Do I have a blown head gasket?

[MikeB]

Hi All,
I apologize for the long post but I feel I should share all of the events that have led up to me thinking that I now have a blown head gasket. I have a new to me 1977 Pearson 323 with a recently Moyer Marine overhauled fresh water cooled A4 with roughly 200 hrs on it.

On the maiden voyage from Little River SC south to Florida when motoring from the marina where I purchased the boat in on the ICW towards the Little River inlet I noticed the water temp gauge creeping up past 180 degrees and finally stabilized around 195 to 200. This seemed to be way too high to me. This is the first fresh water cooled A4 I have had, my two previous A4’s were raw water cooled and always ran around 150 to 160 never skipping a beat. I was running around 1800 to 1900 rpm’s which gets 5.5 to 6 knots and I was getting close to the inlet so I just slowed down backed it down to 1400 rpm’s and that drop the temp back down to 180 until I got out the inlet raised the sails shut the engine down and headed south to my first stop in Charleston. In route I checked the raw water and coolant pump impellers as well as the raw water inlet strainer, everything was all good. Once I reached the Charleston inlet the A4 fired right up like it has every time for me since I bought it. Once it was warmed up I ran it up to 1800 rpm’s and not long after that the temp was back up to 195 to 200. Backed it down to 1600 rpm’s and the temp stayed closer to 190. Still I’m thinking this is too hot, so I was thinking possibly a sticking thermostat. The Moyer thermostat bypass valve is installed on this A4 so once I was tied up in the marina I removed the thermostat to see if that would help. It did! The temp stayed at 140 just running it in the slip and the next day running down the ICW it stayed just below 180 at 1900 rpm’s. I had the bypass valve completely shut and was thinking that may still be a bit warm but way better than 200 degrees and motored the next few days all the way down through Georgia and into Fernandina Beach FL like that no problem it ran great. Dropped the hook there in Fernandina Beach shut the perfectly running A4 down and settled in for the night.

Now the galley sink is located above and a little bit to port of the engine in the Pearson 323’s and while doing the dishes after dinner the fitting under the sink burst spraying fresh water all over the engine compartment and all over the A4. Now I didn’t think to much of it other than a few choice words in the heat of the moment towards the broken fitting. Now also the 323 A4’s were installed with v-drives so aft of the engine is forward locating the ignition coil directly under the burst fitting. Once again I didn’t think anything of it until the next morning ready to pull the hook and leave. There was no signs of life the A4 just cranked and cranked and cranked not even a slight sputter. My thinking went first to the the night before soaked coil, pulled out an old coil from the spares installed it but still no signs of life. I am solo on the boat, I don’t have a remote starter and couldn’t check spark so next I checked fuel maybe the electric fuel pump shorted out from the fresh water bath, so I pulled the carb bowl plug and plenty of fuel came pouring out. I then replaced the fuel water separator and filter but that didn’t work. I decided to pull all of the spark plugs and they all were wet and kinda smelled like gas that made me think it was flooded. Tried cranking it wide open throttle and no choke but still no go so It’s got to be the coil and the old spare the previous owner kept could possibly be bad as well. Pulled the distributor cap and no points it’s electronic ignition and no signs of water intrusion. So After a few more failed attempts to start I gave up called TowBoat US to get towed to a marina to order and receive parts. Few days later I received a new coil from Moyer installed and still nothing. Finally I came up with a plan to tape my phone to the bulkhead with the camera pointed at the #4 spark plug pulled and grounded to the head, hit the video record button and went up top to crank it over. Started to crank and after couple revolutions it started! But obviously roughly with the #4 spark plug pulled so I shut it down quickly. After reviewing the video, seeing a healthy spark and then promptly scratching my head I reinstalled the spark plug went back up top to try and start and sure enough it started right up but still very rough unable to idle and rev above 1500 rpm’s. So I pulled the other plugs one by one and all had a healthy spark but I noticed the all showed a lean mixture. Started it back up and let it run for a little bit hoping it would work itself out but no luck it just got worse so I shut it down and pulled the carb bowl plug again and plenty of fuel came out. Then I decided it’s time to pull the carb apart and see what’s going on. And I found the culprit, it was all gunked up. A carb rebuild kit and a large can of carb cleaner later it was back together and back on the engine. It started right up and ran perfectly above 1200 rpm’s and higher but would not idle and instantly died when pulled back to idle. So I pulled apart the carb again and found I missed the idle passage way up from the main jet to the idle jet was still plugged, cleared it with a length of safety wire reinstalled it and it now runs flawlessly. The temp even stayed quite a bit cooler than it has since I pulled the thermostat. Ok good to go might as well change the oil and start heading south again... Nope the oil looks like a vanilla milkshake! Not foamy with air bubbles just creamy in color. I check the oil every time before I try and start and never noticed anything other than slowly getting dirty over time as normal and I did change the oil about 16 engine hours prior to the night of the water burst with no signs of water just dirty oil. I am religious about closing the seacock before starting because I’ve heard all the horror stories but could I have possibly left it open sometime during all the cranking attempts? It’s possible, but I never noticed the starter struggle in all the cranking attempts like I think it would with raw seawater in the cylinders. So after 4 oil changes and running the engine in between each it’s still milkshake creamy in color when I pump it out but it’s showing clean on the dipstick. I pulled the plugs again and 4,3,2 were perfect but #1 was very wet and didn’t smell like gas. Also the coolant and oil levels have stayed on the full mark and haven’t changed. And that’s where I am at now. It’s running perfectly but the water in the oil.

