Closed Cooling System Pressure Test . . .

[tpenfield]

I have been loosing a small amount of coolant on the closed cooling systems of my engines this season. Not a lot of coolant loss, but enough to be adding a few ounces every other outing, etc.

Here are the engines with the SJE 'Full' closed cooling systems, which I have found to be awesome for salt water use.



So, now that the boat is out of the water of the season, I decided to run a cooling system pressure check to see if I can identify the source of the coolant loss/leaks. I drained the systems to do a pressure test with air, figuring that I could more easily 'hear' any leaks and use soapy water at the external joints and fittings to see any slow leaks.

I have a compressor and re-purposed a cylinder leak test gauge for the task.



I ran about 10 psi from the compressor and it took a minute or two to pressurize. I heard one leak that was fairly noticeable on the port engine . . . hose clamp not tight enough.

I also sprayed all of the external joints with soapy water to see if/where bubbles formed, indicating a leak. I found a couple of small leaks on each of the engines. Here is a picture of one of the supply hose/fitting joints at the exhaust manifold (they are part of the closed system). I found a few other locations like this one. So, a quick tightening of the hose clamps did the trick.



I did notice that the heat exchanger cap on the starboard engine has a leak under the outer seal. . . fairly in consequential, since it has an overflow reservoir.



It did make some nice bubbles though. . .

The good news is that I did not hear anything from inside the engine or the manifold /elbow joints. :thumb:

 

[fen-isl]

Re: Closed Cooling System Pressure Test . . .

Cool, good job. A Nice clean engine bay always makes the job easier:joyous:

 

[alldodge]

Re: Closed Cooling System Pressure Test . . .

I have been loosing a small amount of coolant on the closed cooling systems of my engines this season. Not a lot of coolant loss, but enough to be adding a few ounces every other outing, etc.

Figuring if you where loosing coolant it would show up somewhere; did you ever find coolent in the bildge?

Put a new Merc repower long block in friends boat this season. The engine started loosing coolant as yours did but was a slight bit worst. Located the leak after a lot of looking and it turned out to be the freeze plug behind the cool fuel pump. Called the dealer where purchased in FL and Merc is sending tech to fix.

 

[tpenfield]

Re: Closed Cooling System Pressure Test . . .

Figuring if you where loosing coolant it would show up somewhere; did you ever find coolant in the bilge?

It was tough to tell if there was coolant in the bilge, as I would usually get a fair amount of rain water, etc that made its way into the bilge a few times over the summer. I also replaced the recirculating pump on the starboard engine, as that was leaking at the bearing seal. Which caused some spillage, etc.

So, mostly loosing a little bit of coolant and not quite sure where it was going. I was concerned that it may be going into the engine/exhaust and perhaps the exhaust manifold/elbow joint may have been leaking since these are 'full' closed systems. The oil stayed clear golden color throughout the season.

Anyway, I'll have to see about securing all of the hose clamps during spring prep next year. One of the challenges with a full closed system is that it has lots of fittings and hose clamps, since it runs coolant to/from the exhaust manifolds . . . more possible points of 'failure'.

 

[dan t.]

Re: Closed Cooling System Pressure Test . . .

If you get a leak between the manifold and the riser on a closed system you can usually smell it in the exhaust. I had this problem a couple of years ago, after the motor was fully warmed up if you shut it off for 5 minutes and then restarted it you would get white smoke and a strong smell of hot antifreeze from the exhaust. It turned out to be a aftermarket "green" riser gasket, replaced it with a OEM gasket and all was well.

 

[tpenfield]

Re: Closed Cooling System Pressure Test . . .

If you get a leak between the manifold and the riser on a closed system you can usually smell it in the exhaust. I had this problem a couple of years ago, after the motor was fully warmed up if you shut it off for 5 minutes and then restarted it you would get white smoke and a strong smell of hot antifreeze from the exhaust. It turned out to be a aftermarket "green" riser gasket, replaced it with a OEM gasket and all was well.

Thanks for the tip. Fortunately, I have the OEM gaskets, but even then, I would imagine they should be checked in the manner you describe periodically.

