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CaboJohn

Regular Contributor
Hi all. I am a new member and I hope I can get some advice from experieced Crusader owners. Sorry for the long post but you need to know what did not work. I recently bought a 2003 Pursuit 3000 with 5.7 Crusader Captains Choice engines (fresh water cooled) with just under 300 hours. Starboard engine overheated (gauge and alarm) in sea trails. Seller paid to replace thermostat, clean heat exchanger, replace circulating pump, and belt. Boat successfully ran 2 hours and was purchased and shipped to my 2nd home in Mexico. Ran it first time down here last month and erratically got engine overheat and alarm on the starboard engine, and once got alarm with no overheat on the gauge. Found I could turn fresh water pump (belt slipping) and noted that coolant did not suck back into engine on cool down (but it does on the port engine). Came back down with parts and an IR thermometer. Replaced raw water pump, put on correct factory belt (no slip now), replaced cap and hose to coolant overflow, determined that coolant concentration was correct and ran engine at 1000 rpm until it would take no more coolant. Ran for 30 minutes at various RPMs at the dock today and gauges on both engines get to about 160 but I still occasionally got an engine temperature alarm on the starboard side. I have good raw water flow and IR says everything on the alarmed engine is same or lower than on port engine (which has not had pumps replaced or exchanger cleaned) except for one item. When I shoot the manifold area by the R020019 Sensor (engine coolant temperature) it reads 209 degrees where the port engine reads about 155 degrees. When I shoot the other side of the intake manifold where the R20003 Sender, temperature is located, both engines show 155 degrees. I believe the latter sensors provide information to the gauges whereas the first sensor provides information to the ECM, which in turn is kicking off the alarm. So I still have an actual overheat problem but only in that one specific location and only on the starboard engine. I am hoping that I have resolved the coolant system sucking air issue (I will know tomorrow) but do not understand how this relates to my symptoms, unless running and filling with cap off is not enough to purge the system. And to have overheat in that one location seems strange. I have new sensors I could install but the IR readings suggest the issue is real and not a bad sensor. I must not be getting coolant flow to this one small area, which suggests an immoble air bubble or some curd blocking flow. Exhaust manifolds were replaced last year so curd could be fugitive RTV or something but I really, really don't want to tear the thing down. There is an access plug in the manifold near this spot which I will try to get into it tomorrow (but my wrenchs are normal size, not “old boat” size so it may be tough) and I shall see what is there (maybe). Any thoughts or suggestions??

Thanks for any suggestions.
 
At least you're using a IR gun to see what's happening (which elevates you above many who blunder about until wrecking something). That hot spot concerns me: it's as if (as you noted) there's a coolant blockage somewhere. It's a lot of work (and, as I suspect, a remote repair location for you) but I'd pull the intake and get it boiled out.

Jeff
 
[B said:
noted that coolant did not suck back into engine on cool down (but it does on the port engine). [/B]
Click to expand...


Before tearing this apart, I would like you to hook up a coolant system pressure tester with a working gauge to the fill cap on the heat exchanger. Make sure the engine is cold and the coolant is topped off. Now, with the pressure tester hooked up and no pressure in the system, fire the engine and push the throttle up to about 3000 rpm immediately. I want you to pay attention to the gauge. Does the coolant system begin to build pressure immediately? The pressure should only build with temperature rise. If the pressure rises right away, you may have a slight compression or exhaust leak into the coolant system. Possible head gasket. This can be a result of the original corrected overheat problem.
 
That ECU should have the power reducing logic in its program so the chances of an damaging overheat are low unless it was operated by a deaf, ignorant individual.

I'd be inclined to purge it a couple more times before tearing into it. Then probe a bit more with the IR gun...what temp at t-stat outlet? temp at exhaust manifold inlet & outlet? temp at HX outlet to circulating pump?

You are right about the functions of the sensor and sender. two other Q's as well: 1) what does coolant concentration OK mean, numerically, and how do you know the raw water flow is adequate?
 
Thank you for the suggestions. I went down to the boat this morning and found that the coolant in the overflow tank had in fact sucked back in the engine when it cooled last night. That is a first so the new cap and new suction hose have resolved that issue. With the new (correct) belt stopping the pump slippage I now have resolved two of the known problems. I loosened the sensor until coolant leaked around it so any air bubble there was removed. Topped off the system and fired it up. Brought both engines to temperature at 1000 rpm. Starboard engine was slow to start but kicked over after a couple of 10 second tries. All temps were normal, even around the sensor that was at 208 yesterday. Then I raised rpm to 1900 and after 5 minutes or so got an alarm. Shot the sensor and it was back at 208 with the rest of the starboard engine and the port engine still at normal.


