always something

[cfelton]

I went out yesterday and pulled the end caps off of the heat exchanger to make sure all the water was out before it freezes and found antifreeze in the freshwater chamber on my 170 Merc. I checked the level in the riser tank looks like ive lost about 6 oz of coolant. Anybody got a good used 4in. 470 heat exchanger thats for sale? Or has anybody ever tried to have one of these repaired? I always drain it out of the petcock after running it and Im sure it was pretty empty and did'nt freeze. I cant figure what happened. It looks to be clean and in really good shape. Im stumped. :head:

[spareparts]

take it to a raidiator shop, they can at least inspect it to see if its repairable. Let me know if you need one, I have access to a couple

[cfelton]

I called a couple of radiator shops close by and they would'nt touch it. Looked on the net and found new ones but they must be made of gold, they want an arm and a leg for them. So I checked ebay and all those are 3in and mine is 4in. Spare if you find a good 4in. please let me know. Theres no rush, its 18 degrees here . Too cold for me to take the boat out, but I would like ta get her fixed. Thanks Spare!!

[macojoe]

This is why I went Outboard!! I/O never stops needing something!!

[spareparts]

see if you can find a diesel shop nearby, especially if they are marine oriented. They check and repair intercoolers and heat exchangers on a regular basis. Call them first, they may want more to check it than its worth, I'll see what I can find

[THEFERMANATOR]

They are a bit pricey, $550 for a new 4" one.

http://bpi.ebasicpower.com/pc/HEXMER99438/MER8E/Heat+Exchanger%2C+4%22%2C+Mercruiser+3.7L

Here's an EBAY used one.

http://cgi.ebay.com/ebaymotors/Mercruiser-470-3-7-ltr-4-Heat-Exchanger_W0QQitemZ320333250039QQihZ011QQcategoryZ 50442QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[cfelton]

Thanks fellas, I'm gonna check mine out today and pressure test it ta see where its leaking.Thanks Ferm, I had'nt seen that one, good price so far! I'll keep a close eye on it.

[cfelton]

I got your message Spare, I'll give him a call . Thanks alot!!

[cfelton]

I pulled it off and removed the end caps. I blew it out with compressed air until about dry. I flushed the coolant side out with fresh water. I plugged the hose that goes to the thermostat and made up a fitting for the other coolant hose so I could attach a water hose to it. Filled it with water and then pressurized it for about 15 minutes but never saw it leak a drop. Water pressure is about 60 psi. Maybe I did'nt wait long enough or maybe its gotta be hot to expand the metal enough to leak. What do you all think? The last time I ran it was about a week or so ago and I let it get to 140 degrees, cut it off and drained the seawater side of the heat exchanger side out then. I'm baffeled!:arrr:

[spareparts]

try putting air to it, pull it off the engine. Use regulated air pressure on it(15 psi max should do it) and submerse it in a bath tub, look for bubbles. The only other place I could think of for water and anti freeze to mix would be at the riser, it could have posiibly leaked back down the riser to exchanger hose(just guessing)

[cfelton]

Man Spare, we must be on the same wavelength. I slept on it and thats what I thought about! I'll try running the bathtub half full of really hot water and putting a little air on it. I just put a new riser/tank on it, and thinking about it, looks like the whole exhaust manifold and riser would have to fill completely up before it could run over into the seawater pipe on the riser and back down into the heat exchanger (I think). Its gotta be the heat exchanger, I'll let ya know what I find out. Thanks Spare!!

[cfelton]

I found my leak. I capped 3 of the hoses and made up a fitting for the last coolant hose. I put on one end cap and stood it up on one end and filled the seawater chamber with hot water. Then I put about 20lbs of air to the remaining hose and instantly I could see the bubbles start coming. It has a pin hole on the plate that goes across the end of the tubes. I might be able to braze it up. I think Ill give it a try before I buy one. Im just glad I found it. Thanks guys for your input!!

[spareparts]

don't braze, you'll have to get it too hot, use solder with a pin point mapp gas torch

[cfelton]

I bought a new oxygen/mapp gas mini torch at Lowes yesterday and finally got to use it today. I had a little trouble at first trying ta get the solder ta stick, but after cleaning it really good and giving it another try the solder flowed out like butter. I put 40lbs.of air pressure to it and after sitting about an hour, it looks like I got my leak fixed. I'll put it back on and give it a try.
:sun:

[spareparts]

there is no better satisfaction than doing it yourself:clap:

[randlemanboater]

Good job CF!!!!!:clap:

[reelapeelin]

there is no better satisfaction than doing it yourself:clap:

Agreed!!...good job...:clap:

[cfelton]

Thanks, now if I can just get time to put it back in. Ive been workin my tail off this week. Ive worked two 12hr days so far and they are thinking about working Saturday. I aint complaining, I can always use the money!