# Liquid Swishing Noise from Under Hood?!?!



## desalad (Apr 25, 2005)

Hey All, I have a 99.5 Pathfinder SE Limited. Recently I have been hearing a liquid swishing noise from the front of the car when turning the vehicle. Yesterday, I opened up the hood, with the engine running, and looked around. I noticed in the front of the engine bay, the coolant reservoir was TOTALLY EMPTY!! When I shut the engine off, with the hood still open, I heard the swishing again. 

My wife usually drives this vehicle, and I'm curious as to why the coolant reservoir was empty, there have been no puddles in the driveway.

Would someone here offer some advice as to what to do? What kind of engine coolant should I use to refill the reservoir? Might there be a larger problem I should have checked out?

Thanks in advance.

Scott


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## Animal (Mar 25, 2005)

When did you last check the coolant level? It is normal for the level to drop over time due to evaporation. If it is dropping relatively fast, you may have a small hole or crack in a hose which only leaks when the engine is hot. Another possibility is a blown head gasket, where the coolant is going out the exhaust. 
With the engine off and cold, remove the radiator cap and check the coolant in the radiator. If you don't see any, you may have been running the engine extemely hot (this can cause problems such as warping the head or blowing the gasket). The noise you hear may be what coolant remains being converted to steam. 
There are two major types of coolant, which can be determined by the color (green or orange) and a less common yellow. You should add the same type of coolant as what is already in use or drain and replace with the type of your choice.


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## desalad (Apr 25, 2005)

Thanks Animal. I took a closer look today, using a flashlight this time to look into the reservoir and into the radiator. It turns out that there is indeed coolant in the reservoir, its just about an 1/8 - 1/4 inch below the minimum level. There is also coolant in the radiator, not up to the cap, but cover the heatsinks.

Any idea what that swishing noise might be, if there is coolant in the tank? The engine temperature has been normal, no CEL, its just a little strange.


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## charlie_one (Aug 18, 2005)

Ill got a similar noice in my -88, but it was only a little air in the coolant system, and ill just jacked the car up really high in the front an filled up the radiator, started the car and filled a little bit more, and the the noice stopped.


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## Animal (Mar 25, 2005)

desalad said:


> Thanks Animal. I took a closer look today, using a flashlight this time to look into the reservoir and into the radiator. It turns out that there is indeed coolant in the reservoir, its just about an 1/8 - 1/4 inch below the minimum level. There is also coolant in the radiator, not up to the cap, but cover the heatsinks.
> 
> Any idea what that swishing noise might be, if there is coolant in the tank? The engine temperature has been normal, no CEL, its just a little strange.


Odd that it is not up to the cap in the radiator. Though if it is only a bit below the neck, that may be from the hoses expanding when you removed the cap and relieved the vacuum (the supply and return hoses do tend to collapse a bit as it cools). 
Now back to the noise. I've heard swishing from a half full gas tank, but never from the coolant - perhaps that is due to my less than perfect hearing - though I have heard coolant systems gurgle. Try to isolate the noise to an area (front or back of engine, left or right). It doesn't appear to be a serious problem. I wouldn't worry too much over it.


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## Redwood (Jul 10, 2005)

*air bleeding*

On the V-6, look for the air relief plug on the intake manifold near the throttle cables. Its just a short bolt, takes a 10mm ? wrench. Open it when filling the radiator, and you'll get the air out of the engine. Your owners manual will also give you a procedure to follow along these lines. It can take a couple of heat up /cool down cycles to get the reservoir level to settle out. Remember when heating up to have the heater control set to hot while the engine is on, leave it there, then shut off the engine. Good luck.
Redwood


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## desalad (Apr 25, 2005)

Animal said:


> Odd that it is not up to the cap in the radiator.


It is not just below the neck, looking in, it just covers the coils inside the radiator, so its a couple inches low...



Animal said:


> Try to isolate the noise to an area (front or back of engine, left or right).


It is definitely in the front, coming from the radiator. When I was investigating the other day, I opened the hood with the engine running. I then shut off the engine so I could take a closer look. As soon as I shut off the engine, I heard the swishing coming directly from the radiator area in the front of the engine bay.



Animal said:


> On the V-6, look for the air relief plug on the intake manifold near the throttle cables. Its just a short bolt, takes a 10mm ? wrench. Open it when filling the radiator, and you'll get the air out of the engine. Your owners manual will also give you a procedure to follow along these lines. It can take a couple of heat up /cool down cycles to get the reservoir level to settle out. Remember when heating up to have the heater control set to hot while the engine is on, leave it there, then shut off the engine. Good luck.


Thanks, I may give this a try. I think I will fill up the reservoir to Max and fill the radiator first, and see how that helps. Thanks a lot for your feedback!


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## Animal (Mar 25, 2005)

desalad said:


> It is not just below the neck, looking in, it just covers the coils inside the radiator, so its a couple inches low...
> 
> It is definitely in the front, coming from the radiator. When I was investigating the other day, I opened the hood with the engine running. I then shut off the engine so I could take a closer look. As soon as I shut off the engine, I heard the swishing coming directly from the radiator area in the front of the engine bay.
> 
> Thanks, I may give this a try. I think I will fill up the reservoir to Max and fill the radiator first, and see how that helps. Thanks a lot for your feedback!


The sound is probably the air bubbling up through the radiator. You may also have a leak in the overflow tube or the top seal on the cap which is preventing the fluid to be drawn from the reservoir and is drawing in air instead.


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