Jay351

Ever since I got my truck the coolant would make a small noise.

Here is how it would go down:

-Get into my truck, start it.
-Idle for 5 mins or so
-start to drive and thats when it would start

for about a second or two it would sound like rushing water, I just always assumed it was the thermo opening and the coolant doing its job.

But latley its been getting louder and almost to the point that its screeching.
No my hg is not blown, and I do not have any leaks.

I jacked up the front of the truck, took off the rad cap and ran it till it was warmed up. Some coolant came out as the system built pressure but otherwise not many bubbles came out.

Any thoughts? I just want to make sure my cooling system is in tip top shape for the summer.

thanks guys.

Noltz

I've heard the exact same sound from time to time in my '91 Runner. Same 3.0 too, but not in the last 6 months or so. My '97 Runner (3.4) did it once too. And when I worked at a Toyota dealership, there were a few vehicles that made that same noise. While I never really investigated it my theory went that if I can hear coolant moving, then there must be air in the system. How it got there, I don't know. Pinhole leak in the heater core, allowing the coolant to drain back down? Never saw any coolant at my airbox drain hose but...? A HG would be a common issue (3VZE especially) but I've had no overheating issues. A water pump seal could be allowing air in via the weep hole but not letting coolant out too.

If it is as noisy as you say, I would start by replacing the coolant. If it persists, I would bypass the heater core for a night and see if the noise is eliminated. If so, suspect the heater core does indeed have a pinhole leak and is allowing air to enter your cooling system. If the sound remains you'll have to get under the hood with a stethoscope and try to locate it manually.

rowdy235

does it do it if the heater control is set all the way to cool?

longhungsilver

do u hear this noise inside the cab? or only under the hood?

TOYOTA 1

i here that same noise inside the cab of my 91 22re, i think its water rushing threw the heater core

CoedNaked

I only hear the noise on start up until the truck is warm and I begin driving (the intial "Rush" of water), I'm assuming until the system pressurizes from being heated and I don't hear the sound after the truck warms up.

4Run_95

I do also have this sound. Started after i had a coolant leak, so i would say air or dirt.

toyotalytrevor

a cooling system builds pressure, if there was a pinhole leak, coolant would be getting out , not air geting in.

toyotatom93

I have heard the same sound on my truck...I think I have a HG issue tho, as coolant leaks but I never see it, must be leaking into the exaust or something I figure.

Jay351

I usually keep my heater set on hot (but off) so im not sure if that will make a difference, I will try that tomorrow morning.

The coolant is not very old at all, but I do have to replace my radiator soon so I suppose a coolant change would be a good idea.

Well, kind of an update. I drove it this morning, the noise has quieted down quite a lot. I can almost bearly hear it. I think it was just air in the system. I don't want to count my chickens before the hatch, but im pretty sure air was the problem.

I will burp the system again soon, hopfally that will get the remainding air out.

Thanks for all the help and suggestions guys, I will report back when I drive it tomorrow morning when its cold.

crowley84

Jay351,

I have a similar situation but I have a 22re with a slight coolant leak from one of the small hoses underneath the intake. When I start it up in the morning, if i slide the heater control from cold to hot, I hear a slight water "gurgle/rush" from the heater core. I've bled the system but I assume that I have air getting in the system from the small leak. I don't have a head gasket issue and once the truck is warmed up - no noise.

just a 22re

yeah i have this well i HAD this same sound wanna know how i fixed it????????????? its easy and free!!!!

just a 22re

ha h athough i wasnt going to post it aye? sorry i needed a laugh but yeah under your hood theres a little switch on the coolanyt line that goes to the core just cut or take the cable off of it and move it so no coolant goes though then it stopped for me might more you to

Switchtr3

I've heard this noise in a supra I used to have as well as an old Subaru. Both had bad headgaskets. Might be a coincidence, I'm not sure how true it is but I've heard from other people that that waterfall noise is common with bad HG's. I'd do a compression check if i was you just to be safe, it can't hurt to check

nate V

on my last engine 3.0 the sound began and ot louder unilt i replaced the engine. it was due to a bad HG. It is shurly leeking somewhere.

if your so sure that its not a HG than you have air in there for some other reason.

CoedNaked

I think it's time for a 3.4 swap.

rowdy235

You do realize that completely disables the heater? That cable actually runs to the HOT-COLD control on the dash and is used to move that very valve. Thats right, all you did was basically move the HOT-COLD control to Cold for good. And while that does eliminate the gurgling in the cab, you could still have air in the system which is bad. I would not recommend ever doing anything like that.

Jay351

Im bumping this topic back up. After a delightfull romp offroad last weekend the noise is back. Almost as bad as it was before. If I switch the heater to cold I hear nothing.

So I take it I got air in the system again.

Sound like a heatercore problem? I would rather not take my whole dash apart.

rowdy235

When you set the heater control to cold it closes the valve going to the heater core, so its obviously got something to do with it. Personally I think there is air in the heater core, and you need to get it out.

Noltz

Check your drain hose from the heater box too see if there's coolant dripping from it. The only other thought would be a bad head gasket, with cylinder pressure forcing air into your cooling system. A hydrocarbon test on your coolant will show if this is the case. A shop can do this for you, or if it's a bad leak an AC sniffer would be able to detect it.

Assuming the worst, you can start searching for a 3.0 to rebuild yourself or a 3.4 to swap in. It is not worth buying a rebuilt 3.0, IMO.