Fuel/Oil coming out of Motor exhaust

[MelloLello]

Originally Posted by Valmika

I just went through this myself last year. If your oil level is staying good then it is probably a stuck or clogged injector. You can have them rebuilt for less then a new one if you are in an industrialized area. The thing you said that worries me is that you were spitting coolant. If you start you engine with the coolant cap off are there bubbles in your coolant? If there are you need to pressure test your cooling system. If the pressure goes above about 20 PSI I would suspect a blown head gasket. Not necessarily a cracked head but something that should be taken care of soon. I had to do mine and I figured while I was there I would do the head and injectors. Mine has been running better then ever since I did it.

Oil levels and pressures are fine. Like I said earlier...

No water or milky **** in the oil at all.

Just the spitting of the coolant out the top cap... That cap I think is also a built in thermostat. (Has the spring on it).

That being said. Could the issue be with my heat exchanger as well?

Heat exchanger, thermostat cap and maybe a stick or clogged injector?

The motor runs great other than that. Like really really smooth

[sailor_ed]

The previous posters have given good advice regarding your problem. As an aside your photo does not show a happy situation. Coolant should be showing under your cap and that amount of rust would not please me. You need a coolant overflow reservoir otherwise you just loose fluid every time you run the engine. It is also probably time to drain and flush the system. If you wind up pulling the head though then half the job will be done 😉 P. S. A new cap too.

How many hours are on the engine?

Ed

[stormalong]

The spring in the cap regulates the coolant pressure. It is not the thermostat. If coolant is coming out of the cap replace it.

All that rust around the cap says to me that your engine coolant may be just water. Antifreeze is also anti boil, anti corrosive and a lubricant. Running without it will shorten the life of your fresh water pump. If it is just water the engine needs a coolant flush - maybe multiple flushes until the water runs clean and then a proper water antifreeze mix.

You can buy a coolant overflow tank at most auto parts stores. Connect it to the hose fitting next to the radiator cap to keep antifreeze out of the bilge and the environment. Properly installed the coolant overflow tank will return the coolant back to the header tank as the engine cools.

As for the sheen on the water the first step is to have the injectors checked. Don't delay on this because extra fuel in the cylinder washes the oil off the cylinder wall and can do major engine damage.

[sailor_ed]

An idea on removing injectors as they can be difficult to get out: loosen the hold down bolts but do not remove them. (a turn or so) Then turn over the engine The compression should free them up. Do Not remove the bolts or you will have dangerous missiles bouncing off the overhead! Don't ask. 😀

[Cheechako]

I had the same issue on a 4-236. Some things:
-It is likely a fouled injector spraying raw unatomized fuel which is then pushed out the exhaust. Have your injectors checked. You can diagnose the specific one by cracking off the injector nuts one at a time while running. If one has no effect on the engine that's the one. This happens more often if the boat has sat unused for a while, the injector tip fouls with carbon or even rust.
-My 4-236 ran smooth with the one cylinder not firing. I couldnt even tell, but fuel was growing into the oil sump! About a quart in 8-12 hours.
-In my case we discovered that a valve push rod had jumped off the rocker arm. I had no idea it could even do that. The push rod was true and not bent either.
-In the end the mechanic and I surmised that the aft cylinder had gotten some sea water in it. Just enough that when we started the engine it created force on the valve and that popped off the rod. The water subsequently rusted the injector tip.

Ain't boating fun?

[FionaJC]

My Perkins 4108. Used to push water out the radiator cap. I then fitted an expansion bottle. Temperature stabilised and coolant levels hot and cold were the same. The rad cap pressure is set to 7lbs. If the engine has sat then one of the pistons could have been at TBC. oil will seepinto the cylinders and then coat the waterlock inside. It takes the tiniest amount to make a shed. Run the engine gradually harder and harder and observe temp and pressures. Listen for noise and then after runs totalling 5 hours look again. Check your oil levels and if there is a minimal use then I suspect you are good to go. I would also check with a local friendly marine engine guy. If you hadn't noticed the sheen you wouldn t have worried.

[FionaJC]

A coolant cap acts as two valves. One to let excessive liquid out and another to such it back in when needed. I didn't believe it u too a marine engineer showed me the two valves and how they worked. I use 50:50 coolant to antifreeze.

[Mike Banks]

Sounds like a stuck exhaust valve.

[Valmika]

Originally Posted by MelloLello

Oil levels and pressures are fine. Like I said earlier...

No water or milky **** in the oil at all.

Just the spitting of the coolant out the top cap... That cap I think is also a built in thermostat. (Has the spring on it).

That being said. Could the issue be with my heat exchanger as well?

Heat exchanger, thermostat cap and maybe a stick or clogged injector?

The motor runs great other than that. Like really really smooth

You're getting some good advice here from what I can see.

