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Overheating 1994 Crusader 454

PTG

New member
I have a pair of crusaders with closed cooling system. Starboard engine is overheating. I believe the raw water system is ok because the risers and raw water hoses are cool when running the engine, intake confirmed good, impeller replaced less than a year ago.
That leaves the closed system. I flushed the system in the fall. I replaced the thermostat with new. I found some antifreeze gel under the pressure cap and in the overflow bottle, so I began to flush the system but all drained antifreeze was in good condition. I stopped the flush, topped up the coolant and started the engine. This time I removed one hose to be sure the pump was working and very little coolant poured through. I would assume that the pump needs replacement but could it be an air bubble? How can I rule that out? If I need to replace the pump can I just replace the impeller and gaskets? I have changed the raw water impeller, is this the same level of difficulty? Just looking for some guidance - thanks in advance.
 
what temp... to remove air from system,run engine at 1500 RPM's for about 5 mins.did you test your rad cap for PSI.
If not just take the other one off and install on engine, see what happens

Steve
 
Thanks, I replaced the pressure cap and ran the engine at 1500 for several minutes, when the temp started to finally climb it raced up to 200 and I shut it down. Still unsolved.
 
If you take off the pressure cap, then run the engine, are there a lot of bubbles at the filler neck? btw, my coolant pumps are about 30 years old, I think their life is very long. Can't really comment on their rebuild, but I suspect that a press is needed.
 
I would check heat exchanger, to make sure nothing is block.Do you have overheat alarm going off.Try this use the temp gauge from good engine.Just disconnect wire off over heating engine, and disconnect wire from good engine.Run a jumper wire across and see what that gauge goes to.(do this first)I had one 2 years ago doing the same thing, but only ended up bad gauge.But I had a temp gun to check engine when running....

Steve
 
To ME...it seems like you may not be getting enough raw water to cool the antifreeze. Only MY opinion but my history is that I get 4-5 years on a exhaust elbow, 2 years on the raw water pump impeller and I rod out the heat exchanger every 2 years and try to flush out the u-cooler at the end of every season. When we acquired the boat 6 years ago, it appeared as though we had insurmountable cooling issues. Once we developed a thorough understanding of the system, we have been trouble free since. It may appear to be a hit or miss suggestion but be sure your flow thru is up to capacity in all areas first., including the strainer cleanout caps if you have them.

My normal operating temp stays at a steady 140 or so up to about 1600 rpm. At 2200 or above, when things are starting to clog, it creeps to 180 to 200 .... other wise 160 when clean.
 
I had an issue where the lower hose on the water pump of the engine would suck its self shut as the engine RPMs increased. The hose was old but it look fine until the RPMs got up over 2k. Then it would suck shut and cut off the AF flow to the engine. I had to look real close to see it happen. Actually it was Jeff that mentioned it, good thing he did. I put a hose with a spring inside to prevent it from happening again.
 
I would check heat exchanger, to make sure nothing is block.Do you have overheat alarm going off.Try this use the temp gauge from good engine.Just disconnect wire off over heating engine, and disconnect wire from good engine.Run a jumper wire across and see what that gauge goes to.(do this first)I had one 2 years ago doing the same thing, but only ended up bad gauge.But I had a temp gun to check engine when running....

Steve

Are you suspicious of the helm mounted guage or the engine mounted sensor? I wasn't clear by your explanation - sorry.
 
To ME...it seems like you may not be getting enough raw water to cool the antifreeze. Only MY opinion but my history is that I get 4-5 years on a exhaust elbow, 2 years on the raw water pump impeller and I rod out the heat exchanger every 2 years and try to flush out the u-cooler at the end of every season. When we acquired the boat 6 years ago, it appeared as though we had insurmountable cooling issues. Once we developed a thorough understanding of the system, we have been trouble free since. It may appear to be a hit or miss suggestion but be sure your flow thru is up to capacity in all areas first., including the strainer cleanout caps if you have them.

My normal operating temp stays at a steady 140 or so up to about 1600 rpm. At 2200 or above, when things are starting to clog, it creeps to 180 to 200 .... other wise 160 when clean.

