Volvo KAD300 (coolant issue)

[Daniël Bankert-Boating]

Dear readers!

We have a yacht yard in the southern part of The Netherlands.
At the moment we are struggling with a very strange coolant issue on a KAD300 engine.

The problem explained.....

The starboard engine blows out all the coolant from the exp tank. This only happens when the compressor kicks in. So when running at 800 rpm there's no leakage at all. The pressure build up in the exp tank is very quick, when the compressor kicks in, within a minute the tank is literally empty. It somehow looks like there is air in the system, but whatever we do, the air will not drain (if there is). The coolant keeps blowing out thill there is so much coolant out of the tank we are afraid that the cylinder head is dry of coolant.

What have we done so far....
1. checked all cool water hoses for pollution
2. tested the thermostats
3. runned without thermostats
4. runned without (water heater, boiler) we have valves in the hoses to the boiler
5. renewed all exhaust manifold gaskets
6. renewed turbo gasket
7. measured exhaust gasses in the coolant, there was.... so we thought the headgasket, today we replaced the head gasket and yet..... compressor kicks in and blows all coolant out of the tank...

Maybe very stupid of us, but can this just be an air draining problem? A very big air bubble somewhere in the system? Maybe try to tilt the complete boat to SB/PS while running?
(Ps. we have just put the boat on the lift, tilted it to Portside till the expansion tank of the starboard engine was the highest point. And....... we could run with compressor for 4,5 minutes! We saw the coolant level lowering so air came out! But after that time again a gib blow out that did not stop....)

Whe are a little bit running out of ideas....

Hoping you have some ideas!

 

[stelican]

Something you do not mention but have probably checked.
On some of that family of engines it required the coolant return pipe at the turbo bleeding when refilling the system.
Although from what you describe the coolant is being forced up out of the header tank.
I am not sure if it applies to that particular model.

 

[TK Blue MAX]

Still sounds like head gasket related, extra boost of supercharger pressurising the system, did you check block and cylinder head for flatness , damage , crack's .

 

[Daniël Bankert-Boating]

Something you do not mention but have probably checked.
On some of that family of engines it required the coolant return pipe at the turbo bleeding when refilling the system.
Although from what you describe the coolant is being forced up out of the header tank.
I am not sure if it applies to that particular model.

Thank you for the reply! The hose from the turbo is completely blended...

 

[Daniël Bankert-Boating]

Still sounds like head gasket related, extra boost of supercharger pressurising the system, did you check block and cylinder head for flatness , damage , crack's .

Yeah we agree... We checked the flatness as well cracks, nothing at all... Perfect condition. We didn't pressurise the cylinder head when it was of because we don't have te right tools.. We are doubting to take it of again and then pressurise the coolant channels... Not so nice, 27 head bolts and a new head gasket again and maybe only to figure out again its not the problem.

 

[kashurst]

Have you checked the Charger Air Cooler? (turbo heat exchanger)
When the supercharger kicks in it will pressurise it on the air side. If the gaskets/seal are weak it will pressurise the cooling system too.
If this happens on the dock, You could try it out easily by disconnecting the air pipe from the turbo outlet into the heat exchanger.

 

[FatherTed]

Replacing the injector sleeves in my KAD32 cured the same problem.

 

[Daniël Bankert-Boating]

Have you checked the Charger Air Cooler? (turbo heat exchanger)
When the supercharger kicks in it will pressurise it on the air side. If the gaskets/seal are weak it will pressurise the cooling system too.
If this happens on the dock, You could try it out easily by disconnecting the air pipe from the turbo outlet into the heat exchanger.

In the beginning we thought the same! Even Volvo Penta official said the CAC-cooler. But..... this is cooled with seawater isn't it? So it could never pressurise my coolant circuit, no offence, as said, Volvo Penta itself said this was the problem

 

[Daniël Bankert-Boating]

Replacing the injector sleeves in my KAD32 cured the same problem.

Thank you for this post! One of our ideas is also the injector sleeves, but Volvo cannot confirm that there are coolant circuits around those sleeves. Can anyone confirm this? If so, our next step would be changing the 6 injector sleeves.

