Mysterious Coolant Disappearance

G

Gary S.

Member
Joined
Jun 4, 2019
RO Number
34110
Messages
6
1989 Silverton 40X with 502's

Both engines run right at 140 degrees....consistently. I had to change the fuel pimp on the Starboard Engine about a month ago and as long as I was down there I gave everything a thorough looking at....(hose clamps....check EVERYTHING for leaks.....corroded wires etc.) and noticed that the Port side coolant reservoir was bone dry. It was also dry when I splashed for the season about a month and a half ago and I topped it off of course. Since then I've put about 80 miles on it (hour meter is disconnected for some reason which I'll take care of next week) and now it's dry again. I pulled the engine cover completely off so I could get at EVERYTHING and don't see any visible leaks. I know you're not supposed to mix different types of Coolant but I bought a gallon of RED Coolant and topped the tank off.....ran it for about 30 miles.....Bone dry again.....Checked EVERYWHERE for leaks and no sign of anything red anywhere.....topped it off again with the red....ran it about 20 miles.....bone dry again. This is a closed system and the engine never gets over 140 degrees .....I DIDN't top it off this time but instead took it on about a 20 mile run yesterday......temperature ran right at 140....
This engine doesn't do anything strange such as a misfire or blow any smoke gray or blue.....idles perfectly...starts right up with no problem and has all the power it ever had since I've owned it. (about 5 years now)
Sooooooo......Where's the Coolant going?.....????????????????
 
Leaky heat exchanger , FW to RW side is the Usual Suspect from what you report.

You might be able to smell it in the exhaust, just not as obvious as if it was a head gasket leak. .
It might be possible see some visual evidence in the exhaust in the water but it mixes well with water so it would be much harder to see than crank oil or ATF.

Have you been checking the pencil anode every month or so & replacing it when it looks approx 1/2 gone ( the rest is very porous) ?
When replacing the H/ex. , consider cupro-nickel alloy H/Ex ( if available for that engine) tends to last longer than plain copper ones .

FWIW, " mrcool.us " website has great prices on H/ex.s .
 
"pencil anode" ??? Could you enlighten me?
I've been watching the exhaust for any traces of anything mixed with it and haven't detected anything yet.
I let it run at the dock for about 20 minutes paying close attention to watch for any oily discharge of any kind.
The reason I used the red coolant was so that any leaks anywhere might be easily detected but can't find anything
and there's nothing in the bilge. The only thing I HAVE noticed is that the exhaust on the port side is
considerably louder than the starboard side but that's probably a sign that the muffler might need replacement?
 
If these engines are Crusaders, you have pencil anodes in the heat exchanger and the oil cooler. Should see a brass nut on top right side of exchanger and low right side of oil cooler. Big nut on exchanger, smaller on oil cooler. They should be checked every 30 days and replace when 50% gone. If the exhaust is louder on the port side, could be a sign of decreased raw water flow. My exhausts are loud at start and then when I hear them muffle down, I know I have enough raw water flow. There isn't much to fail on these mufflers. Can you smell antifreeze in the exhaust? You won't see it. I'd stop mixing red and green antifreeze.
 
Gary- who made your 8.1 L /502 c.i.'s and what year are they?

Do you have or can you find an owner's manual so you can get a good idea of needed preventative maintenance schedule, and an online parts list & diagram will show the pencil anodes in the exchanger and coolers.

If the pencil anodes haven't been checked or replaced in at least 5 ys it's not surprising the H.ex is likely corroded through inside . That can happen even if the pencils are diligently replaced but very likely if they are not. The transmission and crank oil coolers may be next to go. But perhaps you have annual servicing professionally done which included those anodes?
FWIW- My smaller Crusader 5.7L MPIs only have a pencil anode in the H.ex. but the larger displacement engines have them in the cooles as well. I usually find that anode to need replacing 1-2x during the season , and it is done at haulout too to be ready for next spring. I would further advise, also make sure the usual bonding wire between the H/ex. and engine block is intact.

With engine off, you don't have to 1st drain anything to remove and check the H.ex. pencil anode as it is on the RW side that drains-back. If the zinc anode doesn't unscrew fairly cleanly from the brass cap, placing the affair into a glass jar of muriatic acid will dissolve the zinc out of the cap for re-use with a new pencil insert. Do that outside on grass or dirt. Its acid.

Especially if you are boating in SW, you might find it beneficial to flush the engine out w/ fresh water before filling the new H.ex. and going through the repeated air-purging and re-topping up w/ coolant-mix process.

As Gregory says, the louder exhaust on the port side isn't due to a muffler going bad, it is a strong indication RW flow is compromised and not enough RW is being injected into the riser exhaust stream exit to quiet it ( & properly cool it to keep hoses from burning up and potentially exhausting CO into the boat ...and sinking the boat.
But normally in that case you will see steam in the exhaust and the top of the risers will be too hot to keep your palm on comfortable & indefinitely.

Mufflers generall only fail for a few reasons. Backfires will dislodge baffles, in rare cases they can be freeze damaged if the engines didn't have sufficient non-tox A/F run through the RW side, ...and lack of RW injection into the exhaust stream can allow internal melting (but the ex. hoses feeding them burn up 1st.)

Only mix colors of A.F. if the new containers CLEARLY say the contents are compatible with all other types of A/F, and of course be aware of whether the contents are 50/50% premixed, or need to be mixed 50% with water you add before putting into the cooling system. Mixing incompatible A/F can lead to gelling & you don't want that in the block.
 
