Milky Oil |
Post Reply | Page 12> |
Author | |
Evilsizer
Groupie Joined: August-29-2019 Location: Ohio Status: Offline Points: 62 |
Post Options
Thanks(0)
Posted: September-13-2019 at 12:30pm |
I have a 78 Ford 351 that got hot but I shut it off when I noticed it. I pulled out the thermostat that was not working and the engine seemed to run like normal and stayed at 140 degrees. Later we went for a ride and the engine lost all power. It would run but only at a very low rpm. I checked the oil and it is now the dreaded milky white oil. Compression test on all cylinders yielded 150 to 140 psi. Question is, should I try a rebuild or is it more cost effective to by a crate long block or short block? Also what would be the best place to purchase a long block if that route is taken? Thanks!
|
|
tryathlete
Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797 |
Post Options
Thanks(0)
|
Can you pull each plug and see what’s up in each cylinder? Might be a leaking head gasket from the overheat (warped head possible too). If it’s one cylinder—might tell you where the water is getting in. Manifold gaskets are a possibility too. I’ll let the experts weigh in. All of my recip engine education was air-cooled Lycoming and Continental engines with an occasional Wright thrown in. In other words, wait for better advice sure to follow.
|
|
Fabcon
Gold Member Joined: August-27-2012 Location: Buffalo. Mn Status: Offline Points: 554 |
Post Options
Thanks(0)
|
Like Peter said do a little more investigating before you replace the motor it could be as simple as gaskets. you need to dig a little more.
|
|
1976 Ski Nautique 351 Escort
1984 Barefoot Nautique (Parting Out) |
|
tryathlete
Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797 |
Post Options
Thanks(0)
|
The sudden loss of power. Can you describe it in detail? Was there ever black smoke from the exhaust at the overheat or afterwards? Could be a collapsed exhaust hose along with a blown gasket (head/exhaust/intake.
Also: when you changed the thermostat: did you make sure to get a good seal on the new gasket? I’m not sure if there’s any chance the thermo replacement could mess things up, but is was the last thing you did. |
|
Evilsizer
Groupie Joined: August-29-2019 Location: Ohio Status: Offline Points: 62 |
Post Options
Thanks(0)
|
Yes, we were just cruising along at about 10 mph and then I decided to put the hammer down. The boat seamed sluggish but then took off. About 3 seconds later the rpms went down to like 500. If I tried to give it gas the engine would stall. The exhaust did sound different. I pulled all the plugs and they all seamed to look the same a little oily but not water. A compression test ranged 150 to 140 on all cylinders.
|
|
Evilsizer
Groupie Joined: August-29-2019 Location: Ohio Status: Offline Points: 62 |
Post Options
Thanks(0)
|
The thermostat was put in by me he day before. I just bought this boat and discovered it did not have one installed. The boat ran cool but I thought it should have it in there. After it over heated I took it back out and ran it the way they did without one. I was just trying to do the right thing and wish I would have left it alone.
|
|
tryathlete
Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797 |
Post Options
Thanks(0)
|
I will speculate but bear in mind the brains on this site are far more capable marine troubleshooters! I wonder if it’s possible for the exhaust hoses to collapse by design from the overheat condition and somehow water in the cooling system backs up somehow into the crankcase oil? Beats me. I think the milky oil is exhaust manifold related somehow since the plugs checked out and cylinder pressures are all high and even. Check your exhaust hoses (not fun) and manifolds in any case.
|
|
8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
Post Options
Thanks(0)
|
Andrew,
Did you by chance check the oil before or immediately after you bought the boat? Wondering if you purchased a previous problem. You did the right thing with putting the T stat in. The engine is designed to run with one. Do check for collapsed exhaust hose. With engine overheats, there are times where the inner layer of hose disbands to the outer and then folds in restricting the exhaust. |
|
tryathlete
Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797 |
Post Options
Thanks(0)
|
Is it possible you put the thermostat in backwards? I’m trying to figure out why it overheated after the thermostat installation. It’s easy enough to do I suppose. I don’t know if it would operate properly in reverse and it could be worse.
|
|
Evilsizer
Groupie Joined: August-29-2019 Location: Ohio Status: Offline Points: 62 |
Post Options
Thanks(0)
|
Yes the oil look nice and clean. So with the compression test good that rules out head gasket or warped heads correct?
|
|
MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3734 |
Post Options
Thanks(0)
|
Good compression normally does indicate the head gaskets survived.
The older boats did have collapseable exhaust hoses. I have had two and been in one that had this happen. With the hose collapsed the engine has no power since the exhaust can't get out or al least is very restricted. You can't see this from the outside as it is an inner liner that collapses. Newer boats no longer have this type hose. It is possible to take water into the engine from the exhaust. I have seen this happen in boats where the flapper is gone from the stern exhaust outlet. We also see it when an exhaust manifold fails and lets water enter a cylinder. As mentioned if you pull your spark plugs and study them you may see exactly where the water is coming in. A cracked head or block could let water in also but that is not very common with the 351W. My first Nautique was a 1978, Im still partial to that boat. It was a great boat we put 1,500 hours on that boat in 8 years. |
|
Evilsizer
Groupie Joined: August-29-2019 Location: Ohio Status: Offline Points: 62 |
Post Options
Thanks(0)
|
Wait I may of thought of something. That evening before we pulled the boat out I had to run the bilge pump a long time. Water was up to the floor almost. Could it have drained through the oil dip stick tube?
|
|
Evilsizer
Groupie Joined: August-29-2019 Location: Ohio Status: Offline Points: 62 |
Post Options
Thanks(0)
|
MrMcD what you just described is what seems to ne happening. Boat has no power and exhaust sounds funny. Will this engine need to be rebuilt now since water has ran through it?
|
|
8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
Post Options
Thanks(0)
|
The water would need to be higher to get into the oil. Where did the water come from? |
|
tryathlete
Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797 |
Post Options
Thanks(0)
|
I think you’re figuring it out with our help. The exhaust hoses collapsed. This killed your power. The high bilge water probably led to the milky oil.
