Radiator VN v6

[Bas / NZ]

Help please I have a VN v6 3.8 in my Black Beddie, have put a new Radiator (VR ) filler cap on top, the proplem even after a short run the radiator water level drops a lot, done a pressure test no leaks, my guess it is going out through the over flow bottle? but why, this is the set up that was in the van when I got it. Going by photo's on the net there seems to be a bypass hose going back to the heater or something? Cap is 13lbs or 13 something , I am told this is correct, if I run the van a short distance and take the cap of there is pressure and the water in the radiator is full, but after cool down it's empty, aleast a litre, the over flow bottle is still at the same level. 2 things I guess might be happening, to much pressure in the radiator forceing it out through the overflow ( but no signs of this), or a leak through the radiator cap not allowing the water to return on cool down, have replaced cap and as I said pressure in the ratiator after a shot run.

Ideas Please............ Thanks

Photo's of the set up

[hotrod]

had something similar
turned out to be the water pump had gone belly up

[Bas / NZ]

Water pump new............ Thanks

[BusyKiwi]

check you have the right type of rad. cap (over flow type)

make sure your overflow bottle is vented, to check this pull the hose out of the bottle (or just sit it in) and run the engine to running temp. i had this problem, the over flow bottle was syphoning the water out

check head gasket

[Bas / NZ]

check you have the right type of rad. cap (over flow type)

make sure your overflow bottle is vented, to check this pull the hose out of the bottle (or just sit it in) and run the engine to running temp. i had this problem, the over flow bottle was syphoning the water out

check head gasket

Thanks, will check it out tomorrow, had the overflow pipe just sitting in an old bottle and it still did the same, not sure if this bottle is vented, came out of the Camper, worked fine in there, Head gasket, hope not, no signs of this oil clear etc, type of cap, ok, thought there was only one type?

[John Abbott]

Baz i have 2 vps and one vn commy. All of them have 2 hoses going to the overflow tank.Now i have read on one of the commy forums that the vn series motor has a low pressure system and the later serieis vp-vr-vs has the high pressure system. I will duck out tomorrow and have a look at my old vn and see if i can spot any differences between mine and yours. cheers....johnno

[matty]

just a thought is the new cap seating correctly on the top lip of the radiator. if its not sealed it will suck air back instead of water.

 

[Bas / NZ]

Baz i have 2 vps and one vn commy. All of them have 2 hoses going to the overflow tank.Now i have read on one of the commy forums that the vn series motor has a low pressure system and the later serieis vp-vr-vs has the high pressure system. I will duck out tomorrow and have a look at my old vn and see if i can spot any differences between mine and yours. cheers....johnno

Thanks, that would be great. The VN radiator does not have a cap on it must be filled from the reservoir bottle that has the cap on it?

PICS BELOW
1 / VN
2/ VP

[Bas / NZ]

just a thought is the new cap seating correctly on the top lip of the radiator. if its not sealed it will suck air back instead of water.

 

Yes it is sitting well, had the same thought, but if I take it off after a little run there is alot of pressure in there, so the cap must be sealing right.

[BusyKiwi]

take it to mechanic and get test done (colour test), that will check if any co2 in the water from blown head gasket