Thanks, I will turn my attention to the raw water side today and see what I find.
 
I had an issue where the lower hose on the water pump of the engine would suck its self shut as the engine RPMs increased. The hose was old but it look fine until the RPMs got up over 2k. Then it would suck shut and cut off the AF flow to the engine. I had to look real close to see it happen. Actually it was Jeff that mentioned it, good thing he did. I put a hose with a spring inside to prevent it from happening again.

I checked, these hoses do have a wire spring inside. Thanks,
 
OK. Problem solved. Thanks for the tips - one of which led to the solution. I cleaned the two electrical connections to the temp sensors at the filler neck, restarted, ran to 155-160 degrees and held it perfectly. Must have been a bad signal that triggered the over temp alarm and guage reading.
Thanks again. Case Closed.
 
I have twin 1993 (or there abouts) Crusader 260's (350ci). Port engine would creep up to over 200 on its way to who knows. They are closed circuit cooling systems. Replaced thermostats, raw water impeller, boiled out/rodded both the main heat exchanger and the transmission cooler and refilled with coolant. It seems you have to bleed the fresh water cooling system otherwise there are air pockets. Anyone else have any issues with this? Also, I believe Crusader was very smart and used the closed circuit coolant system to cool the exhaust manifolds so they should last a long time? They're still running around 205 and should run closer to 180.
 
I've also rebuilt the carbs and the port engine discharges whiteish smoke a lot more than starboard but uses no oil and coolant seems to fill the reservoir. I don't believe there's a blown head gasket as I see no leaks around manifolds and oil is clear. Anyone have any thoughts on this. Whiteish smoke evaporates but it might be unburned fuel too? Both float level's in carb are adjusted to level when bowl's are upside down (Holley 4160 600cfm with crossover fill tube for second bowl)
 
bleeding the closed side of the cooling system is part of the procedure when it gets serviced....yes, the exhaust manifolds will last forever as long as the coolant is maintained....the risers/elbows have a finite life, due to the corrosive environment and the raw water used.

You said the raw water pump impellers were changed, what the rest of the pump inspected? there are many parts that will wear and given the age and unknowns regarding the maintenance history, I'd be inclined to start there....
 
Thanks Mako for the info. Pumps were fine with no leaks and raw water out exhaust is fine, risers seem to flow well. I think it may be Air pockets in the closed system possibly. Just a matter of dialing all that in I think, just wanted to see if I were missing anything specific to these crusaders. They seem like well thought out/engineered and long lasting engines. I’ve always had diesels.




bleeding the closed side of the cooling system is part of the procedure when it gets serviced....yes, the exhaust manifolds will last forever as long as the coolant is maintained....the risers/elbows have a finite life, due to the corrosive environment and the raw water used.

You said the raw water pump impellers were changed, what the rest of the pump inspected? there are many parts that will wear and given the age and unknowns regarding the maintenance history, I'd be inclined to start there....
 
Glad to help.....mine usually are good with one cycle, two on an occasion....

If yours has the bleeder screw in the t-stat housing, that usually helps. purge bottles help too, as long as that system is tight....

as far as the raw water flow, looks are usually like opinions - best to measure the flow at any given point by pulling a hose. make sure the suction side of the pump is tight too - those pumps will pull air if they can.....
 
Have the high running temps been verified with an infrared gun? Nice to know if the sending units and gauges are giving accurate readings.
 
Glad to help.....mine usually are good with one cycle, two on an occasion....

If yours has the bleeder screw in the t-stat housing, that usually helps. purge bottles help too, as long as that system is tight....

as far as the raw water flow, looks are usually like opinions - best to measure the flow at any given point by pulling a hose. make sure the suction side of the pump is tight too - those pumps will pull air if they can.....