Fix: Change exhaust hoses Change oil Enjoy the waning days of Summer! |
|
Evilsizer
Groupie Joined: August-29-2019 Location: Ohio Status: Offline Points: 62 |
Post Options
Thanks(0)
|
Also what is the correct thermostat for this old 78 351 commander? I m sure I put it in correctly. Someone stated that without a thermostat and running at idle for a long period of time in cold water can cause water in the oil. Below is what they described. we were running at idle in no wake zones for a while in cold water but am not sure how that will allow water in engine
1. Water in boat bilge Boat has been submerged or bilge water was high enough to run in through dipstick tube 2. Water seeping past piston ring or valves Refer to "Water in Engine" ("On Top of Pistons") 3. Engine running cold Defective thermostat, missing thermostat; prolonged idling in cold water 4. Intake manifold leaking near a water passage Loose or cracked intake Bad intake gasket Corroded head or intake 5. Cracked or porous casting Check cylinder head, cylinder block, cylinder walls, and intake manifold 6. Valve cover cap or breather missing, ( only gets water when it rains) |
|
Evilsizer
Groupie Joined: August-29-2019 Location: Ohio Status: Offline Points: 62 |
Post Options
Thanks(0)
|
I'm not sure where water came from. plug was in the boat.
|
|
MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3734 |
Post Options
Thanks(0)
|
The only way to know is the fix the problem and find out what you have after the repair.
Hard to say where the water came from we would only be guessing. You need to check it out and learn what you can. The biggest danger from taking on water would be HYDROLOCK. If water is on top of a piston and you hit your start key it can bang the piston against the water compressing the water against the cylinder head. This can bend a connecting rod and then you are in to a full rebuild. If you hit the starter and your engine spins but then locks pull the spark plugs and let the water out before ever hitting the start key again. The exhaust tubes are pretty strong and not easy to pull off. Warm the exhaust hose up at the connection with a Hair dryer, Warm hoses are much easier to work with. Have a squirt bottle with strong soapy water. Slip a small flat blade between the exhaust manifold outlet and the exhaust hose and run soapy water inside. Work your flat blade around and keep adding soapy water inside. Pull it off the exhaust manifold. If it is collapsed it will be collapsed very close to the exhaust manifold where the heat is the hottest. When you look inside you will see the tube collapsed and burned rubber. They stink when this happens you can smell that the tube gets hot when the engine overheats. |
|
Evilsizer
Groupie Joined: August-29-2019 Location: Ohio Status: Offline Points: 62 |
Post Options
Thanks(0)
|
Thanks for your help guys. before any of this the engine ran like a sewing machine. Ill check all the hoses for collapse and top of cylinders for water. Wish I knew how to post pics on here. The boat was a one owner is all original.
|
|
8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
Post Options
Thanks(0)
|
Andrew, Click on the full reply icon above. It's the arrow pointing northeast. Then click the image upload icon. It's the tree with the up arrow. Then a browse box will come up allowing you to select anything off your computer. Mobile devices don't work very well with the site. |
|
Evilsizer
Groupie Joined: August-29-2019 Location: Ohio Status: Offline Points: 62 |
Post Options
Thanks(0)
|
|
|
MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3734 |
Post Options
Thanks(0)
|
Your marine conversion looks differant than my 78, mine was a PCM yours looks to be a Commander, they both work fine' I am just wondering why Nautique would use two sources for engines in the same model year. Good Luck finding the problem.
Nice Looking 78! |
|
tryathlete
Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797 |
Post Options
Thanks(0)
|
Whew. Dats a sweet ride you got der!
|
|
camron18
Senior Member Joined: March-05-2015 Location: Michigan Status: Offline Points: 164 |
Post Options
Thanks(0)
|
Ohio guy with the block M?
Go Blue |
|
Evilsizer
Groupie Joined: August-29-2019 Location: Ohio Status: Offline Points: 62 |
Post Options
Thanks(0)
|
Remember I just bought this boat. I think that sticker is most likely the real problem with it. It is coming off. lol Go bucks!!!
|
|
8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
Post Options
Thanks(0)
|
Mark, Yes, it's a Commander. The 70's were pretty lean years for CC with lots of cash $$$ flow problems so they bought what engines they could. Go back a few years and it was standard to offer 4, 5 or even more brands of engines. Also many models had the OMC upgrade option. |
|
8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
Post Options
Thanks(0)
|
Absolutely!! |
|
Evilsizer
Groupie Joined: August-29-2019 Location: Ohio Status: Offline Points: 62 |
Post Options
Thanks(0)
|
Thanks guys. I have learned a bunch!! I hope it is just a hose collapsed!!
|
|
Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13513 |
Post Options
Thanks(0)
|
Could be a cracked intake manifold letting water into the oil.
|
|
KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11050 |
Post Options
Thanks(0)
|
This may be rather silly of me, but there have been 29 posts in this thread with nobody asking how hot your engine got.
So i'll ask, how hot did it get? Was it billowing steam out from the engine box/exhaust or did you just notice the temp gauge going up? Smell like hot rubber? Your earlier threads dealt with a bad impeller and overheating at idle, how hot were these temperatures at the time? |
|
Post Reply | Page 12> |
Tweet
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |