TAMD40b slight overheat...

[No Regrets]

My 1984 Scand has a pair of these Devils, one is sweet and perfect, the other ever so slightly coarser, but according to our Marina engineer still running well.

The coarser engine had a lot of work done to the heat exchanger around 5 years ago, and starts/runs well with nothing but the usual smoke when first started (disappears within 5-10 seconds) or hammered (Black smoke, this is a SD hull with rarely used Turbo, so not a big issue)

The overheat is not evident on the Upper Thames, but against a heavier flow there is a little steam evident from the exhaust.

New Raw water pump, lots of flow according to the stuff spraying under the bathing platform, do not consider this an issue...

There is a feeder pipe into the Exhaust elbow however which is ever so slightly warm, whereas the Port engine's one is COLD when running at high revs on the mooring (30 minutes at 2500RPM)

Therefore the water exiting at that point is probably a bit too warm, so perhaps the Heat exchanger is a bit blocked, although I did treat it with Rydlyme. Thermostats are both working well...

The funny thing is, once I went tidal and it overheated to Rochester, but ran cool on the way back. This is the bit that confuses me?

Have I missed anything? The Heat Exchanger extracts in a forward direction, but there is a bulkhead stupidly positioned six inches forward of the engine....Gotta love the Scandinavians...



Thanks for reading!

 

[omega2]

Impeller?

 

[volvopaul]

The reason the water is warm is because it is stalling , i.e. Not flowing through at the correct rate so the heat is dispersing slowly from the heat exchanger closed side to the raw water open side. Clean th draw water side and remove them exhaust elbow and check that it's clean and free from rust blocking the outlet ports, funny thing is I learned at lot in my early years trying to find an overheat problem on a 40B which was also in a scand boat. It was that blocked at full rpm it blew the rubber end cover off the heat exchanger! If you need a new end cap I have one in my stores.

 

[Momac]

My friend had a very similar sounding issue on his kamd43.
In my friends case bits of old impeller in the cooler could not pass through the cooler tubes and were restricting the flow . Not initially a problem at river speed - until eventually the overheating problem did occur on the river.
Investigations in his case found very short impeller life and it was concluded the impeller had to some extent been starved of water causing the impeller to overheat . Bits of impeller vane were being shredded off the impeller.
Clearing out the impeller debris from the cooler appears to have solved the problem..

 

[omega2]

My friend had a very similar sounding issue on his kamd43.
In my friends case bits of old impeller in the cooler could not pass through the cooler tubes and were restricting the flow . Not initially a problem at river speed - until eventually the overheating problem did occur on the river.
Investigations in his case found very short impeller life and it was concluded the impeller had to some extent been starved of water causing the impeller to overheat . Bits of impeller vane were being shredded off the impeller.
Clearing out the impeller debris from the cooler appears to have solved the problem..

+1

 

[No Regrets]

Thanks guys.

The water pump was renewed, and all previous impellers were in good order when removed. It has overheated for three years (Not on the upper Thames, only when we go tidal and open her up, hence we just cruise at 10kts, within a safe range of temperature)

Paul, I will try more Rydlyme and check the exhaust elbow is completely clear, thanks for that!

If I can't clear the heat exchanger, it's going to have to stay as it is (Not a big problem!) because the whole side of the inlet system would have to be removed, probably the engine!! Yeuch...

 

[dragoon]

I've been through this with my TAMD40bs so many times now....here's what I've learned;

- the oil cooler is first place to plug up - it's also first in the circuit after the strainer - it's a devil to get to - you need to remove the heat exchanger and the after cooler, but you can rod it in situ.
- the main heat exchanger will also plug up - just rod (I use a coat hanger) from the front. Don't remove the insert unless you want to create a lot of work (and risk breaking the thing)!
- the pipe that goes between the strainer and the oil cooler plugs up at the bottom middle (where there may still be a drain - these break off eventually as they are brass brazed onto the pipe!). I found you can remove the pipe and knock it with some wood (an old wire brush handle) and large clumps of salt will fall out.
- the pipe between the heat exchanger and the elbow plugs in exactly the same way as the above, also near the drain (which eventually breaks off).

Hopefully the above is of some help. Issues with impellers, blocked intakes and elbows etc also apply, but the above seems quite a recurring sequence on my boat! Especially the oil cooler....

