VOLVO PENTA TAMD61A OVERHEATING - PLEASE HELP!

[patoim]

Hello Dear Community, I need your experience, I’m stuck with one of my VOLVO TAMD 61A (1989), It looks like a classic case of overheating but I almost checked all the basics:

Situation:

- When I ran at less that 1000rpm, there is no problem.
- As soon as I take it to 1400/1500 rpm the temperature alarm sounds and
the gauge is marking 100°C. It takes less than a minute.
- If I set the port engine at 1500 and the starboard at 1200, the
temperature is under control. Even if I go a bit further is under control,
always with a 300/400 rpm difference.

Signs:

- There is always water coming out of the exhaust.
- I have some smoke, a bit dark but nothing out of normal, for a 30y old
engine.
- No weird noises or anything
- There is no evidence of water in the oil measuring stick
- Already tested the temperature in order to discard a gauge or sender problem.

Things done:

- Changed sea water impeller.
- Repaired fresh water pump
- Clean heat Exchanger completely
- Put a new Thermostat, I discovered that I was running without one.
- Changed belt.

Next step is to open the cylinder heads…. Which I want to avoid, any ideas?

Thanks everyone in advance!

[rslifkin]

Have you used an IR temperature gun or similar to confirm that it's actually running hot and not just a gauge or sender problem?

[patoim]

Yes, we actually tested with a sensor from inside the water system.

[MARC D]

I am suspecting the raw water pump body is worn out. When you speed the engine the tips of the impeller are too far away from the body.
These pump are designed so that impeller blades scrape the pump body at idle but no contact at high revs. If the body I.D is out of spec you get a bit of flow but not enough to cool the engine.

[JPA Cate]

Sometimes raw water cooled engines develop salt buildup in the cooling passages. We dealt with this by running dilute swimming pool acid through the cooling system. Remove the engine zincs first. We put the bucket of water on the cabin sole in front of the engine, then add the acid to the desired strength, and just let the engine run a bit and then sit--you can hear and feel the chemical reaction. When it quits reacting, run it again, and let the reaction work. Repeat till it no longer bubbles in the cylinder head.

If you try this, and no reaction occurs, it is not salting up. Dispose of the acid water ashore, and look elsewhere for the problem, possibly as suggested above, wear of pump body.

Ann

[patoim]

Originally Posted by MARC D

I am suspecting the raw water pump body is worn out. When you speed the engine the tips of the impeller are too far away from the body.
These pump are designed so that impeller blades scrape the pump body at idle but no contact at high revs. If the body I.D is out of spec you get a bit of flow but not enough to cool the engine.

Hello Marc! Thanks, I will talk to my mechanic about this. I forgot to mention that the engine can we accelerated in neutral (I don’t know the technical term in English) without overheating. And when I do that, water comes out massively form the exhaust.

[patoim]

Originally Posted by JPA Cate

Sometimes raw water cooled engines develop salt buildup in the cooling passages. We dealt with this by running dilute swimming pool acid through the cooling system. Remove the engine zincs first. We put the bucket of water on the cabin sole in front of the engine, then add the acid to the desired strength, and just let the engine run a bit and then sit--you can hear and feel the chemical reaction. When it quits reacting, run it again, and let the reaction work. Repeat till it no longer bubbles in the cylinder head.

If you try this, and no reaction occurs, it is not salting up. Dispose of the acid water ashore, and look elsewhere for the problem, possibly as suggested above, wear of pump body.

Ann

>Thank you very much for your reply! The boat always navigated on rivers, never in the sea.

[SVTatia]

Have you checked the exhaust manifold, where the cooling water is injected into the exhaust?
You need to remove the pipes and check if the passages are clear.

[DougR]

Let’s take it logically:
Sea water system-
- you cleaned the heat exchanger.....did you also clean the water side of the aftercooler
- did you also clean the water tubes for the gearbox cooler
- as someone mentioned....take the exhaust hose off the exhaust elbow and check for corrosion buildup in the elbow
- even though there is a lot of water flow in neutral, can you tell by eye between 65% flow and 100% flow?
- I seriously doubt there is enough wear in the seawater pump to cause overheat at this low rpm, but you can always swap pumps from side to side to check
- thru hull waterpickup and strainer clean?

Antifreeze side of the system:
-you cleaned the heat exchanger....did you remove the element from the housing
and clean the antifreeze side of the tube bundle?
- you repaired the circulation pump....?? Hopefully it’s OK...The speed with which it overheats makes me suspect the coolant isn’t circulating
- the proper thermostat is installed correctly.....?
- did you flush the block and heads? Silicate dropout could be a problem in an engine this old
-Is all the air out of the coolant....system bled at the turbo ?

