Cleaning Diesel Engine

I have an urge to clean up the engine on my '85 300CD. Can I just spray at dollar wash stall? Anything to hurt in the engine compartment? Suggestions appreciated.


Nic in South Carolina

[Jim H]

High pressure spray will force water into electrical connectors which can cause corrosion later. The connectors can resist normal rain and road spray.

High pressure can also blow gaskets out from between the metal surfaces, blast grease out of "permanently lubricated" bearings, and in general force water into places it shouldn't be.

You might be further ahead to spray Simple Green or another de-greaser on the oily surfaces, let it soak, and rinse with a gentle spray from a garden hose.

It got dirty a bit at a time, so don't be in a hurry to clean it! Several gentle applications are usually better than one big blast.

BCingU, Jim.

Thanks Jim, I'll be careful and go slowly. No pressure washing. Will get the green stuff and apply/remove gently.

Nic

Diesel injection pumps get so hot that even warm or hot water (steam included) can seize up a pump at operating temp (about $1,000 rebuilt).
Recommendation from my old Chilton Diesel book: If you decide to do it, do it with a completely cold engine.

I do it to all 3 of my diesels all the time. Not once have I had a problem. There is a proper and improper way of doing it. If you do it wrong, your going to have problems.

Use Gunk and spray it onto the engine, let it soak for a couple minutes, then use the soap, then rinse. Make sure you rinse the paint area as well.

Try not to hold the hose too too close to certain components like electical wires, etc. Start the car and drive around for a while to dry it off and you will be fine.