Drain cleaner (drano, etc) to clean heat exchanger???

[probee773]

Brand new to this site and fairly new (<6 months) to boating. I have a '93 Wellcraft Excel 18sx with a Volvo Penta 230 four-cylinder gas engine that is overheating. I thought it may have just been the guage until it started steeming and spraying out coolant. I've read tons of internet postings, and I'm thinking my most likely problem is either a clog in the fresh-water section of the heat-exchanger, or that I'm sucking in air in the freshwater system through a leak.

I've check the thermostat and it opens properly, the coolant looks good with no particles or corrosion evident, the impeller looks good, but when I hook up the ear-muffs, I get very little water out through the exhaust. I did plug up the hole on the bottom of the outdrive, so I know it's not that.

Now, if it's not sucking up air, and I do in fact have a clog, has anyone ever used a drain cleaner such as drano or liquid plumber to attempt a flush in the fresh-water side of their heat-exchanger? What do you think?

Thanks in advance for all of your help!

 

[Haut Medoc]

Re: Drain cleaner (drano, etc) to clean heat exchanger???

Pull off the endcaps & look....
That is the raw water side......
You can't see the freshwater (closed) side......
The other possibility is scale stuck in your risers inhibiting flow.....
If it were me, I would take it to a radiator shop & have it done professionally........
Welcome to iboats, btw.......​

 

[crazy charlie]

Re: Drain cleaner (drano, etc) to clean heat exchanger???

If the heat exchanger is in fact what needs to be cleaned then I would use radiator flush or muriatic acid before I used drain cleaner.As a matter of fact,I dont think I would even consider using drain cleaner.Charlie

 

[probee773]

Re: Drain cleaner (drano, etc) to clean heat exchanger???

Thanks guys! I guess I should have said "raw-water" not "Fresh-water." I'm going to investigate on Friday, and I'll let you know what I find.

 

[Don S]

Re: Drain cleaner (drano, etc) to clean heat exchanger???

I't probably NOT going to be a clogged heat exchanger.
If you have low water flow, it could be because of air leaks on the suction side of the raw water pump. Those tubes have to seal correctly on the pump or they will suck air. If the bushings in the pump are warn too much they will suck air. the worst place for problems is the hose connection where the water hose attaches to the drive. That hose connections corrodes off and sucks air. This is usually most evident when in the water. Stopped or moving slowly thru the water the engine will cool correctly because that connection is under water. When it's out of the water (when on plane), it sucks air and you get an overheat.
It's a very common problem with the older Volvo's, especially if in salt or brackish water.

 

[probee773]

Re: Drain cleaner (drano, etc) to clean heat exchanger???

Thanks Don S. If that is the case, does anyone know where I can find a replacement hose/ gaskets and instructions on how to replace this hose?

I took a look at it and did not see any visible cracks in the rubber hose, although, it may be sucking air at the connections. Also, it looks like it's not in a very easy spot to access, that's why I'm wondering if there are explicit instructions anywhere.

 

[RubberFrog]

Re: Drain cleaner (drano, etc) to clean heat exchanger???

Do you have a manual?

 

[Don S]

Re: Drain cleaner (drano, etc) to clean heat exchanger???

Is not the hose that causes the problem, it's the alumunim connection that the hose clamps on that corrodes away. Usually looks like it's hooked up just fine.
You aren't going to find any detailed step by step instructions. Best thing to do is remove the upper gear box to access the connector. You will need new gaskets and orings for the upper gear box, and you might as well put on a new ujoint bellows while you have the gear box off if the bellows is more than a couple of years old.

OEM manuals are the best manuals to get, the engine and drive manuals are seperate and cost about 20 bucks each.

 

[probee773]

Re: Drain cleaner (drano, etc) to clean heat exchanger???

I have the Clymer & Seloc manuals for this, but neither is quite what I was hoping for. How hard do you think it would be to replace the hose & connectors without removing the upper gear housing? I really don't want to tear down things to get to this connection as I'm a boat do-it-yourselfer novice, and I can just see other problems being created if I have to remove the upper housing. I will do it if it is neccessary though because I have a nice boat trip planned out for Saturday and I need my girl running top-notch!

 

[BRG25]

Re: Drain cleaner (drano, etc) to clean heat exchanger???

Can't argue with this...