Catalina 310 overheating

[JimHartnett]

2006 with M-25XPB universal.
Raw water circuit is fine but the closed water circuit doesn't seem to be flowing. I take the ends off the heat exchanger and there is still standing water beneath the manifold cap.
Is there something that would prevent water from draining from the manifold back into heat exchanger.

I think I need to replace the heat exchanger
Does the panel behind the engine come off. I removed all the screws but it doesn't budge.

 

[valcour]

Have you checked to make sure the hot water heater is not air bound? When the engine is up to temp (or remove thermostat) then open petcock at heater to make sure you have no air

 

[JimHartnett]

Yes, I removed the heater and the temperature sensor. Burped the line too.
When I opened the heat exchanger it was pretty corroded so I pushed a wire through the honey combs and can see day light through it now but think it is blocked at the engine connection. Nothing past the temperature sensor even gets warm.

 

[Jim 5757]

Pardon my ignorance but when you pull the end covers off the HX doesn't that expose the raw water side only?

 

[jssailem]

pull the end covers off the HX doesn't that expose the raw water side only?

Jim is correct. It is likely that a HX can have corrosion on the Raw Water side. This is what JimH knocked out with his wire.
JimH. The coolant does not move much till the thermostat opens when the engine reaches temperature. Did the engine have time to heat the water enough to open the temp sender?
You can try to flush the system. Disconnect the HX from the coolant system. Connect a hose to the HX engine connection and push water through the engine. It should come out the other side of the HX. You may need to take the Temp Sensor out of the system to open it up. If no flush water then you have an idea where the problem is. Corrosion or blockage could be in the engine channels or in the hoses. Let's hope it is in the hoses.

 

[JK_Boston_Catalina310]

Just a quick read of the problem has me thinking it is airbound. Have you tried bleeding air out of the coolant system?

Look on the C34 tech wiki for over heating. Personally I use the system that Mainesail describes in that post which involves changing the thumb screw on the thermostat housing to a ball valve with a hose barb.

Good luck

 

[Tom J]

2006 with M-25XPB universal.
Raw water circuit is fine but the closed water circuit doesn't seem to be flowing. I take the ends off the heat exchanger and there is still standing water beneath the manifold cap.
Is there something that would prevent water from draining from the manifold back into heat exchanger.

I think I need to replace the heat exchanger
Does the panel behind the engine come off. I removed all the screws but it doesn't budge.

Yes, the panel comes off. Make sure all the trim pieces around the panel, fore and aft are removed. Pull the panel forward and up and it should slide out.

 

[JimHartnett]

Removed the hose between the heat exchanger and the manifold. See the photo below. The manifold intake is totally blocked. Guess regular flushing the closed water circuit would have prevented this.

 

[JimHartnett]

Where I cut the hose from the heat exchanger the saw touched a terminal and a spark flew. Now when I run the engine there is a low periodic alarm from the console. The pressure sensor light goes on when I start but then turns off. Not sure if I shorted a pressure, temperature sensor or if I'm just unlucky and need to change the oil.

 

[jssailem]

Yes. That's a clog. Sure enough.

If you got a spark then an electrical circuit was shorted. Some how you matched a wire with a positive charge to ground. Was the key turned energizing the circuit? That would be the way one of your sensors could be energized to cause a spark when you grounded it with the saw.

Did you need to reconnect any wiring after the sawing? Intermittent can mean the ground of one of your sensors is not securely connected. Could be old wire that has frayed at the connector. Could be a sloppy connector with a stray wire not secured within heat shrink. Could be a mismatched screw on a switch that holds the connectors to the switch but loosely.

 

[Jim 5757]

Here's what we found while removing the transmission. This is the raw water intake fitting to the exhaust riser. Surprising we didn't have any overheating issues other than a slight rise in temp while running at WOT

 

[jssailem]

I have to believe you had a little bit of pressure inside your engine coolant system. Gives new meaning to "takes a licking and keeps on ticking"..... till it doesn't.

 

[Jim 5757]

Y'know... you make a good point there! I'll bet that's why my raw water pump was seeping water from the bearing this past season!!! Can't wait to see how it works this year( I'd best be getting back to that transmission rebuild

 

[JK_Boston_Catalina310]

Where I cut the hose from the heat exchanger the saw touched a terminal and a spark flew. Now when I run the engine there is a low periodic alarm from the console. The pressure sensor light goes on when I start but then turns off. Not sure if I shorted a pressure, temperature sensor or if I'm just unlucky and need to change the oil.

There is a soliniod with a fuse attached on the back of the engine, above the transmission, near the fuel lift pump. This is where your problem likely is. You could have fries the fuse block or the soliniod.

Also, check the oil pressure sender, port side of the engine, low near the engine mounts. This could have been hit in advertently while working on the engine.

Good luck

 

[JK_Boston_Catalina310]

Removed the hose between the heat exchanger and the manifold. See the photo below. The manifold intake is totally blocked. Guess regular flushing the closed water circuit would have prevented this.View attachment 132876

That doesn't look good. How often are you checking the zinc in the heat exchanger?

You should be checking the zinc every month at least. In Boston I could get a whole season out of a zinc. In the Caribbean it's around 5-6 weeks. I check mine every two weeks.

Based on this picture, I would remove the heat exchanger and take it to a local radiator shop for cars. Have them soak the exchanger and then pressure test it.

If it tests fine then put it on and flush the system multiple times with fresh water. Then fill with antifreeze and bleed the system. Look at the C34 tech wiki for how to bleed the system. I use the Mainesail method with replacing the thumb screw with a ball valve and hose barb.

Good luck

 

[JK_Boston_Catalina310]

Y'know... you make a good point there! I'll bet that's why my raw water pump was seeping water from the bearing this past season!!! Can't wait to see how it works this year( I'd best be getting back to that transmission rebuild

No, your raw water pump is leaking at the bearing because it needs to be rebuilt. The lip seals are no good. It's a relatively quick job depending on which pump you have.

 

[Jim 5757]

Damn JK...you're WAY above the times! We still have the old Sherwood pump with carbon bushing! No seals beyond that. Still have one more new bushing to use before doing the Oberdorfer upgrade, but this one's still pretty tight! It always has seeped a few drops here & there, but lots more in 2016. We'll see how it goes with the new exhaust elbow & fittings. Otherwise, everything else in the system is clean.
You make a good point about the HX zinc. Because the P.O. did virtually no maintenance, we had to replace the HX when we got the Merry Bee 16 years ago. At the time I didn't know what that little brass plug was for cuz' there wasn't anything on the inside

 

[JimHartnett]

The pressure warning just went away, but I replaced the overdue oil filter as a precaution.
I ran radiator cleaner through the system and now it loses half a cup of fluid a day.
No water is dripping into the pan so I assume it is inside the heat exchanger. Anyone know if the radiator shop can fix and internal lead? How much should this cost.

 

[jssailem]

A radiator shop seems like the logical place.
Never did it. Would give them a try. They could confirm your suspicion.

My guess is you could remove the exchanger. Attach hoses to the coolant side fittings and run water under pressure thru the system. If you saw water leaking out of the exchanger that would be a good indication that your suspicion is likely correct.

 

[JimHartnett]

I took the heat exchanger to the shop, they haven't tested it yet but I think that is the root cause of all my corrosion. A mechanic just told me that when a leaking exchange cools it pulls salt water back into the closed water system. He also said never fix one buy a new one