Engine Shampoo

Just deciding whether or not to have (or do myself) an engine cleaning on my 1976 230. I've heard some horror stories about what has happened to people when washing the crud out of their engine. I know to cover the distributor and unhook the battery cables, but what else ? Should I even bother ? There is a lot of accumulated grime on the lower parts of the engine.

Let me know what you all think.

Thanks,

AARON ROCHARD
1976 230.4 W115

[Q]

I have cleaned many an engine in my day an never had a problem. Use common sense and avoid areas with a lot of electrical connections. The main thing is to make sure to run the engine for a long while after you clean it to evaporate all of the moisture under the hood. Starting with a warm engine isn't a bad idea either.

[RunningTooHot]

Careful there – slightly warm is O.K., but do not start with a HOT engine. Not only do you subject components to unusual thermal expansion stresses, but starting with a hot engine will (potentially) make things worse. A hot engine will produce water vapor or steam; this is more likely to penetrate into areas that you do not want moisture.

Usually, there is nothing to worry about. Common sense is really all it takes, although some cars seem to be more susceptible to moisture induced problems. Personally, I cover the brake fluid reservoir cap with plastic wrap & a rubber band – there is a vent hole in the cap, and brake fluid being hygroscopic & all…. Common sense also means *not* blasting a high pressure stream of water at sealed electrical boxes, such as ignition units and relays, amongst others.

On gasoline engines, once you are done, remove the distributor cap and dry out the inside surfaces & the wire terminals as well as the rotor. Misfiring may still occur due to moisture at the spark plug end of the wires, or along the wires themselves if they are getting old (read: bad). There are several spray products that are used for electrical system water displacement, although I have never used them. They may be handy if water becomes a problem with other sensitive devices however.

And don't forget that while your washing away the crud, you are also washing away key lubrication at throttle linkages. When I wash the engine, I take them off to clean them and then lube everything when I'm done.

Sorry, everybody. Maybe I'm just lazy (or a jerk), but I don't get the engine wash business. Question: Why wash the engine? I think you're asking for trouble when you use high-pressure wash under the hood. I use shop rags and elbow grease to keep my engine compartment clean. Oh, you can't eat off of the block or anything like that, but anyone looking under the hood will understand that the car is cared for. The only time I'd even consider a high-pressure wash is if I was going to show the car, and that's not likely to happen in my lifetime. I've heard the horror stories about high-pressure wash, too, and I'm sure the victims took what they considered reasonable precautions. Still, they wound up with big-time problems. I'd stay away from high-pressure washes under the hood. You're just asking for trouble.

[RunningTooHot]

In my prior post, I did not mean to condone the use of *high pressure* blasting streams of water. I personally use an engine degreaser and a thorough rinsing.

By the way, if you can find a product made by Gunk called “Steam” engine degreaser, it is EXCELLENT. It comes in a black can, and it cuts through the muck much better than any other product. It is a bit more expensive than the others, but well worth it. I used to get it at AutoZone or Kragen, but I have not seen it for almost a year. Perhaps the State of California has declared this stuff as verboten. Sad.

[G-Benz]

I HAVE done the show-car circuit for over a decade. Because they WERE show cars, the engine compartment never facilitated a full-blown high-pressure flush!

I do however apply the same cleanliness standards to my regular vehicles. It helps tremendously when trying to locate a leak, or discovering a problem and proactively repairing it.

If I procure a vehicle for the first time with a grimy engine bay, it gets an engine cleaning solvent with a followup hosing off at the local car wash with the hose set to "spot-free rinse" pressure. Never at high-pressure rinse! Besides the already mentioned problems with moisture on electrical components, the spray is powerful enough to knock terminal connections and vacuum hoses off. You may not readily see the dislocation occurring, and the resulting performance problems could plague you for days.

Engine washing can be done at home with a garden hose when washing off kicked-up road dust and bugs. DO NOT wash at home if using engine cleaning solvents, since that and associated gunk being removed is not environmentally friendly. The DIY car wash bays are set up to reclaim and dispose of the harmful chemicals properly.

I too have had some engine washing results not come out perfectly, but with experience, you learn what NOT to do with your particular vehicle.

Careful with the straight four or six configurations with the spark plugs mounted vertically down the center of the engine. Even though it's shrouded, enough water can make its way in and form a "lake" around the plugs. This won't help it's performance at all, until you can "Wet-Vac" the area. (Yep, I did that many years ago to a 72 Fiat).

I've had technicians tell me that the cars with the pristing engine bays get preferential treatment at the service facility. Probably in the same manner that an attractive-looking woman (unfairly) gets instant attention and better service than a less attractive one.

Besides, if your engine compartment could not tolerate water, you couldn't drive it in heavy rains. So your car is equipped with some protection from water. So wash away! But with care...

[Q]

There is no way in hell I would blast at my engine components with high pressure water. Garden hose is about as strong as I would ever use.

[RunningTooHot]

Driving down a residential street a few weeks back, I saw someone absolutely BLASTING their engine compartment with one of those little electric power washers.

Ironic in a way – Perhaps karma would ‘get him’ immediately for polluting the storm drains - by screwing up the engine.

[bstreep]

For the first 2 years I had my 190SL, I cleaned the engine every time I washed it (40+ years of gunk in there...). Just engine cleaner on a WARM (not hot) engine, and a garden hose. It took a while, but it's now VERY clean! I just make sure to cover the brake fluid canister and re-lube my throttle linkage. That's it!

[Ron Johnstone]

I use my high pressure rig on the underside of the engine and undercarrige only. A garden hose works fine on the upper region. For a detergent, once the "other peoples mess" has been disposed of by Gunk, I use concentrated "Simple Green". It works just fine. If you really want a nice looking engine, next time you do a valve adjustment take a wire wheel to the valve cover (and the oil filter cover). Shines it up very nicely. Clean a slightly warm engine only. If you are worried, and can work quickly, first start the engine, then hose it off. If you are getting moisture into electrical areas, you will hear it and be able to react before the car stalls. Be sure not to shoot water into air intakes with it running. If you are plagued by those who would not like you to run detergent down the street, park it on the lawn when you hose off the engine. The grass can take it! Afterwards, shoot a little lithium lube into the various throttle links, wipe down your rubber with a light coating of silicone and you will be proud of your engine.

Besides, its nice to be able to work on your car and not come out covered in grease and grit. I put put my hands and arms anywhere in my engine bay and only come out with a bit of road dust. I have methodically eliminated all fluid leaks that were present when I bought the car and I wash the road dirt off every 3 months or so... makes things much more pleasurable to work on

Jason M