Interior fluid/liquid 'sounds' behind instrument panel . . . thoughts?

Hey, folks.

I did a search and only found one thread from Dec '18 that went undiagnosed. So starting a new one for help.

My '97 4Runner emits fluid 'gurgling' sounds from behind the center/top of the instrument panel. Here are the facts:

- Sound only during partial/full heat setting on temp

- Heat DOES work, and works WELL
- No leakage inside footwells, or outside car
- Happens only on acceleration
- AC works fine - VERY cold
- NO overheating issues

3.4L V6
5-Speed
SR5
214,000 miles

Other than that, all good. Any thoughts?

TIA,

Matt​

 

Not sure guessing coolant line passing somewhere behind there? If there's gurgling perhaps air in the system?? Sorry not much help.

 

Sounds like you need to burp the cooling system

 

My work truck does this as well, as does all the other junk chevy trucks we drive, I think it’s just coolant moving in a line or something that runs back there... it’s very annoying that’s for sure...

 

Burp? Can u explain the procedure?

 

I've never done it my self, basically the idea is that there is air trapped in the system. So somehow you have to "burp it" to get the air out. I think a flush will do the trick?

 

I don't know about the Toyota but I had a Land Rover that started doing that when the head gasket slowly started to fail.

 

I don't think I've ever heard of that making an water sound. Perhaps different engine designs?

 

One way to burp cooling system (admittedly it’s old school so there may be some newer technology related quirks I wouldn’t know about).

1. For safety, make sure engine is cold.

2. Temporarily remove thermostat and bolt the empty thermostat housing back in place (this will allow full coolant flow with cold engine).

3. Make sure heater temperature select is set at hot (full flow through heater core).

4. Open radiator cap (not coolant recovery tank) and make sure radiator is full (water is fine).

5. Leave the radiator cap off and start engine and let it idle for a minute. Water level may drop a little.

6. Run engine at fast idle (whatever RPM you’ve heard the gurgling noise at) for a minute or two at the most (you really don’t need nor want the engine to warm up).

7. Check the radiator coolant level and top off with water if needed.

8. Repeat steps 6 and 7 until you don’t need to add any more water. This process shouldn’t take more than a couple of minutes. Turn the engine off before the coolant gets too warm. Note: As engine and coolant warms up, thermal expansion will cause water to eventually start coming out of the radiator (if the cap had been on, this expansion water would have gone into the coolant recovery tank).

At this point any air in your cooling system should have been purged.

9. Unbolt the thermostat housing and replace the thermostat. You should probably replace the o-ring or gasket. The coil spring end of the thermostat goes towards the engine block.

10. If you had put quite a bit of water in the radiator, you may want to drain some out and replace it with coolant.

 

If you had to add quite a bit of water (see previous post), then coolant is getting out somewhere and air is getting sucked in through the coolant recovery tank when the engine cools to replace the missing coolant.

Go down to the local parts place that loans tools, and borrow a cooling system pressure tester (the “borrow” is that you buy the tool then they give you your money back when you return it).

Following the directions on the tester, pressurize the system to the PSI that your radiator cap is rated for, and let it sit for a half hour or so. The pressure should remain the same. If it drops, try pumping it up again. If it still drops, you’ve got a leak somewhere.

From https://mechanics.stackexchange.com/posts/17396/edit

“There are a lot of Quick methods to check the Head Gasket.

- Coolant leaking externally from bellow the exhaust manifold
- White smoke from the exhaust pipe
- Overheating engine
- Bubbles in the radiator or coolant overflow tank
- White milky oil
- Significant loss of coolant with no visible leaks”

 

I don't have an older 4R to see the location of the thermostat but doesn't this defeat the purpose if you need to change the thermostat and lose coolant again?

If it helps any my 99 Camry had this same noise on start up. Ended up being the head bolts which caused the head gasket to fail.

Sound would go away after refilling but would return on next start up after it lost some coolant.

Edit
Yeah pointless to remove thermostat then loose the coolant all over the floor and introduce air back into the system. Just get it up to temp so the thermostat opens.

Those no spill funnels work wonders.

 

Getting air in the upper hose while removing/replacing the thermostat is no big deal. The hose will fill back up when when water is first put in before the engine is first fired up. If the thermostat is left in, it will stay closed for the most part once the engine reaches operating temperature. With the thermostat out, the water cam flow at a high enough volume to flush air out of passages and into the top of the radiator.

 

I always get it up to temp anyways.

Put the spill free funnel in and go have a couple. 10x less work.

 

In most cases, unless the vehicle is actually driving with some kind of load, the engine isn’t generating enough heat for the thermostat to open very far. You’ll see coolant flowing in the radiator, but there won’t be velocity to move air out of the block and into the radiator. I guess maybe blocking the radiator air flow with a piece of cloth or cardboard could eventually allow the engine to get hot enough for the thermostat to open all the way.

 

Never had a problem or low coolant using the funnel. Let it run take it for a drive cool it down and check and top off.

 

Way too simple Dillusion. I studied at the Rube Goldberg School of Doing Things. The more complex you can make it, the greater the WOW factor. :0)