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blk93jeepzj

High engine temp, then returned to normal

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blk93jeepzj

Needing some help and thoughts....2004 340 Monsoon.... 

Last night went for a dinner cruise.  Dropped the lift and started the engine.  Idled while we untied the ropes and got things situated.  Continued to idle as we moved passed the no wake buoy, temp 150ish.  Take off to head to a restaurant for dinner.  Running about 30mph Make it a 1/4 of a mile and the engine bogs, I pulled the throttle back to neutral and check gauges.  High temp flashes on the digital gauge, look at the temp and its reading over 200 degrees. Engine is still running and I can see that the temp has already began to drop back down.  I left the engine running since its dropping and pop the cover for the engine.  Nothing is spraying water, exhaust riser are warm but not hotter than normal, muffler is warm, no water in bilge.  Everything looks and sounds normal.  Engine has come back down to 160 degrees and holding like normal.  We take off again temp climbs to 180 and drops back down to 160 and holds there for the rest of the ride.  Gave dad the steering while while we were underway and I again popped the engine cover, everything looked and sounded fine still.  Nothing felt overly warm and no water was staying or leaking anywhere.    

Ate dinner.  Load up in the boat idle out past the no wake zone.  Take off again make it 1/4 of a mile and the engine bogs down again.  Pulled the throttle back to neutral and the temp again is high but begins to drop down again while the engine is idling.  Gets back to 160 quickly, let it idle to make sure it would stay there.  Take off again and no other issues the whole trip back to the dock.    

Any thoughts on what the cause may be?

I plan to pull the hose and see if there is any debris on the transmission cooler screen and go underneath and check the raw water intake to see if there is anything clogging these spots.  It was gettinga late and dark by the time we got home from dinner or else I would have checked these yesterday.  The impeller was changed this spring.   

Thanks in advance.

Robert 

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h2ojunkie

You probably will find your problem on the trans cooler like ya mentioned. Use shop vac if ya can and suck debris outa there.  If not, replace the thermostat and see what happens. Start w easy fixes first.  Ive had same issues a few times, debris clogged cooler intake side. 

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dlb

Check the trans cooler.  If there is no debris I would replace the impeller,as well as, looking at the T stat as options to solving the issue.

The impeller can look fine but not seal at higher RPMs.  I have had that issue before.  The impeller should suck at least 5 gallons in about 15 seconds.  If you test the impeller under hose pressure, fake a lake or the like, the hose pressure will mask the problem.  Learned that the hard way.

 

Edited by dlb

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blk93jeepzj

Thanks for the input.  

I plan to start easy and with the trans cooler.  May also take down a new thermostat just in case I can not find any debris.  I did change the thermostat 5 years ago when I did the engine swap.  The impeller was replaced this spring and we have been using the boat with no issues up till this weekend.  

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Bozboat

If the raw water impeller is good and the trans cooler is clear.  Check the thermostat by placing your hand on the thermostat cover while the engine is cool, then run the engine to 160 and you should feel thermostat cover go from cool to pretty warm over a very short period of time when the temp gauge shows 160.  If all else fails, you might check the circulation pump.

 

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Woodski

@blk93jeepzj:  When you swapped thermostats did you go with marine, if not corrosion may be the culprit freezing the stat shut.  As noted, even if you did swap impellers, it could also be a culprit.  Your description implies a system blockage (trans cooler most likely) or low output since at low water flow rates the system stays cool and only runs hot when higher water flow demand is needed.  You can do a search on the circulation pump issue, threads on this site also.  Do you have a water strainer, if yes make sure it is properly sealed, if it sucks air around seal the boat can run hot and that is also an area for blockage.

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blk93jeepzj

Yes it was a 160 degree marine thermostat from Bakes.

I will check the impeller.

No water strainer.

 

After the initial limp mode, then cool down.  We drove more than 10 miles no issues till after dinner and it did the same thing within the first 1/4 miles.  Limp mode, slowed down, let cool, then drove over 10 miles with no issues.  Seems to me as if there is a blockage, maybe heavy enough to rest in the bottom of the hose, gets dislodged and clogs the transmission cooler screen when the thermostat first opens? :dontknow:   We shall see this weekend.

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jdeltoro

I've kinda had the same issue. Do you guys have a picture of where the trans cooler screen is? I've been trying to locate it online but cant find anything that pin points where it is on the monsoon 340.

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Woodski

@jdeltoro:  Not 100% sure on the Indmar, but in most cases the trans cooler is a water to oil heat exchanger that is basically a long metal tube inline after the raw water pump and before the inlet to the engine water circulation pump.  Pull off the inlet side water hose and simply check to see if there is debris on that side as the internals are numerous inline tubes that flow water between the trans oil tubes.  That matrix simply ends up being a choke point or debris catcher.  Hope that helps.

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jdeltoro
41 minutes ago, Woodski said:

@jdeltoro:  Not 100% sure on the Indmar, but in most cases the trans cooler is a water to oil heat exchanger that is basically a long metal tube inline after the raw water pump and before the inlet to the engine water circulation pump.  Pull off the inlet side water hose and simply check to see if there is debris on that side as the internals are numerous inline tubes that flow water between the trans oil tubes.  That matrix simply ends up being a choke point or debris catcher.  Hope that helps.

