Crusader 454 getting hot - help please

[oldsalty24]

I have a 33' Egg Harbor with twin freshwater cooled 454's. I have recently replaced both thermostats [160 degree], and both raw water pump impellers. The pumps are good with no wobble. The coolant is filled. This work did nothing to fix my problem. The Starboard engine and port engine run at 160 or less when running under 1800 rpms. When over 3000, the starboard starts creeping up to 195 and possibly higher. I bought a temperature sensing gun and went down in the engine room while running, heres what I found - At 1500 rpms the gun was put on the risers port engine- 124/118 - and starboard engine- 157/121. at 3000 it read port - 160/140 and std - 160/170 and on the manifold it was port - 171/175 and starboard was 195/187. and at the thermostat cover -port -160 and starboard was 185. Do I need risers, a new freshwater pump or what? Thanks for any help, Jon

 

[Dakota47]

Re: Crusader 454 getting hot - help please

Backflush the system.

 

[Don S]

Re: Crusader 454 getting hot - help please

Do I need risers, a new freshwater pump or what?

At this point, it's impossible to say. But pulling the risers off the manifolds and checking to see if the water passages are plugged up would be a good idea.
You might also plumb in a short piece of clear hose on the intake port of the raw water pump and see if you are sucking air. Something as simple as an air leak on the sea water strainer could cause it.

 

[oldsalty24]

Re: Crusader 454 getting hot - help please

thanks ill try that - how do you backflush the system?

 

[rodbolt]

Re: Crusader 454 getting hot - help please

most the 454 crusaders with freshwater cooling also used coolant in the manifold and the seawater exiting the heat exchanger went out the riser, if the riser plugs water cannot exit,
also check the inlets to the oil cooler,clutch cooler and power steering cooler as applicable. old impeller pieces and othe debris can plug them. also remove the end caps on the heat exchangers,if equipped and inspect the tubes.
not only does the water have to get in to cool, the same volume must get out.

 

[oldsalty24]

Re: Crusader 454 getting hot - help please

ok, I backflushed the system - this is a fresh water cooled engine. I ran it for 2 hours, and it still got hot. After I got back from the trip, I pulled off all the hoses on the fresh water system. I know for a fact the water was not circulating - because there was still fresh-water from the backflush in one of the hoses going into the thermostat housing. I have allready replaced this thermostat, is it possible that my freshwater circulating pump is bad? Its not leaking or making noise. All passageways are clear - and the heat exchanger looks new inside. I pulled the risers, and they are clear and new. What else is there to check?? Thanks, Jon

 

[oldsalty24]

Re: Crusader 454 getting hot - help please

ok ya, Im pumping plenty of saltwater, and I replaced the impeller on the raw water pump recently. Saltwater goes through the risers only, not the manifolds on these engines.

 

[Don S]

Re: Crusader 454 getting hot - help please

IF every part is working properly and new, then you don't have an overheat and it's all working properly.
If I were you, I would read and re-read rodbolts post. And do some checking, assume nothing.

 

[1969novamarine24]

Re: Crusader 454 getting hot - help please

You could possibly be getting combustion in your cooling system.Try running the engine with the coolant cap off and observe the coolant.Check for bubbles and the coolant rising and falling just as you would in a car.This condition would cause overheating under load while not at mild load conditions.

 

[dcg9381]

Re: Crusader 454 getting hot - help please

I'd use a leak-down tester to check of combustion leaks rather than the bubble method... It's easier IMHO.

 

[oldsalty24]

Re: Crusader 454 getting hot - help please

I have tried that as well - there is no movement whatsoever in the heat exchanger. No bubbles, nothing. The closed fresh-water system is not moving at all - the only thing that i can assume it would be is the circulating pump, but I have been told that they rarely go, and it would be leaking or making noise. Is this always the case?

 

[rodbolt]

Re: Crusader 454 getting hot - help please

if this crusader isnt modified then why did you take off the hoses from the T-stat for back flushing?
look very closely at the seawater outlet from the heat exchanger. do the go to a nipple at the front of the manifold or to a nipple on a block between the manifold and the elbow.
I guess my first question should have been are you running center rise manifolds or the older log style.
but either way tell me where the saltwater FROM the heatexchanger to the manifold or riser connects.
your riser temps indicate a seawater blockage as they are cooled by seawater and can run cold while the engine melts.
if seawater cannot flow the heat cannot be exchanged in the cooler nor can the risers be cooled, this leads to gradual engine overheat and excessive riser temps and the rubber exhaust hoses overheat and burn.
every ounce of seawter in has to be able to exit, if not the heat exchanger(car radiator) cant work.
in your car its an air to liquid heat exchanger, most big block marine uses a double pass liquid to liguid, just as if you block airflow to half your car radiator the marine heat exchanger reacts the same, block of the flow and it can idle just not run hard under load, if you dont belive it tape a paper bag over half the radiator in your automobile.
you will find it can still idle but wont tolerate highway speeds.
post a good picture of one of your manifold riser assy's.

