possible seized motor?? Input appreciated

On wednesday I checked coolant level and heat exchanger tank was empty added approx 3-4 quarts of coolant, ran motor and all seemed fine.

Thursday went out fishing, both motors run fine holding a steady 150 degree temperature for most of the day. In the afternoon I notice that temp on port motor has risen to 200 degrees and I shut down that motor, let it cool, checked coolant level and found it empty.
Added approx 3 gallons of water started motor, exhaust blew a huge plume of white smoke and oil pressure gauge reading erratically so I shut down the motor and came home on starboard motor.

Back to dock I checked oil and heat exchanger for either oil or coolant contamination and both appeared fine, tried to fire motor and could not get it to turn over. Going down today to pull spark plugs and try and turn motor by hand.

Elbows and risers are approx. 3years old, heat exchanger and oil cooler are approx one year old.

Hoping against hope that I did not blow the motor.

Any thoughts or ideas appreciated.
Regards
Ned

white smoke usually indicates coolant in the combustion chambers....

you never said how old or which engines you have...???

wouldn't hurt to pressure test the cooling system.....if the oil level hasn't risen, you are probably in decent shape as long as the no crank wasn't due to hydrolock and nothing got bent ....some fogging oil while the plugs are out can only help....

Thanks Mark....
Motors are 1986 454's in a Tiara 3100. I tried to turn the motor again this morning and still nothing. Looking at the left hand side of the motor you can tell that that side definitely got hot. Manifold, riser and elbows are discolored and hose from manifold to heat exchanger is starting to delaminate.

I pulled the spark plugs and motor turned ok and pushed a good quantity of coolant of out of the cylinders and the left side. Right side appears normal.
Oil level is normal and no evidence of oil in coolant or vica versa.

So i guess I either had a bad elbow/manifold or blew a head Gasket. Thoughts????

Plan at the moment seems to be either new elbows, risers or new head gasket or maybe all of it.???? Not sure how I can identify the exact cause at this point. Would a pressure test tell??

Lastly, I sprayed WD 40 into the cylinders that had coolant in them. Is that adequate or need something further. It may be a month or so before I get the time to make the repairs.

As always, the input of the forum is valuable and appreciated.
Regards
Ned

These are Engines..... (not motors!)

Ngeogh said:

Thanks Mark....
Motors are 1986 454's in a Tiara 3100. I tried to turn the motor again this morning and still nothing. Looking at the left hand side of the motor you can tell that that side definitely got hot. Manifold, riser and elbows are discolored and hose from manifold to heat exchanger is starting to delaminate.

I pulled the spark plugs and motor turned ok and pushed a good quantity of coolant of out of the cylinders and the left side. Right side appears normal.
Oil level is normal and no evidence of oil in coolant or vica versa.

So i guess I either had a bad elbow/manifold or blew a head Gasket. Thoughts????

Plan at the moment seems to be either new elbows, risers or new head gasket or maybe all of it.???? Not sure how I can identify the exact cause at this point. Would a pressure test tell??

Lastly, I sprayed WD 40 into the cylinders that had coolant in them. Is that adequate or need something further. It may be a month or so before I get the time to make the repairs.

Ned, I would disable the seawater cooling system and I would drain the E/G from the Heat Exchanger.
I would then start this engine and run it for 30 to 35 seconds or so (longer if you dare), and hope that you can blow it dry.

Before tearing it down, perform a cylinder leak down test. This will help steer you in the right direction.

Click to expand...

Thanks Ricardo.
I did not think of running the engine to dry it out. I will do that tomorrow.
Will see if I can get my hands on cylinder leak test equipment and give that a try. Am I right in assuming that if the cylinders hold pressure the problem likely is with the manifold?
Also, what is the typical pathway for coolant to leak from the manifold/elbow into the cylinders? Since I had coolant in all four cylinders on that side I am not sure that a cracked head/head gasket would cause that?????

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Ngeogh said:

Thanks Ricardo.
I did not think of running the engine to dry it out. I will do that tomorrow.
Yes..... you will not want residual water to remain in this engine.

Will see if I can get my hands on cylinder leak test equipment and give that a try. Am I right in assuming that if the cylinders hold pressure the problem likely is with the manifold?
It would be best to NOT assume anything.
Instead, use the tried and proven P of E..... (process of elimination).
Test/check one item or area ONLY at a time.

Also, what is the typical pathway for coolant to leak from the manifold/elbow into the cylinders?
The cylinder head exhaust ports..... via an open exhaust valve that is inhaling due to the intake/exhaust over-lap duration.


Since I had coolant in all four cylinders on that side I am not sure that a cracked head/head gasket would cause that?????
In my opinion only....... that would be unlikely!

Click to expand...

Update from this morning:
1) Drained remaining coolant from heat exchanger and shut off raw water system at thru hull fitting.
2) Since the spark plugs were out I did a compression test on all cylinders and they all came in between 145 - 165 range. Not sure how accurate this procedure is as access is a real issue on this boat, and trying to hold the compression tester is the spark plug hole while lying on top of the motor and a friend cranks the motor is not exactly pleasant.
3) reinstalled spark plugs; motor started and ran normally although with a larger than usual amount of steam out of the exhaust pipe. I ran motor at most two minutes but steam did not stop although motor never exceeded 120 degrees. Not sure if this is indicative of a further problem or motor needed additional time to completely burn off the residual coolant in manifold, riser, etc.

