Ford 7840 blowing water out

[JDF]

For the past couple of weeks my 7840 has been throwing the water out the radiator, doesn't happen on light jobs or roadwork but the second I hook the mower up I get 2 headland passes & it starts throwing it out.

It's full with antifreeze, radiators blown out, I removed the thermostat last night, the temp gauge never says it overheating only starts coming out at 5-6 bars.

I'm guessing the next step will be the water pump? Is there any way to rule that out?

 

[AlCapone]

Have you tried new radiator cap

 

[JDF]

Have you tried new radiator cap

Nope I haven't tried a new cap yet, I will try & get hold of one & see if that fixes it

 

[Lincs Lass]

Maybe the radiator needs a flush out or you have blocked cores in the block

 

[bobk]

For the past couple of weeks my 7840 has been throwing the water out the radiator, doesn't happen on light jobs or roadwork but the second I hook the mower up I get 2 headland passes & it starts throwing it out.

It's full with antifreeze, radiators blown out, I removed the thermostat last night, the temp gauge never says it overheating only starts coming out at 5-6 bars.

I'm guessing the next step will be the water pump? Is there any way to rule that out?

Is it getting hot

 

[Skintagain]

For the past couple of weeks my 7840 has been throwing the water out the radiator, doesn't happen on light jobs or roadwork but the second I hook the mower up I get 2 headland passes & it starts throwing it out.

It's full with antifreeze, radiators blown out, I removed the thermostat last night, the temp gauge never says it overheating only starts coming out at 5-6 bars.

I'm guessing the next step will be the water pump? Is there any way to rule that out?

They should run very hot before blowing water out is it getting hot as in the water boiling? Has anything been changed recently?

 

[Webster8340]

Could be your radiator. It should have the inbuilt expansion tank on top. There's a rubber diafram inside that separates the radiator from the tank. They can split at the edges, and stop the cooling system pressurising properly, and loose coolant up through and out the overflow before she even up to temp.
There might be an easier way, but to test mine I had the radiator off and tipped upside down, then plugged the top hose outlet, left the radiator cap on, and undid the expansion tank cap. If you pour water in through the bottom hose and it comes out the expansion tank, then its probably the diafram.

 

[Boomerang]

Have you tried new radiator cap

Mine was throwing coolant out of over flow when warm, new rad cap sorted it .
Went from 7psi to 13psi one.

 

[Flatlander]

For the past couple of weeks my 7840 has been throwing the water out the radiator, doesn't happen on light jobs or roadwork but the second I hook the mower up I get 2 headland passes & it starts throwing it out.

It's full with antifreeze, radiators blown out, I removed the thermostat last night, the temp gauge never says it overheating only starts coming out at 5-6 bars.

I'm guessing the next step will be the water pump? Is there any way to rule that out?

Unless the impeller has sheared off inside it’s unlikey the water pump. Check to see if there are small bubbles in the coolant by looking in the rad with the cap off. Could be your head gasket starting to let go Or a cracked liner assuming it a wet liner. If no bubbles pull the lower rad hose off and up the hose pipe in the top and see if the flow going thru is restricted.

 

[forblue]

For the past couple of weeks my 7840 has been throwing the water out the radiator, doesn't happen on light jobs or roadwork but the second I hook the mower up I get 2 headland passes & it starts throwing it out.

It's full with antifreeze, radiators blown out, I removed the thermostat last night, the temp gauge never says it overheating only starts coming out at 5-6 bars.

I'm guessing the next step will be the water pump? Is there any way to rule that out?

Removing the thermostat is worse thing possible the way the cooling system works on these engines now means your engine is not getting any lower temp coolant, fit new thermostat.

 

[Ffermer Bach]

I would guess head gasket on the way out

 

[Happy hillbily]

Get yourself one of these to start with, will show any cold/hot spots on the rad

I had a 4600 that I thought the head gasket had gone, ended up being a blocked radiator on the outside. Looked clean but once I took it off couldn't see a torch shining through, took over an hour with a pressurewasher to get it clean. The infared thermometer would have saved me a lot of time diagnosing the problem.

 

[Skintagain]

Get yourself one of these to start with, will show any cold/hot spots on the radView attachment 1120460
I had a 4600 that I thought the head gasket had gone, ended up being a blocked radiator on the outside. Looked clean but once I took it off couldn't see a torch shining through, took over an hour with a pressurewasher to get it clean. The infared thermometer would have saved me a lot of time diagnosing the problem.

I think clogged radiators cause more problems than enough. If I have bucket down on loader tractor she will cook very easy if I don’t lift it up a bit On Road

 

[JDF]

They should run very hot before blowing water out is it getting hot as in the water boiling? Has anything been changed recently?

Is it getting hot

It's not running hot according to the temperature guage, it's about 6 bars.

I've ordered a new thermostat & new rad cap to try. Looks like the water pump isn't the problem I can see it the small bubbles inside the radiator. Il take the rad put & try a proper clean rather than just blowing it out with air.

If that doesn't fix it then head gasket on its way?

 

[bobk]

It's not running hot according to the temperature guage, it's about 6 bars.

I've ordered a new thermostat & new rad cap to try. Looks like the water pump isn't the problem I can see it the small bubbles inside the radiator. Il take the rad put & try a proper clean rather than just blowing it out with air.

If that doesn't fix it then head gasket on its way?

6 bars isn't great

 

[JDF]

6 bars isn't great

I've never taken too much notice to be honest but I think it used to run around 3 or 4 on average.

Now it's at 6 bars but that's flat out with mower conditionner on the back, I'm not sure what it used to be when mowing

 

[Happy hillbily]

It's not running hot according to the temperature guage, it's about 6 bars.

I've ordered a new thermostat & new rad cap to try. Looks like the water pump isn't the problem I can see it the small bubbles inside the radiator. Il take the rad put & try a proper clean rather than just blowing it out with air.

If that doesn't fix it then head gasket on its way?

Before you start ripping the head off there is also test kit available to see if there are combustion gasses in the cooling system.
This is one of the first pages that came up on a Google search https://www.drheadgasket.co.uk/COMB...TER-COMBUSTION-LEAK-DETECTOR-DR-HEADGASKET-UK

 

[Ffermer Bach]

I think clogged radiators cause more problems than enough. If I have bucket down on loader tractor she will cook very easy if I don’t lift it up a bit On Road

I will agree, a lot of rads are blocked and need blowing out to clean the fins

 

[Skintagain]

It's not running hot according to the temperature guage, it's about 6 bars.

I've ordered a new thermostat & new rad cap to try. Looks like the water pump isn't the problem I can see it the small bubbles inside the radiator. Il take the rad put & try a proper clean rather than just blowing it out with air.

If that doesn't fix it then head gasket on its way?

Is she turboed?

 

[agrimax]

I can see it the small bubbles inside the radiator

Head gasket required.