Volvo Penta TMD40A oil alarm and expansion tank

[dragoon]

Yes you are right. Pervious comments deleted.
One terminal of the sensor is earthed though. It has to be to complete the circuit back to battery negative

actually just to confirm as my English was clumsy in my earlier post. Naturally the switch enables a circuit to Earth, but not via the body of the switch (like a car oil pressure switch). Instead there are 2 connections on the VP part -one side goes to an Earth point on the oil cooler (bolt). The other side goes to the buzzer which is live when the ignition is on.

 

[dragoon]

Only one way to go, completely strip the cooling system, clean and look for blockages. Do not forget, rubber hoses can de-laminate from the inside and create "bubbles" in the hose causing restrictions.

I agree to a point. The only caution I would add is not to advise caution on complete disassembly of the coolers. Front plates off and rodding (eg with a straighter coat hanger or similar is fine). I wouldn’t advise pulling any cooler or exchanger apart unless essential as they are easily ruined.

if anything is blocked, my money is in the oil cooler. On these engines they clog regularly. I’ve cleaned mine countless times.

 

[VicS]

I agree to a point. The only caution I would add is not to advise caution on complete disassembly of the coolers. Front plates off and rodding (eg with a straighter coat hanger or similar is fine). I wouldn’t advise pulling any cooler or exchanger apart unless essential as they are easily ruined.

if anything is blocked, my money is in the oil cooler. On these engines they clog regularly. I’ve cleaned mine countless times.

If the oil cooler is blocked won't that mean that there will be little or no flow to the exhaust elbow?
The OP says that is staying cool.

 

[dragoon]

If the oil cooler is blocked won't that mean that there will be little or no flow to the exhaust elbow?
The OP says that is staying cool.

In theory, but I’ve had a restricted (but not completely blocked) cooler leading to overheat at higher rpms under load, but the elbow has remained cool to touch.

I think we’re still missing info from the OP as to exactly when the overheat occurs - ie at the dock or under load to completely rule a clogged raw water circuit out of the equation.

 

[Nunuwawa]

If that top plastic tube is open to the air space at the top of the expansion vessel then I would assume that the coolant system must be running at atmospheric pressure. This will inevitably lead to loss of coolant, one way or another, and overheating.

Do both engines have that upper plastic tube drilled through?

Richard

Yes, both are open.....

 

[Nunuwawa]

Also, is getting to 90C whilst underway or at the dock? I've run mine up at fast idle with the cap off before and not even got the engines that warm, so just curious.

just at the dock with a bit more revs than idle

 

[Nunuwawa]

I was also going to suggest checking the thermostats ... one should start to open at 70C and the other at 76C .... Its unlikely that both will have failed, possible though.

Maybe you ought to look at the coolant pump ????

The thermostats are replaced with new ones.

 

[Nunuwawa]

It definitely looks looks like the low oil pressure warning switch as you say. If his Storebro is set up the same as mine, it will have alarms at the helm station, but no light. I added lights to mine as a visual warning. The old part is no longer available and is replaced by 863169 and a wiring harness conversion 873601. They are seen here - I had to add a new one to mine at some point. TAMD40B - Diesel Engine

also no warning lights, will probably add them like you did
Thank you for the link, does this replacement has the same thread you think?

 

[VicS]

also no warning lights, will probably add them like you did
Thank you for the link, does this replacement has the same thread you think?

The same part is also listed for your TMD40A. It is a genuine VP part so darned well ought to have the same thread
BUT
You will also need the electrical conversion harness ( or cobble something together to save £11 )

See Keypart
and Keypart

.

 

[dragoon]

The same part is also listed for your TMD40A. It is a genuine VP part so darned well ought to have the same thread
BUT
You will also need the electrical conversion harness ( or cobble something together to save £11 )

See Keypart
and Keypart

.

It’s not worth trying to avoid the harness. The connection on top of the switch seems to be bespoke with rounded terminals and shrouded in brittle plastic. Given that access is difficult to the switch anyway the £11 would seem a good investment.

 

[dragoon]

just at the dock with a bit more revs than idle

how many minutes from start up to overheat are we talking?

can you see circulation of the coolant in the exchanger?

I know you report a cool exhaust bend, but to be sure your pump is pumping, have you tried starting with the basket lid loosened? Water should flood out.....

 

[dragoon]

also no warning lights, will probably add them like you did
Thank you for the link, does this replacement has the same thread you think?

