Engine "steamy" type noise and consuming coolant

[reed1v]

Ah the old blown head gasket. Either that or your cooling jacket has blown a seal. Either way its going to get way worse.

[model 10]

Originally Posted by Scaramanga F25

If you could borrow an automotive radiator pressure tester that would be a great help.

It's easy to pressure test anything with the pump and gauge you get with a new dink or paddle board.

[topmast]

Maybe two separate issues. One, the unnatural aspiration device and two ,heat ex leak into the raw water side and out exhaust. ?

[On Reflection]

Pressure test it before you do any serious damage. It could be the head gasket, if you're losing coolant.

[boater 86]

drain oil and check for water ( bad head gasket or could sound like steam if leaking into cylinder ) if oil is clean, reuse it.

[On Reflection]

If the oil on the dipstick is milky (emulsified) then there's water in the system. Blown head gasket, cracked head or worst of all, a cracked block will be the problem. I repaired my Bukh 20 on my last boat with some Chemiweld which lasted for years and might still be going. The trick with using Chemiweld is that you have to sit with the engine running just below boiling point for 20 minutes. This means using an industrial thermometer and constantly adjusting the seacock so just enough water gets in to stop it boiling. The rest of the instructions are on the bottle but you'll need a magnifying glass to read it.
I should add that few marine mechanics will spend the time to do this and will try to sell you a new engine. Try the Chemiweld first. If that fails (and if it is leaking, obviously) try it once more and then re-engine. See your bank manager in advance.

[JPA Cate]

Just briefly, my first thought was the heat exchanger, too.

However, as long as you're stuck in the marina, using the dipstick to check the oil for emulsification is free, except for the rag to wipe the stick, and if it comes up good, there's a huge worry gone fast! If not, at least then you can start coming to grips with it; either is a good outcome.

Ann

[autumnbreeze27]

Back in the marina and internet access again.

So going through the heat exchanger was beneficial. The zinc has turned to mush, so if I had tried to pull it it would have probably all been left inside. I cleaned it out, re-assembled, and am no longer consuming coolant.

The noise persists though. I know longer think it's steam related, it must be mechanical, but I have no idea what.

Oil is fine. Nothing else is abnormal, except the noise. The engine still pushes the boat at 7.5 kts if it's flat at 1500rpm with minimal noise... if I try and push the boat up to 2000 rpm the noise is worse, but it doesn't sound like anything is about to fail... it just bugs me. Not sure if it's a new normal or what, maybe something in the trans?

Don't have the time or money to do exploratory replacement/repair, so will just have to wait and see and use the motor as little as possible, which is the idea anyways

[Lepke]

Most better rental places have cap and radiator testers for rent. Some auto parts stores, too.

[JPA Cate]

Lepke,

You're right, as far as the States I'm familiar with, but I do not remember any such places in La Paz, where autumnbreeze's boat is located. Doesn't mean they aren't there, though, only more difficult than "at home."

Ann

[autumnbreeze27]

Well, after many hours of running the engine at low RPM, I noticed the steamy sound again at higher RPM. If I run the engine at 1400 RPM I have no problems, but 1800 RPM I get the noise, and it's consuming coolant. No coolant in fuel or oil. I talked with another cruiser who was a diesel engineer back in the world, he said it sounded like a head gasket.

I'm going back to the states to renew my visa in a few weeks, should I get the head gasket there or should I be able to source one in la paz? It's a cummins 4bt, should be pretty common?

[topmast]

I read the thread again and still sounds like the heat ex. Can you run to revs/heat with the header cap ajar and see if that effects the sound or coolant levels. Maybe two problems and there is a feather caught in the alternator.

[autumnbreeze27]

Originally Posted by topmast

I read the thread again and still sounds like the heat ex. Can you run to revs/heat with the header cap ajar and see if that effects the sound or coolant levels. Maybe two problems and there is a feather caught in the alternator.

what's the header cap?

and what is a feather caught in the alternator mean?

[jimbunyard]

Well, if the engine runs good, there is no coolant in the oil, and there is no obvious external leak between the head and the block, there is almost certainly nothing wrong with the head gasket.

If the head gasket were leaking into the cylinder, when the engine was running, or even just when you turn it over to start it, engine compression will blow bubbles into the engine coolant side of the heat exchanger. You can usually hear it, and if you take the HE cap you can see it, the coolant will be full of bubbles or foam.

I would bet on a very slight unnoticed leak somewhere, especially if you have limited access to the engine. If you have a 4BTA, there may be a tiny leak into the intake stream from the aftercooler, which would exit through the exhaust, or there could be a leak in an exhaust manifold gasket or seal, or even a pinhole in the manifold itself far enough downstream of the head that it exits (relatively, for now) harmlessly with the exhaust. A hint if this were happening would be the exhaust side turbo wheel being clean rather than sooty black. Without knowing the coolant circuit, it's just guesswork.

Or it could be an internal leak in the heat exchanger, though in my experience the raw water pump more often overpowers the fresh water side and the system makes water, but in a dynamic system, who knows for sure what might happen?

A 4BT gasket set should be readily available at a truck or equipment dealer in La Paz.

[a64pilot]

I have seen a head gasket eat coolant more than once without getting it in the oil or any other obvious things.
However there is an inexpensive test that will determine if there are combustion products in your coolant, done on automobiles all the time and is sort of the definitive test of a head gasket.


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