I have found this forum to be very helpful, so I would like to try to offer a small repayment for all of the great advice I have found here. Unfortunately, I am new to the Jaguar world which limits the specific advice that I can offer. However, I have worked on all kinds of cars over the past 50+ years, and I have learned some general tricks along the way. I would like to offer one of those here.

One problem I often face is cleaning years of oil and dirt build up in hard to reach areas of the engine - such as on top of and below the intake manifold or around the spark plug "valley" on my S-type. The real challenge is cleaning these areas without splattering grime on other parts of the engine. The tools I use for this job include a shop vacuum, several small brushes of various sizes, a squirt bottle filled with mineral spirits, and an air compressor spray nozzle that I have found very useful.

The process is really very simple. I use the squirt bottle to spray an area with mineral spirits, and then I use the brushes to loosen the grime. The final step is to hold the business end of the shop vacuum near the area being cleaned and to use low pressure compressed air to spray the mineral spirits and grime mixture toward the vacuum pickup. This removes the grime from the engine without splattering it into unwanted areas. It works amazingly well.

CAUTION: Do NOT use gasoline or other highly volatile solvents with this technique. The fumes passing through the vacuum could ignite and cause a very significant explosion. I mainly use mineral spirits. If I am working on heavy carbon deposits, I use Marvel Mystery Oil. It is one of the few solvents I have found that will dissolve carbon deposits, but I do not vacuum it up directly. I dissolve the deposits with Marvel Mystery Oil. Then I clean up as much of the mess as possible with rags. Then I clean the area with mineral spirits and vacuum up the residue.

One of the brushes I use is very specific. It is a cheap, 1/2 inch wide, natural bristle, paint brush, and I trim the bristles to only about 1/2 inch long. This allows me to reach into fairly small areas and scrub grime away without scratching surfaces.

The spray nozzle I use is also very specific, and you may need to search for some of the parts. I think I found the basic spray nozzle I am using at Harbor Freight. The only markings on it are "DAPC". It looks like a small pistol, and the end of the sprayer has female threads (about 5/16 inch ID) for accepting various attachments. It just happens that these threads are a perfect fit for the needle used to fill footballs and basket ***** with air. I cut the tip end off one of these needles and attach it to the end of the spray nozzle. I then fit a piece (about 4 inches long) of thin flexible hose over the needle. This setup automatically limits the pressure of the spray and allows me to direct the compressed air into small spaces with very good control.

I hope that some of you will find this helpful. Good cleaning and bright engines.

 

Very useful post.

Many of us are wary about cleaning the engine bay with all the electronic components that can so easily be damaged by water of degreasers but your precision method removes many of the the risks.

Graham

 

Actually, older engines are more prone to problems cause by cleaning with degreasers and water, but the complexity of the electronics on the newer Jags make it harder to locate and resolve those problems once they occur. I have used this cleaning method on many different types of engines, newer and older, and it has never caused a problem.