You wouldn't perhaps mean a certain Yanmar powered vessel named Emerald by any chance.....
Amazing what can come out at Cantler's over a few beers
-David
Independence 31
Emerald
-
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Dreaded Universal 5432 running hot syndrome [Master Thread]
You wouldn't perhaps mean a certain Yanmar powered vessel named Emerald by any chance.....
Amazing what can come out at Cantler's over a few beers
-David
Independence 31
Emerald
Update:
I was out again today and ran the engine hard to see what would happen. It got up around 180*F-190*F and stayed there. That is fine by me. Reality is that I knew nothing about the cooling system on the boat so going through it end to end so to speak was worthwhile just to know how it all goes together. I have no problem with running at 190*F-200*F as most automotive/truck diesels run at these temps without issue. Higher temps actually improve efficiency to a point. I was mainly concerned that something was wrong since I had never seen the temp so high and I was seeing steam from the exhaust. This seems to be gone but I won't know until I run her hard over an hour or so. I am guessing that the water heater was restricting the coolant flow so getting it out of the circuit makes sense. Incedentally, the water heater still makes great hot water even running the engine for a short period of time. I had been concerned that the small 1/2" hoses from the bypass were not going to be enough to produce heat quickly. So far so good. RT
I was out again today and ran the engine hard to see what would happen. It got up around 180*F-190*F and stayed there. That is fine by me. Reality is that I knew nothing about the cooling system on the boat so going through it end to end so to speak was worthwhile just to know how it all goes together. I have no problem with running at 190*F-200*F as most automotive/truck diesels run at these temps without issue. Higher temps actually improve efficiency to a point. I was mainly concerned that something was wrong since I had never seen the temp so high and I was seeing steam from the exhaust. This seems to be gone but I won't know until I run her hard over an hour or so. I am guessing that the water heater was restricting the coolant flow so getting it out of the circuit makes sense. Incedentally, the water heater still makes great hot water even running the engine for a short period of time. I had been concerned that the small 1/2" hoses from the bypass were not going to be enough to produce heat quickly. So far so good. RT
Exhaust diameter?
Rob,
Good to hear you're getting close to being back on an even keel with the cooling.
I was wondering about the size of your exhaust system? The engine guy I hired to go through mine in 2004, after an exhaust system failure, recommended upgrading to the M-40 spec. of 2" diameter. Given the engine heritage and same displacement, we went ahead with it. I am not absolutely sure what difference it made, but I think I gained a half knot at about 1800-1900 rpm. We also have a 3" heat exchanger. I did get a nifty stainless exhaust elbow out of it - a work of art for only $225. I was wondering if anyone had opinions or facts about the effect of exhaust system diameter?
The other thing he did was check my raw water through hull and strainer. He then increased those hoses from 1/2" to 5/8". I have the Oberdorfer raw water pump. My temp gauge, of unknown calibration, reads in the 155-160 range at 2000 rpm. I also have a little steam in the exhaust, which is less than with the previous exhaust system. The steam/no steam debate is interesting too. I wonder if Oberdorfers don't pump enough raw water to keep the steam in the muffler?
Rob,
Good to hear you're getting close to being back on an even keel with the cooling.
I was wondering about the size of your exhaust system? The engine guy I hired to go through mine in 2004, after an exhaust system failure, recommended upgrading to the M-40 spec. of 2" diameter. Given the engine heritage and same displacement, we went ahead with it. I am not absolutely sure what difference it made, but I think I gained a half knot at about 1800-1900 rpm. We also have a 3" heat exchanger. I did get a nifty stainless exhaust elbow out of it - a work of art for only $225. I was wondering if anyone had opinions or facts about the effect of exhaust system diameter?
The other thing he did was check my raw water through hull and strainer. He then increased those hoses from 1/2" to 5/8". I have the Oberdorfer raw water pump. My temp gauge, of unknown calibration, reads in the 155-160 range at 2000 rpm. I also have a little steam in the exhaust, which is less than with the previous exhaust system. The steam/no steam debate is interesting too. I wonder if Oberdorfers don't pump enough raw water to keep the steam in the muffler?
