During my ongoing engine compartment clean up project, it was time to remove all the dirt, grime and oils which can be found inside an engine bay after 45 years - even in a low mileage car. A conventional engine cleaning with a strong degreaser, steam or a pressure washer was not successful when I tried, because the main issue I had was overspray, which you cant remove with traditional cleaning methods.
During the undercarriage project last winter - the paint shop did not cover the engine bay good enough, and a lot of overspray settled down on the entire engine bay. It looked terrible! This overspray is extremely difficult to remove, and this is why I thought of dry ice cleaning for the remains which I could not remove with clay and polishing.
I had some very good results with dry ice blasting during my undercarriage project for removing the undercoating. Dry ice-blasting is a form of carbon dioxide cleaning, where dry ice, the solid form of carbon dioxide, is accelerated in a pressurized air stream and directed at a surface in order to clean it. An alternative media for non-abrasive blasting is water-ice, known as ice blasting. The method is similar to other forms of abrasive blasting such as sand blasting, plastic bead blasting, or soda blasting but substitutes dry ice as the blasting medium. Dry-ice blasting leaves no chemical residue as dry ice sublimates at room temperature. Dry-ice blasting involves propelling pellets at extremely high speeds. The actual dry-ice pellets are quite soft, and much less dense than other media used in blast-cleaning (i.e., sand or plastic pellets). Upon impact, the pellet sublimates almost immediately, transferring minimal kinetic energy to the surface on impact and producing minimal abrasion. The sublimation process absorbs a large volume of heat from the surface, producing shear stresses due to thermal shock. This is assumed to improve cleaning as the top layer of dirt or contaminant is expected to transfer more heat than the underlying substrate and flake off more easily. The efficiency and effectiveness of this process depends on the thermal conductivity of the substrate and contaminant. The rapid change in state from solid to gas also causes microscopic shock waves, which are also thought to assist in removing the contaminant.
Unlike abrasive media blasting you cannot remove rust with dry ice blasting.
With this cleaning process I could remove 99,99% of the overspray and the engine is now extremely clean. I will have to remove all of the remaining surface rust with rust remover, and then re-paint the areas which will then be bare metal. Some of the original paint had flaked off over the last 45 years, but I´m trying to keep as much in original paint as possible and only repaint where it is absolutely necessary. Areas of the block will get some fresh Bill Hirsch engine enamel and I had to repaint some brackets, pulleys and the power steering pump.
Below I have put together a short video to show how dry ice cleaning was done in my engine bay. Enjoy and make sure to watch in HD to be able to view all the details!
Here is a short video I shot during dry ice cleaning - it shows the process and explains it a little. MAKE SURE TO SET THE QUALITY TO HD TO SEE ALL THE DETAILS! Youneed a very strong compressor for dry ice cleaning - even a very good shop compressor is not strong enough and cant supply the necessary capacity of air. Christoph with his dry ice blasting machine. Loose paint will come off easily You can also clean weatherstripping and rubber hoses very well. After cleaning - the overspray is gone :-) After cleaning - the overspray is gone :-) All the hoses and wires are clean again. After cleaning - the overspray is gone :-) All the hoses and wires are clean again. You can also clean the carburetor with dry ice. This is the area underneath the radiator. The surface rust will come off pretty easily with rust removing gel. Afterwards I will re- paint it. As you can see its clean, but there is some surface rust remaining which I will have to remove before applying some fresh paint. As you can see its clean, but there is some surface rust remaining which I will have to remove before applying some fresh paint. I will remove the fuel pump for painting. As you can see its clean, but there is some surface rust remaining which I will have to remove before applying some fresh paint.