- Location
- South east
Get hold of the fan and give it s shack back and forth if it is loss the water pump has had it
DB 990 getting hot, but radiator is cold?
- Thread starter JacobJ
- Start date
Oliveau
Member
- Location
- Indre et Loire, France
Old Daisy Browns don’t have what you call a ‘top tank’
The rad cap just sits in top of the rad and it’s designed to maintain pressure in the rad ( so that it doesn’t boil over) What the OP is describing is consistent with a defective rad cap.. Probably it would be a good idea to dump the thermostat as well.
OK, the top of the rad might not have a tank, but that just means it is somewhere else.
When the water expands it needs somewhere to go.
Netherfield
Member
- Location
- West Yorkshire
Is the bottom hose hot or cold?
Skintagain
Member
- Location
- Perched on the Pennines
Where’s are you located?
Boohoo
Member
- Location
- Newtownabbey
Has it had a new gauge or sender recently?
- Location
- America's dairyland
It's a vertical radiator, so it has a top tank, and that tank is bigger than the bottom tank to give some room for expansion. Since there is no expansion tank, the top is not meant to be filled up full. The tractor should run fine with a rag stuffed in the radiator opening and not lose coolant. If you fill it right to the top, it will run over even with a perfect radiator cap as there is no expansion room.
If the engine is running on water, then it should be boiling when you shut it off and it's overheated. If it's not boiling, then check the engine temp to make sure it's hot enough to open the thermostat.
That is good news I'd say, as it's likely to be a basic problem.
Is water circulating? sounds like it can't be.
Go back to basics...
thermostat?
fan belt?
water pump function?
My money is on thermostat...throw it over the hedge.
Little squeak
Member
- Location
- Lancashire
When the water pump has gone in the past on my 990 it has always leaked, I have had trouble in the past with overheating cleaned the outside of the radiator with no joy took the radiator off and left water running through it still didn't fix it, took it off AGAIN this time ran water through with the hose pipe with the radiator up side down left it running for an hour and its been OK since. If you want to test the sender just unscrew it from the engine and put in a cup of boilng water.
Oliveau
Member
- Location
- Indre et Loire, France
You forget that with DB 990’s they are old technology - no newer than 1980.
when the water expands it goes through the overflow pipe from the filler neck and vents on the ground.
Only if you completely fill up the tank on the top of the rad when you fill the rad.
I always do this, they just vent the excess water and find the correct level themselves, which leaves an expansion zone at the top of the rad.
Normally, when I have drained and filled an engine's water it is because it needs some maintenance. Part of the procedure is checking the water levels after it has been run. This also ensures there is no vacuum, as the water cools and shrinks.
I posted to try and help with the overheating issue. I did not think it necessary to make any distinction between types of expansion vessel.
Is this about something else?
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Okay a short update. Stress testet the tractor yesterday without the thermostat. It went hot again. I took my laser therometer and took some readings. Top engine block was 91 degress, thermostat housing 87 degress. Radiator close to the top (under the expansion part of it) 12 degress.
So I think there is still to much resistance in the radiator, does that sound right?
I also noticed some troubling thing. See attachment. It doesnt smell like diesel, so it might be water. Is that a problem with the head gasket?
So I think there is still to much resistance in the radiator, does that sound right?
I also noticed some troubling thing. See attachment. It doesnt smell like diesel, so it might be water. Is that a problem with the head gasket?
Attachments
It must be diesel either injector leaking or injector washer at the bottom. If water it will dry up instantly with a hot engine I think, but I’m not a David Brown expert
Oliveau
Member
- Location
- Indre et Loire, France
Exfarmer
Member
- Location
- Bury St Edmunds
sure you need a new water pump
the fluid leakage is probably as OP said injector washer. May even be that you have 2 in there which will always cause issues
- Location
- Scottish Highlands
Is the radiator core blocked? You may say this is unlikely but I've recently changed the radiator on my MF 135 which probably has the same technology. The core of the radiator was very seriously blocked and nothing would shift it. Similar symptoms to the OP's tractor, I think. All sand here which in a hot summer will blow and drift and block roads, let alone radiators if air filters are not up to scratch! It gets everywhere.
I had repeated failed head gaskets in a Peugeot 504 many years ago and got used to the symptoms. Just take the rad cap off and rev the engine. The water in the rad would look 'disturbed' as steam rose in the radiator causing agitation. I saw that several times as the genius who kept replacing the head gaskets had not measured or replaced the head bolts. In use, they become fatigued and stretch and will no longer take a torque. Changed the bolts and the problem was fixed.
I see Oliveau beat me to it!
I had repeated failed head gaskets in a Peugeot 504 many years ago and got used to the symptoms. Just take the rad cap off and rev the engine. The water in the rad would look 'disturbed' as steam rose in the radiator causing agitation. I saw that several times as the genius who kept replacing the head gaskets had not measured or replaced the head bolts. In use, they become fatigued and stretch and will no longer take a torque. Changed the bolts and the problem was fixed.
I see Oliveau beat me to it!
You‘ve said previously that you took the the thermostat out and cranked over the engine and water shot out? In my admittedly limited experience that doesn’t sound right, what I’ve seen is you just see a “swirling” of water at the top of the radiator.
The fact it does shoot out that suggests some sort of back pressure perhaps caused by blockage in the radiator, I’ve previously used caustic soda to clean my system - Google caustic soda cleaning of radiators for loads of info - BUT if your radiator is heavily blocked you might not get a circulating flow through the radiator. it really might be best to take off the rad and see what happens if you stick a water hose in at the top and if it flows freely from the bottom.
You could also check the pump at the same time, I’m still not convinced it’s not part of the problem.
The fact it does shoot out that suggests some sort of back pressure perhaps caused by blockage in the radiator, I’ve previously used caustic soda to clean my system - Google caustic soda cleaning of radiators for loads of info - BUT if your radiator is heavily blocked you might not get a circulating flow through the radiator. it really might be best to take off the rad and see what happens if you stick a water hose in at the top and if it flows freely from the bottom.
You could also check the pump at the same time, I’m still not convinced it’s not part of the problem.
Tiny little baby steps Jacob
With engine running, and thermostat out, have you taken off the radiator cap and looked to see if water is gushing from top hose into rad.
If it isn't, water pump isn't pumping water.
Is fan belt tight enough to spin pump? (fan going round when engine's running indicates)
If it spins but don't pump, sounds like a bollixed pump.
'resistance' in rad would be several steps along the line yet.
To clearify. When I did that, I had the thermostat out and not fitted the top hose back on again, so there was free above the pump. Therefore I think the pump is ok.