Removing Water Pump in 1982 1.6 L Diesel Vanagon

[natella2317]

Hello,

I'm currently trying to solve an overheating issue with my diesel Vanagon.
When it gets really hot the radiator fan does not engage and so the engine begins to overheat (I turn it off before it does of course).

I'm not a mechanic so any advice would be greatly appreciated.

I've done the following troubleshooting:
1. I checked that the radiator fan was functioning by connecting the fan directly to the battery. The fan works well on both low and high speeds.

2. I checked the two thermal switches (that turn on the fan at different temperatures). One was not switching on correctly, so I replaced it.

3. I noticed that while the engine was heating up, the hose leading to the radiator was staying cool. So I assumed that the radiator was plugged up. I connected one end of the radiator hose to a water hose and turned it on. At first no water was running through the radiator so I turned on the water at full blast. The water began flowing through the radiator at a steady rate. So the radiator is not plugged up.

4. Next, I removed the thermostat, connected back all the hoses and turned on the engine to check if the water would flow through the radiator. I unplugged the hose at the input to the radiator and no water was coming out. So now I'm assuming the water pump is broken, it's not able to push water up to the radiator and back.

However, the problem is I don't know how to remove the pump. I was able to remove the alternator and housing, which subsequently loosened the pump from the engine block. but I can't figure out how to remove the belt connecting the pump to the crank pulley. There's too much tension in the belt to allow me to remove the pump. The factory manual is useless for this as it only shows a diagram of the cooling system.
Can anyone help me please?

Thanks in advance for any replies.

Adam

[Captain Pike]

Disassemble the water pump pully wheel. 3 bolts, remove them, be ready for lotsa washers to fall out, Don't loose them,they are shims to ajust the belt tension.
_________________
LEARN TO SELF RESCUE
59 Panel bus, 1966 Single cab. 73' 181. 73 Westy. 91' H6 Vanagon 3.3L.
....Bad Sneakers....

[?Waldo?]

Is there a reason you think it isn't a stuck thermostat? Removal of the thermostat is the two bolts holding the flange onto the bottom of the waterpump. Be ready for lots of coolant to flow out.

Andrew

[Captain Pike]

I think he allready pulled the stat,that was my first thought as well.
_________________
LEARN TO SELF RESCUE
59 Panel bus, 1966 Single cab. 73' 181. 73 Westy. 91' H6 Vanagon 3.3L.
....Bad Sneakers....

[?Waldo?]

Ahh, right, step #4.

There are two parts to the thermostat that work simultaneously. The larger side opens to allow cold coolant from the radiator to enter the engine while simultaneously the smaller end moves to block off the bypass hose which allows hot coolant straight down from the head right back into the engine. Soo, by removing the thermostat you made it so the easiest flow path for coolant is down the bypass hose and right back into the engine. If your radiator is even partially clogged or has a pocket of air at the top, then with the thermostat removed you won't get any flow through the radiator even if the water pump is good. Your engine will overheat fairly quickly if the thermostat is removed.

As Bill W mentioned, undoing the bolts of the pulley allow the two halves to separate and the belt to be removed.

By all means check the pump out, but if it is good, then the smart money is on a plugged radiator. The diesel radiators are notoriously good at clogging. When you say that the water was flowing out of the radiator at a steady rate, what was the steady rate? Was it gushing or trickling?

I would also test the thermostat in a pan on the stove and put it back in once it's confirmed to be good and make for darn sure the system is bled properly.

Andrew

[natella2317]

Ahh, thanks for filling me in on the workings of the thermostat. I didn't know it was also blocking the bypass hose.

I tested the thermostat in hot water and it opened and closed correctly.

As for the radiator, when I ran water through it with slight pressure, the water would not flow at all. I'm thinking maybe it should have, regardless of the pressure, but then I'm not sure. But when I turned it on full blast, some crud flew out and then the water began gushing out. Maybe the pressure unclogged it. But then when I was filling the cooling system, I could not get any water to flow through the radiator, even though the expansion tank was full to the brim and the engine was running. Am I filling it incorrectly? Or maybe it is still plugged up. Maybe I'll remove the radiator and try to run very hot water through it to try to unclog it more. Is there enough clearance for me to drop the radiator without having to lift the front up?

Do you guys know the best way to bleed the system? I've checked the forums and there seem to be a debate whether or not to raise the front or the back.

Thank you again for your quick replies. I was almost ready to take it to the mechanic. I'll try out your suggestions today and let you know what happens.

[Petervw]

I was chasing down a similar "sounding' situation " a couple of years ago...I changed out the 20yr old rad and installed a new thermostat, but I still did not fix the problem... only to find out the weeping hole on the water pump would allow air into the system thus causeing it to run hot..but it did not do it all the time, so when testing it with a pressure tester for 30 min. it would prove to be OK...I plugged up the weeping hole with silicone and have not experienced any problem since...when checking the pump, the shaft had no noticable play and would turn over smoothly so there was no need to replace it

[MarkWard]

Remove the grill, raise the front of the van if you don't have an incline and open the radiator bleed valve. Keep the coolant tank full as you let the engine come up to temperature. Once you get a good stream out the bleed screw on the radiator close it. The two switches operate at different temperatures for different fan speeds. The high speed fan and switch are failover for the regular speed. If you have a cooling system presure tester you can accelerate the bleed process by pumping presure into the resevoir and forcing the coolant and air up to the radiator. Don't run without a thermostat. The smaller end of the thermostat blocks off the radiator bypass once the engine comes up to temp. Without the thermostat the coolant won't find its way up front. I also drill an 1/8 hole in the thermostat to help the bleeding process.

[Scorcho]

To remove a water pump in a 1.6 Diesel, do you need to replace the timing belt?
_________________
1963 Bus
1982 Vanagon

[Zeitgeist 13]

No, they are separate. But you should inspect the T-belt while you're in there.
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Scorcho]

Good to know, thanks! Im going to perform a little engine overhaul in the Spring so hoping I can just change the broken pump and keep it going for winter
_________________
1963 Bus
1982 Vanagon