Caution: This article has a yawn rating of 5 - you have been warned :-)

Volvo Penta's 2003T was fitted to many boats between 1986 and 1993. Examples include the larger Westerlies, Tridents Warriors & Voyagers and many Halberg Rassy's to name just a few.

Given their popularity we have compiled these notes to assist anyone who wants to check or refit their oil cooler, heat exchanger or both.

As you will have seen from our previous blog....the oil cooler (OC) and heat exchanger (HE) are vulnerable to corrosion being made of metals not ideally suited to the marine environment. Saying that our engines are 25 years old. The one had it oil cooler replaced 5 years ago and the other we have replaced in the last couple of days. All the parts are readily available from Volvo Penta...but I'll warn you they are expensive!

If our HE was showing any sign of serious corrosion we would look to replace it with an aftermarket one, probably from Bowman and design some custom brackets to hold it on the engine or on a nearby bulkhead. The reason for this is simply cost? This item alone retails at €3,189.16 inc Vat!

If you download the service manual you should note that both the OC and HE should be cleaned & checked every "400 hours / at least every other year". Not a bad suggestion I would say....but bare in mind it takes some time to complete this exercise and will require a new HE gasket as an absolute minimum.

In addition to the usual assortment of spanners and a small socket set you will also need:

1) a long extension bar (22.5cm) that fits your ratchet and 10mm socket - for the small bolt on the back of the OC that holds the seawater pipe in place.

2) a short extension bar (15cm) that fits your ratchet and 19mm socket - for the two hollow bolts that feed oil to and from the cooler

I have not detailed the steps taken to remove the HE or OC but you should be able to reverse the steps outlined.

Our OC was new so there was no need for us to service this part. If you OC looks OK externally I would recommend you undo the centre bolt (nuts at each end) and remove the two end caps with their rubber O rings and then gently slide out the tube stack? This will allow you to check the aluminium casing for corrosion and make your decision. Remember if this part fails you will dump your engine oil very quickly and risk damaging the engine if it isn't identified almost instantaneously! Assuming the casting is sound gently clean up the tube stack ( we found BBQ sticks perfect for this fitting the tubes beautifully) and the end caps. Reassemble ideally with new rubber O rings suitably lubricated. We used Unigel Turbo Gel (TG).

With regard to the HE, undo the four securing bolts and remove the large flange. Gently prise apart the copper end cap...be vary careful no to bend or damage this very expensive pressed piece of copper!

We decided not to remove the tube stack because it looked in good order and our coolant level always remained consistent. Once again we just passed the BBQ sticks through each of the tubes. Reassemble with a new gasket and plenty of gasket sealant. We used loctite SL 5923 (Marmite) and left it 24hrs to dry.


On with the Marmite

Our new OC arrived unpainted, so we started with a couple of coats of paint to provide some external corrosion protection. We then followed it by adding the two oil nipples and new aluminium washers creating the seal. We used some loctite 572 around the thread but this shouldn't be necessary.



Unfortunately the position of the nipples means it is not possible to fit the oil pipes in situ because there is no room for the shoulders of the spanner. This means you need to identify the correct position of the oil pipes before mounting the OC. We achieved this by first mounting the OC using the two mounting bolts in the lower holes, finger tight and then connecting the oil pipes..again finger tight - this bit is possible because you don't need to get to the flats of the nut. You then need to fit the two hollow oil bolts and their washers and again pinch them up finger tight. With the aid of a small ruler resting on the flat of the mounting bracket mark the oil pipes so that you can recreate the exact position that they should be in when everything is removed. Remember it is important to get this bit right otherwise the hollow bolts, washers and banjo fitting will not lie level and leak.

With everything removed we positioned the OC on a flat surface and used blocks of wood made up to the right height to align the pipes correctly before tightening up the oil pipes properly. Remember you can't tighten these unions up later without taking everything apart so make sure you take your time and do it right!

With the aid of the two longer mounting bolts in the upper two holes supporting the OC some 1cm away from its proper position fit the two hollow oil bolts and their respective copper washers to the block. Alternating between both hollow oil bolts, gradually pinch them up whilst sliding the OC home.

Once home fit the two lower OC mounting bolts and tighten them up. You can now remove the two longer mounting bolts from the upper holes.



After cleaning up the seawater intake pipe with a little emery paper (600grade), lubricate with TG and slide on a new washer. Lubricate this liberally as well as the slot into which it slides and push home gently. You will recognise when it is correctly seated and can then fit the horseshoe type clamp and retaining bolt.

Like the seawater intake pipe clean the ends of the seawater linking pipe (it runs between the OC and HE) and lubricate the OC end. Follow the paragraph above. Note this is where you will need your 10mm socket and extension. Once the clamp is done up ensure the pipe hangs almost vertically rather than horizontally at this stage.

Clean up the two ends of the fresh water pipe (one goes into the freshwater circulation pump and the other the heat exchanger. Lubricate and add new washers as above. Unlike the previous water pipe connection there are no clamps to secure this pipe. Here you push the one end of the pipe into the circulation pump socket and then bring the HE into position whilst pushing the other end of the pipe into the socket of the HE. At this point temporally support the HE with one of the longer bolts in the topmost position.





Clean up the ends of the pipe that runs between the HE and exhaust elbow. Note it will probably be necessary to clean up the recess in the exhaust elbow with a small needle file to ensure all the hardened deposits are removed so that the pipe fits properly. With this done lubricate and add new washers to both ends of the pipe as well as the sockets. In this example you will need to move/rock the HE slightly whilst also ensuring the pipe sits correctly on the exhaust elbow. Pinch up the bolts slightly so it is more or less in its correct position.



With plenty of TG on the back face of the HE, rotate the seawater pipe that was hanging vertically with its new washer into position. Tighten up the two bolts that hold the clamp. Now pinch up the rear topmost bolt on the HE properly and add the two smaller lower bolts. Tighten these up also. In our case the front topmost bolt is our '-' battery connection so connect the wires and tighten this also.

All that now remains is to connect the final pipe which runs between the HE, turbo and thermostat. Clean, lubricate and add the appropriate washers. Lubricate the sockets on the HE and turbo. Push the pipe into both of these at the same time. Once home secure with the usual clamps. Note the captive penny washer that backs onto the turbo protrudes slightly even when properly fitted. We used a small washer behind the clamp to ensure that the pressure was more evenly distributed by being held off slightly.

Lubricate the rubber washer which is placed around the thermostat and the socket in the thermostat housing. Place the thermostat in its housing and invert it whilst holding the thermostat in position. Slide and lift into position whilst ensuring the coolant pipe slides into its socket properly. Bolt down the thermostat housing using the longer bolt at the front through the support arm and the shorter at the back with its washer.

That's it....just refill with oil, antifreeze and test thoroughly! Don't forget to do up the freshwater drain plug (directly below the OC in the block), the saltwater drain plug (on the connecting pipe between the OC and HE) and bleed the turbo using the brass stopper on the top front of the turbo.



If you've persevered with this article you can see that there are a lot of connection's...cooling water, seawater and oil and the chances of getting a minor leak are relatively high. With the exception of the oil connection's to the OC most can be worked slightly whilst in place so hopefully can be addressed relatively easily. If there is an oil leak at the OC however, everything has to be removed and you need to start again - sorry.

Thanks again Darthaven Marina (Mike in particular ;-)) for providing and shipping all the Volvo Penta parts and providing the recommendations on the use of TG and Marmite.

Thanks also to MarinePartsEurope.com for the extensive schematics and part numbers.