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On my very first trip with this boat the coolant reservoir cap and the radiator cap blew all to hell and made a mess of Prestone proportions. I managed to keep the rpm and heat down and so limped into the travel lift slot where I’d planned extensive work on the bottom.
Let it be noted this was NOT on the original planned projects. After hearing all the most dire possibilities first, I removed the heat exchanger and found right away it was bad. The water passed through the core within minutes just sitting on a bench. I bought a new one, completely flushed the system (and I did eventually find the block plug on this 71C) many times over and added new 50/50 mix just as the book showed me while running the engine on the hard. I was careful to bleed all the air, as best I could from the system.
So, leaving the dock all is well until I boost the RPM to 2000 and that blows the reservoir cap off and bubbling water spewing. The radiator cap is still secure so I make the call to keep going. That day, the engine purred, at 1800 RPM, 180 degrees, clean exhaust, no steam, no smoke but we had to keep adding little bits of coolant throughout the day to maintain SOMETHING in the reservoir. A couple of times it seemed to be boiling in the reservoir but we maintained a steady visual. No leaks showing, very little in the sump under the engine.
The next day with the cap back on it blew at 2200 RPM but then after keeping the RPM down and the cap put back on it acted normal all day (7hr run) with only having to add the tinyest bit of fluid.
Has anyone the faintest idea why this is happening? If you say head gasket, I’l tell you this engine starts PERFECT and runs perfect at idle with clean exhaust.
Would this happen if there WAS air in the system? I may have let some in at the last minute trying to stop a minor hose leak.
Any and all opinions are welcome. Thanks.
I have intermittent wifi where I am so I may not be able to respond quickly.Ken and Vicky finally floating
s/v Painkiller
St Augustine -
I’m not hearing that your engine is boiling over. It sounds like it’s being discharged for other reasons. I don’t have a W71C, but I would guess it is built like most other marine diesels like my old W60. This engine had a coolant reservoir as part of the exhaust manifold. A crack in the exhaust manifold could in theory allow exhaust gas to escape into the cooling jacket. This would pressurize the cooling system and blow coolant out of the exhaust pressure valve. Such a crack would also allow coolant to seep into the exhaust manifold when the engine is shut down. This is not good for your exhaust valves.
A crack in your exhaust manifold would be unusual. There are other ways for gas to get into your coolant. You stated however that you are sure the head gasket is good.
“A more serious form of internal leak would be one within the engine where the coolant, leaks into the cylinders through a leaky head gasket. This type of leak will usually show up when combustion gases are pushed into the jacket water when the engine is running and under load . It will show up as a steady stream of bubbles being pushed through the clear tubing leading from the heat exchanger to the expansion tank. Do not confuse with normal start up de-aeration. A device called “bloc checkâ€
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Thanks Rich,
I was told that if my head gasket had a leak there should be signs of poor starting and possible white smoke/steam out the exhaust. I really have no idea that it ISN’T bad. There is 1600 hrs on the engine and it really does seem to run perfect. What baffles me is that on the two day run here the coolant problem seemed to get better and better. The coolant was at the add line and stayed steady, no bubbling, as I increased RPM coolant it would draw down into the engine and as I decreased it would fill back in.
At this time I feel somewhat confident to continue down the ditch in protected waters with it as it is. Great fuel economy and a decent speed. I understand the seriousness of a head gasket issue and I’m quite capable of doing the job myself, I’ve been in and out of quite a few blocs and heads. Trouble shooting is the bear for me.
What about the air I might have left in the system?
??? Now that it’s worked itself out it’s running fine????Ken
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Ken
You didn’t say what your temperature guage was doing. Sounds like your coolant isn’t circulating properly. This could cause localized heating in the engine. Suggest you use one of those ir thermometers to see if there is any hot spot. See if the thermostat is working properly and is the right model. Should have a disc on the bottom to cut off recirculation through the block after the engine is warm. I’m guessing that the 71c is similar to the 58 as they are same base engine. Any kind of goo in thermostat housing?
Did you bleed air at the thermostat housing when you replaced coolant? Could be airlocked and not circulating.
Next, check the heat exchanger for debris obstructing flow on raw water side. This will reduce cooling efficiency enough to cause overheating at high rpm.
Any oil in the coolant, or contamination in the oil?
Don’t run out to buy a new head gasket just yet…
Quent -
It seems like you have air in the engine, probably in the water heater
loop. The freshwater pump gets air bound at high rpm. It’s getting better
because you are causing the air to vent out slowly.Bob
On Thu, Mar 13, 2014 at 9:42 AM, Page Two wrote:
Thanks Rich,
I was told that if my head gasket had a leak there should be signs of
poor starting and possible white smoke/steam out the exhaust. I really have
no idea that it ISN’T bad. There is 1600 hrs on the engine and it really
does seem to run perfect. What baffles me is that on the two day run here
the coolant problem seemed to get better and better. The coolant was at the
add line and stayed steady, no bubbling, as I increased RPM coolant it
would draw down into the engine and as I decreased it would fill back in.At this time I feel somewhat confident to continue down the ditch in
protected waters with it as it is. Great fuel economy and a decent speed. I
understand the seriousness of a head gasket issue and I’m quite capable of
doing the job myself, I’ve been in and out of quite a few blocs and heads.
