What's Wrong? Anti-freeze Leak :(

[Carl C]

Getting the boat ready to go today. My coolant reservoir was low so I added about a gallon. I started it up on the hose and some anti-freeze came out the back at first. Then it looked like just water, temp stabilized and I thought I was good to go. I put it back in the garage and now my anti-freeze is dripping out of the raw water intake on the shorty. The reservoir is almost empty again. What is wrong? Heat exchanger?

[Mr X]

Carl, seems like that would be the culprit.

[MOP]

Probably the oil cooler! Tony went through that on his. He had a local guy fix it.

[Mr X]

Probably the oil cooler! Tony went through that on his. He had a local guy fix it.
Phil,
would a bad oil cooler leak antifreeze out of the water pick up?
I thought the only place anti-freeze and raw water came into the same device was the heat exchanger.......?

[Carl C]

The oil cooler could do that?? I am thinking about just putting in the new 525 EFI. I would still need to fix this motor before selling it.

[Carl C]

I don't see any leaks in the engine compartment.

[MOP]

100% wrong no anti freeze there!!!!!!

[Carl C]

OK, then I guess it would be the heat exchanger.

[joseph m. hahnl]

OK, then I guess it would be the heat exchanger.


Carl it could be a bad riser gasket.
To check the heat exchanger pop off the raw water hose . fill up the resevoir and see if it leaks out where the hose goes. I tend to doubt the exchanger would have a hole in it.

[Carl C]

Carl it could be a bad riser gasket.
To check the heat exchanger pop off the raw water hose . fill up the resevoir and see if it leaks out where the hose goes. I tend to doubt the exchanger would have a hole in it.

I don't have riser gaskets. I have CMIs. I will check the heat exchanger. Leaning toward doing the 525 swap now. Replace the bad part on the 496 and get it up for sale. It is still a strong running motor with 4 short Michigan fresh water boating seasons. About 230 hours.

[Pismo]

Get the 496 running perfect again before the swap, then you can sell it honestly with total confidence. One problem/project at a time. One of those many little tubes in the exchanger still had water in it all winter.

[BUIZILLA]

how is the antifreeze getting past the sea water impeller to flow backwards out the drive intake?? the heat exchanger is after the sea water pump right... kinda impossible IMO...

[Just Say N20]

how is the antifreeze getting past the sea water impeller to flow backwards out the drive intake?? the heat exchanger is after the sea water pump right... kinda impossible IMO...

Good point. I don't know the location of the pump in the flow of things. But, at the same time, if it IS dripping antifreeze from the raw water intake, and there is just one hose connected to the intake, where else could the antifreeze be coming from, regardless of where the pump is?

I have had a heat exchange go bad. All it takes is one tiny pinhole. I took it off the engine, and had it pressure tested. Little tiny bubbles showed up. Mine was a transmission cooler for a V-drive, and thankfully there was more pressure on the tranny fluid side than there was in the water system, so oil was forced into the water, not the other way around.

[VetteLT193]

how is the antifreeze getting past the sea water impeller to flow backwards out the drive intake?? the heat exchanger is after the sea water pump right... kinda impossible IMO...

old impeller

[Carl C]

Impeller is not old. It is just a slow drip and seems to be only going down to the level of the exchanger. That is why it only took one gallon of anti-freeze. I'm pretty sure that's what it is. I will check it and replace it if I'm right so I can sell this engine with confidence as pointed out. Thanks everybody. I think this will be an easy repair. Maybe I can "borrow" the one off the 525 to verify that this is the problem and the only problem. This motor will be verified as ready to run before listed for sale.

[BUIZILLA]

can't get back past the impeller, if it's good

absolutely impossible

[RickR]

Buzz
On my 1995 fuel/seawater pump, water seeps past my impeller (even with new impeller and housing) after I shut the engine down.
Engine will slowly drain for hours if I leave the drive down.

Carl
Try a local radiator shop for leak test and/or repair on your exchanger.

[Carl C]

can't get back past the impeller, if it's good

absolutely impossible

Remember that theser things take a set over the winter. I don't think there is a 100 % seal there. It is a very slow drip. When I started the motor there was an initial spurt of orange anti-freeze that had apparantly collected in the heat exchanger, then the exiting water looked clean. After I put it away and put the drain pan under the drive I checked a couple hours later and there was anti-freeze in the pan and a very slow drip from the water pick-up. I'm talking about one drip every 5 seconds. I will look at it more today. Hopefully an easy thing to troubleshoot and maybe I can get on the water this week.

[MOP]

[quote=RickR;506712]Buzz
On my 1995 seawater pump, water seeps past my impeller (even with new impeller and housing) after I shut the engine down.
Engine will slowly drain for hours if I leave the drive down.