So, I am convinced it is an air bubble (not a blocked passageway). The bubble wants to lodge in the raised front left side (looking from the rear) of the engine, right where the sensor is. The bubble was gone early in the test but came back at higher rpm. Why? It is possible it was caught elsewhere in the engine and moved when the rpm increased. (one can hope.) I have heard that sometimes you need several heat up, up cool down cycles to purge the system. Chris's suggestion is more troubling and means the bubble is engine gas and was created when the rpm increased causing an engine gas leak into the coolant system. Sounds like I should get a gauge on the coolant system as suggested. Also troubling is the fact that the suck back means that for the first time I am pressurizing the coolant system. Previously, I could take the cap off of the hot system with no problem. Today I could not, coolant started squirting out (and since it is too low of temp to boil, that says there is gas in the system, but then we knew that). Leaks go both ways, and now when the engine is turned off, this pressure could (likely will) force coolant though the leak and into the cylinder. And today the engine was slow to start!! On the other hand, I should have seen some bubbles in the overflow tank when the engine was running if combustion gas was continuing to leak into the system (although I was not looking for them and may have missed the activity). A 7 psi cap won't contain a combustion leak. Assuming I don't wreck the engine, at least coolant leaking back will let me know which cylinder is the culprit if a leak is the problem. I don't know if I can get a gauge down here, especially on a weekend. Monday, I will top off again, and if it fires up I will immediately go to high rpm. If I am getting a pressure rise before the engine heats (evident either though overflow tank activity or squirting when I loosen the cap), then that kink of nails it. I hope I see no sign of pressure, and this last heat up, cool down will purge the system......but it is hard to be optimistic.


Comments, ideas, or suggestions are still welcome.
 
John,

A block tester, also known as a combustion leak tester, will determine if you have exhaust gases in your cooling system. A combustion test kit can be found at your local NAPA auto parts store for around 50.00. It will give you a visible result, if the test fluid changes color from blue to yellow or green, there are exhaust gases mixing in the coolant.
 
@Makomark I will try some more purges. I did not write down all the temps and should do that. I remember the top of thermostat housing on both engines was exactly 165. Some things were cooler on the starboard (problem) engine such as the heat exchanger. Exhaust manifold also slightly cooler. I attribute this to better water flow with new pumps and the clean heat exchanger although one could argue that if the themostat outlet is the same, everything should be the same. Or maybe not...I am not sure of the plumbing. If I pull the zinc out of the heat exchanger I get a hard flow of seawater, even at idle. Risers (sea water cooled) are same on both engines (and fairly cool, I don't remember but one can leave his hand on them) so I believe raw water flow is good. As for coolant I was concerned it could be too concentrated (it seemed to be as thick as the 100% in the jug) so I added some water last trip. Now that I can test I find I have 60 water/40 Dexcool which I belive is fine in tropical weather.
@Rev Bob Good idea to test for combustion gas. Now if I can just figure how to say that to the locals in Spanish....So I will likely wait and see if at higher rpm I get bubbling coming out of the coolant and if I have a wet plug. I am hoping not.
 
Don't freak out with the pressure tester - as the coolant warms, the pressure will increase solely due to the expansion. Its a continual rise in pressure that infers a combustion leak...may wanna use the good engine to see what I'm talking about. Checking the HX tank for the bubble flow may work - depends upon how violent the coolant circulation is.

You should also make sure the oil level in the pan has not increased - that wouldn't be good. if the access isn't too bad, a visual on the plugs may tell sosme more info, too.

You may wanna call your bud with the scan tool back over. if it's a Rinda tool, it should scan the crusader fine. Your ECU should support a cylinder balance test - a bad one or a bad pair that are adjacent would give you info info on where to look.
 
Lots of good advice from folks that have experience but I would also mention not to overlook any part of the coolant flow including the raw water side. Did I understand that one engine has warmer exhaust manifolds? If you are having a warmer exhaust manifold temp, there is less raw water flowing through that engine than the other. This could be from any part of the circuit including gunk in the pickups (I've even seen it due to layers of bottom paint) to junk due to rust in the raw water portions of the elbows. If the boat is in salt water and there are quite a few years on the exhaust iron, that's an area worth checking.

In principle, it's simply about flow in two cooling circuits (both raw and fresh) and a heat exchanger. In practice, it can drive you crazy finding the exact cause. For example, there can be significant raw water flowing but still not enough.

This is not to argue against any of the previous suggestios but to mention that simple flow issues can be a problem. I know I've has similar problems with a big block.

