Sabre Perkins still overheating

[stuartwineberg]

Ok - new impeller, heat exchanger stripped, cleaned and refitted, oil cooler checked (clear), air charge exchanger stripped and cleaned. Thermostat tested and opening OK. Will run all day at 1200 rpm and 8 knots and is at 82 degrees. Take her up to 2100 revs and the temp creeps very slowly up to over 90 (over about 5 minutes) - I havent dared take her higher. Throttle back and within 10-20 seconds temp is back to normal

My guess is now either a worn raw water pump (boat has about 520 hours) or a partial restriction on the raw water inlet. The latter is a pig to get at due to the way the strainers are fitted but that will be my next step. The boat doesnt come out for the winter so cant easily check from the outside. Any other thoughts? The other engine is fine.

 

[penfold]

As you have already changed the impellor, the raw water pump seems unlikely at that age; do you sail on particularly muddy water as that causes accelerated pump wear? Other possibilities are the fresh water pump and Head gasket, although the fact that it runs fine a lower speed suggests not. Can you take the ground or get a lift out for a scrub? That would allow an external inspection.

 

[Divemaster1]

Ok - new impeller, heat exchanger stripped, cleaned and refitted, oil cooler checked (clear), air charge exchanger stripped and cleaned. Thermostat tested and opening OK. Will run all day at 1200 rpm and 8 knots and is at 82 degrees. Take her up to 2100 revs and the temp creeps very slowly up to over 90 (over about 5 minutes) .......... Any other thoughts? The other engine is fine.

Not knowing your engines it may be difficult to say, but;

1) I do not see a cooling water temperature of 90 - 95 degrees C as overheating for a diesel engine. If she is stable as 95 degrees, then fine...
2) Temperature gauge or sensor may be wrong ... once again, if she is stable, then fine... can you swap the cables on the instruments around to check the insrument? ... if same, it could be the sensor .... but once again is she stable after 15 min + ?

What is your max RPM .... oh ... and are your RPM gauges correct, or do you have an un-even load on the engines ?

Is one engine heating water as well as cooling the engine ? ... if so, you will have difference in temp as the one heating the water have more liquid circulating, thus more cooling capacity and thus cooler liquid....

When we run at 1800 RPM (Max 2300), we run at about 87 deg C on port engine and about 93 deg C on Stb ...(Port engine is heating water).... at WOT we rise to just about 90 and 95 respective ... on the gauges that is.... but we have mechanical gauges near the engines, and they show 3 - 5 degrees less.... but all are stable once temp is reached..

 

[longjohnsilver]

Have you looked to see if there's more steam from the overheating engine? That would be a visual indication. I had a similar problem on one of my engines and it turned out to be a blockage of seaweed/leaves etc in the pipe between the seacock and the raw water pump. I used my dinghy pump to sort of back flush it from the pipe connected to the pump. A few strokes of the pump later and the blockage was gone and engine back to normal. Worth a try, only takes a few minutes so nothing to lose.

 

[omega2]

The book says 90c maximum, we have 180's and have suffered the same, one thing you can check, run the engine up to temp with the filler cap off the header tank, if you see needle bubbles in the water as it crosses the aperture then suspect head gasket. Or better still get a pickavant pressure tester. can you see the exhaust outlet on the transom? are both engines ejecting the same amount of water, is the generator belt tensioned correctly, have you drained down the fresh water, try disconnecting the pipe at the rear of the exhaust manifold and catch the water in a bucket look for dehbris. Also in the pipework from the raw water pump to the intercooler, this sometimes holds bits of broken up impellor. I am assuming that your Sabres are Ford based. Lastly is it your port engine giving problems? Soory misread the OP I see yopu have Perkins, but the advise may still be useable.

 

[stuartwineberg]

Thanks All

To answer the questions. Have drained the fresh water side - no debris - also I know about the mesh debris trap on the sabres and have checked that.

Doubt it is the gauges as the sboard engine doesnt mimic the behaviour - it stays at about 84 degrees at any revs and also the port engine isnt going hot and staying there, the temp changes are engine speed related and drop back as soon as I throttle back

Like the dinghy pump idea - that is at the top of my list. Gen belt good question but the pumps are gear driven not belt. Divemaster - appreciate that 90 degrees is not "overheating" as such but it is the slow creep upwards which is a new event after three years use of the boat and not happening on the sboard side so I suspect something is amiss. The calorifier is on the sboard side so I accept port engine should be a bit hotter but again it is the change in behaviour I dont like.

Talk of head gaskets is a bit scary. Would I get these symptoms - ie - no overheat at 1200 revs (max is 2500) and then slow creep up as revs increase. No loss of power, no coolant loss

Thanks again

 

[vas]

Talk of head gaskets is a bit scary. Would I get these symptoms - ie - no overheat at 1200 revs (max is 2500) and then slow creep up as revs increase. No loss of power, no coolant loss

Thanks again

filler cap of the header tank should help in clearing gasket problems, although gaskets can fail in different ways. Check oil cap for white creamy deposits for another type of gasket failure.
Haven't come across a gasket failure that temps would drop as soon as load was reduced, usually the boiling that takes place has longer term effects even at idle speed. I'm sure someone will come along stating the oposite...

Does sound more like a cooling pump/heat exchanger problem (ie not too expensive and boat lift out)

good luck

V.