1. Is there dark soot coming out of your exhaust at all?
If yes then suspect a stick injector or fuel pump timing may be off.
If no then keep a close eye on your coolant level. Coolant can also leave a sheen on the water.

2 If you are loosing coolant which looking at the photos makes me think you are. Then if there is nothing in the pan below the engine it is
probably blowing out the exhaust.

The heat exchanger is easy to diagnose once you get it off. If you are Unsure of its condition or the last time it was cleaned I would do this
anyway and service it. Easy to do once it is off. Just close of one circuit Raw or coolant, with your hands. Pressurize the other side.(I did it with my mouth) and see if it looses pressure to the other side. Coolant flows through your engine at about 15 PSI. Raw water flow through really under no pressure. If your heat exchanger is compromised you will lose coolant to the lower pressure raw water side and out the exhaust where it may create a sheen on the water. I am not sure where you are located but don't pay Perkins prices for a heat exchanger. There are companies in the US I have found that sell them for about half price (at least half Westerbeke prices)

3 Looking at your tank I think you could really benefit from an engine flush. Lots of info here on how to do it

[Squanderbucks]

So many possibilities. Especially after seeing the photo. First off many diesels will put out a little sheen right after startup. Detroits are bad about smoking a little when first running or after trolling for a while and then pushing down the throttles. smoke then as well but clears up pretty quickly. Looking at the photo it appears to me that there are a number of maintenance issue that may be a factor. All that rust around the heat exchanger makes me wonder what color the cooling fluid is. Does it look like the same color of the anti-freeze fluid that goes in the heat exchanger when it is renewed? Should. If it is clear then I would seriously wonder about your having a leak and that the water in the exchanger is salt water. Not good. When was last time the heat exchanger was removed and "boiled out", new water and antifreeze put in. Does it require zincs to be changed every 6 months or so? If so when were they last changed? If it has been a while I would have it pressure tested. Also how old are the exhaust riser elbows? Normally about 5 years is tops for salt water cooled elbows if they are cast iron type. Next how many hours or years since the engine had a tune up? That is injectors taken out, sent to injector shop and cleaned/serviced. Then put back in and the valve and injector timing rest.
If you don't know when or if never done since you owned the boat then all of this is part of what needs to be checked out.
As others have said like worst case scenarios such as cracked or warped head or block, head gasket, but start with the most common simplest and cheapest solutions first and rule them out. Likely dirty or clogged injectors.

[james247]

Originally Posted by Valmika

You're getting some good advice here from what I can see.

1. Is there dark soot coming out of your exhaust at all?
If yes then suspect a stick injector or fuel pump timing may be off.
If no then keep a close eye on your coolant level. Coolant can also leave a sheen on the water.

2 If you are loosing coolant which looking at the photos makes me think you are. Then if there is nothing in the pan below the engine it is
probably blowing out the exhaust.

The heat exchanger is easy to diagnose once you get it off. If you are Unsure of its condition or the last time it was cleaned I would do this
anyway and service it. Easy to do once it is off. Just close of one circuit Raw or coolant, with your hands. Pressurize the other side.(I did it with my mouth) and see if it looses pressure to the other side. Coolant flows through your engine at about 15 PSI. Raw water flow through really under no pressure. If your heat exchanger is compromised you will lose coolant to the lower pressure raw water side and out the exhaust where it may create a sheen on the water. I am not sure where you are located but don't pay Perkins prices for a heat exchanger. There are companies in the US I have found that sell them for about half price (at least half Westerbeke prices)

3 Looking at your tank I think you could really benefit from an engine flush. Lots of info here on how to do it

I have owned 5 Perkins over the years. They are a basic Diesel engine with a heat exchange bolted on to the marine version. Any decent diesel engineer can help.
Get a rebuild of your injectors and pump flush your heat exchange and a new cap would be in order. Stop wondering and find out what's wrong.
Oil change and all filters.
The diesel guy will test cylinder pressures and see if any are down due to head gasket leak or heaven forbid something worse.
A Perkins engine is akin to a draft horse pretty much unbreakable.

[MelloLello]

Lots of great advice on this forum. I appreciate everyone’s input.

I’m starting small and working my way to big.

Flushed the system 4 times and already have a new cap...

I’ve changed the zinks in the heat exchanger

I pulled BOTH heat exchangers and cleaned out the micro holes.

Replaced the “sea strainer”. It was ****ED!!!

Checked pressure on the coolant system by running the motor with the cap off. (No bubbles, no explosion). That basically rules out a blown head gasket.

The reason I have fuel coming out the exhaust is because the motor has been wet loading.

And I have 2 bad injectors.

I’ll keep everyone updated on the progress.

[JackMcD111]

interesting. I just saw this as I was warming up my diesel Yanmar 75hp. the engine has sat for months on the hard. injectors? it does appear to be diesel.