As Vic said, it’s a genuine part and will fit

 

[dragoon]

also no warning lights, will probably add them like you did
Thank you for the link, does this replacement has the same thread you think?

where are you based? If you’re nearby I’m happy to pop over and have a look . I’m in Gosport with our boat in Port Solent

 

[Nunuwawa]

where are you based? If you’re nearby I’m happy to pop over and have a look . I’m in Gosport with our boat in Port Solent

Thank you for your offer but I am situated in Antwerp Belgium.
By the way, i used to sail a lot in the Solent, beautiful sailing place
I sailed all my life in the channel

 

[Nunuwawa]

how many minutes from start up to overheat are we talking?

can you see circulation of the coolant in the exchanger?

I know you report a cool exhaust bend, but to be sure your pump is pumping, have you tried starting with the basket lid loosened? Water should flood out.....

Yes I did and the water indeed flood out.

As I can remember, the engine did not overheat when I started the first test runs in the harbor.
When we took the boat for test out from the harbor there was the first minutes a strange metallic sound
In this engine which suddenly stopped, then a bit later I saw the temperature rising so I wonder
If it can it be possible there was something wrong with the circulation pump?
Does it happen that the circulation pump stops working?
I just find it strange that the engine overheats in such a short time on idle….
If there is something half blocked one would think there is still a bit cooling?
Maybe a good idea to check the circulation pump first or does this never happen? (broken circulation pump)

 

[179580]

Yes I did and the water indeed flood out.

As I can remember, the engine did not overheat when I started the first test runs in the harbor.
When we took the boat for test out from the harbor there was the first minutes a strange metallic sound
In this engine which suddenly stopped, then a bit later I saw the temperature rising so I wonder
If it can it be possible there was something wrong with the circulation pump?
Does it happen that the circulation pump stops working?
I just find it strange that the engine overheats in such a short time on idle….
If there is something half blocked one would think there is still a bit cooling?
Maybe a good idea to check the circulation pump first or does this never happen? (broken circulation pump)

Seem to have heard that BMW had a problem in the distant past with water pump impellers, so not unheard of.

 

[dragoon]

Yes I did and the water indeed flood out.

As I can remember, the engine did not overheat when I started the first test runs in the harbor.
When we took the boat for test out from the harbor there was the first minutes a strange metallic sound
In this engine which suddenly stopped, then a bit later I saw the temperature rising so I wonder
If it can it be possible there was something wrong with the circulation pump?
Does it happen that the circulation pump stops working?
I just find it strange that the engine overheats in such a short time on idle….
If there is something half blocked one would think there is still a bit cooling?
Maybe a good idea to check the circulation pump first or does this never happen? (broken circulation pump)

yes, it can happen, even if it’s not a common event. The impeller can slip on the shaft, the shaft can shear etc. I suspect the only way you’ll know is to remove the pump and have a look. When removing, soak the bolts in PlusGas for a day or so before trying to undo them.

Given that it’s overheating so dramatically with no load and in a short time, the circulation pump sounds like a distinct possibility.

 

[RichardS]

Seem to have heard that BMW had a problem in the distant past with water pump impellers, so not unheard of.

Several companies have had the problem with plastic impellers. It's is very unusual with the more common metal impellers as these can be pressed much more firmly onto the shaft.

I've not heard of any boat engines with plastic impeller pumps but immediate overheating, even though the thermostat has been replaced, does suggest that the pump might well be the culprit.

Richard

 

[Nunuwawa]

Hello all

I removed the heat exchanger and it was almost not blocked so cannot be the reason.

There is a lot of probably electrolyze on one site in the aluminum case (little holes) , I think this is possible

to fix by welding but then I need to get the core out without damaging.

Question, the pipe which is sticking out on one side where a tube is fixed on,

Does someone know if this is part of the core?

Difficult to see……..

Thank you for any advice removing the core

.

Walter

 

[dragoon]

If I'm not mistaken that's a model A heat exchanger. You should be able to find exploded schematics for that here Volvo Penta Exploded view / schematic Heat Exchanger and Thermostat with Installation Components: A AQD40A - MarinePartsEurope.com

Volvo seem keen on using square section o-rings on coupling pipes. I expect that's one of those pipes you can see sticking out of the exchanger, but you can check with the diagram. If so, it should just pull out with care. Maybe work it backwards and forwards, but careful not to distort it. It will be expensive.

I suspect your case is very thin if you have holes in it. You may be better trying to source a second hand one. You can try Coastal Rides for such parts. Good luck removing the core , but you should find info online - on an A this is a cooling plate design so should be possible - I know removing the core (tube bundle) was challenging and damaged one of my cases in the past.