Bruce Clarkson
 
Tried at the dock again yesterday. The engine had sucked in coolant again on cooling so that looked good. Engine temps were fine on idle warm up. Went to higher rpm and once again temp rose quickly at the R020019 sensor to 208-210 and overtemp alarm tripped. As before, rest of engine was still at 165 or less and the port engine that ran though the same routine had no issues. I am going to quit fooling with it until I can buy locally (or have brought down) a kit to detect exhaust gas in the coolant. I can pay the local marina mechanic to do the pressure rise test that has been suggested, but he does not have a detection kit for gas in the coolant and I don't want to tear up the engine (yet) without definitive proof of an exhaust leak. @Bruce (above), it is the "bad engine" that runs slightly cooler exhausts, likely due to all of the new parts installed. Overheating is only at sensor area.

In thinking about past overheat experience, I believe it is possible that we only occasionally saw it because we idled out of the marina (engine is fine at idle), and then once in the ocean the wave action rocked the engine enough to get the bubbles to move to the (leaking) cap and be expelled. When sitting at the dock in still water, the 8 degree slope to the rear of the engine encourages the bubbles to collect in the front of the manifold around the sensor.

IF the theory is correct, then I believe we will find a leak from #1 (or maybe #3) cylinder to be the problem as the gas cannot have moved far or it would have been cooled to coolant temp. As it is, it appears that even though the sensor and the casting around it is dry of coolant (or at least circulating coolant), the temp is still much higher than the surrounding area. That suggests a source of very hot gas. And there should be no heat source up there other than the coolant, which is at 160 or so. We had discussed earlier the possibility of a coolant blockage in that area, but that is unlikely to be the source of the problem since on top of the manifold the coolant is the source of heat. A blockage should result in a lower temperature, not a higher temp. Likewise, the idea that a bubble from inadequate purging(what I was hoping for) is the issue makes no sense. An air bubble around the sensor should result in a cooler reading, not a higher reading. I am left with the exhaust gas scenerio.

Those of you that might have a better understanding of the engine could have a different idea. I would appreciate any feedback. Thanks for the information so far.
 
an air bubble around the sensor will give you a higher temp. The air (relative to the coolant) is an insulator. The running engine makes heat; without something to remove it, the localized temp will rise. That's just basic thermodynamics.

If the level in the gas bottle dropped again, that means the liquid drawn back into the engine displaced some air. The issue is related to the air - is the 'bubble' getting smaller or is it 'regenerating'. The amount of coolant tanken from the degas bottle is a clue to the answer.

I think your "hot gas theory" won't float; if it is a compression leak, it could be any cylinder as the source. Any bubble formed will find the highest spot in the system and then start insulating that spot (it will get hotter).
 
You are on the right course John, one can get lost chasing symptoms, the cause is the target. Perhaps a test kit from NAPA is available on-line, or by phone with a credit card from a NAPA store in the San Diego area?
 
@makomark. Actually I have a degree in thermodynamics. But I am not a trained engine mechanic which right now would be more useful. I have done some shade tree work but I am new to marine. It strikes me that other than incidental friction, the source of all engine heat is the combustion chambers. Yes, air is an insulator but the issue at any point where the metal goes dry, is whether the coolant (now absent) was carrying heat away, or actually adding heat to that area on its way to the heat exchanger. Heat from the combustion can be spread to the rest of the engine either by conduction though the metal to other metal parts (in this case from the head though the manifold gasket/bolts and then though the thin metal of the top of the manifold to the region next the the thermostat housing that holds the offending sensor). Or heat can be move from the head/block to the coolant where it heats the rest of the engine on it way to the heat exchanger. Coolant temps are normal in the engine so that is not the source of the overheat around the sensor. And since the sensor is supposed to be wet and reflect coolant temperature, I am assuming it is dry. The temp of the engine head (IR shot on the nearby end) is normal, exhaust manifold is normal, etc. These are admittedly surface temps, but so is the hot spot and it is a long ways from the head, which I think is the only source of heat that could conduct to this point (other than leaking exhaust gas). Unless there is a crossover in the manifold that heats the front and not the middle of the manifold (which seems unlikely). Heat flows "downhill" so if it is just an air bubble in the manifold at that point, and the region at 208 that holds the sensor is just a few inches the themostat housing at 165, then everything between the hot spot and the source of heat (the head) must be appreciably higher than 208, and so far I have not found it. But as you know, it is kind of tight in there. I think we can all agree that if I find exhaust gas when I get a tester we need to go into the engine. If not, I am flummoxed. But it won't be the first time! Thanks for your comments.
 
