Volvo Penta TMD40A

[Trumpeter]

Hi all.
I have recently bought a cruiser which is powered by two Volvo Penta TMD40A diesel engines.
The port engine has been running hot and the problem appears to have come on suddenly.
I replaced the seawater impeller after checking the strainer. No result. Then I put two new thermostats in. No result. I have removed the heat exchanger housing with a view to removing and cleaning the core. This particular heat exchanger does not have two end caps. The housing is solid at one end and after the other end is removed, I can see the end of the core but I cannot get any purchase on it to safely remove it without damaging the core, which appears to be made of soft metal, possibly copper etc. I thought about preparing a mild acid mix to pour into the housing but I am not confident I can do this without causing damage to the core. Does anyone have a suggestion about how I can remove this core and/or clean it.

 

[PaulRainbow]

Stand it on end, mix some brick acid with water, 50/50 and fill it up. Leave to "soak" until it's clean.

When it's all re-assembled you can connect a pump to the raw water circuit and put it in a bucket of 50/50 brick acid and pump it round and round for an hour or two to make sure the whole system is clean.

 

[volvopaul]

Use Rydelime not brick acid , brick acid atracks the solder on any joint rendering your internal core scrap .

 

[Trumpeter]

Stand it on end, mix some brick acid with water, 50/50 and fill it up. Leave to "soak" until it's clean.

When it's all re-assembled you can connect a pump to the raw water circuit and put it in a bucket of 50/50 brick acid and pump it round and round for an hour or two to make sure the whole system is clean.

Hi Paul. Another member says brick acid may damage the solder and to use Rydelime. Do you agree?

 

[Trumpeter]

Hi Paul. Another member says brick acid may damage the solder and to use Rydelime. Do you agree?

Will MURIATIC ACID do the job?

 

[volvopaul]

Hi Paul. Another member says brick acid may damage the solder and to use Rydelime. Do you agree?

100% I only use rydelime .

 

[oldgit]

Been there ...and repaired a few times.
Would suggest that you might like to check the first item in the system after the raw water pump ie, the oil cooler has not collected any bits of blade.
In the past ,removal of hose at front of oil cooler and flushing the chamber out with a mains hosepipe did produced chunks of impellor blade..
A quick heads up . The body of the aluminum oil cooler has reputation for being rather fragile after 40+ years in service and some servious thought should be given to any removal or servicing.
Having said that there are folks out there can reweld and refurbish the alloy casings.
Suspect the heater matrix is no longer available but amounts of the matrix can be lost without that much effect on cooling.

 

[Trumpeter]

And you removed your heat exchanger core? How did you do that?

 

[superheat6k]

Be very careful with the tube nest. The core cost me ~ £1,100 when I had to replace one on my Turbo 36 ~ 2013. Rare as hens teeth, and easy to pierce - when mine failed it revealed itself because the fresh water side kept overfilling as the pressure on the seawater side was higher than the FW side. Despite much trying I could not get the piercing, which was just visible from one end, could not be sealed.

The tubes will come out as they are held and sealed by two O rings. Always use VP original seals for these.

I would not use any aggressive acid - Muriatic is hydrochloric acid. Instead either vinegar for a couple of days, or sulphamic acid.

I did think about re-engineering the engine to allow use of an external cooler, such as a Bowman.

Incidentally if the gearbox oil cooler ever gives up then these can be replaced with a Bowman for a fraction of the price of a VP original.

 

[oldgit]

And you removed your heat exchanger core? How did you do that?

superheat6k. Rare as hens teeth, and easy to pierce - when mine failed it revealed itself because the fresh water side kept overfilling as the pressure on the seawater side was higher than the FW side.."​

100%



It helps if you have the delicacy of Brain surgeon and the the skill of the God Thor................ but using a rubber hammer.

Gently undo the bolts holding on the header tank to expose end of the heater matrix ( no pipe stack, as in later versions but literally a folded up radiator matrix).
The clever bit is dislodging the heater matrix out of its rather tightly fitting aluminium container.
On my version there was no way of "pushing" it out from the other end or gripping that exposed square brass end cap without damage.

In the end inertia was my friend, by " gently" dropping the end corner of the cooler sharply on the edge of the wooden bench , the heater matrix became dislodged and was persauded out under its own weight.
This probably will not apply to you but several of the matrix channels had failed (collapsed) and at the time (1990s) Volvo had either stopped supplying or the £800 + replacement cost fro matrix alone, represented a large proportion of the boats value.
Ordinary soft solder used to seal off a damaged section and with homemade gaskets , new "O" rings, plus a tube of that not to be reccommended under any circumstances instant gasket, it all went back togther .
It was still working several years, many hundreds of hours later when the boat was sold on with no obvious signs of any lack of cooling.

 

[Yamaha240]

Use Rydelime not brick acid , brick acid atracks the solder on any joint rendering your internal core scrap .

Hi Paul

My apologies for responding on this thread. I can’t seem to PM you. Hope this is okay.

I am looking at a rib (9m tornado) with the 420sti engine and Yamaha outdrive. I have it almost bought but was stopped in my tracks when I spoke to a marine engineer who told me that outdrive is a disaster and will break my heart. He said he worked on them and will never do it again. This particular outdrive was rebuilt in 2022 and currently has no apparent issues.

Can you advise me on your opinion here, I will use the rib for rib tours in Ireland. I intend getting the engine completely rebuilt and factored this in. But would this be the wrong thing to do if I’m ultimately going to be stung badly every season with a failed outdrive.

I would like to get your view in terms of preventive maintenance (if it exists) or the extent to which it would cost if it were to go.

Much appreciated

 

[volvopaul]

The Yamaha hydra drive is a good unit but the oil must be changed every year.

 

[Seastoke]

Most people doing rib tours use OB

 

[Yamaha240]

Most people doing rib tours use OB

Why I wonder

 

[Trumpeter]

Okay folks just a reminder this thread is about

Volvo Penta TMD40A and in particular, the heat exchanger and other cooling issues , hopefully someone might offer their own experiences with that particular engine cooling system. Thanks.​

 

[Yamaha240]

Okay folks just a reminder this thread is about

Volvo Penta TMD40A and in particular, the heat exchanger and other cooling issues , hopefully someone might offer their own experiences with that particular engine cooling system. Thanks.​

Yes apologies my fault for diversion.