Craig,
I think that the exhaust system is at leat 1.5" diameter. The exhaust exits the new factory exhaust elbow/mixer and dumps into a screwed in plumbing style pipe that has to be at least 1.5" ID, then down to a 90* elbow then a short piece of marine exhaust hose to the waterlift muffler then out to the transom. I have a bit of trouble believing that the exhaust is undersized as-is. Small automotive diesels like VW's get away with 1.5" pipe and that is hot exhaust gas. Marine exhaust is cooled drastically by the raw water dumping into the exhaust stream. This cooling will cause a decrease in exhaust gas velocity and volume. These factors alone make me think that 1.5" is more than adequate. I do understand that more flow and less backpressure may result in a slight power increase that you have experienced. I will change the T-stat when I get it and hopefully that will be that. I don't remember what size the raw water seacock is and I think the hose is 5/8" Will update when I can, RT
I think that the exhaust system is at leat 1.5" diameter. The exhaust exits the new factory exhaust elbow/mixer and dumps into a screwed in plumbing style pipe that has to be at least 1.5" ID, then down to a 90* elbow then a short piece of marine exhaust hose to the waterlift muffler then out to the transom. I have a bit of trouble believing that the exhaust is undersized as-is. Small automotive diesels like VW's get away with 1.5" pipe and that is hot exhaust gas. Marine exhaust is cooled drastically by the raw water dumping into the exhaust stream. This cooling will cause a decrease in exhaust gas velocity and volume. These factors alone make me think that 1.5" is more than adequate. I do understand that more flow and less backpressure may result in a slight power increase that you have experienced. I will change the T-stat when I get it and hopefully that will be that. I don't remember what size the raw water seacock is and I think the hose is 5/8" Will update when I can, RT
Rob,
I've been watching this thread closely because my 2 year old exhaust system is bound to start acting up and there's lots of troubleshooting ideas here. My weak exhaust link broke before overheating really became an issue for me.
My old exhaust system was 1.5" and I suspect it worked great for the first 20-odd years and would be fine today if I'd not opted to increase.
I can't tell if the raw water fittings in my system are 5/8" or not, even though the hoses are 5/8". They are male to female elbows with a hose barb screwed into the female end.
Cheers,
I've been watching this thread closely because my 2 year old exhaust system is bound to start acting up and there's lots of troubleshooting ideas here. My weak exhaust link broke before overheating really became an issue for me.
My old exhaust system was 1.5" and I suspect it worked great for the first 20-odd years and would be fine today if I'd not opted to increase.
I can't tell if the raw water fittings in my system are 5/8" or not, even though the hoses are 5/8". They are male to female elbows with a hose barb screwed into the female end.
Cheers,
e38sailorman
Member II
I've been following this thread as I've been running quite hot on my 89 38. Had the mechanic down to the boat and he suggested a new heat exchanger.....boy what a difference. With the old heat exchanger temp was 180 when loofing along and up to 200+ when running up to 2200 or so, any time it went to 200 I'd slow down and after the heat spiked even a little higher it would cool down. Last weekend was out for a local double handed race and motored over to the start and back after the finish. Temp was maybe to low now! Running about 130 to 140 so the new heat exchanger sure fixed the problem.....now I guess a higher thermostat?
Marc
Marc
Shadowfax
Member III
Yeah 130 to 140 is pretty cold. It is possible that you gage is off. To check, buy or steal a candy therometor from your wife and bring the engine up to operational temp. Carefully remove the cap and insert therometer into the coolant and read the real temp. This can also be done with an inferred therometer available at your very good friend mechanic or auto parts store for about $80. It is a point and shoot device and has amny other uses, like weather striping the house if you need to convince the wife that you have to have one.
Tom Metzger
Sustaining Partner
Warning!!
Not a good idea. :0305_alar
On most of our engines there is a coolant overflow jug above the level of the engine, along with a hot water tank coil, that will empty on your hand and engine if you open the cap.
Not a good idea. :0305_alar
On most of our engines there is a coolant overflow jug above the level of the engine, along with a hot water tank coil, that will empty on your hand and engine if you open the cap.
Geoff Nelson
Member II
No running hot anymore!!!
