cd31 engine still overheating

[John Martin]

Thanks everyone for all of the input and suggestions from my original post of 4/24/02. So far I have:

- removed thermostat, soon to be replaced, not sure if good or bad.
- installed new impeller.
- have good exhaust water flow.
- removed, cleaned, and re-installed 2" heat exchanger.
- will up-grade to 3" heat exchanger when I get a chance.
- replaced hose's, into and out of, heat exchanger.
- topped off 50/50 coolant.
- bled air from coolant system.

Engine will run for about 11 min at about 1000/1100 rpm and heat up to between 180 and 200.

The next step is to check the re-circulating pump, this week.

With this said, we had a GREAT sail Sunday afternoon. With frustration level high, and wind HIGH, I said to-hell-with-it and left the dock under sail. The wind was 15-25 out of the west. We sailed for about 3 hours in sunny/warm weather. We were making between 5.5 and 7.5 most of the day with stay-sail and full main. This is what sailing is all about. Had a great day. Who needs a stinking engine.

John & Nancy Martin
CD31 #85 CARINA
sailing on Lake Lanier, GA



johnmartin55@hotmail.com

[len]

john

what a pesky problem! - i'm glad you are sailing anyway -

you've probably already done it, but i would keep bleeding the engine letting it heat up to 200 degrees and bleed some more - when i did this i found it took quite a while, also it would heat up and then cool down showing that the air block was getting relieved - it also helped to push up the RPMs while bleeding

let us know what happens

len



md.frel@nwh.org

[Ernie Smith]

Thanks everyone for all of the input and suggestions from my original post of 4/24/02. So far I have:

- removed thermostat, soon to be replaced, not sure if good or bad.
- installed new impeller.
- have good exhaust water flow.
- removed, cleaned, and re-installed 2" heat exchanger.
- will up-grade to 3" heat exchanger when I get a chance.
- replaced hose's, into and out of, heat exchanger.
- topped off 50/50 coolant.
- bled air from coolant system.

Engine will run for about 11 min at about 1000/1100 rpm and heat up to between 180 and 200.

John, I have had this problem with my Universal M30 in my CD330. Fortunately I received the engine manual with the boat which describes the solution to what is probably just an air bubble block in the closed cooling system. The solution is to ensure that the coolant is topped off in the expansion tank (while engine is cool). Start engine and let idle (at about 1100 rpm on the M30). The engine temperature should appear to rise slowly over about 3-4 minutes, then take off for the overheat side of the guage rather quickly. As soon as the needle starts to accellerate in the overheat direction, rev up the engine aggressively for one or two short bursts of power. Repeat the rev up 2-3 times if necessary. The short burst of power should be enough to push cooling water past the bubble, and you will notice the temperature drop to normal range IMMEDIATELY! If it does not, shut the engine down, let it cool, then try this again. It sometimes takes 3 or 4 attempts before the air bubble blockage is overcome...but it eventually will clear, and temperature will drop to normal. Good luck. Ernie, S/V Everness, CD 330, hull # 136



ernsmith.ems@att.net

[bobm]

I know you stated you have good water flow out the exhaust-how do you know? This is basic and you probably already did it, but I did not see you mention the strainer, if you have one-and how bout the intake cover grill along your keel-maybe you are not getting enough raw water up there
Bob
HR31



merrick@pop.net

[David Brownlee]

As I've reported before, we licked this problem by upgrading to a 3-inch heat exchanger (P/N 299835), as recommended in Westerbeke service bulletin 195.

David Brownlee
CD31 #1 "Windrush"
Havre de Grace, MD



dbrownle@sas.upenn.edu

[len]

david et al

i'm wondering if the ambient temperature of the sea water makes a big difference - i'm in the northeast and even in august the sea water is fairly cold - i still have the original 2 inch heat exchanger and the engine temp stays low (lower than it used to after putting in a new raw water pump last year) - my fresh water pump died last year too, doing so with spectacular grinding noises, and changing that led to the overheating/bleeding scenario i've described

len



md.frel@nwh.org

[D. Stump, Hanalei]

Captain Martin,

Honored Sir, and may I suggest something that might just help? First, if you aren't sure the thermostat is working, boil it! A little thermometer in the water hanging off the side of the pan, will tell you if it is working. Or, since ya have it out, just put in a new one.

To help blow out any air bind, try running the engine without the cap on the surge tank, ie. no pressure in the system. Watch the temp guage, when it is high enough that the thermostat should have opened, let it run a few minutes and shut her down. Now, put the pressure cap on again, and see if it still overheats. Don't know, might work....IMHO......

Dave Stump
Captain Commanding
s/v Hanalei CD-30C

Hey, John & Nancy, John are you going to be cabin boy on Evening Light this year, and Nancy, are you going to be galley wench (same vessel) for the great NE randevous? Just wondering what to expect this August next......I may need to enlist extra crew to repell boarders.......

[David Brownlee]

Len,

Yes indeed. Our overheating didn't manifest itself when we bought our "new" boat in November 2000, nor when we launched in March last year. But by May, with the Chesapeake warm enough to swim in, we couldn't make the suggested RPMs without overheating. We do have a 3-blade wheel, and that surely contributes to the problem, but I'd rather have a large prop than a small heat exchanger!

David

CD31 #1 "Windrush"
Havre de Grace, MD



dbrownle@sas.upenn.edu

[Boyd]

Hi John...

