Volvo 2003 Heat Exchanger

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Cspirit

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I have just taken this apart in order to remove the impeller blades that were shed from the seawater pump (don't ask). However, when I (eventually) got it back together, with no leaks, I now have a new problem in that the engine overheat alarm starts to buzz after about 20 minutes or so running at 2,000 revs. Slowing to about 1700 revs shuts off the alarm. I did not have this problem before I removed and took apart the heat exchanger, so I'm wondering if I have reassembled it incorrectly. Does anyone have a diagram or can assist in determining the correct orientation of the end cap? Of course, the problem many lie elsewhere - perhaps a blockage somewhere in the cooling system, fresh or sea water. It's not the thermostat (replaced) or the seawater pump (brand new). Any suggestions gratefully received. Bob
 
It's a 2003 non turbo. Gwylan - yes that is the one I have but the diagram does not indicate how the end plate with the two in- and out- seawater pipes should be oriented. There are at least two possible positions for this end plate and depending upon which is selected, the water flow will be different.
 
Cspirit said:
It's a 2003 non turbo. Gwylan - yes that is the one I have but the diagram does not indicate how the end plate with the two in- and out- seawater pipes should be oriented. There are at least two possible positions for this end plate and depending upon which is selected, the water flow will be different.
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Shouldn't make any difference, the seawater flows along the pipe stack to the other end, then back to the outlet pipe. If you install the end plate 180 degrees out, the same thing will happen.
 
This may not be relevant but I had a very confusing overheat problem which after many investigations turned out to be the impeller on the circulation pump slipping on its spindle under load. An IR temperature sensor from maplin was really useful in tracking thr site of the problem.
 
I have a 2003 , water cooled with this heat exchanger. I was warned before first taking it apart that it was important to align the end cover (which accepts the raw water pipes) correctly. So I marked small scoreline on the cover and body to ensure alignment.

IIRC, the raw water passes through the exchanger in 4 separate passes from one end to the other, and if the end cover with connects to the raw water is not orientated correctly, these 4 separate passes may not occur, but maybe only 2 of the 4

So - simple answer may be yes - you may have incorrectly assembled the exchanger!
 
West Coast said:
I have a 2003 , water cooled with this heat exchanger. I was warned before first taking it apart that it was important to align the end cover (which accepts the raw water pipes) correctly. So I marked small scoreline on the cover and body to ensure alignment.

IIRC, the raw water passes through the exchanger in 4 separate passes from one end to the other, and if the end cover with connects to the raw water is not orientated correctly, these 4 separate passes may not occur, but maybe only 2 of the 4

So - simple answer may be yes - you may have incorrectly assembled the exchanger!
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I think the 2003T exchanger is a multi-pass design, but didn't think the 2003 version was.
 
pvb said:
I think the 2003T exchanger is a multi-pass design, but didn't think the 2003 version was.
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It is, well certainly the one I have from year 1993 is - there are baffles which seperate the 4 sets of passages and so direct the water at each end of the exchanger - I was trying to find some photos to illustrate this but failed so far.....
 
West Coast said:
It is, well certainly the one I have from year 1993 is - there are baffles which seperate the 4 sets of passages and so direct the water at each end of the exchanger - I was trying to find some photos to illustrate this but failed so far.....
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As the forward end plate's orientation is fixed, presumably then there's a chance of getting the aft end plate out by 90 degrees?
 
pvb said:
As the forward end plate's orientation is fixed, presumably then there's a chance of getting the aft end plate out by 90 degrees?
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Yes, I think that must be right. I have serviced this same HE a few years before and apparently reassembled it correctly since I had no problems. Sadly I did not do as I should have done, and as previously noted, marked the case and end cap to ensure correct reassembly......
 
pvb said:
As the forward end plate's orientation is fixed, presumably then there's a chance of getting the aft end plate out by 90 degrees?
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No - the aft plate is just a plain plate and gasket, so orientation is not an issue. But orientation it is critical with the forward plate, so the ports for the raw water line up with their correct quadrants.
 
West Coast said:
No - the aft plate is just a plain plate and gasket, so orientation is not an issue. But orientation it is critical with the forward plate, so the ports for the raw water line up with their correct quadrants.
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If that's the case, it can't do 4 passes as you suggested.
 
West Coast said:
No - the aft plate is just a plain plate and gasket, so orientation is not an issue. But orientation it is critical with the forward plate, so the ports for the raw water line up with their correct quadrants.
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Yes I'm sure that you are correct. My problem is knowing which is the correct orientation since none of the exploded diagrams show this.
 
pvb said:
If that's the case, it can't do 4 passes as you suggested.
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Ah, but it can.

At the forward end, the exchanger has two baffle plates - the first right across the diameter from the 3 to the 9 o'clock position and a second from the 6 o'clock position to the centre of the first baffle plate. At the aft end, there is a single baffle, running across the diameter from the 12 to the 6 o'clock position.

So - if all set up correctly, water enters the exchanger and moves aft along the 6 - 9 o'clock quadrant, is then returned forward along the 9 - 12 quadrant, then aft along the 12 - 3 quadrant then forward along the 3 - 6 quadrant.
 
Cspirit said:
Yes I'm sure that you are correct. My problem is knowing which is the correct orientation since none of the exploded diagrams show this.
Click to expand...

Agreed - it is not clear at all from VP diagrams that I have seen.

However, because of the other ports in the heat exchanger body for the FW circuit, and the VP fancy pipework arrangements, it is fairly easy to get the general orientation correct. What is important is when aligning the forward cover plate, make sure the raw water ports are aligned with the two 90 degree quadrants formed by the baffles on the forward end of the exchanger body. With the front cover removed, I would score a line on the exchanger body in line with each the baffle plates. Then, when the front cover is fitted and you are setting the alignment before tightening the clamp bolt, you can make sure the raw water ports are within their quadrants.
 
West Coast said:
Agreed - it is not clear at all from VP diagrams that I have seen.

However, because of the other ports in the heat exchanger body for the FW circuit, and the VP fancy pipework arrangements, it is fairly easy to get the general orientation correct. What is important is when aligning the forward cover plate, make sure the raw water ports are aligned with the two 90 degree quadrants formed by the baffles on the forward end of the exchanger body. With the front cover removed, I would score a line on the exchanger body in line with each the baffle plates. Then, when the front cover is fitted and you are setting the alignment before tightening the clamp bolt, you can make sure the raw water ports are within their quadrants.
Click to expand...

Many thanks West Coast -that is exactly what I need.
 
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