Want To Buy: Cylindrical heat exchanger for penta md 21b

[Taff sailor]

Part is classed as obsolete by Volvo Penta, so I am looking for a decent sceond hand one which doesn't leak.

[Polar Opposite]

I'm not sure it's the same heat exchanger, but I have one from a Volvo Penta Model 2003.

[jamhass]

Fuggetaboutit.

We have one (probably leaking internally) and a spare on our Volvo 2003T. Most of the used ones (ours included) have corroded casings -- which are no longer available from Volvo. Even the tube sheets (which are fairly robust) are on the order of $3000, and at last check there was only 1 new one available.

We had a similar issue with the oil cooler on the 2003T, also no longer available.

We changed out the oil cooler with an inexpensive ($150) after market NiCu unit easily retrofitted, and are in the process of doing the same with the HX. The aftermarket HX, also NiCu, was on the order of $400. Will need to modify two of the original coolant pipes, but a quite simple modification.

May not be an option on some Volvos where the HX is integral with the exhaust manifold.

[Taff sailor]

Thanks guys, but I think mine is unique to this engine type. Here's the daigrammatic:Volvo Penta Exploded view / schematic Heat Exchanger with Thermostat and Installation Components MD21B, AQD21B - MarinePartsEurope.com and unfortunately the tube stack on this model is integral, so replacing that is not an option.

[jamhass]

As usual, Volvo keeps the plumbing together mainly by the "geometry" of the part. i.e. the pipes are only held in place by the location of the mating parts, not by threaded or otherwise secured joints.

While this complicates aftermarket replacements somewhat, it is not an insurmountable obstacle. For example, #38 can be secured to #45 by brazing a support link held in by screw #50.

Remember, the aftermarket HX does not HAVE to be mounted on the engine. It could be on a nearby bulkhead. On the other hand, since at least one end is simply clamped to the engine, you might well work up a similar solution for the other end.

I went through an identical exercise with my 2003T. It wasn't all that hard and saved me thousands. Literally. And ... I'm not having to rely on suspect second (or third) hand parts.

I had great success with Lenco.com. Give them a call. When I called with questions, they knew my engine right off the bat, and had just fabricated an HX for another identical engine and knew exactly what I needed. Very satisfied. Note that you don't have to take one of their "stock" HXs. They will modify the plumbing, etc to meet your needs.

[Scout 30]

I also recommend Lenco. I replaced my 2003T oil cooler with one of there units. Very helpful people to work with.

[Scout 30]

I was watching Jay Leno's Garage the other day & he was explaining how they were saving a fortune by reproducing parts for antique cars using a 3D printer. I immediately thought of my Volvo 2003t. The designs of the oil cooler & heat exchanger are great but the aluminum they made them out of really sucks.

[Polar Opposite]

I have a Volvo 2003 and the HX is heavy NiCu, I think. Same with an older Volvo 2003 I took apart. Aside from old rubber gaskets (easily re-made from NAPA rubber sheet gasket material), they were essentially untouched by 30+ years of use. One had the bracket break off, but it was a $40 braze job to get it reattached.

2003Ts have aluminum HX?

[Stu Jackson]

In addition to Lenco, try Sendure.

[Scout 30]

Originally Posted by Polar Opposite

I have a Volvo 2003 and the HX is heavy NiCu, I think. Same with an older Volvo 2003 I took apart. Aside from old rubber gaskets (easily re-made from NAPA rubber sheet gasket material), they were essentially untouched by 30+ years of use. One had the bracket break off, but it was a $40 braze job to get it reattached.

2003Ts have aluminum HX?

The 2003T casings for the HX & oil cooler are aluminum. The tubes appear to be brass. To be fair my heat exchanger is fine but the oil cooler looks like termites ate it. Luckily it started leaking at the dock & I caught it before it lost too much oil but if I had been out it could have killed the engine.

[jamhass]

Originally Posted by Scout 30

The 2003T casings for the HX & oil cooler are aluminum. The tubes appear to be brass. To be fair my heat exchanger is fine but the oil cooler looks like termites ate it. Luckily it started leaking at the dock & I caught it before it lost too much oil but if I had been out it could have killed the engine.

The tube sheet is copper -- both in the HX and oil cooler. As such they are susceptible to corrosion especially if not kept clean, as contaminants will cause enough conductance between the Cu and Al that the Al just "goes away ..." And no, they do not have a zinc. Guess Volvo thought this was where they could make some $$$ on replacement parts.

[Scout 30]

Originally Posted by jamhass

The tube sheet is copper -- both in the HX and oil cooler. As such they are susceptible to corrosion especially if not kept clean, as contaminants will cause enough conductance between the Cu and Al that the Al just "goes away ..." And no, they do not have a zinc. Guess Volvo thought this was where they could make some $$$ on replacement parts.

I wonder if there's a way to drill & tap the heat exchanger for a pencil zinc? All it needs is a zinc to solve the problem.

[jamhass]

Originally Posted by Scout 30

I wonder if there's a way to drill & tap the heat exchanger for a pencil zinc? All it needs is a zinc to solve the problem.

No room.

I've had mine apart, and there is nowhere to put any kind on zinc, at least not pencil zincs.

I finally just went after market, both HX and oil cooler. From Lenco as I see you did too, at least for the oil cooler.

[Taff sailor]

Thanks for all the comments and advice and sorry I've been a bit slow in replying but I've been in hospital having knee surgery.

I think the way to go for me is to mount a similar sized HX on a bulkhead and fix rubber hoses on to the metal sleeves which provide the joint between my HX and the cylinder head. I'm based in the UK and postage from the USA of such a heavy item is likely to be expensive, so I'm researching UK based suppliers at the moment.