 

[blueglass]

had exactly this issue on my Sabre Perkins 225Ti's - it was always an irritation, but never came to anything. Shortly after buying boat the problem arose when I first cruised at speed in my semi d atlantic 38 . Fine all day at displacement speeds but once above 14 knots - up the temp went on starboard engine. Had engineer strip everything down and he found nothing at all to cause problems. he said it was normal and just to carry on and reduce revs if temp crept towards 100deg.
We cruise normally at displacement speeds so it was never a major issue until 5 years and many thousands of miles later we had the boat up for sale and the buyer was unhappy (understandably) At our expense, an engineer spent a week, stripping, sea trialling, part after part. Water pump housing backplate was found to be a little worn and replaced - made no difference. minor sludging around thermostat housing and themostat replaced - still no difference. Not an engineer myself , but the guy went through everything with a fine tooth comb and other than those very minor issues he found everything in tip top order and finally came to same conclusion as engineer #1. Perkins were consulted and they said the temp rise was within normal paramaters. Fair enough, but still didn't explain why the other engine allways ran cooler. Incidentally and paradoxically to me, the hotter engine in my case was the one runnning the calorifier!
The buyer was satisfied and bought the boat and is still happy with his purchase.
So OP, like you I was never happy with it, but learnt to live with it! If you don't get to the bottom of it try not to lose too much sleep.
I will watch the thread with interest to see if a solution arises.

 

[fisherman]

In re the head gasket, Mermaid (Ford) said if the gasket was blown the engine would reach a certain temp and then blow the cooling water out, and this would happen each time at a progressively lower temp. I had a new engine (Ford) which had the wrong thermostat and allowed a much higher temp than spec for marine use, still fine for a road engine, but it did blow the head gasket.

 

[Forty_Two]

I have the 135's with a similar number of hours & every time I have had an increase in temp on one engine it has always been a blockage in the inlet strainer, which in my case are part of the seacock. This happens every year to me in the med at some point.

It's surprising how little you need to block the flow to get a small increase like yours. Depending on the type of seacock/strainer you have I would remove hoses & check they are clear & see how the water flow is. In my case its easy & I can push something straight down through the strainer & seacock.

At this number of hours the engines are all but new if they have been well cared for so it is most likely to be something simple.

 

[Red]

I suggest you check that the sea water intake is not blocked. The inlet can get blocked if there is debris or weed in the water. Depending on how the access is to your seacock and you want to solve the problem while afloat - turn the seacock off, remove the water intake pipe attached to the seacock, open the seacock to see if water is coming in or is blocked. If it is blocked get a stout but flexible pole and push it quickly through the valve once open, any blocked material will then be seen coming into the boat. Shut valve, replace pipe and start up......

 

[omega2]

I suggest you check that the sea water intake is not blocked. The inlet can get blocked if there is debris or weed in the water. Depending on how the access is to your seacock and you want to solve the problem while afloat - turn the seacock off, remove the water intake pipe attached to the seacock, open the seacock to see if water is coming in or is blocked. If it is blocked get a stout but flexible pole and push it quickly through the valve once open, any blocked material will then be seen coming into the boat. Shut valve, replace pipe and start up......

Agree, could even be a half open sea cock, or half shut if your a pessimist. is the pipework identical to both engines? are they flexible's or metal, remove pipe from sea cock and jabsco and clear, opening the sea cock and desludging will not sink you, just jam your bare foot on it, hardly any pressure there. Check that the cock is opening fully. We have had gatevalve types break up, leaving the "gate" floating around in the housing. Also the cheap ball valve type, who's handles twist and bend without moving the ball.

 

[stuartwineberg]

Definitely

Agree, could even be a half open sea cock, or half shut if your a pessimist. is the pipework identical to both engines? are they flexible's or metal, remove pipe from sea cock and jabsco and clear, opening the sea cock and desludging will not sink you, just jam your bare foot on it, hardly any pressure there. Check that the cock is opening fully. We have had gatevalve types break up, leaving the "gate" floating around in the housing. Also the cheap ball valve type, who's handles twist and bend without moving the ball.

Yep - partly blocked intake is my best hope. Sadly the ability to get a flexible object down the pipe is virtually nil due to the way it is all plumbed together. I have used a piece of rigging wire (ex Raggie!) on the sboard engine but cant reach the port intake the same way. Previous poster suggested the dinghy pump and will give it a go when I am next down. Jammed ball valve hadn't occured but would also make sense - Thanks

 

[nedmin]

I have a 135 and had same problem ,found it was a faulty temp.sensor.As you have 2 engines why not swap them over.I inherited a bottling themometer and was able tp prove by putting in the header tank,Mine normally runs at 80 deg,

 

[omega2]

One of these may assist you??

http://www.ebay.co.uk/itm/DIGITAL-L..._Measurement_Equipment_ET&hash=item3a64cd6397

 

[Forty_Two]

I have a 135 and had same problem ,found it was a faulty temp.sensor.As you have 2 engines why not swap them over.I inherited a bottling themometer and was able tp prove by putting in the header tank,Mine normally runs at 80 deg,

Yes thats a good idea. You could also buy yourself one of these http://www.maplin.co.uk/handheld-non-contact-thermometer-590711, very useful & will help check if problem is with guage/sensor.

 

[capsco]

One of these may assist you??

http://www.ebay.co.uk/itm/DIGITAL-L..._Measurement_Equipment_ET&hash=item3a64cd6397

I agree, good bit of kit.

 

[david_bagshaw]

have you considered a worn or wrong cam in the seawater pump?

 

[vorne]

Just a thought have you replaceed the rubber hose from the seacock to the raw water pump. I had similar problem with a Perkins ht 6354, turned out the hose was delaminating inside and under greater revs and ofcourse greater suction the hose was collapsing inside

 

[stuartwineberg]

Definitely

have you considered a worn or wrong cam in the seawater pump?

This one (along with a blocked or nackered exhaust elbow) is at the end of my list when I have looked at the cheaper options. I would ahve thogutn both engines would have worn at the sameish rate


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