I had similar problems... my 5432 runs OK at 1800RPM (temp 195), starts to get hot at 1900RPM (210) and opening her up was not an option. Been this way for 2 years since I have owned her. Stdbtack came down to SD and helped me do the recommended H2O heater bypass modification and helped me acid out the heat exchanger but neither helped significantly. Over time, the problem is getting worse. Then, leaving for Catalina on Thurs, I can't keep up 1700RPM without hitting 210+. We turn around and spend Friday working on the problem. New raw water impeller, clean out filter, no improvement. Change thermostat... no improvement. Then I get the bright idea to check into the EYo forums and see what people say. I am ready to open up the fresh water pump when I remember about the mod of removing the flapper valve in the exhaust system. Jim at SD Marine Exchange thinks it may be the water/exhaust mixer being gouped up with salt from the excessive heat, but agrees this is an easier first try. I take out the old manifold, and I can hear the flapper flopping around in there... it's not attached, just rolling around. I make a new manifold, install and to go for yet another speed test. IT'S AWESOME!!!
1800rpm I hold 165-170
1950rpm 180deg
and wide open at 2200 for 30 mins it is stuck to 195.
I have never been able to open her up and it's great!!! Not that I'll spend much time there (the speed improvement is negligible) but it's nice to know I can.
Thanks all for your help... you guys rock. I am not around to contribute as much as I should for what I get out of the group (too much time wasted on Sailing Anarchy!) but I am glad I pitched in my $40 last year so I can at least sleep at night!!!!
Cheers,
jefe
I had similar problems... my 5432 runs OK at 1800RPM (temp 195), starts to get hot at 1900RPM (210) and opening her up was not an option. Been this way for 2 years since I have owned her. Stdbtack came down to SD and helped me do the recommended H2O heater bypass modification and helped me acid out the heat exchanger but neither helped significantly. Over time, the problem is getting worse. Then, leaving for Catalina on Thurs, I can't keep up 1700RPM without hitting 210+. We turn around and spend Friday working on the problem. New raw water impeller, clean out filter, no improvement. Change thermostat... no improvement. Then I get the bright idea to check into the EYo forums and see what people say. I am ready to open up the fresh water pump when I remember about the mod of removing the flapper valve in the exhaust system. Jim at SD Marine Exchange thinks it may be the water/exhaust mixer being gouped up with salt from the excessive heat, but agrees this is an easier first try. I take out the old manifold, and I can hear the flapper flopping around in there... it's not attached, just rolling around. I make a new manifold, install and to go for yet another speed test. IT'S AWESOME!!!
1800rpm I hold 165-170
1950rpm 180deg
and wide open at 2200 for 30 mins it is stuck to 195.
I have never been able to open her up and it's great!!! Not that I'll spend much time there (the speed improvement is negligible) but it's nice to know I can.
Thanks all for your help... you guys rock. I am not around to contribute as much as I should for what I get out of the group (too much time wasted on Sailing Anarchy!) but I am glad I pitched in my $40 last year so I can at least sleep at night!!!!
Cheers,
jefe
Attachments
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new exhaust.jpg
Geoff,
I assume the pic is the new exhaust system? I have never seen the "flapper" some have spoken of so I don't know what I am looking for anyway. My exhaust looks very similar to yours so I figure that mine has already been modified. My engine has not run hot since the bypass mod. 180-190*F is as hot as it gets now. I have a new T-stat but I think that will wait until the end of the season. RT
I assume the pic is the new exhaust system? I have never seen the "flapper" some have spoken of so I don't know what I am looking for anyway. My exhaust looks very similar to yours so I figure that mine has already been modified. My engine has not run hot since the bypass mod. 180-190*F is as hot as it gets now. I have a new T-stat but I think that will wait until the end of the season. RT
Geoff Nelson
Member II
TStat is easy
The Thermostat is a 20 minute fix max... if you do it yourself. If you have two other people onboard to help you (one an electrical engineer and one a mechanical engineer- and they are married) then it takes three times as long. This is because they pass the new and old one back and forth comparing them and then they invariably pass you the old one to put back in so that when you are done and you find one sitting on the counter that is shinier than the one you just put in, you realize they handed you the old one and you start over again. This only happened TWICE before I got the right one in.