 

[TK Blue MAX]

In the beginning we thought the same! Even Volvo Penta official said the CAC-cooler. But..... this is cooled with seawater isn't it? So it could never pressurise my coolant circuit, no offence, as said, Volvo Penta itself said this was the problem

Could it pressurise the coolant circuit if there was a leak between the seawater and freshwater circuit? as in a split internally with another cooler, just clutching at straws really, but the excess pressure must be caused by the supercharger and entering the freshwater circuit somewhere to produce your problem. possibly time to start swapping parts from the other engine rather than chucking money towards Volvo, as they are in a win-win situation

 

[volvopaul]

Dear readers!

We have a yacht yard in the southern part of The Netherlands.
At the moment we are struggling with a very strange coolant issue on a KAD300 engine.

The problem explained.....

The starboard engine blows out all the coolant from the exp tank. This only happens when the compressor kicks in. So when running at 800 rpm there's no leakage at all. The pressure build up in the exp tank is very quick, when the compressor kicks in, within a minute the tank is literally empty. It somehow looks like there is air in the system, but whatever we do, the air will not drain (if there is). The coolant keeps blowing out thill there is so much coolant out of the tank we are afraid that the cylinder head is dry of coolant.

What have we done so far....
1. checked all cool water hoses for pollution
2. tested the thermostats
3. runned without thermostats
4. runned without (water heater, boiler) we have valves in the hoses to the boiler
5. renewed all exhaust manifold gaskets
6. renewed turbo gasket
7. measured exhaust gasses in the coolant, there was.... so we thought the headgasket, today we replaced the head gasket and yet..... compressor kicks in and blows all coolant out of the tank...

Maybe very stupid of us, but can this just be an air draining problem? A very big air bubble somewhere in the system? Maybe try to tilt the complete boat to SB/PS while running?
(Ps. we have just put the boat on the lift, tilted it to Portside till the expansion tank of the starboard engine was the highest point. And....... we could run with compressor for 4,5 minutes! We saw the coolant level lowering so air came out! But after that time again a gib blow out that did not stop....)

Whe are a little bit running out of ideas....

Hoping you have some ideas!

Had this before last year on a job it was a cracked exhaust manifold

 

[Daniël Bankert-Boating]

Had this before last year on a job it was a cracked exhaust manifold

Also a struggle to find! We have found at that the 2nd cilinder is leaking coolant from the sleeve inside the cylinder when pressurise the coolant system. Now we are almost sure that this is the cause of the problem. Have you ever had a leaking injector sleeve?

 

[alt]

Does it happen immediately? Does the temp gauge rise??

I'm just throwing an oddball one out there.... check that the COOLANT pump is working.... the shaft sheared on one of mine a few years back. Visibly, everything looked fine from the outside... it was only when I took the pump off, could see the sheared shaft.

However, if it's blowing coolant immediately when the SC kicks in, you can most likely scrap my post!

 

[Daniël Bankert-Boating]

Does it happen immediately? Does the temp gauge rise??

I'm just throwing an oddball one out there.... check that the COOLANT pump is working.... the shaft sheared on one of mine a few years back. Visibly, everything looked fine from the outside... it was only when I took the pump off, could see the sheared shaft.

However, if it's blowing coolant immediately when the SC kicks in, you can most likely scrap my post!

Thanks for the reply! But it is blowing coolant immediately when the SC kicks in.
A worn pump is not the case I think. I will post if we replaced the injector sleeve

 

[stelican]

Also a struggle to find! We have found at that the 2nd cilinder is leaking coolant from the sleeve inside the cylinder when pressurise the coolant system. Now we are almost sure that this is the cause of the problem. Have you ever had a leaking injector sleeve?

Have you removed the cylinder head again? If so check that the cylinder liners are not pinholed. I have seen this once on AQD31 in a Volvo Penta workshop.. They thought it might have rusted through due to the coolant. I don't know what the symptoms were and now too long ago to ask.