Volvo KAD 32

[Hipower]

I have a Volvo KAD 32 that is losing antifreeze somewhere. There are no visible leaks, I have done the Charge air cooler and the raw water pump has been rebuilt. No heat problems as long as I keep the reservoir full. Any ideas where to go next??

 

[Mr Googler]

Are you losing coolant into the bilge

 

[Momac]

On a cold engine the coolant should be on or just over the low mark on the reservoir. This is to allow room for expansion in the reservoir.
If you fill the reservoir it will expel coolant . Is that what is happening?

I did add a drop after taking this photograph

 

[Hipower]

Are you losing coolant into the bilge

No, there are no visible leaks.

 

[Hipower]

On a cold engine the coolant should be on or just over the low mark on the reservoir. This is to allow room for expansion in the reservoir.
If you fill the reservoir it will expel coolant . Is that what is happening?

I did add a drop after taking this photograph

I don't think so, I fill it with the engine running and it drops down too empty. There is no pressure in the res tank when I take the cap off.

 

[spannerman]

If its not leaking externally then its losing it internally, it could be leaking over to the seawater side in the heat exchanger or it could be the head gasket. Never had a head gasket go on a KAD32 but always a first time. Would try a pressure test and remove the seawater hose on the heat exchanger and see if coolant is present, if not then it points to the head gasket.

 

[GusC@AK]

Also (at risk of stating the obvious), if you have a hot water tank or cabin heater which tie into your coolant line, check for leaks at the appliance.

 

[BruceK]

Another candidate to look at. The pipe from the thermostats to the heat exchanger, where it connects to the heat exchanger has been known to leak on my 42. The jubilee clip can be awkward to get to to tighten as it hides hehind the intake manifold to the rootcharger and butts against the bracket of the heat exchanger. If the screw mechanism butts against the bracket when tightenning it twists the jubilee clip skew. I have tightenned on up before thinking it's on straight but it wasn't and the pipe leaked out once pressure built up. Tell tale is the coolant lands on the oil hoses running between oil cooler and filter. It's a right pita to get to to check. You have to remove air filter box and drop the root charger manifold to get to it, but try checking if it's wet there. Also that hose rubs up against some exhaust stud bolts. There should be rubber nut caps protecting the hose from these but they tend to get lost in the bilge over time. The hose wears against these bolts and needs replacing over time.

 

[Momac]

I don't think so, I fill it with the engine running and it drops down too empty. There is no pressure in the res tank when I take the cap off.

Yes the coolant level does drop when the engine is started. But when the engine stops (after running a few seconds) does the coolant level return to the level it was before?

 

[Hipower]

Yes the coolant level does drop when the engine is started. But when the engine stops (after running a few seconds) does the coolant level return to the level it was before?

No, the coolant level drops and stays low.

 

[Hipower]

Another candidate to look at. The pipe from the thermostats to the heat exchanger, where it connects to the heat exchanger has been known to leak on my 42. The jubilee clip can be awkward to get to to tighten as it hides hehind the intake manifold to the rootcharger and butts against the bracket of the heat exchanger. If the screw mechanism butts against the bracket when tightenning it twists the jubilee clip skew. I have tightenned on up before thinking it's on straight but it wasn't and the pipe leaked out once pressure built up. Tell tale is the coolant lands on the oil hoses running between oil cooler and filter. It's a right pita to get to to check. You have to remove air filter box and drop the root charger manifold to get to it, but try checking if it's wet there. Also that hose rubs up against some exhaust stud bolts. There should be rubber nut caps protecting the hose from these but they tend to get lost in the bilge over time. The hose wears against these bolts and needs replacing over time.

I have no sign of coolant in the bilge.

 

[Hipower]

If its not leaking externally then its losing it internally, it could be leaking over to the seawater side in the heat exchanger or it could be the head gasket. Never had a head gasket go on a KAD32 but always a first time. Would try a pressure test and remove the seawater hose on the heat exchanger and see if coolant is present, if not then it points to the head gasket.

Thanks , I will have to pressure test it.

 

[Hipower]

Also (at risk of stating the obvious), if you have a hot water tank or cabin heater which tie into your coolant line, check for leaks at the appliance.

Thanks, I have checked the cabin heater and hoses, all dry.

 

[Momac]

No, the coolant level drops and stays low.

If you keep feeding it with coolant and it keeps consuming coolant it does sound serious . Not sure what to suggest .

 

[volvopaul]

Exhaust manifold gaskets ,they leak slowly but the heat in the block burns off the coolant leak so you don’t see any in the bilge , just a stain down the block .