Do I have a blown head gasket on #1? And if I do, was it because it must have been running lean this whole trip and that being the reason it was running hot in the beginning? The head gasket just finally gave up and coincidentally at the same time the fresh water fitting burst? Or am I overthinking this and need to keep changing the oil until all the milky oil is gone because when I first pulled the plugs and noticed them wet thinking it was gas flooded in fact was raw sea water from the exhaust?

I am going to try and get my hands on a gauge to check the compression on #1 before I pull the head. But would there be much of a psi loss if it’s just a small burned out part of the gasket between the cylinder wall and a water jacket that’s causing this water in the oil?

Please any input on this helps even if it is to point out something that I may have done wrong.

Thanks everyone
Mike

Below are a picture of the gunked up carb bowl and the milky oil

[ndutton]

If it were me I would not remove the head until a compression test on all 4 cylinders and a cooling system pressure test is complete. Please report back with the results. I did not read that you noticed a surging in the coolant reservoir, something that would indicate a head gasket problem. Let's find out where the water in the oil came from before tearing things apart. Most importantly right now is keep the engine moving with some oil in the cylinders.

If your distributor suffered a good dousing, everything within is suspect including the electronic ignition, distributor cap, rotor and plug wires.

[joe_db]

That oil looks
First obvious question: Are you missing coolant?
Please do a compression check ASAP. You may be the victim of an incredible coincidence. I also think you may have flooded the engine with water from the exhaust with the attempts to start.

[Dave Neptune]

Did you notice the block vent "slashed hose" from the block to the spark arrestor dripping or full of gooh? Thinking maybe the hose that burst may of been leaking while you were motoring?
I am a bit perplexed as to how the ""throat" has so much emulsified gooh coating it~~very weird. It must of come from the slash tube (block) or an external source possibly the sink.
Are you sure about the fluid levels?
Gat the compression check done and keep spinning the engine with the water off so it does not seize.

Dave Neptune

[MikeB]

Ok compression checks came in at (the gauge I have is in 5 psi increments)
#1. Between 85-90psi
#2. 90psi
#3. 90psi
#4. 95psi

Now I pulled all the plugs at the same time to hopefully limit pulling gas into the cylinders and the electric fuel pump fuse pulled. Liquid did spurt out of every cylinder and it doesn’t smell like gas, about double the amount of liquid came out of the #1 and #4 cylinders compared to the #2 and #3.
The raw water seacock is closed and has been close since after the last time I ran it.
I use a green coolant and none of the liquid had any kind of green tint to it.
Am I safe to assume the head gasket is fine even though number one is a little bit lower in compression than the others? And if this is sea water back filling through the exhaust manifold does that indicate a exhaust riser or water lift muffler problem?
The water lift muffler is a plastic one.

Here are pics of the exhaust riser I have and of the amount of water that spurted out of the cylinders
iPhone pics are turned left 90 for some reason

[MikeB]

The coolant level has not changed. The block vent is fitted with the pcv valve kit and looked dry when I removed the hose from the intake spacer between the manifold and carburetor

[Dave Neptune]

Good news I think. the compression looks absolutely fine. Now I would FIRST do a pressure check of the manifold~not difficult at all. If the manifold is compromised it will easily allow water into the "intake system" BUT you should show a decrease in coolant. Remember it does not take much liquid to really mess up the oil.

Do the manifold check and then the block. Either of these would only allow your coolant into the engine.

If the water did not come from the coolant it had to come in outside of the engine system itself like maybe the sink issue.

