Oil in Intercooler 12V71

[scottinsydney]

In 2025 we serviced the starboard engine's two intercoolers. The rear intercooler, which is fed air from the outboard turbo, was very oily. This may well have accounted for the considerable blue smoke when we cleared the engines every so often.

We also cleaned the rocker cover mini vent filters, installed new hoses and mounted the vent filters higher than before. We also tested blowby and there was nothing sinificant. Turbos were checked on supply side and spin nicely and are dry.... no oil.

But this weekend we have oil oozing out the out the top of the rear intercooler (below the air intake section) and also oil leaking onto the turbo body.

I believe the oil could only be from the outboard rocker cover breather.

Ideas? Suggestions? How to test? Resolve?

 

[Captain Ralph]

The valve cover vent is a rather simple and crude device. A ball of coarse steel mesh.
No baffle, no oil trap, as long as the hose connect is pointing up a lil and oil is not getting trapped in the hose, all is good.

I do not want to bash your services but but gaskets and hoses leaking oil mean they are leaking boosted air while making that mess.
A little turbo slobber leaking is normal Like from the shut down flapper shaft ends. Is that oil on your flapper shaft end or a Sharpie mark?
You may have a bit much.
Check the oil drain hose and check valve from the Walker.
Is there oil puddling in the hump hose between the Walker and turbo inlet?
Disconnect the hose to the walker and go for a ride.

If the inside of that walker to turbo inlet is dry, I fear that is a turbo oil leak.

How much oil are you consuming?
OZ, Qts, Gallons?

 

[scottinsydney]

Here is a short video of the issue. Normally the engine is quite clean so this is an issue that has been developing recently.

Thank you for the responses. I have not had a Turbo issue before on any Boat so this is all new.

Comments greatfully appreciated.

 

[Captain Ralph]

That oil around the turbo is blowing out of the orange connect hose to the intercooler.
A fresh hose or better position on the clamp will help.
Oil coming out of the intercooler is just more of this oil mist in the compressed air leaking out from the gaskets.
If there was oil in the connect hose between the Walker and the turbo inlet, The Walker assembly is not draining or a saturated Walker Coalescing filter, if that was dry, it is a bad front shaft seal in the turbo.

There is a life span of these Walker's Coalescing filters.
Later Walker models have serviceable filters vs replacing the whole assembly.
#1, Check the drain system including its check valve.

Also, When was the last time you serviced the air box drain/check valves?
If they are leaking air box pressure, They may interfere with the Walker drain.

Way out there question, Did you take the turbos off on the top end service?
Service the turbo oil return hoses?

 

[scottinsydney]

I am on the boat now and will go take a look with my scredriver and spanner.

 

[Avenger]

If there's oil on the compressor wheel blades it's likely pullover from crankcase ventilation. While an intake restriction or seal failure can cause the compressor side seal to leak oil, it wouldn't show up on the outer blades, it would be leaking on the back side of the compressor wheel.

 

[Captain Ralph]

it would be leaking on the back side of the compressor wheel.

You are more into the turbos than I, but if the compressor wheel spins out oil from behind, all over the inside of the housing, I can imagine some dripping down the inlet side.
It was a thought I had while working on mine, Now all dry.

But those OLD Walker units can be an adventure. As simple as they seem, extra aspirin is required at times.

 

[Captain Ralph]

Is there a Walker rep down under?
I used to deal with a rep on the left coast.

 

[scottinsydney]

So I am back from the engine room with only a couple of battle wounds.

- The intercooler hold down nuts had no torque. I guess after the intercooler service last year the intercoouler and its top had settled down on the new gaskets. Anyway they are now quite snug. May well solve the leaking oil out the top.

- The connecting hose clamps between the turbo and intercooler top was indeed looser than expected as suggested by Capt Ralph. They are now clamped down

- I degreased the turbo housing, the inside of the turbo and cleaned the front side of the blades. There was no oil in the Walker Air Seps bellows or metal housing.

- I replaced all of the Walker Airseps about 7 years ago. They have twice been cleaned and oiled since then. They would have a maximum of 500 hours at 8 knots on them.

- The Walker drain hose loops around the back of the engine and connected to the other turbo drain hose. I will need to investigate the valve/connection into the sump later on.

