Water loss from cooling system - 1997 Volvo 850

If your Hyundai H1 2018 model is losing water from the radiator at an alarming rate, even with a new radiator that is not leaking, there are a few potential causes for this issue:

1. Coolant leak: While you mentioned that the radiator is not leaking, there could still be a coolant leak elsewhere in the cooling system. Check for any visible signs of coolant leakage, such as puddles under the vehicle or wet spots on hoses, connections, or the engine. Coolant leaks can occur at various points, including hoses, water pump, heater core, or even the engine block itself. If you cannot identify any external leaks, it is possible that the leak is internal, such as a blown head gasket or a cracked engine block.
2. Faulty radiator cap: The radiator cap plays a crucial role in maintaining the proper pressure and preventing coolant loss. A faulty radiator cap can cause coolant to escape from the system. Inspect the radiator cap for any signs of damage, such as a worn-out gasket or a cracked cap. If necessary, replace the radiator cap with a new one and see if it resolves the issue.
3. Internal engine issue: Internal engine problems, such as a blown head gasket or a cracked engine block, can cause coolant to mix with the combustion chamber or leak into the oil system. This can result in rapid coolant loss without any visible external leaks. Look for symptoms such as white exhaust smoke, coolant in the oil (appearing as a milky substance on the oil dipstick), or an overheating engine. If you suspect an internal engine issue, it is recommended to have the vehicle inspected by a qualified mechanic to diagnose and address the problem.
4. Improper coolant filling or air pockets: If the coolant was not properly filled or if there are air pockets in the cooling system, it can cause coolant loss. Air pockets can prevent the proper circulation of coolant and result in overheating and coolant loss. In such cases, bleeding the cooling system to remove air pockets and ensuring the coolant level is at the correct level may resolve the issue.

Given the significance of the coolant loss and the potential complexity of the underlying problem, it is advisable to have your Hyundai H1 2018 model inspected and diagnosed by a qualified mechanic or Hyundai service center. They will have the expertise and necessary diagnostic equipment to identify the specific cause of the coolant loss and provide the appropriate repairs or solutions.

Are the cooling fans coming on ? Go under the hood in the engine compartment , with the vehicle running have some one turn on the A/C , do you see and or hear the cooling fans come on ? Could be the coolant temperature gauge is bad ! How many miles on the vehicle ? Ever have water pump replaced ?

1

Check for a loss of system pressure.
Is there a loss of system pressure?
--
Go to Step 2 yes
Go to Step 3 no

2

Inspect and repair any faulty hose connections.
Does the engine still overheat?
--
Go to Step 3 yes
System OK

3

Check for low coolant protection (-37?°C/-34?°F).
Is there low coolant protection (-37?°C/-34?°F)?
--
Go to Step 4 yes
Go to Step 5 no

4

Test solution. Replace the coolant if necessary.
Does the engine still overheat?
--
Go to Step 5 yes
System OK

5

Check the water pump belt for low tension.
Is the water pump belt tension too low?
--
Go to Step 6 yes
Go to Step 7 no

6

Replace the water pump belt tensioner.
Does the engine still overheat?
--
Go to Step 7 yes
System OK

7

Check for an inoperative thermostat bypass.
Is the thermostat bypass inoperative?
--
Go to Step 8 yes
Go to Step 9 no

8

Replace the bypass.
Does the engine still overheat?
--
Go to Step 9 yes
System OK

9

Check the water pump.
Is the water pump inoperative?
--
Go to Step 10 yes
Go to Step 11 no

10

Replace the water pump.
Does the engine still overheat?
--
Go to Step 11 yes
System OK

11

Check the radiator fins for obstruction.
Are the radiator fins obstructed?
--
Go to Step 12 yes
Go to Step 13 no

12

Inspect and clean the radiator fans.
Does the engine still overheat?
--
Go to Step 13 yes
System OK

13

Check the cooling system passage for obstruction.
Is the cooling system passage blocked?
--
Go to Step 14 yes
Go to Step 15 no

14

Inspect and flush the system. Reroute or replace the hose if necessary.
Does the engine still overheat?
--
Go to Step 15 yes
System OK

