Projects: Engine Cooling Hose Replacement


I believe it was some time during our Pentwater fuel problems that we also discovered that our freshwater pump was beginning to leak from the weep hole. It began with a mysterious rust-colored spray pattern on the sides and cover of the engine compartment indicating that something somewhere was leaking. We monitored it for a day or two, thinking that perhaps we’d spilled a bit of water on the alternator when filling the header tank and that’s where the mess was coming from. When we finally determined it was the freshwater pump, we ended up deciding to replace the whole thing and be done with it. While we were at it, we noticed that a couple of the engine cooling hoses appeared to be in need of replacement, one of them – the hose located between the header tank and the exhaust manifold – had an unsettling bulge that looked like it might let loose at any time. It was at that point that we decided that new hoses would be in order during winter layup – another item added to the list.


About two weeks ago I yanked all of the old hoses off of the engine and heat exchanger and matched them up with some new ones at my local Napa Auto Parts – a quick call to Trans-Atlantic Diesel in search of Perkins replacement hoses confirmed that “the hoses are unavailable; find replacements at an auto parts store.” I only needed three preformed hoses, and it wasn’t too difficult to match them up. The other hoses were simple straight pieces, so I bought two lengths – inch and inch and a quarter – of Napa’s premium hose and cut them to length.


The hose mentioned earlier, the one with the bulging belly located between the header tank and exhaust manifold, was, as anticipated, the most difficult hose to contend with. Because of the proximity of the header tank to the exhaust manifold, it was necessary to remove the header tank completely to remove the hose. I wasn’t too anxious to do this because I was certain that one of the retaining studs was certain to give me grief; I figured the whole stud would come loose when I tried to remove the nut. My fears turned out to be unwarranted; I easily removed the nut and the bolt that hold the tank in place. A couple gentle raps on the bottom of the tank coaxed it loose, and the whole thing slid up and off the locating stud, freeing the hose and exposing the thermostat.


With the header tank off, I cut and placed my new hose, installed a new thermostat and gasket, and bolted the tank back in place. For those with a Perkins 4.108, I replaced the old thermostat with a stainless steel, heavy-duty 180-degree thermostat from Napa. The thermostat is a standard Chevy 350 thermostat. Email me if you’re interested in the part number.

While I had all the hoses off I went ahead and removed the heat exchanger for flushing and happened to notice that the cover had a hairline crack in it. I took it to a local welder and had him braze and smooth the piece. I then flushed the exchanger with a radiator flush and hot water, and reinstalled it.


The peace of mind afforded by the new hoses will be well worth it, but I have to admit that I’m a bit anxious about start-up in the spring. Hopefully there won’t be any leaks!



Replacing this hose required removing the header tank.



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