Thanks go out to Sandy and Gregory.....
To your point Gregory...Yes these are Crusaders....You say the anodes should be checked every 30
days....???.... (you're gonna wanna slap me)......Going on the 5th year with this Boat and I
don't think they've EVER been checked. (at least not since I'VE owned it)....
I've always pretty much just trusted the Marina Owner at my last Marina to pretty much take care
of things with pretty much an open check-book. I don't remember ever seeing anodes being on any Bills.
You can be sure that I'll be in search of and checking and pretty obviously replacing them this weekend.
Thanks for the input.

I guess also that next week I'll put on my To-Do list....Flushing the engine block and re-filling with
fresh Anti-Freeze.
I'm familiar with what you're talking about when it comes to the exhaust noise level after it runs for a minute
and I HAVE in the past noticed that exact thing. Strangely though....the exhaust/water flow out of the Starboard side
is significantly LESS than the Port side and that side is quiet...????????
 
The Crusader manuals do say check those pencil anodes every 30 days in their preventative maintenance schedule.
Crusader didn't offer 502/8.1 engines in (edit)1988. You still didn't say what model or year so I couldn't look up the definite part.

As an example in this parts manual for the 2005 8.1 L , the H.ex. pencil anode's brass cap is #10 in Fig.13 on P.34.. Crusader part # R168005 .
The anodes can be purchased at most any marine supply store or anode website online , with or without the brass cap.but you have to get the right size anode (i.e. correct cap thread size ( and SAE. not metric) and pencil zinc diameter and length so it's not too long & hits the tubing bundle inside.

I'd suggest taking your anode cap and any anode remains to the store and matching it up, buying a couple pencils with caps so you always have extra caps you can have ready to install, and buy a few extra pencils for each engine to keep onboard.

FWIW, my 2003 Crusader 5.7 MPIs H.Ex take size "EO" pencil anode which are 1 3/4" long x 3/8" dia. on the unthreaded part and anode threads are 5/16"-18pitch . It is the same Crusader part # R168005 . I also have some marked CMEZO size. Same thing. Hve 6 spares in my hand now.
http://www.campcompany.com/Pencil-Anodes/

https://www.westmarine.com/buy/martyr--engine-cooling-system-pencil-anodes--P004_122_002_006?pCode=307314

Note also, the brass cap and H.Ex. threads are tapered, so do NOT wrench them in too tight or you will crack the fitting and cause a RW leak. No Teflon tape on the threads as electrical continuity must be maintained for the anode to do it's protective sacrificial job. Paste sealant only, if needed.

Downloadable Owners' and Parts Manuals:
http://www.crusaderengines.com/classic#owners

Like mine , your engines ...may... not have an ATF/crank oil cooler that requires a pencil anode. ( But the 7.4L/454's do.)

Re: "Strangely though....the exhaust/water flow out of the Starboard side
is significantly LESS than the Port side and that side is quiet...????????"

As advised above, when the engines are fully warmed up to temp. , put your palm on the top of each of the exhaust elbow ( Merc calls them risers) at both idle and underway at cruise speed. If you can't keep your hand there indefinitely, that tells you there is insufficiently RW flow and that needs to be fixed very soon before your hose burns. It's a very basic important inboard test every I/B owner/operator should perform often. I bet the stbd feels cooler.

But ... if your transom exhaust outlets have external flappers to keep wake water out, make sure that is not missing on the port exhaust.

 
Thanks again Sandy,
I CAN keep my hand on both the Starboard and Port side risers when up to temperature (140 on the gauges)
both at idle and at my normal cruising speed (3000 to 3100 rpm's).
This has side exhaust and no flappers.
I located the Owners Manuel for this Boat (actually I knew where it was) and it definitely portrays this as a 1989 WITH 502 engines.
Today will be the first time since my last post that I have an opportunity to get down to the Boat and use it for the day. I'll
report back in the next day or so what I find or don't find out.
 
Gary, my apologies if those engines are are 1989. I didn't think they were offered until later years and I have the Crusader Owner's Manual for the all 1988 engines which only went up in size to their 454ci/7.4 L engine. So that has to be the 1st year offered.

That's very good you have good RW flow all the way through the elbows. I'd expect the fully-warmed engine gauge temp to be more like 160*F but the RW cooled elbows would get hot well before that if RW flow was insufficient. But the good RW flow and no exhaust exit flappers tends to contradict the louder noise.

If preferred , you might be able to perform a heat exchanger pressure -leak test. ( I never did this, but have replaced several heat exchangers and an oil/transmission cooler- semi-under my engines , ugh!.)
Possibly rent the equipment for radiator pressure test from an auto parts store?

Or perhaps: https://www.ebay.com/i/122712080106...MIkuv6_9Wj4wIVVODICh0lYAeqEAQYASABEgLkGvD_BwE

But if the coolant is not in the bilge or oil pan and the engine runs well with no exhaust steam or coolant smell it sure doesn't sound like a head gasket leak so that leaves leaky heat exchanger.

I wouldn't keep running it with coolant disappearing like that. It's not going to get better. And there could be an exchange of fluids so SW could get in the engine, or lack of coolant in the engine could spike engine temps quickly.
 
Well......Fortunately my Oil Coolers are in a much better location and a MUCH better design than on my previous Cruisers Inc.
with 5.7 Mercruisers. I already checked those too.
SO.........NOW it gets even MORE interesting (if that's possible)......
Went out Saturday and just let it run at the dock at about 1300 rpm's for TWO HOURS......
Didn't lose a drop of coolant....Took it out on a 22 mile run.....Tank was empty.

By the way...this is a fresh water boat and has been it's entire life.
 
Do you smell antifreeze in the exhaust? It's going somewhere. What doe the oil look like? If you've always been in fresh water, your engine zincs are probably ok because they don't work in fresh water.
 
You must log in or register to reply here.
Back
Top