VP TMD40 overheating at high RPM

Has the oil cooler end cap been removed and checked/cleaned.? If it hasn't I'll bet it's clogged even if you flushed with Rydlyme. For cleaning agents like Rydlyme to work, you need some flow already through each tube. The oil cooler is small, first in the circuit after the strainer and prone to clogging.
 
MartynG said:
A friend with kamd 43's has cleared out his heat exchanger in an overheating engine (there were old bits of impeller in the tubes ). A new raw water impeller had been trashed in a few hours running. Then he found the raw water pump was worn. A water pump rebuild kit immediately improved the flow of water (a lot cheaper than a new raw water pump). A run in a few weeks time will prove whether it has worked.
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TAMD40s have the strainer after the RW pump, so the strainer captures the impeller pieces, so should be straight forward for the OP to check.
 
I had the problem. We changed to a new sea water pump and the problem was gone.
The shaft and housing of the old pump had been worn out.
 
The cast iron elbow on my 40A developed rusty weeps over time, mainly around the clamp holding it to manifold.
When attempting to remove and inspect / reseal, it crumbled to bits.
Only thing left intact was the stainless interior pipe.
A new one, be it VP or otherwise are not a lot of money,
Amazed they last so long, plder Mercruiser versions are notorious for their lack of longevity.
 
dragoon said:
Has the oil cooler end cap been removed and checked/cleaned.? If it hasn't I'll bet it's clogged even if you flushed with Rydlyme. For cleaning agents like Rydlyme to work, you need some flow already through each tube. The oil cooler is small, first in the circuit after the strainer and prone to clogging.
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That is certainly worth checking, presumably the heat exchanger needs to be removed to get at the oil cooler? Lots of dismantling needed. I guess that if half the tubes were blocked - for example - then the rest would still allow enough flow for good cooling up to a certain load then overheating could occur. I can see the point that Rydlyme cannot help with completely blocked tubes.

With hindsight perhaps it would have been better to do the dismantling and clearing of any gross obstructions before using Rydlyme?
 
Some Volvo coolers use the end cap to direct the flow which can mean fitting the cap incorrectly can actually reduce the efficiency of the cooler so its worth checking that you are getting the flow correct.
Ie some have the water going along the northeast quadrant across the back via the south east back along to the front across to the south west to th back and finally out through the northwest
Not sure if your engine is this arrangement.
 
Don't forget to Rydlyme the internal cooling circuit as well.

I managed to remove an awful lot of crap from mine!! (TAMD40b)
 
scottie said:
Some Volvo coolers use the end cap to direct the flow which can mean fitting the cap incorrectly can actually reduce the efficiency of the cooler so its worth checking that you are getting the flow correct.
Ie some have the water going along the northeast quadrant across the back via the south east back along to the front across to the south west to th back and finally out through the northwest
Not sure if your engine is this arrangement.
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I assume you are referring to the heat exchanger rather than the oil cooler? What would be the correct orientation of the endcap? Is it obvious by looking at it, or does it have to be removed to check the alignment?
 
Leighb said:
Thanks, that has already been done.
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OK, sorry, must have missed that!

I ran mine with the thermostats out, and a hosepipe in the top, revving the engine stirred up all the sediment and brown sludge which shouldn't have been there as it had regular coolant changes! Only revving the engine forced the stuff out (thats a big water pump compared to the 12v inline one!)

Good luck, sounds like the Rubber gaiter possibly... :encouragement:
 
Leighb said:
That is certainly worth checking, presumably the heat exchanger needs to be removed to get at the oil cooler? Lots of dismantling needed. I guess that if half the tubes were blocked - for example - then the rest would still allow enough flow for good cooling up to a certain load then overheating could occur. I can see the point that Rydlyme cannot help with completely blocked tubes.

With hindsight perhaps it would have been better to do the dismantling and clearing of any gross obstructions before using Rydlyme?
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Yes, afraid so, the heat exchanger needs to be removed to get to it, so you will need to drain coolant (I use a hosepipe, and such it out the drain with a pump, store and reuse) . The positive side is that the oil cooler can be accessed and cleaned without removing it. Just one end cap to come off (4 bolts) - probably will need an overnight soaking with Plus Gas to free them off if you've never opened it before.
Don't attempt to remove the tube stack though from the case - that's asking for trouble. Just inspect tubes, blow through with an air line and the ones that are really blocked you will need to gently rod with a striaghtened coat hanger - take it easy though and don't force anything.