 

[banshee owner]

Re: Closed Cooling System Pressure Test . . .

tpenfield that's a neat trick with the air (only wish it were that easy to do on cars and trucks )

being twin engines do they share the same coolant from one engine to other or is two separate cooling systems

i kinda figure it would be 2 separate systems so if there was a catastrophic failure on one it wouldn't affect the other

 

[tpenfield]

Re: Closed Cooling System Pressure Test . . .

tpenfield that's a neat trick with the air (only wish it were that easy to do on cars and trucks )

being twin engines do they share the same coolant from one engine to other or is two separate cooling systems

i kinda figure it would be 2 separate systems so if there was a catastrophic failure on one it wouldn't affect the other

Yup, 2 separate systems . . . each with their own set of hoses and fittings to check :facepalm: I had to drain down the anti-freeze coolant in order to pressurize the system with just air.

I do like the closed cooling systems, since I run in salt water. I did a rebuild on my last boat/engine and was mortified to see what 15-20 years of salt water can do to the insides of an engine.

I'm thinking of getting a LCD Borescope to check the exhaust manifold/elbow seal without disassembling the joint. That's my biggest concern . . . if there was a slow leak that the air would not make enough noise to be heard, since it cannot be seen easily.

 

[banshee owner]

Re: Closed Cooling System Pressure Test . . .

borescopes are the cat meow may i suggest if you get one make sure it has a small camera on the end for tight places ive seen cheaper one with a honking huge camera and you couldn't check whats in your fridge with those suckers lol. also a video out so you tape and review the footage seems to be a cool idea too just my opinion.

 

[tpenfield]

Re: Closed Cooling System Pressure Test . . .

I am thinking about the Extech BR70. It costs about $125 and has a 3 ft 'gooseneck' and a 2.5 " screen.

i've seen one a few years ago, but that is about it.

anyone know more about this brand/model?

 

[banshee owner]

Re: Closed Cooling System Pressure Test . . .

thats a cool little scope

i like the atachements and that it is waterproof

only setback is the camera size it might fit into a spark plug hole but 17mm is still pretty big

i guess it all depends on what you intend to inspect and how much you will use it

 

[tpenfield]

Re: Closed Cooling System Pressure Test . . .

thats a cool little scope

i like the atachements and that it is waterproof

only setback is the camera size it might fit into a spark plug hole but 17mm is still pretty big

i guess it all depends on what you intend to inspect and how much you will use it

I was thinking that I could go into the exhaust elbow . . . Inspect the gasket and joint between the elbow and the exhaust manifold. . . And with a little luck, keep going and take a look at an exhaust valve or two. Sort of the engne's equivalent of a colonoscopy

 

[alldodge]

Re: Closed Cooling System Pressure Test . . .

I picked up this one a few years back and it works pretty well. There could be better prices out there just picked the first one with google search

General Tools & Instruments The Seeker 300 Video Borescope System ? 3.5in. Camera Scope, Model# DCS300 | Scopes| Northern Tool + Equipment

 

[banshee owner]

Re: Closed Cooling System Pressure Test . . .

the Milwaukee at the bottom of the page is smaller camera its 9 mm

FREE SHIPPING ? Milwaukee M-Spector 360 Digital Inspection Camera ? Tool Only, Model# 2313-20 | Scopes| Northern Tool + Equipment

it just doesn't look like it comes with a battery and also looks like it uses a specif Milwaukee battery which would drive the price up

but im looking at the size of the camera you would be able to get into a spark plug and see the cylinder and its a nice feature with the dimable LED lights also

Again what ever one you choose will an added benefit

 

[fen-isl]

Re: Closed Cooling System Pressure Test . . .

If you want a really good borescope I recomend the snapon BK6000 or BK5500 they have a 8.5 mm camera. Also they have dropped in price since snapon released a new version last year that is wireless and can see straight and to side with push of a button as standard feature.

I personally have the BK6000 with the optional camera that can see straight and to the side by fipping a switch. Works great I m always flipping back and forth. It also records and takes still pics U can pick color or black and white modes.

Usually can find on ebay (used) or if you see a snapon truck just stop or flag him down he may have a used one that was traded in.

Good Luck