Is it okay to drive with no coolant in the upper radiator hose?

The fact that your engine is overheating isn’t the only clue that your radiator hose is leaking. Fluid leaks on your driveway or garage floor are some symptoms of a broken or damaged radiator hose.

If you see green or orange fluid, it suggests your coolant is leaking, and you should look for cracks or wear in the radiator pipe. A broken water pump might potentially leak coolant, so make sure it isn’t leaking.

How far can you drive a car with no coolant?

When you have to start your car without coolant, it should be able to run for approximately a minute without causing too much harm.

Based on the engine, car model, and how hard you’re forcing the machine to work, you might be able to get away with up to 5 minutes of running without coolant.

However, that is not a good idea. Even with those very brief runtimes, your car is still at risk of severe and perhaps dangerous internal damage.

Why is the top radiator hose hot & the bottom cold in my honda?

The thermostat is frequently, but not always, located near the top radiator pipe. After the thermostat is opened, the top hose becomes hot in either case. A chilly lower radiator hose often accompanies a blocked or defective radiator.

The radiator may need to be replaced, but it may also be emptied, cleansed, and a new coolant installed in some circumstances. When the top radiator hose becomes hot before the engine thoroughly warms up, the thermostat is not properly shutting or is always open. The thermostat is blocked if it does not become hot at all.

It would be better to change the thermostat promptly in both circumstances.

Why is my car’s upper radiator hose not hot but bottom cold?

The lack of heat in the lower radiator might be due to insufficient coolant in the engine: Upper and lower hoses transport coolant into and out of the radiator.

As a result, the lower radiator hose heats up. It’s possible that your automobile may run out of coolant and will be unable to reach the bottom radiator. As a result, cold air is emitted from the bottom hose.

Water leaks are the most typical problem that causes this difficulty. These leaks can be traced to several locations. As a result, double-check the upper and lower hoses for any damage. The lower radiator hose will not heat up adequately if there is a leak.

A defective thermostat, a damaged water pump, or a low coolant level are typical causes of a chilly lower radiator hose. Airlocks or a blocked coolant system might also cause it.

Is the bottom radiator hose supposed to be hot?

Always keep the lower radiator hose colder than the higher radiator hose. The top line carries hot coolant from the engine to the radiator, while the lower hose has coolant back into the machine.

It’s conceivable that the coolant isn’t flowing properly through the heater core or that the air from the blower isn’t reaching its destination. As a result of the heater core difficulties, the lower radiator cannot execute its duty.

As a result, make sure the heater core is in excellent functioning order. If your heater isn’t working correctly, you may also use auto maintenance techniques to determine what signs your car is sending you.

It is also possible that your car’s thermostat gauge is faulty or malfunctioning. Perhaps you may be aware that if the thermostat fails to notify the car that the engine is hot, the coolant will not flow to the heater, and the air will remain chilly.

Consequently, coolant will not reach the bottom radiator and will only produce cool air.

Why is my top radiator hose hot and bottom cold?

In most cases, a chilly lower hose will only appear when the automobile is initially started with a cold engine.

Coolant flow will commence after the engine has warmed up (approximately 5 miles in the summer) and heat the upper hose and radiator.

The coolant will lose most heat to the outside air while traveling through the radiator. However, that isn’t all of it. As a result, the lower house will also become heated, although not nearly as much as the top hose.

Overheating can be caused by a variety of factors. The primary function of the radiator is to transmit heat generated by the engine to the outside air.

The engine pumps coolant through the radiator when operating to accomplish this. The top hose brings hot coolant from the engine into the radiator.

Why is my bottom radiator hose hot?

Sometimes there is no problem with a chilly lower radiator hose! The engine must be scorching and practically overheated before the thermostat allows the coolant to pass.

When your car isn’t overheating, but the lower coolant line feels chilly to the touch, it’s possible that it’s not hot enough and that your engine is refined. The coolant system may become blocked in rare instances. This is not a regular occurrence because the primary coolant pipes are large.

Nevertheless, if your automobile was previously driven without coolant and only with water, it is possible that the engine developed a lot of rust.

 Thus, a failing head gasket might result in a large amount of coolant system muck. If you’ve exhausted all other options, cleanse the coolant system.

Why does my radiator hose have no pressure?

A damaged hose does not cause this symptom. If you can squeeze a radiator hose, it suggests there isn’t enough pressure in the cooling system, although this might signify a problem. Cooling systems are made to withstand pressure.

This boosts the coolant’s boiling point, allowing it to operate at temperatures higher than 212 degrees Fahrenheit.

These symptoms point to the possibility that the thermostat is stuck open. Once you drive for a short distance, a jammed available thermostat will let the engine overheat.

In fact, pressure in the cooling system varies for various reasons, and you might just be squeezing the hose at a moment when there isn’t any.  An infrared thermometer is the best way to check a motor’s actual temperature. You can get one reasonably from your local car parts store.

Should my upper radiator hose be challenging when the engine is warm?

Because of a faulty head gasket or fissures, hard hoses might indicate cylinder pressure entering the cooling system.

Although the hoses are supposed to harden as the engine warms up, you ought to be able to squeeze them, specifically after a quick journey in which the automobile achieved operating temperature.

If the hoses are hard before you reach working temperature, you have a cooling system failure.

How to fix the radiator hot at the top and cold at the bottom?

Did you realize that one or both of your radiators has a chilly bottom? This is frequently the consequence of a clog or sludge build-up.

Blockages can cause leaks and other problems. Therefore it’s preferable to solve the situation as quickly as possible. Fortunately, it’s a simple remedy, so you might be able to do it quickly.

Follow the steps below to carry out an easy fix:

  • Turn off the Thermostat.
  • Cover the radiator with sheets.
  • Any valves should be shut down.
  • The radiator should be bled and drained
  • Re-start the heater.

Make sure that your thermostat radiator valves are turned on. After that, go around your house and feel all of the radiators. Examine the top and bottom for any chilly places.

When your radiators aren’t working, you’ll notice that a room in your house is freezing, even if your thermostat is set to the highest.


For your vehicle to function effectively, you need the coolant system, cause the coolant circulates through your car and extracts heat from various features. In fact, keeping their operating temperature within normal parameters is very paramount.

Don’t forget that without COOLANT, there’s nothing to take away this heat and these parts quickly overheat and break down.

Sincerely speaking, the less coolant you have in the engine, the faster it will help heat up. Also, if you make use of water instead of instead of anti-freeze mix, there is every possibility that the engine will take longer to heat up, as water has much higher specific heat.

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