Puking Coolant
 

Puking Coolant it’s never a good day for it.

Twin 496 Mag ho’s RAYLAR 600 starboard engine is Puking coolant out of tank. Gauge and IR readings are the same. Temp rises to 180 at idle. I’m running merc 160 T-stat. It has been tested in water but that was when new before installation.
Only pukes when running at speed.
Head’s were rebuilt because of this previous problem it still occurs.
doesn’t really get over 180 maybe a few degrees. Guardian mode sets in.
New Hardin sea pump and impeller.
Had a serious impeller blockage last year at oil cooler which blew a couple of hoses because of high pressure. New hoses installed
New power steering cooler
New oil cooler
New circulating pump
New water pressure sensors

When you loosen cap tank is holding pressure. Which leads me to believe it’s not a leaking head gasket from cylinder to water jacket. Just strange that it would blow coolant out at 180 without extra pressure from cylinder.

It takes 10-12 minutes for temps to rise 180 at idle on the hose. No Puking occurs at this time only at higher rpm.

Can you BURP this engine platform? Other than leaving cap open for awhile?

Swapping caps doesn’t help.


ALL verifies temps at different location.

Have you pressure tested the Heat Exchanger?

have a radiator shop boil out the heat exchanger,sounds like it may be scaley

Do you know anyone at an automotive shop that might have a combustion gas tester ? If not they are not that expensive and it would be easy to see if it is a head gasket leaking combustion gas into the cooling system.

https://www.harborfreight.com/combus...tor-64814.html

Another alternative would be to use a radiator pressure tester but I dont know what your cap is like and if there would be an adapter available to fit.

From the symptoms you are describing it almost has to be a head gasket.

Leaking heat exchanger will allow seawater into the cooling system overfilling it and causing it to puke. Been there done that.

I don't mean to insult anyone's ability, just making a suggestion because it has happened before. Are you sure the head gaskets are on in the correct orientation? The 496 is slightly different in cooling passages from the front to rear of the engine and the gaskets can be installed backwards, causing cooling issues.


Also, how old are the Raylar heads? Early versions did have some issues with cracking.

When the heads were rebuilt, was the block surface checked for flatness?

only the coolant system has been tested but one would think that if it is holding pressure then the heat exchanger is not leaking. Is that correct?

Heat exchanger is completely clear of any debris end gaskets are new end of last season all be it our season never ends in Phoenix.

One would think so. At cruise speed you may have 25-35psi seawater pressure inside of the heat exchanger. At what pressure did you test the cooling system?

Would never insult me we have owned an auto repair shop for 40 years, we do build race motors for the off-road community as well. We are aware of the head gasket’s orientation but when someone ask is it done correctly I have to wonder if I did do the right way. I am not perfect but I do specifically remember checking and re checking. For me if I messed up that bad I will be laughing at myself along with the online community cause I will put myself on blast lol.

RAYLAR heads were completely reworked with no cracks. Per the machine shop. You would think they would inform me. They have been doing our machining for 30 years.

cooling system can only test up to 15 PSI

It would be nice if there was a way to see the water in the coolant lol

I would have to agree with you about it being a head gasket. But the tests are inconclusive thought about running a test with pressure gauge between tank and heat exchanger overflow hose to see if pressure increases quickly which it shouldn’t if head gaskets are good. Only raise pressure as heat climbs.

the coolant will be watered down/ lighter in color. You could always test the coolant with a tester to see the freeze/boil value.