Leaking volvo penta heat exchanger

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cinnabar8

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Under load the heat exchanger pressure cap leaks (at idle no leak) which I think suggests a back up of pressure due to a blockage somewhere. Anybody got any suggestions as to where blockage might be and how to clear it? If dismantling is required where can I obtain replacement 'o ' rings etc? /forums/images/graemlins/confused.gif
 
There is a known issue with the D4 heat exchanger, if your engine is under warranty get an engineer to it sooner rather than later.
 
This a known fault and if the plastic end cap leaks (as in this case) it should be replaced under warranty.
The upgrade is to replace the plastic cap with a phosphor bronze one. There is a charge though, the part costs £72 plus labour for fitting.
 
Hi

There are several reasons for the cap leaking but you really need to give more details of the engine. Which one would do for starters!
 
My 40A heat exchanger is a very ancient piece of stone age technology and hence easy to get to bits and fix.You can get a kit of rubber bits from Keyparts or such like for around £80 ish.Some of which you may not use as unless very knackered some stuff can be reused.
The scary bit is the internal heat exchanger which costs three arms and four legs to buy from Volvo,but despite everything you will be told can be fixed.Split in my matrix was soldered up 4 years ago and still going strong.
Good luck
The mysterious internal gubbins in that green box.
DSCN1767.jpg

A leak in the matrix will enable sea water to be forced into the internal system and the pressure will force water/antifreeze out somewhere or other.
This of course is worst case scenario,it my be something dead simple.
 
Hi

Now I know the engine I can answer your question. I had 2 of these engines in my Sunseeker for 18 years so hopefully I won't go on too long for you.
Looking at your post the reason for the leak under the heat exchanger cap is the plastic moulding it goes on will have a crack under the top flange, this happened on one of mine at the beginning of a season and by the end of it the other one required changing, got the spares from Keypart.
Now if the leak was from the the radiator style cap I would first look at the cap (car shop part number FC41) these I seem to remember were off a Skoda (no jokes) and are a low pressure setting. From there I would ask you how old is the exhaust manifold and when was it last flushed through, I used to remove mind each year, back flush and leave in a oil bath during the layup. If it has not been off for a few years I would remove it to clear the waterways and to check for corrosion, clearing them as required. Replacement exhaust gaskets are Vovlo car block B21, car 244DL size 2127cc. Once the manifold is off, oil filter removed, using a 28mm ring spanner remove the oil cooler, remove the centre screw and remove the end covers, this will expose the ends of the heat exchanger tubes that the water flows through, these need to be checked that they are clear. I don't like using metal to check, one I like is a WD40 spray tube, it fits just right.
The other items to watch are the cam belt pulleys for corrosion, you don't want a belt to go, I used to replace the every year, once again spares from car shop.
I have listed below various part numbers for spares from car spares shops.

Oil filters - FramPH2857A/Halfords HOF202/Champion C102

Cam Belts - TRW48-47520/Powertrain992636/
Masterparts MTB25 PMTB18

Spark Plugs - BP7ES

Dist Cap - 4419

Rotor Arm - Bo1 234 332 215 or 47115

Condenser - Bo1 237 330 275 or 3350

Points - Bo1 237 013 044 or Lucus DSB 432 or 22700

I hope some of this is of some help to, let me know how you get on.

Steve
 
Thanks. There's no evidence of damage to the moulding and the cap works perfectly on the other engine. With some help from a friend who knows his way around engines we're going to remove the heat exchanger for a start. The parts info is very much appreciated. Thanks once again. /forums/images/graemlins/ooo.gif
 
You will not see any damage as such to the plastic moulding on top of the heat exchanger, the crack is caused by age hardening and the tension caused by the 'jam jar type' cap. I would probably even be prepared to put money on this being the problem. I would look very carefully around the top of the moulding especially inside the rebate where the cap tangs fit before you take the heat exchanger off and I would not recommend taking it (the exchanger) apart.

Just to make sure we are talking about the same thing, it is the cap on the plastic moulding, the one with a large rubber washer in, not the radiator style one you remove to put in the anti-freeze in.

Steve
 
cinnabar8 said:
Under load the heat exchanger pressure cap leaks (at idle no leak) which I think suggests a back up of pressure due to a blockage somewhere. Anybody got any suggestions as to where blockage might be and how to clear it? If dismantling is required where can I obtain replacement 'o ' rings etc? /forums/images/graemlins/confused.gif
Click to expand...
Peanuts said:
You will not see any damage as such to the plastic moulding on top of the heat exchanger, the crack is caused by age hardening and the tension caused by the 'jam jar type' cap. I would probably even be prepared to put money on this being the problem. I would look very carefully around the top of the moulding especially inside the rebate where the cap tangs fit before you take the heat exchanger off and I would not recommend taking it (the exchanger) apart.

Just to make sure we are talking about the same thing, it is the cap on the plastic moulding, the one with a large rubber washer in, not the radiator style one you remove to put in the anti-freeze in.

Steve
Click to expand...

Hi, how did it finish? I now have the same problem :)
 
I know but the solution remains the same i guess... I have 2 penta 140 aq in my boat and one of the engines has the same issue... so any help would be great.
 
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