Hi all,
Apologies in advance if this has been addressed, I have searched and can't seem to find the answer so I'm throwing this out for your help/advice...
We have a 1994 Catalina 36, hull #1317 with a Universal M35. She is a lovely boat, we are her second owners and she was well cared for by her first owners. Recently we had an overheating issue and, through troubleshooting and visual clues, determined it was the heat exchanger. When I removed it, it definitely was clogged, through entirely my fault of not changing the zinc soon enough. Had it pressure tested, cleaned it out, replaced gaskets and hoses and re-installed. Ran the engine under load at the dock for about an hour to check for leaks, etc and the temp came up to a nice 160. Plenty of water out the back, no steam or smoke so I thought YAY! We took her out last week for an actual "live" test, to run her a bit harder and the engine temps would not go above 130, despite trying hard. Everything down below looked good, the engine was hot to the touch but as I didn't have an IR gun to shoot the temps (I do now...), my hand couldn't really tell the difference between 130 or 160 deg.
So here are my questions... I suspect either the thermostat is stuck open somehow (I tapped on the housing to no avail), or the sender/sensor is bad. Or both... I am going to the boat this week to investigate and I don't believe the thermostat is that difficult to access or replace, pending finding the part. Not really sure if I need to drain the coolant, guess I will figure that one out. And not sure about the sender either... But for those of you who have had this problem and or have done this replacement, do you think I am on the right track? And are there any "gotcha's" that I should be aware of ahead of time?
Thank you soooo much!
Patti
Brizo (previously Aloha Nui)
1994 Catalina 36
Hull #1317
Since you have seen a temperature of 160 I believe the sender is good. Before taking it apart, take a thermometer and measure the ocean water temperature and your marina slip water temperature. This may indicate the diffetence.
Also measure the temperature of the water from water heater. It appears to me that all is well.
If you decide to replace the thermometer, you might aswell flush the antifreeze.
Sail La Vie 1999 Catalina 36 MKII, M35B-17031, Coyote Point, San Mateo, CA
About Sail La Vie
Hi Haro,
Thanks for the reply. I couldn't wait until later this week so I went down to the boat today and ran the engine under load in the slip. The gauge once again would not go over 130 but I shot the engine, thermo, block, cylinder head, etc. with an IR gun and they all were within normal operating temps, 160 to 170. So I do suspect the sender may have bitten the dust, or the gauge has lost it's mind. I am going to order a new thermo and sender and just go ahead and replace both since it seems to be a pretty straightforward replacement. As for the water temps, we have a pretty normally cool water here in SoCal, I don't believe there would be a huge discrepancy between the marina and the bay just outside the marina. And I flushed and replaced the coolant just a couple of weeks ago when I replaced the heat exchanger so wasn't looking to do so again if I didn't have too and I don't think I will have to. I also should probably have mentioned that we do not have the traditional "water heater" found on Catalinas. The PO removed the standard water heater and installed an "on demand" propane fueled water heater so the plumbing and flow are a bit different. Again, thanks for the reply!
Haro
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Since you have seen a temperature of 160 I believe the sender is good. Before taking it apart, take a thermometer and measure the ocean water temperature and your marina slip water temperature. This may indicate the diffetence.
Also measure the temperature of the water from water heater. It appears to me that all is well.
If you decide to replace the thermometer, you might aswell flush the antifreeze.