Cheers,
Paul

 

[Medway Mudlark]

Gents,

I have a AQAD40b/280 (165) on a fjord which I bought 2 years ago. The symptoms are very similar, other than it does not appear to overheat, although the temp gauge rapidly approaches 90 deg over about 3000 rpm. on lifting the hatch, however there is a significant water dribble coming out of the 'radiator cap' on the heat exchanger, and the header tank is full. I have drained and refilled the tank with the correct amount of coolant, and once throttled back the level in the header tank drops to its normal level, just above the thermostat plate. The exhaust elbow is cool. It occurs to me that the pipework on the freshwater side may be 'bunged', the boat having spent since 2001 on the upper Thames, and back pressure building up somewhere within causing this? Please excuse the slight ignorance on this matter, but I have just graduated to this big diesel after 16 years with a smaller AQ130 in my other boat. So the learning curve starts again.....Your suggestions appreciated. This is another Scandinavian installation with the engine set 6 inches away from the forward bulkhead. I am considering Rydlyming both fresh and raw water systems in the near future, does anyone see any issues with this?

 

[oldgit]

On my 40A. The header/expansion tank only required filling to about 25mm from the bottom.
Filling the header tank to where you might think it should be 50mm or so from the top merely resulted in water being expelled into the overflow bottle when you opened the throttles and made the engine work.
This state of affairs was the norm for years until after one trip out the overflow bottle was starting to fill up on regular basis without me adding anything to system.
The heater matrix had failed and the water pump was forcing raw cooling water into the freshwater circuit.
Removed internal matrix and a bit of diligent work with solder and a gas torch sorted the problem.
Did lose some of the matrix but made no obvious difference to running temps.
Was either a bit of solder or about £700 quid.

 

[dragoon]

When you say water is coming out of the radiator cap, do you believe that the coolant side is experiencing levels that increase when the engine is running?

If so, you may have salt water passing from the raw water to the fresh water side.

That can occur in one of two ways. Either the tube stack is leaking, or it's passing through the rubber boot 'interface' on the rear of the heat exchanger. If you look at the back of the exchanger, you should see 2 large diameter jubilee clips - one of these seals the boot to the case (this is sealing the fresh water side) and the other aft most one stops water passing between the fresh and raw water systems. Check the boot looks home properly and these clips are tight.



You may have a block causing back pressure also. Likely candidates are the pipe from the bottom of the heat exchanger to the exhaust mixing elbow (this pipe also includes a branch for the gearbox). I take this off to clear it out properly - gently knocking it with some wood releases solids. Also check the mixing elbow and exhaust bend for restrictions.

The old 90 degrees over 3000 sounds familiar with these engines. If it's never been done, and it's been used in salt water, I'll bet the oil cooler needs cleaning out on the sea water side - it's something I have to do every 4 or 5 years.

General guidance - if you strip anything to clean, I advise to NOT remove any tube bundles from their cases (with the exception of the after cooler that comes apart easily). All the others are not likely to go back together.

As for Rhydlyme, I don't see a problem with the raw water side. Not so sure about the fresh water side though - others may have a view?

 

[oldgit]

Did "Rydlyme" my present Perkins freshwater system by rigging up a enclosed pump system and leaving it to circulate for 30 mins at the recommended dilution.
Knackered the steel impellor in the temporary pump but no difference regards high indicated temperature when engine was working hard,about 10 degrees over normal.

Eventually bit the bullet,removed the tube bundle entirely and marinated the flipping thing in a high strength solution of brick cleaner for 10 mins.
Used an old fender with the top cut off as long thin container.
Immediately solved problem which had been bugging one of my engines for several seasons.
Both engines now running at 82 degrees again.

 

[omega2]

Thats what has to happen, remove the core and steam cleaning did it for us. No trust in chemicals.

 

[Medway Mudlark]

Thanks guys for your input. The boat when we bought it 2 years ago had languished in an upper Thames marina for 2 years unused, it has been up there since about 2001, and before that, the Hamble. This is bourne out by previous bills of sale.

Here's the scenario. Have drained F/W cooling system and got 17 litres out, VP owners manual says it takes 11. Refilled with water at this stage and vented the system until the water just covered the thermostat plate. Took boat from Allington downriver to the Estuary 90% of the way at 2500 rpm, got to Queenboro' and checked header tank. Levels at this point all OK. Checked water from heat exchanger and could not detect any taste of salt in it. Return trip, off Queenboro spit buoy and cranked her up to 3500 rpm, temp went up to 90 deg fairly quickly and seemed to remain over the next 2-3 miles throttled back, lifted hatch and saw water dribbling out of cap. Removed cap and water level was up to the top, so had nowhere else to go, Carried on homeward at about 2000 - 2500 rpm pretty much all the way. Once back on the mooring checked again, and the water level had returned to its normal ( just kissing the thermostat plate). On the basis that the boat normally lives in freshwater, one would assume that with this run, 3 - 4 hours non stop each way, I would have expected to detect salt in the water if one of matrices had given up

I am also surmising that, judging by the amount of lime scale I had to remove from the waterline externally, god only knows what its like in my engine!!!