Ok, I wanted to make sure I was pulling the right hose. I think im going to just pull all the hoses to the cooling system one by one and clean them out. Thanks for the reply.

61755048-16E6-4AE4-B687-C16DA0215FFF_zps

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OLDGUY

Check the hose clamps on the suction side of the impeller pump to make sure they are tight and your not sucking air. I had an over heating issue one time and that was the problem.

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Woodski

@jdeltoro:  I would make sure the entire hose is free of debris, given the angle, the debris could 'fall' back down to the lowest point.  As noted, poor sealing particularly on suction side will reduce performance.

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blk93jeepzj

Just wanted to follow up.

Pulled the hose off of the intake side transmission cooler and there was debris stuck in the mesh screen.  Cleaned it out and that seems to have stopped the overheating issue.  I did suck out all the water in the hose just to make sure that there was no debris that had settled in a lower spot.  Thanks again for all the replies.  

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blk93jeepzj

So the overheating has returned... Or never quite went away.  Was only doing it on high speed runs 25-30mph cruising or wakeboarding.  Now it is happening more frequently even at surfing speeds.  Temp per gauge rises to 170-175 engine goes into limp mode, leave engine running and watch temp come back down to 160 and take off again.  Engine does not feel hotter than normal to the touch.  

I have replaced the thermostat, still overheating.

Checked the transmission cooler screen for debris, none there.  

Switched out the new impeller I installed this spring with the old one that was two years old to see if that was the problem, still over heating.  All the vanes were intact and still looked good 

 

Plan on testing and/or replacing the temp sensors.  Anyone have any other thoughts?

Edited by blk93jeepzj
Added additional information.

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oldjeep
7 minutes ago, blk93jeepzj said:

So the overheating has returned...  

I have replaced the thermostat, still overheating.

Checked the transmission cooler screen for debris, none there.  

Switched out the new impeller I installed this spring with the old one that was two years old to see if that was the problem, still over heating.  All the vanes were intact and still looked good 

 

Plan on testing and/or replacing the temp sensors.  Anyone have any other thoughts?

How many hours did you put on it between when you thought it was fixed the last time and the next overheat?

Edited by oldjeep

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blk93jeepzj

5-6 hours mostly surfing.  

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blk93jeepzj

Update.

Replaced gaskets on the thermostat housing since I had to reuse the originals when I first replaced the thermostat.  Replaced the impeller gasket too, have had the cover off a couple of times to inspect impeller and hadn't replaced it.  Thought air was possibly getting into the system.  Added a coiled wire to the J-hose to prevent it from collapsing (all new replacement J-hoses have the spring wire in them).  Rechecked the transmission cooler screen as well. 

Still overheating.  

Surfed for awhile and though that the problem was solved, then it showed up again.  Had my wife drive while I watched things in the engine bay.  J-hose was not collapsing at all, in-fact  it was very rigid while underway.  Going faster seems to expedite when the overheat will show up.  Exhaust riser were getting hot to the touch, not just warm, while we were running at higher speeds right before an overheat.       

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minnmarker

Riser temp is independent of the thermostat so the thermostat should have no impact on the risers - but inadequate water off the impeller could impact both engine and risers.  Were both risers getting hot?

Perhaps stupid question but could someone have re routed the cooling hoses? 

It's pretty hard to see the impeller on an LSV.  Are you sure it's in good shape all the way from edge to edge?

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blk93jeepzj

Yes both risers were getting hot.  

Hoses have been the same for 5 years, issue started mid season this year.  

Impeller is fine.  I pulled the impeller out 3 weeks ago and swapped in another, thinking maybe the hub was spinning.  (Swapped in my used/back up impeller from this Spring's replacement.)

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oldjeep

I'd pull the circulation pump and see if its impeller cracked

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minnmarker
Just now, oldjeep said:

I'd pull the circulation pump and see if its impeller cracked

:plus1:  But that does not explain the hot risers...  Maybe they're not really that hot?

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minnmarker

One more thought: could something have gotten hung up in the V drive cooling chamber?  - or in the hose from there to the impeller?

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blk93jeepzj

What are the chances of the circulating pumps impeller cracking?  Not that it couldn't and I'm willing to try any suggestion.  

Maybe the risers are not as hot as I think they were.  Didn't have a temp gun with me.  The hoses around the engine were not feeling overly hot to the touch or the thermostat housing.   

Something could be stuck in there from point A to B.  

Thinking about replacing all the hoses, 12 years old maybe getting air in the system somewhere or breaking on the inside.

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oldjeep

You're running out of things to check.  Only takes 4 bolts to pull the circulation pump and another 6 to pull the back plate off of it - you will need new gaskets if it is OK

http://www.michiganmotorz.com/circulation-water-pump-p-55.html

Easy enough to pull the hose from the raw water pump and blow through it to see if there is restriction between the pump and the water inlet on the bottom of the boat.

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blk93jeepzj

Sounds like the logical next place to check then.  

Wow, great price at Michigan motors.  Beats Bakes and even Skidim by a long shot.  Recommendation on where to get gaskets if the old pump is still good?  Are they the same as automotive gaskets?   (Nevermind found the gaskets locally)

When the boat goes into limp mode the gauge is reading 180.  No audible alarms are sounding.  Just change in tone from the exhaust as the boat throttles down.  

Edited by blk93jeepzj
Found gaskets

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