Engine room checks

2 042606008
2 042606008
Belt dust is typically an indicator of belt misalignment, which is often encountered on after-market or high-output alternators.

During a recent over-the-phone troubleshooting session, a client and I were trying to determine the source, as well as the rate, of an oil leak. I asked, “was it there the last time you did an engine room check, and how long ago was that?” His response took me aback: “I checked the engine room before we got under way yesterday.” You can’t check the engine room too often. Some do them hourly, which is very conscientious, while I suggest no less than every four hours.

Pre-cruise walk-through

When I evaluate a vessel, I carry out a pre-start up inspection of the engine room, following a routine I’ve established over the course of many years and many hours in engineering spaces. Routines are important aboard your vessel. They establish regularity and regularity thwarts one’s tendency to forget or overlook items, some of which can be critical. 

While in my case it’s a different engine room every time, I have established a routine that begins in the same location in the engine room: port forward each and every time. There are two goals in this process. The first one is obvious: look for and expose problems or potential problems. Beginning at that location I walk, look, touch and sniff my way around the space in a counterclockwise rotation, using my senses to identify anything that might be loose, chafing, overheating, leaking or otherwise out of the ordinary. The second is less obvious; aboard your own vessel, doing this over and over again will establish an intimacy with this space, which will virtually guarantee that anything that changes will capture your attention, which, once again, drives home the need to establish and follow a routine. 

While not an exhaustive list, specific areas to check include: all fluid levels, crankcase oil, transmission fluid (some designs require it be running and warm to do this), coolant for all engines (check the recovery bottle every time, and under the pressure cap at least monthly), and hydraulic fluid; belt tension and signs of misalignment and slippage (misaligned belts generate fine dust, while slipping belts overheat and glaze, which causes them to become brittle, cracked and shiny on the surface that touches the pulley); transmission and throttle cable linkages (look for loose parts, corrosion or wear on pivot pins and eye terminals, retaining clips should be safety wired, pivot points should be oiled periodically); fixed fire suppression system charge, pressure switch wiring and manual cable engagement (loose switch wiring can lead to an unplanned engine shut down or failure to start. So make sure the service pin is removed, enabling the extinguisher to be manually discharged). Place your fingers on every one of the shaft coupling and motor mount fasteners. All should be tight. Look for signs of fretting, fine brown dust that is generated when ferrous metal parts move against each other. Check the security of the exhaust system, looking for signs of leaks, salt and soot, and loose hardware, especially support struts. Look for signs of coolant and seawater leaks on engine hoses and expansion tanks. Seawater and coolant leave behind distinct residue even when dry or “cooked” by engine heat. Mark the location of the coolant in each recovery bottle. It should rise above this mark when the engine is hot and return to it after the engine has cooled off. If coolant returns to a level lower than the mark, there’s likely a leak somewhere in the system.

Underway check

Working in an engine room while a vessel is underway presents inherent risks that must be taken seriously. Ideally, belts and pulleys should reside behind or under guards. While this is de rigueur for new engines, many older models provide no such protection. Move through this space carefully and deliberately — don’t rush. As someone who spends a great deal of time in engine rooms, I routinely remind myself to move carefully. A few years ago, while conducting an engine room check in stocking feet, I slid on a slick gelcoat deck; my foot grazed the rotating shaft coupling, which was equipped with a set screw and seizing wire, the bitter end of which yanked my sock off. It was a close call and a stark reminder that rotating machinery and limbs don’t mix. While on the subject of personal safety, when entering an engine room, ear and eye protection is a prerequisite; avoid wearing loose clothing, drawstrings or hooded sweatshirts with drawstrings or long ponytails.

Your most effective tools for these checks remain the ones you were born with: sight, smell, touch and hearing. Leaking fuel and coolant, particularly if they are leaking onto a hot surface, have a distinctive smell. Even if the source isn’t immediately obvious, don’t ignore these clues.

Your next most effective tool is an infrared pyrometer. The checklist for areas where it can be used is a long one; however, a brief list follows below. As good as IR pyrometers are, they are not foolproof, their results can be skewed by highly reflective surfaces like chrome or polished stainless steel (this can be overcome by placing black adhesive tape over the location to be measured, or painting a small area flat black), and because their sensing footprint is cone-shaped, their accuracy diminishes as the distance between them and the object being measured increases. Therefore, no more than a few inches should separate the gun from the surface whose temperature it’s measuring. Keep notes of typical temperatures in an effort to identify anomalies and trends.

Fuel vacuum gauges should be installed at every primary fuel filter. If they are the recording variety, and they should be, note and reset the position of the drag needle before getting underway (be careful, it’s easy to get these backwards so the drag needle is on the wrong side of the reading needle). During the underway check, review this gauge once again. Anything above about 5” Hg is cause for concern. Anything more than 10” Hg calls for immediate filter element replacement, or switching to a clean filter. 

Finally, engine room checks aren’t very useful if they aren’t carried out regularly. Once again, while you can’t check this space too often, doing so once every hour or two makes it likely that you’ll identify problems before they become critical. n

Steve D’Antonio works with boat builders, owners and others in the industry as Steve D’Antonio Marine Consulting. He is an ABYC-certified Master Technician and sits on that organization’s Engine and Powertrain, Electrical and Hull Piping Project Technical Committees. He is a long-time ON contributor.  

By Phil Nance