We’ve been really lucky with our engine. Sure, we haven’t used it that much, but it’s never failed us, and until recently, overheating wasn’t an issue. For something that’s 43 years old with an unknown number of hours or maintenance history, that’s pretty good. So when the high-temperature alarm for our trusty Perkins sounded, needless to say, we were surprised. It happened shortly after we ran aground just west of the Antioch Bridge. We suspected that we’d sucked up some mud and silt when the towboat pulled us off the shoal. However, the sea strainer only had a very small amount of silt in it.
Investigating the raw water system was next. The impeller still looked really good. We replaced the heat exchanger about 5 years ago, so we were pretty sure that wasn’t’ the problem. Rich took it apart and it looked fine as well. The thermostat was tested next. It’s a little more complicated because the header tank has to be removed to access it. In the process, Rich found some crusty, gelatinous goo under the header tank on top of the thermostat. He tested the thermostat and our spare thermostat and found that the one currently in use was still good. Our spare thermostat, which was a Perkins brand, didn’t open until almost 200 degrees. So we’ll probably get a new spare.
Conclusion
After all of this, we could not come up with a definitive reason why the engine is overheating. When we put the system back together, we used regular antifreeze this time. Previously we had used an environmentally safe version and we suspect that’s what the goo was. I’m all for products that are environmentally friendly, but not at the expense of our engine and certainly not our safety. We’ve run the engine several times now and it no longer overheats. Problem solved (we hope).
Good!!! Nothing worse than worrying about over heating.
After a rebuild and firing my mechanic I found out the reason my 4.107 overheated was that I needed to put a vent valve on the top of the riser to bleed out the air. Now operates flawlessly.