Agree 100%

What is dripping out after the drive dries off say ten minutes or so is one of the best indicators of the impellers/pump condition a slow drip is normal, a brand new pump will drip at a rate of about one drop every 5-10 seconds. When it becomes a fast drip it is time for a pump job. Next time you haul out take a minute to see what your pump is doing. Also the next time you start up notice how long it takes for the water to come out of the pipes, if the system was completely full it would be near instantaneous not the usual 5-10 seconds.

[Carl C]

[quote=RickR;506712]Buzz
On my 1995 seawater pump, water seeps past my impeller (even with new impeller and housing) after I shut the engine down.
Engine will slowly drain for hours if I leave the drive down.

Agree 100%

What is dripping out after the drive dries off say ten minutes or so is one of the best indicators of the impellers/pump condition a slow drip is normal, a brand new pump will drip at a rate of about one drop every 5-10 seconds. When it becomes a fast drip it is time for a pump job. Next time you haul out take a minute to see what your pump is doing. Also the next time you start up notice how long it takes for the water to come out of the pipes, if the system was completely full it would be near instantaneous not the usual 5-10 seconds.

That's funny. Mop, you posted that at the same time that I posted that it was about one drip every 5 seconds! ESP.

[Carl C]

It's the heat exchanger. I winterized the motor. Don't know what happened. Maybe the shop ran it on the hose and didn't tell me or maybe it just failed or maybe somehow I didn't get all the water out but now I need an expensive part.:(

[gcarter]

It's the heat exchanger. I winterized the motor. Don't know what happened. Maybe the shop ran it on the hose and didn't tell me or maybe it just failed or maybe somehow I didn't get all the water out but now I need an expensive part.:(
Maybe not too bad. I've seen a number of new ones on ebay for $400.00 or so.

I mean compared to shorties, headers, and new engines, that's cheap.

[joseph m. hahnl]

It's the heat exchanger. I winterized the motor. Don't know what happened. Maybe the shop ran it on the hose and didn't tell me or maybe it just failed or maybe somehow I didn't get all the water out but now I need an expensive part.:(

You could always change it to raw water cooled:biggrin:

[Carl C]

You could always change it to raw water cooled:biggrin:

Got to fix it right and sell it. I'll do some price shopping. George, I didn't see one on e-bay. I think I need to buy a new one. ......Hey MP.....

[VetteLT193]

Got to fix it right and sell it. I'll do some price shopping. George, I didn't see one on e-bay. I think I need to buy a new one. ......Hey MP.....

you might want to list it as optional... you never know if you will find a guy that blew an engine and needs a quickie replacement that already has a good exchanger.

[Carl C]

you might want to list it as optional... you never know if you will find a guy that blew an engine and needs a quickie replacement that already has a good exchanger.

That's a thought but I wouldn't want anyone to think there might be a problem with the motor. It is still a good running motor. Might do that though. The money tree is drying up!

[mattyboy]

this is just me but a heat exchanger is not optional anything with oil or cooling is a must for me starters and alternators are optional. you'll recoupe the money in sale price plus the time in which it sells,

Carl if they ask you what happened what will you tell them it failed over the winter?? which will lead anyone who has freezing weather to think that it froze and had a problem and wonder about the motor

again just me it happens alot up here by me and has been a deal breaker on a few boats I have looked at this time of year might not be so down by Vette so this is more a personal/ location preference

look at it from the buyers eyes why did he pull a good engine and there is no heat exchanger is the motor good ???

[BUIZILLA]

i'd bet Raylar has plenty of them laying around..

[Carl C]

this is just me but a heat exchanger is not optional anything with oil or cooling is a must for me starters and alternators are optional. you'll recoupe the money in sale price plus the time in which it sells,

Carl if they ask you what happened what will you tell them it failed over the winter?? which will lead anyone who has freezing weather to think that it froze and had a problem and wonder about the motor

again just me it happens alot up here by me and has been a deal breaker on a few boats I have looked at this time of year might not be so down by Vette so this is more a personal/ location preference

look at it from the buyers eyes why did he pull a good engine and there is no heat exchanger is the motor good ???


i'd bet Raylar has plenty of them laying around..

Good advice, I'll call Raylar. I will guarantee this motor to be 100% good. Not a warranty but a guarantee that it is being sold with absolutely no defects. I don't know what happened to the heat exchanger. The water pump looks good but I will inspect it and install a new impellor before listing the motor. Even if it did freeze damage would be limited to peripherals since the engine was filled with anti-freeze. I pumped all the water out just like every other winter though. The 496 is very easy to winterize with an air pump.