Pressure Testing Yanmar 4BY2 on 2010 Ranger R25

[captstu]

Hi, I'm chasing a coolant leak on my R25. Did the obvious, removed and had the heat exchanger tested, removed and bridged domestic hot water heater and "bus" heater, inspected all hose clamps and replaced any doubtful ones, lined the engine with diapers and looked for leaks - no more "easy" ideas.

How do I Pressure Test the coolant system? I can't get to the heat exchanger cap because it is under the door.

Before I cut fiberglass to gain access, is there a tester/adapter I can purchase to gain access via the auxiliary hot water outlet on the engine water pump above the alternator?

Is there an adapter available to access the heat exchanger cap?

What can I safely remove or cut out to gain access to that area?

 

[NorthernFocus]

Wouldn't an easy spot be where you "bridged" the cooling lines to bypass the heater? Just install a couple of tees with a gauge and necessary fitting to apply pressure. But are you sure that's a good idea? If you have a manifold gasket leak you could push coolant into a static engine. Probably not something you want to hear but seems like you've eliminated about everything other than a gasket leaking coolant into the engine. I'm not familiar enough with that specific engine to suggest where/how that can occur. But it is a common enough problem on most engines.

 

[Cutwater28GG]

is there a high pressure overflow on the yanmar?

 

[BB marine]

If you can not get to the pressure cap you can tap into a drain port have a fitting made up with a small shut off valve to attach pump and gauge. I agree with NorthernFocus most likely a gasket but I would pressure check to make sure it is not something else being over looked.

 

[captstu]

Access to the coolant fittings on the domestic hot water heater is very difficult, beyond me. I can access# the feed lines at the engine and put a t on the water pump to pressurize it there.

The overflow line to the expansion tank is at ambient pressure. I think I can pump air into the system there to listen fir a leak.

Removal of the head gasket requires removal of the engine. I think that requires cutting the cabin entrance sill off, if I do that, I’ll put in a new engine since the labor will be extreme,


Stuart Bell
Ranger 25: Shearwater
(561) 352-1796

 

[daveo]

Have you checked the engine oil level? If the oil is above full, you found your antifreeze. Can you get a camera over the "radiator cap"? Put it in gear and watch for bubbles coming up.

 

[captstu]

The oil level is normal. There is no milkiness in the oil.

The cameras a good idea, as soon as the heat exchanger is back in I’ll try it

 

[captstu]

Two weeks, still no idea where the coolant is going. The heat exchanger went off to the shop for cleaning and pressure tested ok.


The mechanic cut the hoes to the heat exchanger and can’t find the replacement parts. Apparently two versions of the hose exist with the same part number.??

Yanmar only lets a very limited number of shops sell parts so I can’t just buy the part directly.

“For want of a hose.”

Anyone know of a place that makes Hose’s?

Since I may have to replace the engine, anyone know if Volvo has the same parts policy?


Stuart Bell
Ranger 25: Shearwater
(561) 352-1796