Dave Neptune

[MikeB]

Update... I think I have come to the conclusion it was seawater backflow from the exhaust. I did 3 more oil changes today running the engine in between and also pulled and checked the plugs in between each oil change. The oil now looks clear of any water and the plugs were dry. The only thing I did differently was starting it with the raw water seacock closed and then also closed it before I shut it down to blow all the water out the exhaust, which I am not a fan of doing. A practice that may cause me to run through impellers quite frequently.

So is it possible that the exhaust riser isn’t high enough and can quickly fill up with water?

And I have an idea about installing a y valve somewhere in between the raw water pump output and the exhaust riser to divert the water out an unused thruhull located through the transom that was used to vent the propane locker that no longer is installed. That way it saves the pump from running dry on startup and shutdown, what do you guys think? Or would it just be putting a bandaid on a problem with the exhaust design?

[Mo]

Absolutely. it is possible for water to run back into the engine if the riser isn't high enough. You need a risen area right after the manifold if it can be done. Also ensure your water lift muffler is oriented and installed correctly.

I've tried to upload a sketch here. This is how my C&C 30 is done. Note that rise right after the manifold...if there is room make that happen and it cuts out a lot of grief.

[Dave Neptune]

Mike, great news for you.

RE the impeller "frying", if it is only for a short time remember the pump is still wet and below the waterline so it would take some time to fry. However starting a dry pump impeller is bad news. I started my beastie with the water off for many years (20+) and no problem. I changed the impeller 3 times and not due to failure in those years. The original pumps housing became worn and was replaced as it did not pump well.



Dave Neptune

[MikeB]

Thanks Mo! From your sketch I think I see my problem now.

My riser is limited to its current height because of the cockpit floor. The raw water discharge line and exhaust hose from the muffler are located in the port side locker to run higher. The exhaust hose runs all the way up to the underside of the deck which may be creating the backflow into the manifold after shut down being at least 2 feet higher than the riser.

I’ve made two sketches of my own. One of the current set up in the other my idea to remedy the issue.

I have concerns of lowering the exhaust hose any lower that could cause backflow into the engine from following seas.

I am thinking about installing a Y valve in the raw water pump discharge hose between the pump and the exhaust riser to divert the raw water discharge from the riser to an existing not used thru hull in the transom. That way I could leave the raw water intake seacock open during engine startup and shutdown and divert the water away from the exhaust riser only during startup and shutdown so that the raw water pump never runs dry. That way the engine exhaust will blow any remaining raw water out of the exhaust system just before shutdown.

What do you guys think? Will it work?

[ndutton]

Not so fast

I don't think the exhaust water backflood theory is conclusive yet so I wouldn't be so fast to reconfigure anything. There still hasn't been a cooling system pressure test or a manifold pressure test, both of which have been recommended as diagnostics to help us help you. They both may be fine but maybe not. The tests will tell us for sure.

If you had the raw water intake thru-hull closed as you have said more than once, exhaust backflooding is extremely unlikely if not impossible.

Also, it is entirely possible the water came from the sink water dousing via the carburetor intake horn and aspirated into engine during running or even cranking. The point being, there are still possibilities on the table other than the exhaust.

Edit: About your diverting Y valve idea, it will bring a significant risk of an unintended consequence. The waterlift "muffler" you have is a Vetus LP40 and it is the least tolerant of heat of all the available waterlifts. This forum has experienced them melting or popping the seam with even 60 seconds of operation with no cooling water which is exactly what your diverter valve will do.

[GregH]

With the placement of the "Y" diverter upstream of the vented loop, doesn't that indicate that the vented loop is not working if water can be sucked back?

or what am I failing to understand?

[ernst]

Here are pics of the exhaust riser I have and of the amount of water that spurted out of the cylinders
iPhone pics are turned left 90 for some reason

Looking at the first of your pictures, with the exhaust riser: Given that this is a new-to-you boat, I would have a look at the water injection port (meaning take it off, see how it looks like). From the way it looks to me, there should be a quite long nipple going down the exhaust pipe to avoid water splashing backwards into the branch coming from the manifold. This long nipple lives in a very corrosive environment, perhaps it broke off? Or it was not long enough to begin with?

Very simple thing to check, and if that is the case, it would explain all your symptoms (I think).

[ndutton]

Greg, I think you're understanding fine. My assessment of the drawing of the existing exhaust system is it is exactly the way it should be with the possible improvement of locating the water injection a little lower after the hump.

Here is an article from Good Old Boat discussing waterlift exhaust systems with an excellent drawing near the end: