Perkins overheated - Possible damage?

[Houdsie73]

Last weekend cruising on our new to us 82 Mainship 34, the cover for the screen on the intake did not fully seat and I believe led to lack of pressure for the intake. Our flybridge gauges do not work and stupidly I did not go down to check the temp once we were underway. As soon as we heard an ghastly noise from the engine, I shut it down. We anchored and let the engine cool a bit. We were able to limp home at about 1000 RPMs with the temp hovering around 200F. After sitting at the dock for a few hours, we restarted her to put her out to the morring. The engine sounds OK and performed OK.

My plan for the upcoming weekend, per posts I read, is to change the oil and filter plus check the impeller for damage. I also read that I need to check the exhaust for cracks. Is there anything else I need to do or any suggestion on how to check if there is any damage?

Thanks.

 

[DavidM]

The best news is nothing is damaged. Far behind but tolerable is a warped head. The worst is a cracked block.

Watch for oil in the antifreeze or dropping antifreeze levels which would indicated one of the two bad outcomes.

If the engine sounds ok, I can't see any problem running at moderate loads to watch for any of these indicators.

David

 

[syjos]

Those engines are robust. 200 degrees doesn't sound that hot but, could lead to a leak in the headgasket. Look in the coolant for oil and oil for coolant. While the engine is running, look in the coolant expansion tank for air bubbles.

Run the engine at idle and with a wrench, loosen the nut on injector 1's fuel feed pipe a little bit (1/4 to 3/4 turns is usually adequate). The idle speed should drop and/or you should detect a change in sound if that cylinder is firing.

If the speed or sound doesn't change, that cylinder is not firing.

Tighten the nut and proceed to do the same with the other 5 cylinders, one at a time. Record the results.

Make sure to wrap a cloth around the nuts while loosening to keep high pressure diesel from spraying all over. Good idea to wear glasses and nitrile gloves.

If two adjacent cylinders are not firing, it can indicate a head gasket leak between those .

 

[Jc180]

Sounds like the cover for the screen you referred to is the sea water strainer which allowed air into the sea water pump. If the cover was way loose should have been leaking water into the boat before engine was running. Not sure which Perkins engine you have. Mine on the Mark I is the 160 hp version. The thermostat is set at 180F. So 200F not alarming. Suspect you still had some sea water flow. But what may be alarming is the noise you heard. Trying to think what could have caused the noise and then went away at lower rpms. Sea water pump bearings? Turbo? In any event need to inspect and replace your sea water pump impeller. As others have said look closely at oil level and for water in oil. If the engine starts immediately would indicate compression still ok discounting blown head gasket or valve damage. Then ease up rpms under load slowly and see if noise returns. Try to determine source of noise. May get lucky and find noise unrelated to overheating event.

 

[Swa]

Thinking the intake screen on your Perkins is more than likely not your cause of running hot. Check for leaks and milkshake looking antifreeze. pumps and clean tube stacks. Temp gauge on flybridge is a must have. Read members posts in the Mainship section. of this forum. Good luck

 

[Jc180]

Another thought. Was noise your high temp, low oil pressure alarm? Could be that alarmed at high temp at higher rpms due to insufficient sea water flow (more air leaking in at higher rpms), but sufficient water flow at lower rpms?

 

[Gdavid]

My perko 493 strainer recently did the same thing, I noticed it earlier (I watch my temp like a hawk) but the gasket in the cap was dry rotten and a crack allowed the raw water pump to suck air instead of water. I was able to get it to seal temporarily by over tightening the wing nuts and have since rebuild the strainer with a full gasket set and plastic cylinder. Perko is very proud of that design ($$) but it isn't the best in my opinion.

 

[jleonard]

What was the gage reading when you shut down?
Next time reduce to an idle and take a reading. The temp should reduce at an idle with a diesel.

My old Perkins 160 spun a belt off and I saw 240 on the gage. Let it idle a few minutes before I shut it down and the temp went down to about 210. Changed the belt and all was good until I sold the engine a few years later for a repower.

Those engines have a lot of iron and I doubt you hurt it. They are pretty tough and forgiving.

 

[Jc180]

My perko 493 strainer recently did the same thing, I noticed it earlier (I watch my temp like a hawk) but the gasket in the cap was dry rotten and a crack allowed the raw water pump to suck air instead of water. I was able to get it to seal temporarily by over tightening the wing nuts and have since rebuild the strainer with a full gasket set and plastic cylinder. Perko is very proud of that design ($$) but it isn't the best in my opinion.

Thanks. I’ll inspect my gasket

 

[Gdavid]

Thanks. I’ll inspect my gasket

An easy way to test for air leaks is to close the sea cock, open the strainer lid and drain or siphon the water level in the strainer down to about 1/2. Put the lid back on, open the sea cock and start the engine, the water level should come right back up to the lid.

 

[Jc180]

An easy way to test for air leaks is to close the sea cock, open the strainer lid and drain or siphon the water level in the strainer down to about 1/2. Put the lid back on, open the sea cock and start the engine, the water level should come right back up to the lid.

Actually did a similar test by default. Hauled boat, left sea clock open. When launched, sea water pump self primed. My AC circ water pump did not self prime, however.

 

[mike66]

AC pumps typically don't self prime. Looking for answers why they're not self priming.

 

[Gdavid]

AC pumps typically don't self prime. Looking for answers why they're not self priming.

The AC pumps have a magnetic coupling drive which saves them in case of blockage but it couldn't work with an impeller or diaphragm pump, really any self priming pump. You wouldn't want that anyway as the service life would be anoyingly short.

 

[Jc180]

The AC pumps have a magnetic coupling drive which saves them in case of blockage but it couldn't work with an impeller or diaphragm pump, really any self priming pump. You wouldn't want that anyway as the service life would be anoyingly short.

Lost prime twice. First time my fault for forgetting to close sea cock when hauled. The second time got rolled excessively by a wake. Real pain to prime. I’m going to try a Sureflo self priming ac circulating pump. Flow rate at lower end of what I need. Plan to replace when I winterize soon. Time will tell about flow rate as water temp rises next summer and about service life.

 

[syjos]

AC pumps typically don't self prime. Looking for answers why they're not self priming.

Add a high quality industrial check valve to maintain the prime.

 

[High Wire]

Did you remove the radiator cap and check the coolant level? Do not trust the coolant overflow bottle level if you have one. The engine could be completely empty of coolant and you would not know it from the outside. Check the engine oil level to see if coolant went there. Higher than normal level or milky oil.

 

[Barry Bellotti]

The best news is nothing is damaged. Far behind but tolerable is a warped head. The worst is a cracked block.

Watch for oil in the antifreeze or dropping antifreeze levels which would indicated one of the two bad outcomes.

If the engine sounds ok, I can't see any problem running at moderate loads to watch for any of these indicators.

David

Does anyone know where the antifreeze/rust inhibitor drain cock is on the Perkins 6.345 block?

 

[rgano]

AC pumps typically don't self prime. Looking for answers why they're not self priming.

I have a bubble extractor on my AC pump obtained from Yandina.com. Boat kept in lift so quite necessary.

 

[rgano]

Another thought. Was noise your high temp, low oil pressure alarm? Could be that alarmed at high temp at higher rpms due to insufficient sea water flow (more air leaking in at higher rpms), but sufficient water flow at lower rpms?

My though exactly. Where was the coolant high temp alarm virtually all of us have? Should be audible at both helm stations. If the awful noise heard was pistons screaming up and down against hot cylinder walls; well, let's not go there. I had an overheat due to a burst hose once. Thank goodness for the bilge and overheat alarms which simultaneously went off. I took an oil sample before changing the oil. Hopefully the OP did too.

 

[lady sue]

I'm sure you will benefit from all the advice, but there is an unwritten insurance policy that comes with every Perkins/Mainship: Change the impeller each year. You will automatically discover the condition of the water pump and the belt.
Jim Ferry
Lady Sue, 1982 Mainship I Perkins 165T

 

[cbouch]

A/c pumps will always self prime if located below the waterline otherwise not..

 

[Steve DAntonio]

Hindsight is 20-20 as they say, but a wet exhaust temperature alarm would have caught this long before any damage was done, within 30 second of losing water flow.

It's not too late to invest in one, and it is a requirement for ABYC compliance.

https://stevedmarineconsulting.com/onboard-alarms-part-i/

Regardless, and you clearly already know this, make sure your high temp and low oil pressure alarms are working at both stations. The alarm should sound a test every time you turn the key to the on position. It never ceases to amaze me how many vessels I inspect that have no working audible alarm. If you don't hear that beep, chirp or buzz when the ignition is switched on, for any engine, something is wrong.

 

[rslifkin]

Regardless, and you clearly already know this, make sure your high temp and low oil pressure alarms are working at both stations. The alarm should sound a test every time you turn the key to the on position. It never ceases to amaze me how many vessels I inspect that have no working audible alarm. If you don't hear that beep, chirp or buzz when the ignition is switched on, for any engine, something is wrong.

And if you don't hear anything at key-on, just leave the key on for 10 - 15 seconds and wait. Some setups (like my boat) have a delay timer at key on before the alarm circuit becomes active. So you don't hear the buzzer on a normal start, but you can leave a key on to test it.

 

[FlyWright]

Rule 1. Always check your ER and fluid levels before starting, looking for leaks, belt dust, ...anything out of the ordinary.

Rule 2. Always check RW flow out the exhaust.

Rule 3. Always check and monitor your temps and pressures.

Fortunately for you, you have a very forgiving engine. Once my port Perkins 4.236 oil cooler failed and I was forced to run 5 hrs with it bypassed to get home. (I consulted with our local Perkins dealer for advice.) Temps stayed at 240 or less and all was well. Engine cooling raw water flow is essential and needs to be closely watched.

There are more causes for low flow than just impellers. Buy a cheap laser thermometer to monitor the various engine temps.

 

[Solly]

Pull the raw water hose off the exhaust elbow, stick in a bucket, start up and check for flow.
if the over temp and low oil pressure alarm works it was probably that going off.

 

[High Wire]

Does anyone know where the antifreeze/rust inhibitor drain cock is on the Perkins 6.345 block?

On the side of the block above the starter and on the opposite side. They are just simple brass plugs.

 

[Arc]

200 Deg. @ 1,000 RPM is hot. My Cummins won’t make more then 130 at that. I can’t get to operating temp [ 176] unless I’m at 1,600 RPM.

 

[Steve DAntonio]

And if you don't hear anything at key-on, just leave the key on for 10 - 15 seconds and wait. Some setups (like my boat) have a delay timer at key on before the alarm circuit becomes active. So you don't hear the buzzer on a normal start, but you can leave a key on to test it.

What engine manufacturer does that? IMO that makes no sense, for obvious reasons you want it to test every time you start up. Few users will wait, or even know about this delay, for the test, so most of the time you have no idea if the alarm is working? The alarm test should be passive. If you have that arrangement, you should let it test with every start up.

Having said that, some Yanmar panels allow the user to turn the alarm off, permanently, using a switch, which also makes absolutely no sense. I have seen set ups where a spring loaded switch can be used to defeat the alarm temporarily on start up so as not to disturb those who may be sleeping, assuming the engine won't wake them, or in quiet anchorages, but that at least requires the user to hold the switch on the off position.

 

[rslifkin]

What engine manufacturer does that? IMO that makes no sense, for obvious reasons you want it to test every time you start up. Few users will wait, or even know about this delay, for the test, so most of the time you have no idea if the alarm is working? The alarm test should be passive. If you have that arrangement, you should let it test with every start up.

Having said that, some Yanmar panels allow the user to turn the alarm off, permanently, using a switch, which also makes absolutely no sense. I have seen set ups where a spring loaded switch can be used to defeat the alarm temporarily on start up so as not to disturb those who may be sleeping, assuming the engine won't wake them, or in quiet anchorages, but that at least requires the user to hold the switch on the off position.

Mine are mid-80s Mercruisers. If I remember correctly, the manual describes the delay as ~7 seconds. I do make a point to test them periodically, although not at every start. Realistically, even leaving the key on isn't a complete test, it only confirms the oil pressure switch and buzzer are working. The trans and coolant overtemp switches don't get tested.

I'm now a bit curious and am going to dig around and see how they implemented the delay. I might put in a warning light in addition to the buzzer, but I'd bypass the delay for the light, so at least I'd get some confirmation that the system is working. I'm not sure if the buzzer is disabled while cranking (and it's a horrendous buzzing / squealing noise rather than a beep on my setup), so they may have used the delay to avoid having to listen to it while the engines crank. It also might have been for the early morning departure case. On many boats I can hear the alarm from across the marina, then nothing when they actually start. My engines are pretty quiet, so it would likely be a similar case of the alarm making far more noise for the neighbors than anything else.

 

[rgano]

Having said that, some Yanmar panels allow the user to turn the alarm off, permanently, using a switch, which also makes absolutely no sense. I have seen set ups where a spring loaded switch can be used to defeat the alarm temporarily on start up so as not to disturb those who may be sleeping, assuming the engine won't wake them, or in quiet anchorages, but that at least requires the user to hold the switch on the off position.

Mainship Pilots unfortunately did not come equipped with the Yanmar panel. Maybe a price point issue. However, a single piezo buzzer behind the panel for the SIX different alarms the engine could send seemed user UNFRIENDLY to say the least, especially considering the supplied skimpy Faria cluster gauge set. I installed a Seaworthy after market lighted and audible alarm panel to help give me a clue. I also installed an alarm silence toggle because if for instance the overheat alarm went off, but I was in no position to shut the engine down, I'd have to listen to it until I shutdown. There might be a situation where by hauling back on the throttle, I could allow the overheat condition to moderate while watching the gauge without having to put up with the whining alarm. I can think of other troubleshooting scenarios where the alarm noise would be superfluous if not downright annoying. Before startup, I run my hand across the alarm silence toggle to ensure it is on AND that I get a low oil pressure buzz.

One day while strolling along at 3400 RPM with my hair on fire, the buzzer sounded. High Coolant Temp light plus just across the console, the bilge pump light (both connect to the buzzer). Instant cognition! The bilge was flooding with raw water coolant at a potential 142.6 quarts a minute, and the engine coolant was HOT with gauge pegged. Without the lighted indicator panel, I am sure I would have lost the engine in the delay (burst seawater pump outlet hose) as I sorted out what was causing the high water. Instead, I hit the engine stop button as I pulled the throttle/clutch to neutral falling off plane in a rush. Buzzers are good but buzzers and discrete alarm lights are better.