Jump to content

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

'06 RLXI Exhaust Manifold Question - after overheating


Recommended Posts

This may be a stupid question, but here goes....

'06 RLXI.....the boat got hot recently.  After dipping it in the water and idling from the ramp about 600 yards or so, I smelled something burning, looked at the temp gauge and saw no reading so I shut the boat down.  After checking all the hoses, I realized there was no water flowing from the raw water pump.  Turned the valve off the inlet and disconnected the hose from the pump then turned the valve back on....and no water coming through telling me the intake was blocked.  I blew through it several times until the blockage was clear.  Still not sure what blocked it.  Started it back up with water going through it now and temp was reading just over 200 and then it came down quickly.  Noted that the plastic fitting on the bottom of the exhaust manifold was leaking.  There appeared to be some thread sealant of sorts that was compromised due to heat and there was a leak on both sides.  

After inspection, nothing else seemed wrong.  Exhaust hoses were not damaged, at least not per a visual inspection, and nothing else seemed to be a problem.  

 

  1. What sealant is used on the plastic fitting?  They are both lose now and need to be tightened, but while I do so, I want to be sure it's done correctly.  Should I replace the fittings?
  2. What else should be done, besides an oil change due to the heat, to protect it?
  3. What else should I look for that may have been damaged due to the heat??


Hoping that @Woodski or @tvano or @Engine Nut may have some insight......

 

 

Edited by inlandlaker
Link to comment
9 minutes ago, inlandlaker said:

looked at the temp gauge and saw no reading

I'd add fixing the temp gauge to your list.  The overheat alarm should have gone off, no?

Link to comment
2 hours ago, Eagleboy99 said:

I'd add fixing the temp gauge to your list.  The overheat alarm should have gone off, no?

without water in the block the temp sending unit may not send accurate info; likely nothing wrong with the temp gauge.

chris, there are lots of links online that report synthetic oil will take the heat.

if it were mine i'd re-seat those melty fittings, take it easy for a couple laps on the lake (under a watchful eye) then drive it like you stole it.

rip n grip.

 

  • Like 2
Link to comment
14 minutes ago, tvano said:

without water in the block the temp sending unit may not send accurate info; likely nothing wrong with the temp gauge.

chris, there are lots of links online that report synthetic oil will take the heat.

if it were mine i'd re-seat those melty fittings, take it easy for a couple laps on the lake (under a watchful eye) then drive it like you stole it.

rip n grip.

 

Agree with this.  Open cooling means no water in, no water flowing past temp sensor to be read.

Link to comment

If the nylon fittings on the exhaust manifolds warped (confirming that the engine temp did indeed get up over 200), replacements are <$10 ea.  

Link to comment
11 hours ago, John I. said:

If the nylon fittings on the exhaust manifolds warped (confirming that the engine temp did indeed get up over 200), replacements are <$10 ea.  

I know.  It's a different style now.  They're no longer a single piece with 2 sizes of barbed hose fittings.  They are now 2 fittings per side and there is a manifold plug that needs to be removed to install them.  I don't think they're warped, however.  I plan on simply tightening the fittings and seeing if they still leak.  If so, then I'll replace them.  

10 hours ago, Chaabo said:

check your impeller!

Yes, that's a given.  I have a new Globe Run Dry impeller in there currently and have a new Johnson impeller laying around, so I will swap that for sure.  It only ran for a bout 5-6 minutes at idle.  Long enough to leave the dock and travel about 600 yards.

Link to comment

Uh oh, the notorious blue impeller...

Yeah well, I tried that one as well. Once. It needed a high rev every start up to prime. First time out with the Globe I didn’t know and engine overheated while idling from the boat house over to the slalom course. Made weird noises as well, didn’t like it and went back to a Johnson impeller.

  • Like 2
Link to comment

@inlandlaker- Personally I would swap out the plastic elbows although they may be okay for years to come.  My friends boat that had pretty much same scenario needed them swapped out as a twist attempt simply cracked them (due to the heat making them brittle).  Plumbers tape works fine also as a sealant.  If you want to do a bit of a deep dive, a leak down test or a compression test would make sense.  If you simply do re-tighten and seal on the elbow fittings I recommend listening to your starter as you crank to ensure it spins free.  If you hear a pitch change or thump as you start it, you are probably getting water in to one of the cylinders (remote probability but paying attention to it doesn't cost you anything).  Check oil to make sure it remains clear & no water in crankcase.  Per your inspection, did you look at the inside of the rubber exhaust hoses, you probably won't see external damage?  Probably worth popping off the exhaust manifold and taking a look inside.

Link to comment
1 hour ago, Woodski said:

@inlandlaker- Personally I would swap out the plastic elbows although they may be okay for years to come.  My friends boat that had pretty much same scenario needed them swapped out as a twist attempt simply cracked them (due to the heat making them brittle).  Plumbers tape works fine also as a sealant.  If you want to do a bit of a deep dive, a leak down test or a compression test would make sense.  If you simply do re-tighten and seal on the elbow fittings I recommend listening to your starter as you crank to ensure it spins free.  If you hear a pitch change or thump as you start it, you are probably getting water in to one of the cylinders (remote probability but paying attention to it doesn't cost you anything).  Check oil to make sure it remains clear & no water in crankcase.  Per your inspection, did you look at the inside of the rubber exhaust hoses, you probably won't see external damage?  Probably worth popping off the exhaust manifold and taking a look inside.

Great points, @Woodski!  Thank you.  I'll take a look inside the exhaust hoses.  I'm hopeful that it didn't get hot enough to damage a head gasket or anything.  I did check the oil and it was clear.  Checked it again the following day and it was still clean and had no water in it.  I've gone ahead and ordered the new fittings.  Thanks again.  

2 hours ago, Chaabo said:

Uh oh, the notorious blue impeller...

Yeah well, I tried that one as well. Once. It needed a high rev every start up to prime. First time out with the Globe I didn’t know and engine overheated while idling from the boat house over to the slalom course. Made weird noises as well, didn’t like it and went back to a Johnson impeller.

Yeah....totally understand.  In my experience, I've not had that issue of lack of prime.  This case had nothing to do with the impeller.  Something blocked the raw water intake.  Don't know what the heck it was, either.  

 

Link to comment

re: exhaust hose inspection; with the price of bore scopes i'd take a look at buying a scope before wrestling with the exhaust manifold and exhaust hose interface.

  • Like 2
Link to comment

@Woodski is on to something.  It's an '06, probably with original hoses.  I would inspect them as I threw them in the trash.  The easy way to pull them is to take the risers with them.  You probably need new riser gaskets anyway. 

What better way to sink a boat than with ruptured 4" hoses that terminate below the water line? 

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...