Your guess on the effect of restricted flow is accurate - that's what happens in my experience. I'm about to clean mine again - I do it every 2-3 years. The first time I opened one up the bottom half of the cooler was completely blocked.
 
Leighb said:
I assume you are referring to the heat exchanger rather than the oil cooler? What would be the correct orientation of the endcap? Is it obvious by looking at it, or does it have to be removed to check the alignment?
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If you've got the type B cooler which I think you stated you have, then you have the same arrangement as me. You can't get that wrong as it lines up the input and output pipes when are 135 degrees apart.

Of course, you could have a problem with the end cap not being seated right or sealing which can lead to bypassing of the heat exchanger. This is also quite common, and if you're going to take the heat exchanger out you may want to look at how this seals on the metal separator on the back of the exchanger. If the cap is seriously buckled where it seals you can get new ones for about £100 from Keypart.

I would still wager you have a restricted flow somewhere - the likely culprits IMO are;

- oil cooler
- pipe into oil cooler (they block at lowest point)
- pipe from exchanger to gearbox (they block at the lowest point)
- exhaust

I've been where you are chasing these down - I did it for the first few years of ownership of our Storebro, and I got there in the end, so keep at it and you'll get there - none of it is rocket science, but the cooling equipment is heavy and awkward to remove from the engine.

Even when you've got it 100% you'll find the issue creeps back and you have to clean stuff again. Of course, once you've got it all clean you can use Rydlyme to keep it clean - I've only done this once, but plan to use it more often.
 
It's actually a shame you don't live a bit closer, I'd offer to come over and help you resolve this. I could always do with a hand getting the exchangers on and off our boat as well :)
 
dragoon said:
The positive side is that the oil cooler can be accessed and cleaned without removing it. Just one end cap to come off (4 bolts) - probably will need an overnight soaking with Plus Gas to free them off if you've never opened it before.
Don't attempt to remove the tube stack though from the case - that's asking for trouble. Just inspect tubes, blow through with an air line and the ones that are really blocked you will need to gently rod with a striaghtened coat hanger - take it easy though and don't force anything.

Your guess on the effect of restricted flow is accurate - that's what happens in my experience. I'm about to clean mine again - I do it every 2-3 years. The first time I opened one up the bottom half of the cooler was completely blocked.
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I have looked at the exploded diagrams of the oil cooler on the net, and I had the impression that there were endcaps at both ends, admittedly looking at different views so I might have been confused. If it is only open at the aft end, how is it possible to rod through the tubes? Surely any crud would just be rammed up to the far end?

Thanks again for your helpful advice.
 
Leighb said:
I have looked at the exploded diagrams of the oil cooler on the net, and I had the impression that there were endcaps at both ends, admittedly looking at different views so I might have been confused. If it is only open at the aft end, how is it possible to rod through the tubes? Surely any crud would just be rammed up to the far end?

Thanks again for your helpful advice.
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Is this the boat I surveyed at a Penton Hook for you ?
 
Leighb said:
I have looked at the exploded diagrams of the oil cooler on the net, and I had the impression that there were endcaps at both ends, admittedly looking at different views so I might have been confused. If it is only open at the aft end, how is it possible to rod through the tubes? Surely any crud would just be rammed up to the far end?

Thanks again for your helpful advice.
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The end with the anode doesn't remove, just the end with the plate on (aft end). The idea is that if you need to remove the tube bundle, the plate comes off and then the whole stack pushes from the front end - it's then mounted on o-rings. I'm not recommending removal of the stack though.

If you rod from the aft end, you're correct the debris will build up in the other end, but if it's salt crud it just breaks down into powder. It's possible to blow stuff out by removing the anode and blowing in the hole with an air gun. You may find bits of anode loose in there also which don't help with the restrictions.

Note that once you remove the plate, you will need a gasket to replace it. I've bought them from Keypart for about £10 or so each I think. You'll need to use some instant gasket also to seal it.

https://www.marinepartseurope.com/en/volvo-penta-explodedview-7744060-26-18319.aspx
 
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