No temp alarm? and HX abrasion

gwp · July 29, 2011, 10:26:44 AM

Lost coolant due to a punctured heat exchanger and fortunately smelled funky odor and shut down before melting engine (25xp) . No alarm sounded. Anybody know if the oil pressure buzzer doubles for temp? If so, I may have bad temp sender. Otherwise I will install horn or something. Upcoming weekend project in case anyone has tips. Heat exchanger was a minor silver solder job. Test for sender function is to ground sender wire at sender and should get 12v at alarm.....right? Thx much

Stu Jackson · July 29, 2011, 10:32:57 AM

Call Seaward, the maker of your cockpit panel, and get new alarm buzzers. We have made checking the temperature gauge a regular habit. I can't hear very well anymore anyway, and the buzzer we have can't be heard too well when the engine is running. Ach, maybe it's the stereo...

When you put your HX back on, put a rubber bicycle tube between the plate and the HX. See "Critical Upgrades" http://c34.org/bbs/index.php/topic,5078.msg37297.html#msg37297 We write 'em, but we can't "make" you read 'em.

In the interest of full disclosure, I have changed the topic subject to reflect the subjects discussed.

Ron Hill · July 29, 2011, 05:48:40 PM

gwp : Your panel probably did not come with a hi temp alarm. The oil pressure alarm does NOT have anything to do with the hi temp - unless you were to run the engine so long that you were to loose oil pressure!!

Where did the leak spring out in the HX ??

When you call Seaward they have a kit that can attach to the thermostate that will both register temperature as well as sound an alarm. you have to do some drill/taping !

BTW, what did your temp gage read when you smelled the coolant?

The test of sender to ground is ONLY if you have the "dog house" PC board temp alarm attached to your temp gage.

A few thoughts and questions

Stu Jackson · July 29, 2011, 07:02:51 PM

Ron's right, of course, since our buzzer is only for the oil pressure (we don't have an oil pressure gauge, right?) and I watch the temperature gauge 'cuz we don't have a temperature buzzer.

Glad to hear you were able to fix your HX. Was it from abrasion on the bracket? Do you have hose clamps that keep it on?

gwp · July 29, 2011, 09:35:16 PM

Thanks guys.....the HX became loose in its "big hose clamp cradle" and vibrated up against frame slowly cutting a slit along a port which just happen to be on the pressure side.....dumping the coolant into the bilge. I have a habit of glancing at the temp gauge too, but only when it's running at normal temp

I think it blew it out pretty quick....The gauge was close to max when I looked. Thank heavens all is OK as I just today motored to pump holding and it ran great. Another note.....after getting all back together it ran hot even after burping and making sure there were no air locks. Refusing to believe that the 1 yr old thermostat had gone belly up, I finally took it out and it ran cool. Perhaps the thing jammed when it got so hot??? Anyway......I will call Seaward to rig a temp alarm cause otherwise.....after this debacle.....I will probably be watching the temp gauge more than where the heck I'm going. Will also reinstall the HX with an inner tube asap....great idea, as that copper is soft.

Ron Hill · July 30, 2011, 01:25:05 PM

gwp : The reason that HX clamp broke is because there is too thick an insulation wrap on your exhaust riser.

In the mid 1990's I wrote a Mainsheet article and recommended that all C34 M25/XP owners take a dollar bill and make sure that you can slip it between the HX and the riser. HX & riser should NOT be touching each other!! The pressure from the riser presses against the HX and breaks the starboard hose clamp.

If you put a piece of rubber between the HX and it's "saddle" for cushioning and you can't slip that dollar bill between them, you have just made things worse!!

Great info in those old Mainsheet tech notes.

mel low · July 30, 2011, 09:29:40 PM

When I bought my 86 last year there were no working alarms. My boat has the smaller HX so I wanted to make sure I have warning I have installed an 4 inch fire bell to my system. I put a high temp switch in the side of my engine where the petcock was. It is a 185 degree switch. I then hocked up to the oil pressure switch. The alarm will sound for both. To silence the alarm when starting I removed the light and put a push /off switch in the panel were the label said "alarm". The switch matches the start and glow plug switches. The bell is mounted on the end of the water tank supports directly below the switch panel and can be heard through out the boat. Cost for all was under $100.

Ron Hill · July 31, 2011, 01:33:12 PM

mel : I like the way you did that modification!! I tried to find a similar fire alarm, but couldn't find a 12v at the time.

As a suggestion - I'd change that alarm silencing switch the a momentary (spring loaded) toggle, so that no one could forget and accidentally leave it in the OFF postion.

Good Job