[patoim]

Originally Posted by SVTatia

Have you checked the exhaust manifold, where the cooling water is injected into the exhaust?
You need to remove the pipes and check if the passages are clear.

Thank you, I will try this.

[SY Harmony]

Do the engines draw raw water from a common manifold or separate seacocks?

[patoim]

Originally Posted by DougR

Let’s take it logically:
Sea water system-
- you cleaned the heat exchanger.....did you also clean the water side of the aftercooler
- did you also clean the water tubes for the gearbox cooler
- as someone mentioned....take the exhaust hose off the exhaust elbow and check for corrosion buildup in the elbow
- even though there is a lot of water flow in neutral, can you tell by eye between 65% flow and 100% flow?
- I seriously doubt there is enough wear in the seawater pump to cause overheat at this low rpm, but you can always swap pumps from side to side to check
- thru hull waterpickup and strainer clean?

Antifreeze side of the system:
-you cleaned the heat exchanger....did you remove the element from the housing
and clean the antifreeze side of the tube bundle?
- you repaired the circulation pump....?? Hopefully it’s OK...The speed with which it overheats makes me suspect the coolant isn’t circulating
- the proper thermostat is installed correctly.....?
- did you flush the block and heads? Silicate dropout could be a problem in an engine this old
-Is all the air out of the coolant....system bled at the turbo ?

Hello Doug, thanks for your time.

Sea water system-
- you cleaned the heat exchanger.....did you also clean the water side of the aftercooler I dont know, but will find out
- did you also clean the water tubes for the gearbox cooler
I did not, will do
- as someone mentioned....take the exhaust hose off the exhaust elbow and check for corrosion buildup in the elbow
I already mention this to my mechanic, will update soon
- even though there is a lot of water flow in neutral, can you tell by eye between 65% flow and 100% flow?
- I seriously doubt there is enough wear in the seawater pump to cause overheat at this low rpm, but you can always swap pumps from side to side to check
I wasnt sure if that test was possible, but if it is, will do
- thru hull waterpickup and strainer clean?
Last time we checked, it was clean
Antifreeze side of the system:
-you cleaned the heat exchanger....did you remove the element from the housing and clean the antifreeze side of the tube bundle?
A Specialist cleaned it, so I can only guess, but will write it down if prior tests dont work
- you repaired the circulation pump....?? Hopefully it’s OK...The speed with which it overheats makes me suspect the coolant isn’t circulating
How can I test this? because yesterday we give it a spin after installing the new thermostat and one can hold the finger inside de water recipient, even when the engine was hot.
- the proper thermostat is installed correctly.....?
It was running without thermostat before and was overheating anyways, furthermore, the port engine is also laking thermostat (I already order one) and is working normaly
- did you flush the block and heads? Silicate dropout could be a problem in an engine this old
What do you mean by flushing? Like from the outside?
-Is all the air out of the coolant....system bled at the turbo ?
According to the mechanic, the turbo is working fine

Thanks, the mechanic is coming on monday, so I will explore all there suggestions.

[patoim]

Originally Posted by SY Harmony

Do the engines draw raw water from a common manifold or separate seacocks?

Hello, thanks for your reply! Frome separate seacocks. But boths seems to be unbloked.

[patoim]

Hello everybody! Well, my quest continues... we revised all heat exchangers, minor repairs in all of them, exhaust elbow is clean, exhaust manifold is good, fresh water pump pipes are fine, turbo is fine, took out thermostat, test water flow coming out from exhaust while running, all ok, flow increased as expected, also checked exhaust pipes, nothing seems to be blocking it. Today we open one of the cylinder head, pictures below... all looks good. This week will ipen second cylinder head but my mechanic told me he sees no damage on engine block or cylinder, and expects the same for the other cylinder head. So, he wants to go back to the basics. Any ideas?

The problem remains the same, 1000rpm all is good, go to 1500rpm and temp rises really fast until alarm. Temperature seems to concentrate near exhaust manifold.

[Sailormantx]

I am working on a boat with Volvo TMD40A engines at the moment. After cleaning the cooling system and refilling it I had similar issues. The service manual isn't very clear with their descriptions but it is essential to get the air out of the cooling system at the turbo which is the highest point in the engine. On the TMD40A there's a small metal tube with a banjo fitting and a bleed screw with copper washers on both sides to seal it. My problem was that the hollow vent screw and it's hole in the side were packed full of gunk so nothing came out when it was loosened. After clearing that blockage I successfully vented the cooling system and the problem was solved. Note that the venting of the air is done when a clear bubble free steam of coolant comes out the same as venting the fuel system. This is done with the engine running so beware of hot coolant.