[kspatrick]

   
Hi all - first time poster. I have a 2006 2900 Open Classic with 2006 Crusader 6.0L engines.

Last season both engines maintained a 170F temp... and there were no issues. At the time of winterizing the coolant was checked and was noted to above the freezing point for the port engine. So the coolant was drained and then new coolant added. This season at commissioning the degas bottle was essentially empty, it took about 2.5 gallons to bring it up to a consistent level. So we figured something was not right.

On the short shake down cruise the port engine was running at ~178F, it fluctuated a bit, but never got over 180F. When we returned to the dock, we checked the degas bottle and there was only brown sludge in the bottle. The engine did not run rough, stall or otherwise indicate a more serious problem such as combustion gas.

The port engine heat exchanger was pressure tested, failed and requires replacing. It was ordered and will be here Wednesday.

Upon removing the T-stat housing from the bad heat exchanger the thermostat was installed opposite or upside down (See pic) what the Crusader parts manual shows (see pic & manual page attached). Can anyone confirm the proper installation direction for me please?

I could not find any info or service bulletin that would suggest installing the thermostat as it had been. Just looking get it installed the proper way. I will be checking the starboard engine to see how that thermostat is installed as well. My thought is that it should be installed per the manual diagram,  but wanted to be sure that there was not a reason to installed it as it was found.

I appreciate any help/guidance!
txs

   

[Sans Peur]

Seems to me that you would install it as in the picture. The spring side should be on the hot flow side of the system.

[kspatrick]

Seems to me that you would install it as in the picture. The spring side should be on the hot flow side of the system.

Thanks Sans Peur - To be clear then the hot side would be up into the thermostat housing, spring side up (or OUT) from then heat exchanger and not as I found it correct?

Coolant flows from the manifolds/elbows into the T-stat housing. Once the coolant reaches 170F, it opens and allows coolant to flow into the heat exchanger to be cooled.

Obviously it worked installed backwards for a period, but it didn't seem correct to me with the spring INTO the heat exchanger as that is where we want the flow to go when the thermostat opens for the hot coolant to be cooled.

[Medicone]

At least for the 8.1L Captain's choice, it is my understanding that the spring side should be sticking out of the heat exchanger - not the pointed side.  The spring is in contact with the hot engine coolant.  When the engine coolant gets too hot, the spring is biased away from the heat exchanger which causes the bypass tube from the thermostat housing to be blocked so that ALL of the engine coolant flows from the engine into the heat exchanger for cooling.  Also, the thermostat usually has markings on one side that say "to rad" (e.g., to radiator).  If the spring were inside the heat exchanger, while it still would probably work, you may get a slower reaction because the temperature of the coolant in the heat exchanger should be lower than the temperature of the coolant coming from the engine (e.g., outside of the heat exchanger).  Also, I'm not sure about the length of the spring extension (minimal), you would want to avoid having the spring extend into the heat exchanger and damage the tubes therein.

The parts manual and user manual shows the thermostat in the correct orientation (e.g., spring side up).

Also, Page 83 of the Parts Manual shows how the thermostat works within the thermostat housing during warm up, normal operation and overheat.  You should definitely look at the Page 83 as well as the water flow diagrams.

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Best of luck!

-M1

[kspatrick]

Medicone - Perfect thanks, that's how I read it as well.... it was only that it ran at 170F last year that caused me to question it....

Appreciate the input and confirmation of the logic.

Will be installing the new heat exchanger today or tomorrow.. will post the outcome after...hopefully a good ending and back to  boating.

txs!

[Medicone]

I don't know what your normal operating temperature is supposed to be on the 6.0, but if you have 170 thermostats I imagine that running under 180 cruise/WOT would be considered to be within normal limits.  On my 8.1Ls, under 180 is normal.  I just replaced both oil coolers and heat exchangers on my boat (the buyer should be very happy) and it runs comfortably below 180.

Some things to keep in mind:
-the coolant in the degas bottle fluctuates with temperature.  When the engine cools, it should suck some of the coolant out of the degas into the engine.  Check the operating manual for the proper procedure for adding coolant to the appropriate level.  The procedure for my 8.1 is different than your 6.0 because coolant is added initially to the heat exchanger, and then subsequently to the degas bottle.  I don't think the 6.0 has a coolant fill in the heat exchanger - just the degas bottle.
-when you drain/change the coolant, you should flush it a few times to get any sludge out and make sure you are using the same coolant (e.g., GM approved w/Dexcool for my 8.1Ls - usually pink or orange'ish).  You can't mix the green stuff with the dexcool or it will gum everything up
-after you add the coolant, you have the burp the system to get any air bubbles out (see operating manual).
-if you have sludge (make sure it is not oil), I have been told that you can run "Cooling System Cleaner Restore Plus" through it which will clean everything out
-if you see temperatures creeping up, it often is a raw water issue.  A lot of gunk/growth gets caught up at the oil coolers and the heat exchanger raw water sides.  I would check the inspection ports on your heat exchangers/flush out the tubes with fresh water as well as backflush the raw water side through the oil coolers.  It's interesting to see what comes out.
-

[kspatrick]

Thanks all for your input.... all seems well and running at 171F with the thermostat installed as the manual shows, with the SPRING side into the Thermostat housing.

Not sure why it was installed opposite as it was maintained by the same Tiara & Crusader dealer since new.

But i learned a few things as a result and the heat exchanger replacement was easy and uneventful.

Back on the water, txs again!