Trouble shooting is the bear for me.What about the air I might have left in the system?
??? Now that it’s worked itself out it’s running fine????Ken
Ken and Vicky # 91……Writing a New Chapter Page by Page in an Old Book._______________________________________________
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Bob Fine
s/v Pelican
Pearson 424 Hull #8
http://thesailinglife.blogspot.com
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Thanks Dan, I’ve seen these in the videos being used, I’ll keep that link.
I’m still holding off on that for now, because only one of the five things
they say it helps solve is only part of my problem, loss of coolant. If I
keep losing coolant on my next run south I’ll more than likely use
something like this to be sure it’s combustion gases leaking. Somehow, my
gut feeling is that it is not the head gasket! Not enough typical symptoms.
Wishful thinking maybe, maybe not.Ken
On Thu, Mar 13, 2014 at 1:37 PM, kalinowski wrote:
Ken: go to blockchek.com for the tool described. Easy to use and around
$50 with free shipping if you get the kit plus an enlarged cover for the
reservoir tank opening.Dan Kalinowski
Jolly Lama #135
Ke’ehi Lagoon, O’ahu_______________________________________________
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Thanks Quent, this sounds more like what the problem may be. The engine
temp is right on normal readings. Running the engine on the hard the
thermostat would kick in at 170 and only run that high for as long as I ran
the engine. First time I dropped into the river it took a lot longer to
come up to temp with the colder water. While running down the ditch
straight on 180 degrees, all day all rpm, although I wasn’t able to run it
high because of the coolant reservoir. I think an airlock is it. As I said,
at the last minute before departure I had a DUMB moment and I let some air
into the system. I’ll work on bleeding out the air better.Ken
On Thu, Mar 13, 2014 at 3:16 PM, quent wrote:
Ken
You didn’t say what your temperature guage was doing. Sounds like your
coolant isn’t circulating properly. This could cause localized heating in
the engine. Suggest you use one of those ir thermometers to see if there
is any hot spot. See if the thermostat is working properly and is the right
model. Should have a disc on the bottom to cut off recirculation through
the block after the engine is warm. I’m guessing that the 71c is similar
to the 58 as they are same base engine. Any kind of goo in thermostat
housing?
Did you bleed air at the thermostat housing when you replaced coolant?
Could be airlocked and not circulating.
Next, check the heat exchanger for debris obstructing flow on raw water
side. This will reduce cooling efficiency enough to cause overheating at
high rpm.
Any oil in the coolant, or contamination in the oil?
Don’t run out to buy a new head gasket just yet…
Quent_______________________________________________
maillist mailing listhttps://pearson424.org/mailman/listinfo/maillist_pearson424.org
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Thanks Bob, I’m going to go through the whole bleeding again and see!
Ken
On Thu, Mar 13, 2014 at 3:49 PM, Robert Fine wrote:
It seems like you have air in the engine, probably in the water heater
loop. The freshwater pump gets air bound at high rpm. It’s getting better
because you are causing the air to vent out slowly.Bob
On Thu, Mar 13, 2014 at 9:42 AM, Page Two wrote:
Thanks Rich,
I was told that if my head gasket had a leak there should be signs of
poor starting and possible white smoke/steam out the exhaust. I reallyhave
no idea that it ISN’T bad. There is 1600 hrs on the engine and it really
does seem to run perfect. What baffles me is that on the two day run here
the coolant problem seemed to get better and better. The coolant was atthe
add line and stayed steady, no bubbling, as I increased RPM coolant it
would draw down into the engine and as I decreased it would fill back in.At this time I feel somewhat confident to continue down the ditch in
protected waters with it as it is. Great fuel economy and a decentspeed. I
understand the seriousness of a head gasket issue and I’m quite capable
of
doing the job myself, I’ve been in and out of quite a few blocs and
heads.
Trouble shooting is the bear for me.
What about the air I might have left in the system?
??? Now that it’s worked itself out it’s running fine????Ken
Ken and Vicky # 91……Writing a New Chapter Page by Page in an OldBook.
_______________________________________________
maillist mailing listhttps://pearson424.org/mailman/listinfo/maillist_pearson424.org
—
Bob Fine
s/v Pelican
Pearson 424 Hull #8
http://thesailinglife.blogspot.com
_______________________________________________
maillist mailing listhttps://pearson424.org/mailman/listinfo/maillist_pearson424.org
_______________________________________________
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Thank you everyone for your opinions and suggestions, it was an air block. When the engine was running under load I bled the valve at the thermostat and released hot steamy air. When the engine cooled it drank more coolant out of the reservoir. Next day did the same thing and now the engine is holding coolant in the reservoir expanding and contracting as it should.
Now….if my damn fuel tank leak would fix itself over a period of three days I’d be happier camper!!!!!Ken
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