Anybody converted a VP 2002 from fresh water to raw water cooling?

[scottie]

Like yourself, I am a long term owner (16 years).

Just a thought, you are probably aware that their is a copper pipe going through the block where water always passes irrespective of the coolant temperature.

Any blockage is liable to be in the engine galleries circuits which then lead to the thermostat and then into the exhaust elbow. I found it essential that the thermostat must be taken out when using brick cleaner to have any effect on the blockage.

I found it easier just to take out the thermostat and cover , then pour the liquid in directly into the engine galleries. It is very comforting to see and hear all the fizz. Also, the drain plug is on the left hand side of the engine as you look at it, and you may have to shove a small screwdriver up there to let all the crud out. Mine is always blocked.

Apologies. Just realised that you have a VP2002 . I have a VP2001. Things might be arranged differently.

As an aside, I have always been led to believe that these engines were designed to be raw water cooled right from the start which is unusual. They therefore were designed much thicker in the waterways department than the usual engines which are converted for marine use. Can anyone confirm this ? .

Yes and when supplied via a dealer the dealer had to convert them except for 2003T
A conversion kit was supplied as an accessory and was cheaper than the heat exchanger or water pump on their own

 

[DaveS]

Hi Dave

Take a look at this link - http://www.ybw.com/forums/showthread.php?354841-Volvo-2000-series-Raw-water-cooling

PVB posted a very helpful plan of the cooling system of a 2002.

With regard to the amount of mixture to get up to the thermostat, it depends if you plug the ends of the copper tube through the block . I found it easier to disconnect fore and aft of the tube and place wooden bungs. I reckon I then filled up with about a pint and a half of liquid. That was for a VP2001.

The bungs arranged so that they leak a bit will tell you that the two 3mm drillings in the copper tube are now completely clear. These feed the galleries. Remember to take out the anode of the metal bung then replace before fizzing. After about 10 minutes the fizzing stopped and I started flushing with clean water. I don't know if you should leave it any longer but this has worked for me. Keep flushing until clear water from the drain plug.

With regard to the two 3mm drillings in the tube I have no idea how they really work. I can only guess that there is some kind of suction or venturi effect from the exhaust elbow that sucks the coolant through via the thermostat.

Best of luck

Thanks again. As before, most helpful. Only 10 minutes till fizzing stops? Wow! Was this with the engine hot or cold?

I take your point about partially bunging the ends of the copper tube to confirm that at least one of the small holes (I think the 2002 has 4) is clear, but that does mean a bit more dismantling. My initial thought was to leave the pipework alone (other than the thermostat and cap) and just fill it up to almost thermostat level (leaving some room for frothing) and, with the input hose full of water and the exit hose going upwards to the exhaust bend, the acid solution should be trapped. I had intended to take out the zinc anode, but if exposure to acid is as little as 10 minutes, maybe that's less critical?

Like others, I'm not sure I completely understand the circulation system: I'll have a think about it again when I have the thermostat and cover off and try to work out exactly what the opening thermostat actually does.