 

[oldsalty24]

Re: Crusader 454 getting hot - help please

heres a pic of engine

 

[Fireman431]

Re: Crusader 454 getting hot - help please

Some things that seem too obvious haven't been mentioned. I'm sure they have been checked:

1) Thermostats were removed. They weren't put back in upside down, were they (has happened before)?

2) Clogged raw water intake. Water can't circulate if it can't get in. Check more than the filter. See if the through hull fittings (if equipped) are clogged with barnacles/crap.

3) Water won't circulate on the engine side if the thermostat isn't open. Make sure it's at temp when checking (don't open it hot!).

4) Air trapped in the closed system.

5) Bad engine water pump, but usually you will see a leak or hear bearing squeal if it's bad. I have never seen one break where the impeller mounts to the shaft? Has any one else?

Good luck with it.

 

[oldsalty24]

Re: Crusader 454 getting hot - help please

Im sorry if I am frustrating anyone with this, but I have no idea what is wrong with this engine. Ive tried everything Fireman just said, and everything else previous. Its still getting hot. I replaced the thermostat again, with a new one. Again, the raw water impeller was replaced. I took the end caps of the heat exchanger off, and inspected - There was no blockage of any kind on either side, i took a clothes hanger and put it through each hole. I hooked up a clear hose to every inlet and outlet on the freshwater and the raw water sides of the engine. There is plenty of flow, with no air bubbles. The circulating pump is working. My gauge is accurate, because I used an infared temp gun on the top of the thermostat housing. Even at 1800 rpms, its running at 170 degrees, with a 160 thermostat , and goes up 190-200 at 3200 rpms within 5 minutes of running. My other engine has none of these problems. Any other ideas?

2nd issue - The boat will not go faster than 16 knots wide open. Its supposed to cruise at 18 and max at 25. I just had the bottom cleaned. The props were recently balanced. I do know that I need the shafts alligned, would this cause such a slow down? What else would cause it?Thanks, Jon

 

[dkaelber]

Re: Crusader 454 getting hot - help please

I have '87 Crusader Model 350s (454 ci) and have the same problem you describe. If you've fixed it, please share.

I have cleaned inlets, cleared strainers, acid cleaned oil cooler and main Heat exchs, replaced thermostats and impellers, flushed the fresh water side with radiator cleaner. I'm still running hotter than I should.

I've measured raw water flow straight out of pumps. I'm running about 80% of the rated 28.5 gpm flow at 3000 rpm. I may rebuild the pumps to get the rest, but doubt it'll improve much.

Next stop is to replace the risers and elbows after 6 years of fairly fresh water service, recognizing nothing I do there will improve raw water flow.

I did read the Osco website (http://www.oscomotors.com/catalog/catalog79.asp) that the thermostat element (spring side) should be placed up (cone side down). Is this correct? Thx

 

[4100scb]

Re: Crusader 454 getting hot - help please

I had an 1985 Trojan 10M with twin 454 crusaders.

Would run fine up until you broke the 2000 rpm range and the port engine would overheat.

I exhausted all avenues then deiced to replace the heat exchanger and once I did this I no longer had an overheat issue. At the very least have it cleaned and retry.

Good luck

 

[jerryjerry05]

Re: Crusader 454 getting hot - help please

How old is your unit? Risers last somewhere between 10-20 years.The heat exchangers are like a radiator.They will gunk up and restrict flow. While your working remove the riser and replace then get the exchangers rodded..
The Manifolds can go bad even with antifreeze in them.Flow check them and the risers.
Usually if an engine slowly overheats,the risers are usually the first to suspect!!!! Jerry

 

[vlade]

Re: Crusader 454 getting hot - help please

Incorrect timing can affect engine temperature. Also, old fuel can lose octane and burn at a different rate than your timing is set for. I am sure you did this but make sure your RW pump belts are tight.
Good luck!

 

[31silver1979]

Re: Crusader 454 getting hot - help please

Thank u all for your adding your knowledge and insight! Its funny I have same problem as old salty. I have 1979 silverton 31 with crusader 350 cid. Don't know much about engines, but learning! Any idea where I can diagram of this engine? Thanks again!