My plan at the moment is to remove manifold, riser and elbow on both sides then conduct a cylinder leak down test as I hope access will be easier with these out of the way. If the cylinders hold pressure Ok then I will proceed with the manifold, riser, elbow replacement. My main concern at the moment is the excess steam out of the exhaust.

Thoughts and input appreciated.
Regards
Ned

Feel your pain ! One more place to investigate is the gasket/surface on the bottom side of the block off plate between the elbow and exhaust manifold. A leak there would allow coolant to leak into the exhaust gas flow and fill cylinders with coolant after shut down. Since compression is good the head gasket may be OK but really can't be sure without further testing. Good Luck.
FL Panhandle

Many thanks Mulletwagon. I suspect/hope that is the issue as this boat is old enough, and has enough other issues that major engine work would not be a very good investment.
Regards
Ned

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Ngeogh said:

Update from this morning:
1) Drained remaining coolant from heat exchanger and shut off raw water system at thru hull fitting.
2) Since the spark plugs were out I did a compression test on all cylinders and they all came in between 145 - 165 range. Not sure how accurate this procedure is as access is a real issue on this boat, and trying to hold the compression tester in the spark plug hole while lying on top of the Engine and a friend cranks the Engine is not exactly pleasant.
For accuracy, you should be using a cylinder pressure gauge with an extension hose and threaded fitting for the spark plug port.
Since the hose will consume volume, each cylinder being tested should be cycled through at least 2 or 3 compression cycles..... or, approximately 5 or 7 crankshaft revolutions.

Do this, and look at your numbers!

3) reinstalled spark plugs; motor started and ran normally although with a larger than usual amount of steam out of the exhaust pipe. I ran motor at most two minutes but steam did not stop although motor never exceeded 120 degrees.
Use caution..... with NO liquid contacting the Temp Sender, you will NOT see an accurate reading!

Not sure if this is indicative of a further problem or motor needed additional time to completely burn off the residual coolant in manifold, riser, etc.
Possibly!

My plan at the moment is to remove manifold, riser and elbow on both sides then conduct a cylinder leak down test as I hope access will be easier with these out of the way. If the cylinders hold pressure Ok then I will proceed with the manifold, riser, elbow replacement. My main concern at the moment is the excess steam out of the exhaust.

Use the tried and proven P of E..... process of elimination. One item ONLY at a time!
When used systematically and methodically, it won't let you down!


Thoughts and input appreciated.
Regards
Ned

Click to expand...

Rick
Thanks for the feedback and advice.
1) I will redo the compression test as suggested and see what the numbers are, if they come in within range would a leak down test still be advised?? These are old motors and I am certain will show significant leakage. For my problem of coolant in all four cylinders what issue would the leak down test potentially identify? cracked head, head gasket?

2) I agree on the temp sender, I will run again but keep it under a minute as I want to ensure that all coolant id out of the cylinder and manifold.

3) Can I get a little clarification on the process of elimination? My thinking at the moment is to remove manifold, risers and elbows (they are probably due for replacement anyhow as they are approx 3 years old) then try to assess if there is a problem with the head/head gasket via leak down test and or compression test. If these tests indicate further problems I will remove the head and have it evaluated. If compression/leak down tests come back ok, I will leave head in place and reassemble with new manifold, risers, etc. Am I leaving any steps out?? Given the age, value and general condition of the boat repairs that go beyond head, manifolds, etc, it is probably not economically feasible.

Regards and thanks again
Ned

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Ngeogh said:

Rick
Thanks for the feedback and advice.
1) I will redo the compression test as suggested and see what the numbers are, if they come in within range would a leak down test still be advised??
The cylinder leak-down test is great for learning where pressure may be escaping.
It will offer info for cylinder pressure loss only..... in other words, it will not help you with an exhaust system issue.

These are old motors and I am certain will show significant leakage. For my problem of coolant in all four cylinders what issue would the leak down test potentially identify? cracked head, head gasket?
Well.... that's tough to say.
It is doubtful that all 4 cylinders on one cylinder bank are all failing equally.
It's more likely from a bad exhaust Manifold, Spacer/Riser and/or Elbow.

2) I agree on the temp sender, I will run again but keep it under a minute as I want to ensure that all coolant id out of the cylinder and manifold.

3) Can I get a little clarification on the process of elimination?
Ned, the P of E idea suggests that we DO NOT just simply just start taking everything apart.
Nor do we start throwing all new parts at a problem, nor do we start haphazardly replacing parts without some type of methodical and systematical directive!

The P of E can be used for almost any type of trouble-shooting.


My thinking at the moment is to remove manifold, risers and elbows (they are probably due for replacement anyhow as they are approx 3 years old) then try to assess if there is a problem with the head/head gasket via leak down test and or compression test. If these tests indicate further problems I will remove the head and have it evaluated.
Yes... only after confirming that.


If compression/leak down tests come back ok,
FYI... these two tests are NOT the same.

I will leave head in place and reassemble with new manifold, risers, etc. Am I leaving any steps out?? Given the age, value and general condition of the boat repairs that go beyond head, manifolds, etc, it is probably not economically feasible.

Click to expand...

Any updates on this issue?

Brownie289 said:

Any updates on this issue?

Click to expand...

No....I have not had the time to start on the repairs. I did go back and run the motor again just to make sure it was dry and it ran normally, although with excessive steam out of that exhaust. Will update once I get the elbow, rise and manifold off.
Regards
Ned