volvo heat exchanger

layzeeboi

Cadet
Joined
Dec 13, 2009
Messages
18
i have a 1985 bayliner 4cyl volvo engine with volvo penta i/o. Can anyone please tell me how does a heat exchanger work? Like give me a website, or an article about heat exchangers. When i turn on the ignition for a while it over heats, but its not on the water its in front of my house. Is this why it overheats? Im wondering its overheating because it is not running in the water? thats why i want to learn more about heat exchangers? My dad is a mechanic, and he wants to know how the cooling system works, so he can fix it. Any websites or articles would definity help. thx;)
 

Jeepster04

Chief Petty Officer
Joined
Jan 5, 2009
Messages
481
Re: volvo heat exchanger

Do you know how a radiator in a car works? Its very similar to that except its a water to water exchange instead of an air to water.

Do you have muff's hooked up to the outdrive when you are running the engine at your house? If you do not then yes, this is why it is over heating. The water from the lake cools the engine. The water from the lake passes through the exhanger and cools the coolant thats running through the block.
 

layzeeboi

Cadet
Joined
Dec 13, 2009
Messages
18
Re: volvo heat exchanger

thanx alot jeepster...thats what i needed. i didnt had the water running thru the muffs, thats why it overheated...thankyou!!!!:D
 

captmello

Captain
Joined
Jun 30, 2008
Messages
3,826
Re: volvo heat exchanger

You'll need a new impeller if you've been running without muffs. You need to have the muffs on at all times when running!!!

The impeller is up front in the small round brass housing. You can get the impeller here on Iboats or at a local dealer or even an aftermarket impeller from Napa. You need to know the engine model number. If you know the engine model AQ125 or aq131 or ..., you can download manuals.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: volvo heat exchanger

It goes the same for the ocean too right?

Yes, ocean, lake, river, whatever the boat is setting in. aka Raw Water

Along with burning up the impeller when running with no raw water to the engine (muffs), you may have burned the inside of the big hoses that hooks the exhaust manifold to the exhuast pipe. The water keeps them from burning. When you replace the impeller, you will need to find all the broken blades of the impeller.
 

tbear1964

Petty Officer 3rd Class
Joined
Mar 4, 2007
Messages
94
Re: volvo heat exchanger

Here are some pics of an '83's impeller housing, for reference. AQ125A. Yours will be similar
 

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PiratePast40

Lieutenant Commander
Joined
Mar 21, 2009
Messages
1,734
Re: volvo heat exchanger

If you go back to the beginning of this section you'll see an "Adults Only" thread and an "Information for DIYer's" section. Look through those to find a manual for your engine. The manuals aren't tutorials but will go a long way toward getting a better idea of how things work.
 
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