Cleaning the undercarriage

[MaineShark]

What's the best way to get the undercarriage clean? I have a lot of greasy gunk on the underside of my car. Between the oil leak that it had, the power steering leak that it had, the transmission leak that it had, and all the coolant that spilled in the process of replacing the radiator, there's a lot of goo down there.

Somehow, the idea of taking a pressure washer to it seems like not the greatest plan, with the risk of damage to the electrical system, and of forcing water past seams, into the interior.

Joe

 

[76L82]

With my Camaro project car, I used an off the shelf engine degreaser product that foamed and then set for 30 minutes. Came right behind it with some rags and all the goo came off...the thing blew a power steering pump and a transmission line.

Seeing that similar degreasers have highly corrosive chemicals in them which may not react well with fiberglass...my 76 has the metal pan and I can't remember if your 79 went back to fiberglass or stayed with metal...you may want to stick with something like "Simple Green". I have used this before on undercarriages in full strength and it worked great. Just spray the heck out of it and let it set overnight. The downside is that you'll need to put in a lot more effort than the more corrosive degreasers...

 

[C3forME]

Pick up some Castrol Super Clean, spray it on, wait 30 minutes and then hose it off. Used full strength, this stuff just melts grease and grime away.

 

[paintdaddy]

Another vote for castrol super clean.I have to clean alot of engine bays and this stuff works great.Be careful though,at full strength sometimes it will eat the paint off of brackets and things.The generic form of it is called power clean by coastal.It works good too.

 

[MaineShark]

Alright, so that's the cleaning agent...

How about application and cleaning techniques? I don't have a lift, and sliding under the car on a creeper and spraying solvents right over my face seems like a bad idea...

Joe

 

[C3forME]

It's definately a bad idea, this stuff at full strength will without a doubt burn your skin. Cover up well and try to work at an angle so that your not right under it. Start at the center and work your way out doing small sections at a time. Let it sit for 15-30 minutes or so and the hose it off with a strong stream of water. Only the real heavily soiled areas may need to be scrubbed a bit, but usually a second application will do the trick. If it's breezy out avoid spraying this unless your absoultely sure that your upwind of it. This stuff when used properly cleans like nothing else.

 

[resto75]

I use engine degreaser or super clean and a 3200psi pressure washer. It will come out very clean that way. If you don't have a pressure washer hanging around go to a do it yourself carwash and bring the cleaning solvents with you. Just let your engine cool down if you plan on washing that too. Cover your distributor
and wires with a plastic bag or at least a old towel.

 

[MaineShark]

Hmmm...

Would it maybe be a good idea to see if a place that does undercoating (Ziebart, or somesuch) would be willing to wash it for a few bucks? I'm not sure what they'd be willing to do, but I think it would probably end up similar in cost, compared to buying the cleaners, and all the time it would take to do it myself.

Thoughts on that one?

Joe