Cheers,
G-
The Thermostat is a 20 minute fix max... if you do it yourself. If you have two other people onboard to help you (one an electrical engineer and one a mechanical engineer- and they are married) then it takes three times as long. This is because they pass the new and old one back and forth comparing them and then they invariably pass you the old one to put back in so that when you are done and you find one sitting on the counter that is shinier than the one you just put in, you realize they handed you the old one and you start over again. This only happened TWICE before I got the right one in.
Cheers,
G-
Thermostat decision
I just upgraded my 5424's heat exchanger to a 3 inch and it is cooling better than ever. Of course, cooling too well. I'm in the low 160's and need 170-190 for operating temp. I normally ran around 190-195. Any advice on what temp T-stat I should get? I was thinking a 180, but I'm having a difficult time finding one for my model. Thanks.
I just upgraded my 5424's heat exchanger to a 3 inch and it is cooling better than ever. Of course, cooling too well. I'm in the low 160's and need 170-190 for operating temp. I normally ran around 190-195. Any advice on what temp T-stat I should get? I was thinking a 180, but I'm having a difficult time finding one for my model. Thanks.
Captainpeter
Member II
Model 40 Engine running hot cure
My 23 year old E38 Universal 5432 started running hot when it was about 4 years old forcing me to limit rpm's to around 1400 rpm. I replumbed the heater circuit, and did everything else that has been discussed on this thread. When all failed to cure the problem, I took the heat exchanger to a radiator shop and had it "boiled" out. Presto !! the engine then ran normal temperatures again (190). It turns out that after a few years of use a very thin deposit of minerals builds up on the inside of the heat exchanger. This thin deposit is virtually undetectable to the human eye (at least to my eyes) but is enough of a heat insulator to lower the heat exchange efficiency of the cooler to cause increased operating temperatures. Now every 4 or 5 years (depending on how much I use the motor) the temperature starts climbing and I pull the heat exchanger off and boil it out (I now do it myself using diluted muriatic acid- obtainable from most hardware stores or pools supply stores). Perhaps a larger heat exchanger would avoid the problem altogether, but I've gotten so I can remove and replace the original fairly quickly. Also, this chore is a good opportunity to change the coolant and zinc and check all the hoses and hose clamps.
Peter
My 23 year old E38 Universal 5432 started running hot when it was about 4 years old forcing me to limit rpm's to around 1400 rpm. I replumbed the heater circuit, and did everything else that has been discussed on this thread. When all failed to cure the problem, I took the heat exchanger to a radiator shop and had it "boiled" out. Presto !! the engine then ran normal temperatures again (190). It turns out that after a few years of use a very thin deposit of minerals builds up on the inside of the heat exchanger. This thin deposit is virtually undetectable to the human eye (at least to my eyes) but is enough of a heat insulator to lower the heat exchange efficiency of the cooler to cause increased operating temperatures. Now every 4 or 5 years (depending on how much I use the motor) the temperature starts climbing and I pull the heat exchanger off and boil it out (I now do it myself using diluted muriatic acid- obtainable from most hardware stores or pools supply stores). Perhaps a larger heat exchanger would avoid the problem altogether, but I've gotten so I can remove and replace the original fairly quickly. Also, this chore is a good opportunity to change the coolant and zinc and check all the hoses and hose clamps.
Peter
Last edited:
My M40 ran hot our first season last year. This spring I pulled the heat exchanger to have a look. Mine was too far gone it seems since the zinc was non-existent and I had leakage between the fresh water and raw water sides. I got a new one from Lenco that was an exact fit (http://www.lencocoolers.com/88.htm) for HALF of what Universal charges (h/t to Rob Thomas) - and Lenco is an OEM supplier. Problem solved. BTW, Lenco says that neglected zincs are the number one cause of heat exchanger failure!
Hey John, glad to help! I love the Lenco HX, especially for half price. Lenco and a local mechanic explained to me that if the zinc's are not maintained then the interior of the heat exchanger will start to look pink. The metal is compromised at that point and no longer transfers heat well. I swapped in the Lenco and all is well. Just remember to change the zincs each season and all should be well. RT
Here is a successful diagnosis and solution:
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