Old Coolant Hoses

[Plonk]

Hi All, 

Please could I have a little advice.

My boat is fitted with a lister lpw4 water cooled engine and is now 20 years old. I changed the large hoses to the skin tank about 4-5 years ago, but whilst doing a couple of jobs yesterday realised that there was a small hose, running from the exhaust manifold marked 1999! I guess that the (Bowman?) heat exchanger end caps and water pump hose are the same age,  they look OK, - no cracks etc outside, although the small pipe seems quite hard.  Would it be recommended to change all the  hoses as a matter of course? prevention better than a cure etc. I don't want to waste time and money needlessly! The motor is fitted with an overheat alarm, however, would this be likely to sound sufficiently early in the event of a hose failure to prevent engine damage? The engine is below some substantial boards so I doubt that I would see steam.

Thanks in anticipation,

Pat.

[Chewbacka]

12 minutes ago, Plonk said:

Hi All, 

Please could I have a little advice.

My boat is fitted with a lister lpw4 water cooled engine and is now 20 years old. I changed the large hoses to the skin tank about 4-5 years ago, but whilst doing a couple of jobs yesterday realised that there was a small hose, running from the exhaust manifold marked 1999! I guess that the (Bowman?) heat exchanger end caps and water pump hose are the same age,  they look OK, - no cracks etc outside, although the small pipe seems quite hard.  Would it be recommended to change all the  hoses as a matter of course? prevention better than a cure etc. I don't want to waste time and money needlessly! The motor is fitted with an overheat alarm, however, would this be likely to sound sufficiently early in the event of a hose failure to prevent engine damage? The engine is below some substantial boards so I doubt that I would see steam.

Thanks in anticipation,

Pat.

I would change 20 year old hoses.  In the event of a catastrophic hose failure, do you mind if all the coolant is dumped in the engine space, and you can no longer use the engine if this happens in the middle of nowhere?  If not the engine overheat alarm may be adequate to alert you.

[Tony Brooks]

I would look very hard at the ends of the hoses where the hose clip causes them to bulge out either side. If there are no signs of cracks there then squeeze the hose to asses how hard it is. By an large old hoses tend to either go very soft where they have been expose to hydrocarbons or the inside layer goes hard. If you feel the inside layer cracking when you squeeze the hose it is time for a change. As it is if there are cracks on the hose side of the clip. If there are only a few shallow cracks on the end of the hose it will probably be OK for a few more years.

Edited March 6, 2019 by Tony Brooks

[Tony Brooks]

18 minutes ago, Plonk said:

Hi All, 

Please could I have a little advice.

My boat is fitted with a lister lpw4 water cooled engine and is now 20 years old. I changed the large hoses to the skin tank about 4-5 years ago, but whilst doing a couple of jobs yesterday realised that there was a small hose, running from the exhaust manifold marked 1999! I guess that the (Bowman?) heat exchanger end caps and water pump hose are the same age,  they look OK, - no cracks etc outside, although the small pipe seems quite hard.  Would it be recommended to change all the  hoses as a matter of course? prevention better than a cure etc. I don't want to waste time and money needlessly! The motor is fitted with an overheat alarm, however, would this be likely to sound sufficiently early in the event of a hose failure to prevent engine damage? The engine is below some substantial boards so I doubt that I would see steam.

Thanks in anticipation,

Pat.

The alarm should sound once the coolant temperature reaches just below 100C so you will do no damage if you stop PDQ. In fact as long as the engine is still full of water it can't overheat enough to do damage unless you refill the hot engine with stone cold water. Damage is done when the coolant level drops thereby allowing parts of the engine to get to a high temperature.

[Plonk]

Thanks Tony and Chewbaca. 

I will see how they go on for a while.