Comments and contributions welcome.......I would dearly love to sustain 26 knots for more the a couple of miles!!

 

[omega2]

Did it stay at 90? if so no worries, could be reading a little high but 85/90 is not unheard of. The loss of water probably due to normal expansion and too much being put in, Also could be sender/gauge related, next time run her at your preferred speed, and if it stays a 90 no worries, if it climbs to 100 then there may be a problem.

 

[rlw]

Before troubleshooting check temperatures with an IR temp gun. A corroded connection on the temperature gauge can cause it to read higher. On my third boat with AD41, KAD44's as engines.
The 2 temp issues I had in that time turned out to be gauge related. I now have an IR temp gun on board at all times. Once ran into a marina in a force 5 on one engine for no reason other than a connector on the gauge shifted coming of a wave.

 

[superheat6k]

My boat before last had a TMD40A which was almost the same engine without the aftercooler. This suffered minor overheating until I throughly descaled the heat exchanger sea water side with Fernox, and then caustic soda to dissolve the weed that was growing right through it. Do not skimp on replacing the O rings. I have the sizes written down somewhere if you don't want to pay £s at Volvo Penta dealers instead of pence at your local bearing stockist.

On the fresh water side have you vented the turbo coolant pipe with the engine running ?

Check your seawater coolers do not have any remnants of anode inside. It is not uncommon for pencil anodes to break off at the base leaving the bulk behind inside the cooler. Once this happens the electrolytic decay stops because there is no electrical circuit. My current Cummins had 3 one side and 4 the other.

As other have suggested Rydlyme on the seawater side although I have had good success with both B&Q plumbers general purpose powder descaler and more recently sulphamic acid.

On the TAMD60C there was a small 1/4" BSPT (I think) plug on the seawater pump housing outlet into which I screwed a fitting attached to a hose then used a simple hand pump to fill the system with the descaler, used hot, and ideally on a hot engine. The hotter the more effective the acid becomes.

Remove any zinc anodes prior to using any acidic descaler.

Once the descaler has had time to react flush it through with the normal flow. If you watch the engine outlet the crud that comes out can be horrific.

 

[dragoon]

The TMD40A has a different plate type heat exchanger. The B (with or without after cooler) has a bundle type exchanger.

Be careful stripping tube bundles out of their cases - these engines are years old, the tube bundle grows into the alloy cases over time and when you try to strip it things will likely break. At 2000 quid for a bundle and similar money for a case it could be an expensive experiment.

Quite honestly though, the fresh water side of the bundle should not be calcified - it lives in coolant and can be flushed with an additive if needed (check compatibility with alu alloy though).

I will still put money on the oil cooler as a major contributor (but possibly not the only thing). The cooler is tiny, first in the circuit, at the bottom of the engine, and cooks in hot oil after shutdown. I've cleaned out both my engines at least 4 or 5 times over 15 years and they are always solid with calcium and debris.

If you eliminate cleanliness and flow of the system, the next step is to consider the boot dividing plate on the exchanger. This stops sealing over time and allows the system to bypass the heat exchanger. A new boot is around 100 quid from Keypart.

 

[Medway Mudlark]

Gents,
Apologies for the late reply.
Thanks to all for your contributions. Its certainly given me a direction to work towards. As regards venting the turbo cooling I was given to understand that after draining, partially refill the header tank and start the engine, add more coolant to the required amount (In this particular case 11 litres) and leave header tank cap off. Is this correct, or is there an alternative method for doing this as I have downloaded the owners manual and the engine manual from the VP website and neither of these make it very clear how to perform this, other than the 'venting' aspect

 

[dragoon]

There is a banjo fitting on top of the turbo - basically you will find a bolt on a pipe - the other end of the pipe goes to the header tank in the heat exchanger. Slacken the banjo bolt at the turbo end. When you refill the coolant, keep adding until water leaks from this point. Then tighten it up. You should have now vented the turbo.

 

[Medway Mudlark]

Aaaaah..... Thanks for that. That's the bit that the owners manual doesn't mention. I will investigate this, and the other 'fixes' further, but will probably wait now until the early spring .....Watch this space, I'll let you know the outcome. If I whizz past you Fred. It means I've fixed it.