Now we have a clean turbo and a baseline, I will take the boat for a run down Sydney Harbour later in the week. Would anyone like to come for the ride?

 

[Captain Ralph]

Now we have a clean turbo and a baseline, I will take the boat for a run down Sydney Harbour later in the week. Would anyone like to come for the ride?

Wow, I would luv a ride down there.
Thank you for the invite but sadly, I'm not able to make it.

 

[Captain Ralph]

Also, the coalascing filters are not the external air filters that you clean and oil.
These are internal. These filters cool down the hot crank case gasses, the oil mist cools and drains from these internal filters.
They are not serviceable like the newer assemblies.

 

[Captain Ralph]

If you could find a real Walker rep, he may be able to offer a copy of the original life specs on your older model Walkers. They may offer some support to help also.
The last time I tried to find anything on their web site, all material was for the newer stuff.
I'll be back at my desk tonight and may still have more info in my notes.

 

[scottinsydney]

There are no coalascing filters inside the Walkers. I have heard of them before but they were not installed.

 

[Captain Ralph]

There are no coalascing filters inside the Walkers. I have heard of them before but they were not installed.

Brother, trust me, they are in yours, just not visible, serviceable or removable.
Hence the life of the whole assembly.
Later assemblies have serviceable coalescing filters.

Walker has done a great job of washing their hands of the older assemblies. Nothing on their web page.

I lost so much on my server crash years ago, this may be the only page left available that even admits there were two different models. With springs holding the air filter on vs a clamp holding the air filter on.
Other than the air filter itself that K&N makes, there is nothing for it.

But that original assembly had a life span.
I have witnessed old assemblies, when dissected was full of mud and not passing any crank case vapor.

 

[Captain Ralph]

In short
Most of Walkers employees were were not born yet to just out of diapers when the original design (yours) was discontinued. All other employees have long retired.
All sales and support are geared to the latest design, the only design these wet kids know, the clamp on air filters / serviceable coalescing filters.
The latest support to the original design, from the US left coast (Sun Valley, CA) to me was; When in doubt, replace it.

I do invite anybody to find any different information.
support@walkerengineering.co

 

[scottinsydney]

Hi Captain Ralph,

To be clear or clarify I have Red Cone shaped filters with springs. There is nothing on the inside of the filters or on the inside of the circular metal body that has the filter at one end and attaches to the turbo at the other. There is a drain hose from the circular metal body to the sump.

I was able to buy the replacement filers here in Oz about 7 years ago after contacting Walker Air Sep in the USA.

I read the document.... so are these these the "old style" with the filter is incorporated into the metal body?

 

[Captain Ralph]

I read the document.... so are these these the "old style" with the filter is incorporated into the metal body?

Think of a donut inside of a donut hidden in that circular can. There is filter media hidden in there.
If you try to clean it, the media will fall and settle.
If it is saturated with oil and oil-mud, it will settle.
Once it settles, it will not drain correctly and any oil collected will puddle and not drain back easily.

Once you understand what I am trying to explain, we need to find a way to test it.

SWAG test #1; do you feel ANY oil on the inside of that walker donut tube? You may feel some holes or slots in the inner tube.
Squeaky clean?

SWAG test #2; roll the assembly upside down (hose inlet pointing down, drain pointing up) and let sit for several hours.
Any oil drain out?

If squeaky clean and no oil drips out, then there in no oil coming from the Walker.

 

[Captain Ralph]

Oh, How much oil does this engine consume?
The same as the other?
I ask to also compare to the same engines in my boat with Racor CCV.

 

[cenger]

There should’ve a check valve at the bottom of the Airsep that drains back to the block which is prone to leaking. Check if the valve is wet. This spring I had a similar issue. Airsep sells the valve $76.

 

[Captain Ralph]

#1, Check the drain system including its check valve.
Also, When was the last time you serviced the air box drain/check valves?
If they are leaking air box pressure, They may interfere with the Walker drain.

There should’ve a check valve at the bottom of the Airsep that drains back to the block which is prone to leaking. Check if the valve is wet. This spring I had a similar issue. Airsep sells the valve $76.

Thank you. the drains and check valves, from the Walkers and air box, can all be contributing issues.
Lets see how SWAG test #1 & #2 (post # 17) prove out.