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Everything is tight. The peculiar thing on the port engine is the coolant reservoir tends to fill up to the top after running a while. These crusaders have a filler neck at the front where 4 hoses attach and the senders are located, heat exchanger on the aft part of engine. I'm wondering if there might be some blockage somewhere in the closed circuit (I would think that is quite unlikely) and producing either excessive heat or restriction causing the coolant to flow to the reservoir. The port engine has a bit more smoke than the starboard discharges at 3,000rpm. Doesn't use oil or coolant other than filling its own reservoir so I don't suspect any head gasket issues. From what i've researched these crusaders use coolant to cool the exhaust manifolds. When I had the boat out a few days ago, the engines were running around 205 degrees F (170 t-stats)
 
205 is hot. Should be around 180. When you changed the impeller's did you check the housing and cover plate for scoring? Mine had some scoring on the cover which you would not think is a big deal but it was causing an overheat condition on mine. I would change out the raw water pump.
 
The filler neck is also known as the fill(er) riser.....you should be able to put a pressure tester on there....head gasket leaks don't alway yield a visible issue....

And agree that 205 is too much....

when were the elbows (& risers) last changed?
 
The filler neck is also known as the fill(er) riser.....you should be able to put a pressure tester on there....head gasket leaks don't alway yield a visible issue....

And agree that 205 is too much....

when were the elbows (& risers) last changed?

Good question, not sure when the elbows/risers were changed out last. I attached a nozzle to each side of the elbow/riser and good flow was coming out the exhaust. At 2,000Rpm's the engines run between 180-200 degrees. When you push them up to 3,000 is when the temps start to creep up north of 205 degrees.
 
Does anyone know the best way to dial in carburetors. Should you set the fast idle screw first then adjust the idle mixture screws so their running smooth or vice versa.
 
The elbows are the root of many 'running hot' scenarios.....The cast iron is exposed to water (& minerals) & high heat, with corrosive by-products of the exhaust....what normally happens is the rust parts accumulate at the mixing port (where the 'raw' water is actually introduced to the exhaust stream) and restrict the flow.....restricted flow = less heat removed from HX = higher operating temp.

Visual attempts at assessing the flow of water in the cooling system are varied at best.....there is no substitute for actually measuring the flow (bucket and stopwatch).

On your carb query, if you are talking about the idle mixture screws, most do it iteratively....set idle speed, adjust mixture, reset speed (if necessary) tweak mixture, etc....the only thing that's critical is to ensure the idle speed used only permits the idle circuit to be active......too high of a speed can enable the transfer ports to start flowing at which point the mixture screws will have diminished (or limited) effect....
 
Howdy fellas, I've had the same issue with my port Crusader 260 (350CI), at 3k rpm temp creeps above 200 and continues. Maybe replacing the closed circuit hose from exchanger to pump may fix it if they're prone to internally collapse. I've gone through the raw water side and replaced just about everything but the right riser heats up extremely hot at idle. any ideas are greatly appreciated, trying to dial it in.
 
Thanks a mil Mako, excellent info. I've been off the forum for a while but I greatly appreciate your input. I replaced the elbo's and still running hot to the point it's distorting the starboard exhaust hose and starboard elbo is too hot to touch, so I assume not enough water is mixing with exhaust. I installed new impeller, exchangers are clear, going to replace some more raw water hoses. Does it matter that the engines are counterrotating, I would think the raw water pumps are configured as such?

Completely understand what you're saying on the carbs. I've rebuilt the carbs however at idle there's a drip coming from one of the primary venturi's, the floats are set properly but trying to figure out this drip is a challenge.
 
I'd be more worried about the cooling than the drip in the carb right off the bat....

LAck of water will distort the hose which, in many cases, causes sufficient damage to warrant replacement.

Did you inspect the guts of the pump or just change the impeller? On the counter rotation question, as long as the impeller is installed with the proper rotation, it should work just fine.....tension on the belt ok????
 
What did the inside cover on the water pump look like? Any scoring at all on the inside of the face plate means you most likely have the same scoring on the housing and the pump should be replaced. Did not seem like much to me but it is what fixed my over heat issue.
 
Right Mako, I need to get to the bottom of the heating issue over the carb but just thought i'd include in same post for consolidation. When I replaced the impeller, I inspected, looked fine, no leaks. I'll have to replace the hose as its distorted and delaminated and that happened in gear at idle for about 15 mins.

Thanks again for your input, greatly appreciated
 
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