As I found to my peril--after a rag or ?? blocked the water intake on my port engine--steam does a lousy job of cooling an engine! In fact, it burnt the paint off the heads ans spun a rod bearing after 30 SECONDS on plane at only 2,500 rpms.

So....If the coolant isn't getting to a spot where the heat IS, then the temps will quickly soar. I suspect a coolant blockage somehow. It wouldn't be the first time that some doofus left a rag inside a passage "to keep dirt out" and forgot to remove it.

Jeff
 
If you think its a compression leak that large, you should be able to see the 'bubble trail' in the HX's reservoir.

There are coolant crossovers, in the intake manifold, at the front and rear.

Any indications that the thermostat, intake, or cylinder head(s) were recently removed?
 
makomark said:
If you think its a compression leak that large, you should be able to see the 'bubble trail' in the HX's reservoir.

There are coolant crossovers, in the intake manifold, at the front and rear.

Any indications that the thermostat, intake, or cylinder head(s) were recently removed?
Click to expand...

Coolant crosses over only on the front of the manifold.
I had an FWC Mercruiser that had a cracked head, it would only leak combustion into the coolant at higher rpm's and it was not enough pressure to over come the cap on the exchanger.
 
John... just a thought but, is there a way you can loosen the sender that is over the hot spot to vent the air out then tighten it back up and see what results you get.....Lee
 
Thanks for the suggestion Lee. I have loosened the sender and allowed coolant to come out around the threads to make sure the engine was "burped" on before startup. Of course the connections keep me from turning it while running but I could take it out altogether, replace with a plug, start up and measure overheat with my gun. When the area overheats, loosen the plug and see if it "burps" and runs cool for a while. Then again I might cook my hand!

I went down to the boat today. The coolant system "sucked back" as on the other engine, which means that coolant was under pressure after the engine was shut down last time and the system stayed sealed during cool down. Looked in the oil. No water. Took out all the plugs. No water. So my partner will bring down a combusiton gas detector on Friday and we will test next Tuesday. That will give proof of a combustion leak or not. I suspect we will find it is leaking, but since all cylinders are dry we will have to do a complete tear down to find it. And if it is not leaking, I will drain and pull the intake manifold and find out what's up.

All suggestions welcome!

CaboJohn
 
if it is a compression leak, you can use a coolant system pressure tester to find the source cylinder(s). Stant's manual explains the whole testing process. thanks to Chris for defining the internal plumbing path.
 
Right from the Stant Manual.

Compression or combustion leakage into the cooling system can be
detected as follows:
1. With the system and radiator pressure cap cool, carefully
remove the pressure cap and apply the tester to the filler neck.
2. Let the engine idle and warm up to normal operating
temperature. WATCH CAREFULLY - IF THE GAUGE
INDICATES PRESSURE IS BUILDING UP FAST, RELEASE
THE PRESSURE BY TURNING OFF THE ENGINE AND
ROTATING THE PRESSURE VALVE RELEASE HANDLE
ON THE TESTER HEAD CLOCKWISE UNTIL IT IS
PARALLEL TO THE TESTER HEAD HANDLE. (See step 11
below) Since this tester is not designed to release pressure
below 30 p.s.i., do not allow the pressure to build up past the
arrow indicating the maximum for each system. When
pressure builds up fast, a leak exists as a result of a blown
gasket. Replace the head gasket.

3. If pressure does not build up immediately, then operate the
tester pump until the gauge reads within the range for the
system being tested. If the gauge hand vibrates, this indicates
a compression or combustion leak into the cooling system.
Location of a compression leak is determined by
disconnecting one spark plug at a time. (Refer to ignition
system guidelines for the proper procedure. Some systems
will be damaged if this test is performed improperly.) The
gauge hand will stop or decrease vibrating when the spark
plug of the leaking cylinder is shorted out. Retest the system
after repairing the leak.
 
Thanks Mako and Chris. Having worked in industries where I used and manufactured a lot of capital goods, I can really appreciate the use of the correct test equipment. And it is frustrating to be located in paradise (Cabo) but having little personal access to test equipments, and great difficulity finding anyone that does have them, knows how to use them, and will come to the marina. What I need is for Chris to load up his stuff and come down for a little repair, and then some fishing, golf, beaches and great weather.

In the absence of that happy event, I am intrigued by the suggestion of spark plug disconnect. Right now, because of the dry plugs, if we find a combustion gas leak on Tuesday, I have no way of knowing where it is. So I suppose if I can find a pressure tester down here and if we get the vibrating needle, I could then do the plug trick and it may allow me to home in on the problem. I am still thinking #1 or#3 since I don't think the gas could travel far without cooling to coolant temperature, and as we know that temp is still under control.

