Slow water leak.

[mestrezat]

I check my engines systems just about every time I start it and have just noticed that the water/coolant water is not as high in the tank as it normally is. I topped it off and when I check it the next time, it’s lower again. Thinking heat exchanger or maybe head gasket? Don’t see any leaks from hoses and nothing in the pan under the engine. Don’t see any oily residue in the water near the exhaust outlet like coolant should leave a skim on the water.
Suggestions?

[a64pilot]

I think your right, it’s likely either of those.
There is a kit you can buy to test your coolant for the presence of combustion gases, if it’s a head gasket 99% of the time the test will find combustion gases in the coolant.
For heat Ex, it’s likely you need to clean it anyway, hopefully it’s one of the O rings.

[Cheechako]

Are you sure it isnt just dumping out the overflow because you fill it full when cold?

[mestrezat]

I’ve got a Ford Lehman 80hp. Specs say to keep the water about one inch down from the filler neck. Been that way for a long time. Had to have the heat exchanger cleaned in US Virgins when the coolant went crazy and ended up clogging the exchanger with a putty like material. A real mess. That was about a year plus ago. Been fine since.
I check the engine before starting so it is cool when I fill it(if it needs it).
Any idea where I can get the test mentioned in the first response? Been out of the US fir the last nine years seeing the world. Now in the Sea of Cortez, close to being home.

[MV Wanderlust]

Originally Posted by mestrezat

I check my engines systems just about every time I start it and have just noticed that the water/coolant water is not as high in the tank as it normally is. I topped it off and when I check it the next time, it’s lower again. Thinking heat exchanger or maybe head gasket? Don’t see any leaks from hoses and nothing in the pan under the engine. Don’t see any oily residue in the water near the exhaust outlet like coolant should leave a skim on the water.
Suggestions?

A friend of mine just went through the same mystery. We borrowed a pressure tester from a local auto shop and pressurized the system. No leaks around any hoses. We popped open the heat exchanger but no leaks. After a couple of hours of trial and error, it was finally determined the exhaust manifold (originals from 2007) had rusted internally and the coolant was seeping into the exhaust but so slowly that it wasn't leaving a sheen on the water's surface. Replaced the manifolds and the problem went away. Just food for thought.

[jkishel]

A blown head gasket will usually result in bubbles visible in the coolant while the engine is running (start up and run with the radiator cap off). A pressure test will establish whether the heat x is leaking or the tank/exhaust manifold is cracked. Remove the plumbing downstream of the heat x to expose the heat x discharge. Pressure way again. If coolant drops out of the heat x, the heat x is leaking. Otherwise dismantle the tank and exhaust manifold to find where it is cracked.

[JPA Cate]

You'll have coolant in your engine oil, if it's the head gasket. And the "oil" level shall have risen. If it hasn't, and the oil looks "normal", then that would point to its going somewhere else.

Ann

[captstu]

There is a kit you can buy to test your coolant for the presence of combustion gases, if it’s a head gasket 99% of the time the test will find combustion gases in the coolant.


What is the name of this test? Thank you

[a64pilot]

Originally Posted by JPA Cate

You'll have coolant in your engine oil, if it's the head gasket. And the "oil" level shall have risen. If it hasn't, and the oil looks "normal", then that would point to its going somewhere else.

Ann

Ann,
Jim can explain better, but sometimes there can be a break in the head gasket that connects a coolant passage to the combustion chamber, and oil is not affected.
Sometimes, not always.

I don’t want to be a jinx, but sometimes a cracked head can also just connect coolant to the combustion chamber

[a64pilot]

Originally Posted by captstu

There is a kit you can buy to test your coolant for the presence of combustion gases, if it’s a head gasket 99% of the time the test will find combustion gases in the coolant.


What is the name of this test? Thank you

This google search link should explain it better than I can, it should have links to how to videos, links to buy etc.
I just googled “coolant combustion gas tester”
Link doesn’t work?
Google coolant combustion gas tester and you should get a lot of hits

[a64pilot]

A how to link.
I’ve not viewed it, but it’s simple really, should show you how easy the test is.
https://youtu.be/B4FoUc6fRNs

[flyingfin]

Originally Posted by Cheechako

Are you sure it isnt just dumping out the overflow because you fill it full when cold?

Good Answer, Good Answer. Dont check it constantly, monitor it for several weeks, then refill. see if it really looses coolant every time you use or just that initial expansion

[wagsea6b]

Do you have a water heater that utilizes your engine coolant?

I had the same problem of a slow coolant leak...found the culprit when I looked under my hot water heater.

[captstu]

Are ranger is fitted with both a school bus type hot water heater and a domestic water hot water heater rigs in series Christmas tree style. I disconnected the school bus type heater completely, bridging the input and output lines. I really don’t need heat in July is South Florida.

I’m not exactly sure how to test the domestic water heater. I sprinkled a bunch of cock a roach killer underneath to see if the white powder became damp. This led to replacing three of the original hose clamps and finally finding and fixing my domestic water leaks. With all the leaks fixed I dried underneath the hot water heater and put more white powder in place. Not a drop of dampness showed up.

I also close the through hole and removed the Seachest cover leaving water pressure on. I expected if there had a leak, the domestic water would’ve leaked into the heat exchanger since I lose about a quart of water every 15 minutes when the engine is running. There were no leaks.

The heat exchanger has just come back from the shop after it was pressure tested and seemingly repaired?? I haven’t seen the report yet, however I am hopeful.

If it isn’t the heat exchanger I’m out of ideas. The engine would not run at all if this volume of water was making its way through leaking head gasket.

[Nineteen]

Originally Posted by a64pilot

Ann,
Jim can explain better, but sometimes there can be a break in the head gasket that connects a coolant passage to the combustion chamber, and oil is not affected.
Sometimes, not always.

I don’t want to be a jinx, but sometimes a cracked head can also just connect coolant to the combustion chamber

I had this on a BMW of mine - coolant would slowly disappear but nothing in the oil, no external leaks(glycol based coolants have a distinct sweet smell outside the engine particularly when it is up to temperature), and no bubbles in the coolant.

Ended up being a crack between the inlet and exhaust valves and the only way I found it was to pull the head. Nothing showed as an issue other than the loss of coolant. All tests were normal.

On the up side - I did not have to de-coke that cylinder to see the crack as it was perfectly steam cleaned[emoji106]

Hope yours is just from overservicing and being pushed out by thermal expansion.

Cheers Tom