Draining volvo 2000 series

[RIBW]

........ if that is the case what is the point of having a thermostat. My understanding is that water flows over the head to cool the exhaust until the engine gets warm. Then the stat opens and allows water to circulate around the block.

Hi again, When first faced with owning a 2003 engine I had heard about overheating problems so I did a pretty thorough search of previous postings on the subject and as many VP (and other) manuals as seemed directly relevant. As I said earlier, I found the documentation pretty ambiguous so wrote myself a precis of what I thought happened (apologies for any plagiarism of Wotayottie, Reeac and others). My summary follows - I'd welcome corrections!
Cheers
Bob
"Two streams of water are required in all raw-water cooled engines, one to effect cooling, regulated by the thermostat, the other, known as the bypass, flowing at all times to cool the exhaust system. On the VP2003 the branch occurs inside the cylinder head.
The raw water is pumped into the front of the cylinder head and continues into a perforated brass tube in the head. At the back of the engine this tube is connected to the exhaust manifold by a copper pipe with three right-angle bends. This path provides a continuous supply of water to the exhaust mixing elbow to cool the exhaust gases. Until the thermostat opens (theoretically at 60ºC), all the water from the pump flows through the brass tube in the cylinder head and into the exhaust manifold.

At 60ºC, the thermostat opens and some of the cooling water passes into the engine and, using the perforations in the bypass pipe, through the channels in the engine and exiting through the thermostat into the horizontal tube along the top of the engine, passing via the calorifier take-off to the exhaust mixing elbow. Note that the calorifier may take a while to achieve an adequate temperature because a raw water engine thermostat is set much lower than that of a fresh water cooled engine."

 

[KREW2]

Like yourself the cooling system has always baffled me as to how it flows.
My understanding now is that water gets into the block before the thermostat opens.
Once open, some of it is now allowed to flow back from the exhaust elbow, via the pipe on the top and go back entering the cylinder head at the point from where it entered the cooling system from the pump.

 

[Dipper]

I use a round flexible file about 6" long. It's blocked every year but after a good poke, plenty of water comes out.

 

[PabloPicasso]

I use a round flexible file about 6" long. It's blocked every year but after a good poke, plenty of water comes out.

I tried for ages the day before yesterday, to clear the blocked drain tap with various thicknesses of sharpened wire. But no joy. I didn't want to risk attempting to remove the drain itself, although the nipple unscrewed easily.

Is the drain a straight run up from the bleed valve inside the engine block, or does it turn or angle in a different direction?

 

[RichardS]

I tried for ages the day before yesterday, to clear the blocked drain tap with various thicknesses of sharpened wire. But no joy. I didn't want to risk attempting to remove the drain itself, although the nipple unscrewed easily.

Is the drain a straight run up from the bleed valve inside the engine block, or does it turn or angle in a different direction?

If you can unscrew the entire drain fitting I would do that. On my Yanmars the plug at the end of the fitting has a conical taper type of seal which leaves a hole only a few mm across. If you unscrew the fitting from the block you leave a drain hole about a cm across which really blasts out any crud very easily, particlularly if you get the engine hot and then unscrew it whilst it still under pressure .... but no so hot that you scald yourself!

Richard

 

[Len Ingalls]

Some photos,etc to show location of drain spigot under starter motor. Hope they help. Merry Christmas!View attachment 55216

Guess I'm only allowed one image.

You can see the drain spigot in this pic of a stripped block. The complete assembly can be removed with a deep socket.

 

[Dipper]

I tried for ages the day before yesterday, to clear the blocked drain tap with various thicknesses of sharpened wire. But no joy. I didn't want to risk attempting to remove the drain itself, although the nipple unscrewed easily.

Is the drain a straight run up from the bleed valve inside the engine block, or does it turn or angle in a different direction?

Sometimes I remove the drain plug as well as the nipple. It seems a straight run through. The rough edges of the file helps to remove crud and enlarge the hole. I don't actually file the sides, just remove the deposits. If I forget to bring the file then a screwdriver does the job.

 

[PabloPicasso]

Sometimes I remove the drain plug as well as the nipple. It seems a straight run through. The rough edges of the file helps to remove crud and enlarge the hole. I don't actually file the sides, just remove the deposits. If I forget to bring the file then a screwdriver does the job.

How easy is it to remove the drain plug from the block? I was a bit worried as, after applying a release spray, I was using a lot of force and was worried I might strip the thread

 

[RichardS]

How easy is it to remove the drain plug from the block? I was a bit worried as, after applying a release spray, I was using a lot of force and was worried I might strip the thread

If it's not moving I would first suggest getting the engine hot and using a coat-hanger wire whilst the coolant is hot and under pressure. Wear a glove or something in case it clears suddenly.

Richard

 

[Dipper]

How easy is it to remove the drain plug from the block? I was a bit worried as, after applying a release spray, I was using a lot of force and was worried I might strip the thread

Mine came out with the bleed nipple one year. You shouldn't need to remove it. I don't think it makes it any easier. Maybe you just need a better 'poker'. If it is well clogged, you need something that will drag the debris out. Maybe a long drill bit held in your fingers that you can turn by hand to cut its way through. Don't get it stuck up there though!

 

[PabloPicasso]

Mine came out with the bleed nipple one year. You shouldn't need to remove it. I don't think it makes it any easier. Maybe you just need a better 'poker'. If it is well clogged, you need something that will drag the debris out. Maybe a long drill bit held in your fingers that you can turn by hand to cut its way through. Don't get it stuck up there though!

Hmmm. Yes a drill bit sounds like a good idea. I'll give it a go.