I did find the Crusader engine repair manual on line, and the head removal/installation looks like pretty standard Chevy 350 stuff with only the exhaust manifold/riser being different. I will need a torque wrench and then should be good to go. Does anyone know whether special marine head gaskets are required or will autopart store stuff (available down here) do the job? Are the exhaust manifold gaskets diffferent from automotive? Do people still use new head bolts or is that a thought I have left over from the old high compression days?

CaboJohn
 
You can take a pressure gauge(0-15 psi) and a bushing, and screw it into the intake manifold where the temp sender is located if you do not have access to a pressure tester. As for coming to Cabo, Thanks for the invite but the winter work is stacked up and I have an appointment with St Marteen in Feb.
 
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I'm chiming in very late on this thread.
Here's what I would generally recommend regardless of engine, but with the Closed Cooling system:
(sort of a cut/paste from my other postings...., so forgive me for any redundancy)


Right in line with what I think that Reverend Bob is eluding to....... Use the P of E (process of elimination)!
And use it while going right down your list of probable and likely causes, one item, and one item ONLY at a time, while doing so systematically and methodically.
If done properly, a P of E won't let you down.


The E/G/h2o (ethylene glycol) side of our systems intrinsically are generally not prone to causing issues.
If the PH balance has been kept within specs, we don't tend to see the corrosion issues as we do on the sea water side.
The sea water side is a more likely suspect, IMO. (see **'s below)
Have you gently rodded the interior of the tube bundle?

As noted, your IR gun reading is a great indicator for the location of hot areas, but why the hot area?
IOW, what's causing this?
** After the sea water leaves the H/E tube bundle, it is to be divided/diverted equally to each exhaust component (V engines only).
Is your system dividing this correctly?
** Any internal hose de lamination?
Wrong fittings being used?
** Exhaust man/riser sea water transfer ports.... are these clean and non-restrictive?


Suction line breach.
One tiny suction air leak, and we kill the system... however, this generally causes over-heating in more than one location. Just a suggestion.
Follow the sea water path from the initial inlet to the sea water pump.
Crustaceans can and will grow within our sea water systems and will restrict flow.

Sea Water pump:
A new impeller does not necessarily restore a pump.
Look at the cam for any wear (exceptions: the Merc eccentrically positioned impeller pumps).
Look at the two impeller thrust surfaces.... are they near pristine? Any grooves worn into them?

Note and a long shot regarding above:
(perhaps worth the mention)
Johnson's and Jabsco's large volume crankshaft pumps share the same impeller blade count, impeller diameter, impeller shaft-drive configuration.
Of these two pumps and replacement impellers, there is a .090" difference in the impeller width and pump body depth.
Wrong impeller in wrong pump body, and you'll have flow issues.
Parts counter guys get this wrong often because these two look so similar to one another.
Verify that your impeller is correct for the pump body.
You have twins, and the two impellers could be swapped for a test... or at least compare them.


Twins will also allow you to swap temp and alarm senders and to note if the alarm issue swaps places.


Ditto Chris in post # 3 and # 9. You'll want to do this test, IMO.
However, if your exhaust manifolds are sea water cooled, it may not explain your hot spot (noticed via the IR gun) since I believe this would be more related to the sea water flow, and not on the E/G side.

Also make certain that the pressure cap is correct for a coolant recovery system.
It must seal in two areas, and offer the reverse flow valving... and with no breach in the recovery reservoir line.
Post #8.... looks like you're OK in that area.

Again, I'm coming in very late on this, and I may have missed a few points here.

makomark said:
Don't freak out with the pressure tester - as the coolant warms, the pressure will increase solely due to the expansion. Its a continual rise in pressure that infers a combustion leak...
Click to expand...
I think that this is why Chris suggested a quick fire up and quick RPM increase to 3k, and to watch the pressue.
This would not give time for any real heat expansion, and I believe that's what Chris was suggesting.
IOW, cold and quickly. Yes/No?



Reverend Bob said:
John, Use marine head gaskets, the head bolts on these old school engines are quite forgiving, in my opinion.
Click to expand...
Bob and John, I see no need for the Marine head gasket set for an engine equipped with a closed cooling system.
Save a few dollars, but use a high grade automotive set.

If there's any chance in hell that these '03 5.7L Crusader engines are NOT fitted with the Full Dished pistons, then be sure to select the correct gasket thickness dimension.
(not sure which pistons Crusader would have used in '03... most likely dished)


Good luck, John..... and again, sorry for any redundancy.
Some of my suggestions are simply routine, in general, and may not pertain to your exact scenario.
 
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