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!

87 Sunsetter overheating

Recommended Posts


Ill try to keep this short but id appreciate some feed back and advice. ill a** the cliff notes to the end. This is my first boat but i am very mechanically inclined, i have built my own engines etc. 

the story i got with the boat was the previous owners took it out and it started over heating, pulled it out of the water and found the impeller had completely disintegrated. They installed an impeller and relaunched the boat, found it still would not stay cool. they somehow diagnosed it as a blown head gasket. Tore it down, had the heads machined etc and never reassembled. this is how it was when i bought it. I reassembled and fired it up only to find it gets hot when running off the hose. replaced the impeller, thermostat and inspected the water pump, everything looks fine. I then took the coolant hose off the heat exchanger and found half an impeller stuck in the inlet. pulled all the pieces and now it stays cooler, but still isn't right. Running off the hose at full blast it will fluctuate between 160-180 BUT the port side exhaust rubber hose is smoking hot (literally) while the starboard side is cold. both risers themselves are cold, its only the top half of the rubber hose that is hot and smoking. have a very solid flow of water coming out both exhaust ports. i pulled the hoses off the risers and flushed the with water, both seems to flow no issue with the hose on full blast. 

Pulled the riser off port side, light rust but i have seen much worse on functioning boats i have worked on for friends. 


Any ideas? 


Cliff notes: new to me boat. new thermostat (140), new impeller, visually good water pump. running 160-180 on the trailer with the hose. Port side exahust rubber is hot enough its smoking even though the manifold and riser are cool.

Link to comment

After doing more reading maybe this is normal on the hose. at idle it stays around 150*. at about 22-2300 steady rpm is when it gets up to 180 and starts smoking. Perhaps it will be fine once in the water? 

Link to comment

Definitely try it in the water.

Definitely change the exhaust hoses if you have smoked them.  With that age boat, they are probably overdue for a change anyway.  Do the fuel lines also.

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.

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...