparation I have

- removed the radiator and oil cooler (for more room and I'm going to re-tap the lower oil cooler fitting anyway)

- removed the air cleaner housing
- removed the alternator
- removed the fan
- protected the ac "radiator thing"
- removed the battery

I plan on wrapping any accessable electrical fittings and capping/sealing any open hoses or tubing, or fittings (valve cover breather for example)

Are there other precautions I should take or be familiar with?

looking forward to a fresh look at where all the leaks are coming from.....

[rg2098]

I would take off the aircleaner and seal off the turbo inlet. Better access to that side of the block.

[Pete Burton]

I would repeatedly soak in kerosene and then use a small amount of pressure only - like a garden hose. High pressure will drive moisture deep into wiring harnesses, sensors, vents, seals, etc. You get the engine really clean and you'll soon have surface rust on the block and head - believe me, I know.

[kip Foss]

One of the best engine cleaners I have found is oven cleaner. It is relatively high in caustiic, which is what really cleans baked on grease, is sprayable, and the new stuff doesn't have much smell. It also works great on soap scum in the shower which things like Lime Away won't touch.

I get 50% caustic from work and aside from the fact that it will eat your fingers off it is really good for any kind of grease/carbon that has baked on over the years, driveway grease, paint stripping. etc

[Pete Burton]

I would not use oven cleaner because there are a lot of rubber parts under the hood. Ovens generally don't have rubber. Almost every engine degreasing spray product you find is basically spray kerosene. I've tried a number of different products for degreasing engine parts and keep coming back to kero. Cheap, safe and effective. No matter how you do it though, it's messy.

[kip Foss]

You can wash your hands with oven cleaner without much discomfort so I doubt that it will effect rubber in the short term. I have had no trouble rubber and 50% caustic.

If you choose to use a petrolium based solvent save your money with kerosene. It is usually expensive and hard to find. Diesel is only about one step below kero in the cracking process and will clean as well as kero. There are soaps that you can mix with Diesel which enable you to rinse with water. It turns the Diesel milky when the water hits it.

But for baked on oil/grease I still recommend caustic.

On the top of the transission there is a vent. When the engine is washed the water runs right down from the rear of the engine along the top of the trans and it can run into that vent and into your trans, turning the inside into a strawberry milkshake.

[stayalert]

Originally Posted by Old Deis

On the top of the transission there is a vent. When the engine is washed the water runs right down from the rear of the engine along the top of the trans and it can run into that vent and into your trans, turning the inside into a strawberry milkshake.

Thanks for that tip. Is this breather/vent suffciently accessible to block or wrap?

[Pete Burton]

yeah, Old Deis makes a good point. It's a black, rounded button looking thing about an inch in diameter. Maybe a few layers of aluminum foil around it? Also, don't direct the water down along the top of the bellhousing.

I don't understand. Do you have all this stuff off the engine because you are rebuilding everything?

In the 533,000 miles that I drove my 240D, I'll bet that I pressure washed the engine compartment at LEAST 50 times with absolutely no ill effects from it. If you are talking about a 123 MB, there's nothing to prep.

On later computer controlled, gas engine cars you need to be careful and just sort of lightly wash out the engine compartment, but on earlier, especially diesel cars, just get after it.

Good luck,

[stayalert]

I bought the car a month ago. its my first mercedes. its unregistered and has a number of issues that I am going to address. Among these issues is a thick layer of gumpa (grease oil sand, coolent, refridgerant, ?) over everything. I have the pieces out that I've mentioned to help shorten my learning curve on what the car has vs. needs. Degreasing & washing the engine/engine bay will help me as I go throught he car to bring it back to spec. When I get the car operating properly I aspire to install a two tank WVO system.

I'd like to think (whimsical rationalization perhaps) my process has purpose...

I removed the battery to remove the tray to search for rust. I removed the air cleaner to replace the mounts that rattled and access motor mounts & engine shocks I removed the alternator to clean it and assess the brushes. I removed the readiator to clean it/flush it and straigten the fins. I removed the fan/shroud to clean the fan clutch & allow access to the vac. pump....I'm in the midst of a planned and scheduled shipfitters desease of a mechanical makeover.

I bought a cheap mercedes estimating I'd be putting significant amounts of time and money into it. So far I'm not dissapointed...

As I recall Larry had a stick shift 240, but the point is well taken that these engines do not require elaborate prep before a pressure wash.

[dieseldiehard]

I would avoid caustics including any oven cleaners. Some say they use the stuff on alloy wheels but I don't.
The latest engine degreasers use a citrus based chemical that will loosen up gumpa well. Sometimes two applications are necessary to get heavy deposits off. I use a stiff brush working it down in layers and it works better on a warm engine. Then use a regular hose with spray nozzle. A pressure washer would be nice but I've seen it take off paint so watch where and how you use it.
Following the degrease operation I use simple green or similar to remove the film and you are on the way to a better looking engine bay.

Okay, I understand now. When reading your original post, I got the idea that you thought that you had to take all these parts off before you could wash the engine compartment.

Yes, I drove a manual 240D, in fact I had two of them and my wife had one, my wife also had a 300TD and my daughter had a 300D. I washed the engine compartment in all of them. I have washed the engine compartment in most every vehicle I've ever owned with no trouble except for drying out distributor caps in the old days.

I only lightly wash the dust off in the newer computer controlled gas engine cars.

Good luck with your WVO project.

Have a great day,