I had a slow overheating condition on my Westerbeke 21A when I first got the boat. Part of the fix was to rebuild the raw water pump...not just replace the impeller but all the parts. There is a brass hump (for lack of a better word) that flexes the impeller inside the housing. It was worn by the abrasive nature of Charleston harbor silt but looked ok to the eye. After replacing this part the quantity of cooling water coming out of the exhaust almost doubled. Also check the exhaust cooling injection elbo. If the point of water injection is restricted then the cooling water quantity may not be enough. These engines are so marginally designed on the cooling capacity end that any small reduction in water flow results in overheating. I also flushed the engine block by taking off the thermostat housing and sticking a hose in the expansion tank. Amazing the crud in there. Coolant circualtion pumps rarely fail and the failure is usually the bearing seal. I dont suspect it in your case. Like others have said... just replace the thermostat they are cheap. On my engine there is a small sill cock on top of the thermostat housing. It is the highest point in the system and is used to bleed the glycol circuit. If one is not present you could drill the housing and add one.

Check the seawater intake at the exterior strainer. A couple of barnicles can make a big difference.

Boyd

Thanks everyone for all of the input and suggestions from my original post of 4/24/02. So far I have:

- removed thermostat, soon to be replaced, not sure if good or bad.
- installed new impeller.
- have good exhaust water flow.
- removed, cleaned, and re-installed 2" heat exchanger.
- will up-grade to 3" heat exchanger when I get a chance.
- replaced hose's, into and out of, heat exchanger.
- topped off 50/50 coolant.
- bled air from coolant system.

Engine will run for about 11 min at about 1000/1100 rpm and heat up to between 180 and 200.

The next step is to check the re-circulating pump, this week.

With this said, we had a GREAT sail Sunday afternoon. With frustration level high, and wind HIGH, I said to-hell-with-it and left the dock under sail. The wind was 15-25 out of the west. We sailed for about 3 hours in sunny/warm weather. We were making between 5.5 and 7.5 most of the day with stay-sail and full main. This is what sailing is all about. Had a great day. Who needs a stinking engine.

John & Nancy Martin
CD31 #85 CARINA
sailing on Lake Lanier, GA

Boyd@wbta.cc

[Joe Valinoti]

Thanks everyone for all of the input and suggestions from my original post of 4/24/02. So far I have:

- removed thermostat, soon to be replaced, not sure if good or bad.
- installed new impeller.
- have good exhaust water flow.
- removed, cleaned, and re-installed 2" heat exchanger.
- will up-grade to 3" heat exchanger when I get a chance.
- replaced hose's, into and out of, heat exchanger.
- topped off 50/50 coolant.
- bled air from coolant system.

Engine will run for about 11 min at about 1000/1100 rpm and heat up to between 180 and 200.

The next step is to check the re-circulating pump, this week.

With this said, we had a GREAT sail Sunday afternoon. With frustration level high, and wind HIGH, I said to-hell-with-it and left the dock under sail. The wind was 15-25 out of the west. We sailed for about 3 hours in sunny/warm weather. We were making between 5.5 and 7.5 most of the day with stay-sail and full main. This is what sailing is all about. Had a great day. Who needs a stinking engine.

John & Nancy Martin
CD31 #85 CARINA
sailing on Lake Lanier, GA

You should try and borrow a temperature gauge of the type that you aim anywhere at the engine. See if the temperature is even throughout and not in the area by the sender. You could have rust buildup in the block preventing true circulation. Also, after 32 years as a mechanic, I'm found that a normally hot engine (watercooled) will let you place a hand on the valve cover with out burning. It should feel very hot. It it's overheating, you can't touch it.
Joe



vwman@coastalnet.com

[Jonathan Erb]

I too had very frustrating problems on my CD31 with overheating three times:

1. The u-shaped stainless water exhaust with the air vent was clogged with corrosion from the sulphur in the exhaust (sorry if I can't think of the name of the part). It was cleared with a screwdriver.

2. A broken blade of the water impeller (when changed by prior owner) had broken off and eventually lodged in the bronze elbow joint on the water intake line.

3. My heat exchanger was clogged and cleared by taking to a radiator shop and boiled up and refurbished. I thought I had good exhaust water flow, but really the clogging just happened so slowly that I did not notice the change. A mechanic looked at it and said, "doesn't look enough to me." If you can compare your water flow with another boat of similar engine size, that may help.

I solved a repeat of #3 by installing a Groco sea water strainer and closing the seacock when not in use. Even if the strainer on the hull is gunked with weed and painted over some, it still runs cool.

The only other idea I have is that it is very difficult to get the airblock out of the line when I change the coolant (which I do every few years- not often enough). I have the expansion tank in the cockpit locker and it is awkward to fill the hose to it. I end up with coolant all over the bilge.

So from my experience, (1) water temperature doesn't matter; (2)dirty strainer on hull doesn't matter; (3) air vents don't matter.

Although no mechanic, I would start with the basics and do it again. Each time I had the problem, I thought I had looked at that link of the system. Try blowing or running water through each section in the line, or a wire, or actual visual. Since the heat exchanger has the smallest sections, and is hardest to see, I would suspect that unless you actually reamed it out with a dowel. Then I would think through the fill up procedure to make sure you have no air block.

Good luck. Mine drove me nuts. I installed a blower, bigger cowl vents, and pondered whether my sound insulation partitions and sound foam were the problem (which had taken me forever to install.)



jerb@plawp.com