15

Check the water pump belt for damage.
Is the water pump belt damaged?
--
Go to Step 16 yes
Go to Step 17 no

16

Replace the water pump belt.
Does the engine still overheat?
--
Go to step 17 yes
System OK

17

Check the cooling fans.
Are the cooling fans inoperative?
--
Go to Step 18 yes
Go to Step 19 no

18

1. Inspect the electrical connector. Replace if necessary.
2. Does the engine still overheat?

--
Go to Step 19 yes
System OK

19

Check the throttle body circuit flow.
Is the throttle body circuit flow restricted?
--
Go to Step 20
Go to Step 21

20

1. Inspect the orifice and associated hose. Replace if necessary.
2. Does the engine still overheat?

--
Go to Step 21
System OK

21

Check for a stuck thermostat.
Is the thermostat stuck in the closed position?
--
Go to Step 22
--

22

Replace the thermostat.
Does the engine still overheat?
--
--
System OK

one way to bleed out of a cooling system is to
open the heater control
ensure that the engine is cool,
loosen off the highest coolant hose ( normally a heater hose
run the engine so that coolant is circulated
when all air is out tighten the hose clamp
keep water loss to a minimum by only having the loose hose drip

White smoke is usually a sign that there is a problem with the cooling system. Blue smoke is fuel related.
Have the cooling system checked at a guess I would say this is water leaking into the cylinders which indicates a cylinder head gasket fault. A faulty cylinder head gasket would also cause slight loss of compression which could explain the loss of power. remove the oil filler cap on the engine if there is a sign of a light brown (cream) coloured substance (water contaminated oil) on the cap or in the cover then the head gasket needs replacing also check the dipstick.
Hope this helps.

If you mean coolant loss, then you need to pressure test the cooling system to see where it's leaking from.

I assume you have checked the cooling system to ensure that first, that it is completely full of coolant (not just the overflow tank) with no air locks and second that there are no leaks and the radiator cap is in good condition. The heater hoses and those pesky little bypass hoses in the cooling system tend to go hard and split if they are over 10 years old, allowing coolant loss. Those spring type hose clamps tend to be less effective in clamping as the hoses become hard. Worm drive ones are the best to use.

If there are no leaks or air locks, the over heating could also be caused by a clogged radiator (more than 15% restriction in the radiator flow capacity will cause overheating problems), a faulty water pump or a faulty thermostat.

If there are no leaks but undetected loss of coolant, then it could indicate a problem with the head gasket (Usually caused by allowing engine to become excessively overheated when cooling system has run dry) allowing high pressure combustion gases into the engine water jacket, which super heats the coolant which then boils off, and is released via the cap.

If unsure take vehicle to cooling system specialist and have them do a pressure test and more thorough diagnosis.

I assume you have checked the cooling system to ensure that first that it is full of coolant and second that there are no leaks and the radiator cap is in good condition. The heater hoses and those pesky little bypass hoses in the cooling system tend to go hard and split if they are over 10 years old, allowing coolant loss. If there are no leaks or air locks, the over heating could also be caused by a clogged radiator (more than 15% restriction in the radiator flow capacity will cause overheating problems), a faulty water pump or as you suspect, a faulty thermostat.
If there are no leaks but undetected loss of coolant, then it could indicate a problem with the head gasket (Usually caused by allowing engine to become excessively overheated when cooling system has run dry) allowing high pressure combustion gases into the engine water jacket, which super heats the coolant which then boils off, and is released via the cap.
If unsure take vehicle to cooling system specialist and have them do a pressure test and more thorough diagnosis.

may be the water pump, a cooling system pressure check to pin point the leak

It sounds to me like the serpetine belt broke, DO NOT continue to drive it. The water pump (for engine cooling), the power steering pump, and the alternator (electrical system) are no longer operating. Have it towed to a shop or have someone put a new belt on it.

possible blown head gasket and head repairs is in order.
combustion is leaking into cooling system
can do a few checks
T.K. head check
remove spark plugs when engine is warm with cooling system under pressure (radiator pressure tester)
leave for 10-20 minutes inspect for pressure loss
if so pressurise system and crank over with plugs removed and check for water (mist) commong out of cylinders