Mercruiser Heat Exchanger/Fresh water cooling.

[yamhoss86]

Hey guys, do any of you know if this heat exchanger will fit a 1990 Merc 4.3?
Please see pics below, Thanks for any feedback.

 

[Bondo]

Ayuh,.... Where'd ya find it,..??

What do ya know 'bout it,..??

What size is it,..??

 

[yamhoss86]

Ayuh,.... Where'd ya find it,..??

What do ya know 'bout it,..??

What size is it,..??

Found it on Craigslist.
It came out of a 2006 Volvo 4.3.
I don't know the size, but i think its 5x21.

 

[alldodge]

If it came off a 4.3 Volvo, then it will work on a 4.3 Merc. Does appear to be a Merc heat exchanger. Unable to find a 90's model closed cooling system online to check part numbers, but later 4.3 used part number 864395T01

 

[yamhoss86]

If it came off a 4.3 Volvo, then it will work on a 4.3 Merc. Does appear to be a Merc heat exchanger. Unable to find a 90's model closed cooling system online to check part numbers, but later 4.3 used part number 864395T01

Thanks for the info, so can i use this on my 1990 Merc 4.3?

 

[alldodge]

Thanks for the info, so can i use this on my 1990 Merc 4.3?

If it came from a 4.3 (or larger motor), and if there is noting wrong with it the IMO yes it should work. I'm just looking at a pic.
The Merc web site shows the dimensions at weight 35.20, length 32.5, width: 14 and height: 12.88

http://www.mercruiserparts.com/864395t01-heat-exchanger

Only other question is this would be installed on a newly rebuilt motor?

 

[yamhoss86]

If it came from a 4.3 (or larger motor), and if there is noting wrong with it the IMO yes it should work. I'm just looking at a pic.
The Merc web site shows the dimensions at weight 35.20, length 32.5, width: 14 and height: 12.88

http://www.mercruiserparts.com/864395t01-heat-exchanger

Only other question is this would be installed on a newly rebuilt motor?

Thanks for the response.
Its an original motor. Under 300 Hours.

 

[alldodge]

Being under 300 hours is rolling the dice. My memory is not what it use to be but I think it's under 20 hours for conversions

 

[yamhoss86]

Being under 300 hours is rolling the dice. My memory is not what it use to be but I think it's under 20 hours for conversions

ok, why is that? Does it matter that it was only used in fresh water?

 

[alldodge]

ok, why is that? Does it matter that it was only used in fresh water?

The reason behind it, is ever motor builds rust inside that doesn't have antifreeze in it. It will pick up sand, mud or over things also as it is operated. The little bit od build up in a raw water cooled motor is of no concern. As some of it breaks loose it just goes out the exhaust. Closing up the system will keep any of the crud in the motor and will collect on the thermostat, heat exchanger and other areas.

So it may need to be drained and refilled every so often if issues show up. Salt water motors are worst then fresh, might even be 20 hours for salt and 50 for fresh. I can look around and find it but the note is it is less then 100 in any case.

You can do it, just most all do not recommend it. Maybe some others can comment.

 

[yamhoss86]

The reason behind it, is ever motor builds rust inside that doesn't have antifreeze in it. It will pick up sand, mud or over things also as it is operated. The little bit od build up in a raw water cooled motor is of no concern. As some of it breaks loose it just goes out the exhaust. Closing up the system will keep any of the crud in the motor and will collect on the thermostat, heat exchanger and other areas.

So it may need to be drained and refilled every so often if issues show up. Salt water motors are worst then fresh, might even be 20 hours for salt and 50 for fresh. I can look around and find it but the note is it is less then 100 in any case.

You can do it, just most all do not recommend it. Maybe some others can comment.

Good info thanks so much.

 

[yamhoss86]

If i were to change the antifreeze every month, would that help? or will i be facing problems that go beyond this?

 

[alldodge]

I don't think that would help, the issue is the stuff will break loose a collect on things like the thermostat. As before a fresh water boat stands a better chance, but the problems have been with regards to overheating from things clogging up.

Maybe if closed up and run some cleaner in the motor for a short time, then flush it out which would include not installing a thermostat. Don't know for sure just spit balling. If you watch your gauges close you should see it coming before it happens. Don't see it going from just fine to overheat, it will probably be a slow build up over time.

That said I wouldn't do it just for all the unknowns. Being in fresh water you shouldn't need it any way. Is there a reason you want to install one?

 

[Bondo]

Ayuh,.... The problem will be when crud passes into the exchanger, 'n plugs it,....

The antifreeze side is sealed, no cleanin' it,....
unless ya taken the exchanger completely apart,...

I drain my motor every winter, so I know there ain't much, to no crud in it,....
You could try flushin' yer motor,....
Fire it up on the muffs with excess water flow, 'n pull all the drain plugs, 'n run it abit to see what comes out,....
As ya pull each plug, take note of the amount of crud that 1st passes out,....

You could knock out the core plugs for a better cleanin', but that's better done on a stand, not in the boat,....

 

[philbullet]

Found it on Craigslist.
It came out of a 2006 Volvo 4.3.
I don't know the size, but i think its 5x21.

How much did it cost? If you don't mind me asking.
Iam kind of in the market

 

[yamhoss86]

How much did it cost? If you don't mind me asking.
Iam kind of in the market

I got it for $150.
Kind of got it right after the posting went up.

 

[yamhoss86]

I will purchase a remanufactured engine (includes 2bb carb, new heads and pistons) with new risers, manifolds (intake and exhaust manifold). The rest will be used parts.

 

[philbullet]

I got it for $150.
Kind of got it right after the posting went up.

Well dang, if you see another like that please let me know.