Alarm sounds but no overheating

[dprvashon]

 

My 88 C34 M25 recently overheated to 200 degrees due to no raw water.  I caught it early but a total meltdown of the impellor.  Replace, the engine was run for 30-45 min with temps around 160. I did note impellor peices in the hose which I drained.

I ran it today for 30 min and when I increased the RPMs to 2000+, the alarm came on yet the temp guage showed 160.  There was some smell of a hot engine.  The exhaust and raw water flow looked okay but maybe a bit weak.  Where do I start? Does the temp guage and alarm measure different areas of the engine.. (bit of a novice with these engines). Does the alarm sound if there is high oil pressure (I topped off the oil to max.  I appreciate any advice.

Thanks
Dave R
Opus 2

[Ron Hill]

Dave : The factory 1988 C34 did not come with an engine instrument panel that included a "Hi temp" alarm.  Your origional (silver color) panel only had 2 audio alarms - one for the low oil pressure and one for the starter ingage!!  Both buzzers stopped sounding when the engine was running and the oil pressure was up and the starter disengaged. 
So you're going to have to explain to us how and what wiring you have, before we can really help you. 

If there was water coming out of the exhaust you should be OK. 
No, the oil alarm should not sound if you overfill the amount of oil (high oil pressure?).  It sounds to me like you might have a bad water temp sender/wire/and or gage.  You need to do some testing.  If the gage goes back down and then up when you run the engine it's probably OK.  Look at our web site and you should find a Temperature gage check that I posted from Seaward. 
:thinkSorry that I can't be of more help.

[Stu Jackson]

Dave

This may be one of those unusual times when you have to disconnect what you may think are cause and effect.  Normally, one would strive to make a connection between your overheating issue and the alarm, and think that they are related.

Given the fact that the panel you have does not appear to contain a temperature alarm, and that it has only the temperature gage, and that the alarms are only for low oil pressure and when the key switch is on before starting the engine, you may need to consider a different approach than thinking the alarm is temperature related.

The wiring for your era panel is included in the Wiring Harness Upgrade at the top of the Projects page (http://www.c34.org/projects/projects-harness-upgrade.html).  Scroll down to the bottom of that article and check out the wiring diagrams in the gif files.

If your temperature gage is OK, but you feel you still have an overheat issue, check out the operation of the temperature gage.  A search on "Teleflex" will find you many good bits of information as to how to do that.  Or use the New Knowledgebase Table of Contents. See the Message Board Post on that, or go to the Tech Notes web page to find it.  That'll help you find Ron's referenced post.

If your oil pressure is OK, then that leaves only the ON switch which triggers the buzzer.  If that's the case, then check the key switch itself and its connections.  As with anything electrical, check the grounds.

It could very well be that your two issues are unrelated, and merely coincidences.

[dprvashon]

Thanks for the input.  I had the engine checked and "shore nuff" there was a secondary alarm put on the exhaust lift that measures the gasses, water, both. We ran the engine up, in gear until the alarm sounded yet the engine registered only 160.  The alarm was disconnected until I can have the engine serviced next week when she gets hauled for a new bottom, rails, dodger and furler. 

Thanks
Dave