shimmy

I have a 92 runner with 3vze I recently purchased. My problem is that when the heater valve is open I hear gurgling through the core. It sounds like trying to suck cola through a broken straw.

I tried purging any air out of the system and flushing the heater core, nothing but clean water came out. I thought I found the problem after that, the heater core valve had a broken plastic nipple, so I replaced that, still the same problem.

Of course it could be a leak in the head gasket, but I'm not seeing any distinct symptoms of this. No gook under the oil cap, no water in the oil, the coolant is fresh and green with no oil in it and I can't smell exhaust in it, no gook around the tail pipe and it doesn't smoke or overheat. In fact it takes it excessively long to warm up it seems, so I may try to replace the thermostat. It starts right up and runs fine, and once warmed up to operating temperature the tranny shifts flawlessly into overdrive.

1000 miles before I bought the truck, the timing belt, upper seals and water pump was replaced. The shop did not note any found problems with the head gaskets, but stated the radiator needed replacing, which the previous owner did himself.

Any ideas? Its driving me crazy. I figure that maybe I would pressure test the cooling system to see if there is a pin leak letting air get in next and go from there. Has anybody experienced this problem after burping and flushing the heater core? Any help or ideas is appreciated.

justin_4runner

park on a hill or the front up in the air, it more then likely air is in the system and not all bleed out, mine does this only when its air in the system. also when u said u flushed the heater core did u flush it backwards or operation direction?

shimmy

I tried parking it on an incline, maybe it wasn't steep enough, and I flushed the core both ways, nothing but clean water, I even tried filling up the core from the core hose, no luck. The heat and everything works just great, front and back heaters, I'm just at a loss here. Thanks for the input.

btu44

Probably not a free fix but this may help?

MudHippy

Yeah...probably not. Since it's a 92.

shimmy

Thanks for the thought BTU44, but like MudHippy said it is a 92'.
It just seems I may have a very small leak in a hose somewhere. My next step is to pressurize the system and see if I can find anything, and I will be replacing the thermostat and cap as well just for good measure since the truck is also taking too long to warm up to operating temps. Hopefully I will find something when I pressurize the system, it does have some very old hoses. The main hoses are new and the radiator, but the heater hoses look to me to be all original, probably wouldn't hurt to replace them either way. Any other advice is much appreciated. Thanks.

RBX

I have the same issue in my 88. When I got the truck however, the PO had added someone of stop leak junk in the system and I think it has clogged part of my heater core. I have also flushed the system in both directions until clean. After purging the system all was good for about a year, but the sound is back again. I'm about to do my head gasket so I will flush it again and purge the system of air better. I have a spare heater core incase it is clogged with stop-leak junk.

shimmy

Thanks for the input. I bought this runner from the original owner and I went back and asked him about that, if had ever put any stop leak into anything, he said he didn't at all and never would have. I have no reason not to believe the guy, he did take immaculate care of this truck, but then again who knows.

I'm hoping its not a head gasket problem, but haven't completely ruled it out yet either. Though its showing none of the telltale signs of this, it could still be. I'm going to rule out any leaks in the cooling system first before I buy the test to stick in the radiator and see if I have exhaust fumes in the cooling system.

The coolant is perfectly clean though, no exhaust smell at all or oil, no water in the oil, no smoke, no gunk under the oil cap, no gunk at the exhaust tip, never overheats even a bit. So it continues to baffle me for now, I should be able to pressure test the cooling system this weekend.

ALLDATAdiy INFO

How is your Coolant Recovery tank setup? ALLDATAdiy suggests that the air is to be bled from the Coolant Recovery Tank.

MudHippy

There's no way for air to become trapped in the coolant reservoir tank. The cap has a passage(hole) in it to vent air, or coolant should it become "overfull" with either. Not to mention the fact that where the rim of cap itself closes against the tank isn't a completely air/watertight seal in most cases. Because, for obvious reasons, it's not required to be(since it's never supposed to be full of enough coolant that it needs to be). And the fact that THERE'S SUPPOSED TO BE SOME AIR IN IT!!!!

Bleed the coolant recovery tank? Seriously? What kind of fool do you take me for?

93toyrunner2

I had the exact same noise in my heater core. The problem was air in the cooling system. Unable to get all the air out, I removed the thermostat, refilled the system, bleed air out, and the noise was gone. I drove it this way for 2000 miles, no issues, no overheating. I then put in an aftermarket thermostat with a hole drilled in to to vent out the air, hole at 12 on the clock position. Filled the system, drove it for 1 week, and the cooling system would get to over 3/4 on the gauge before the temp came back down. Not good for the 3VZE, especially when without the thermostat, it never went above 1/2 way on the gauge. I removed the aftermarket thermostat, installed a Toyota thermostat with the jiggle valve at the top, bleed the system, and no more air, no more heater noise, temp range perfect.

shimmy

Thanks for the advice. I've been thinking along those lines. Another problem I'm having is that the runner takes a really long time to get to operating temperature, but it will after like 15-20 minutes, so it won't shift into OD until it gets there, I've been suspecting a faulty stat, and was just going to replace it with an aftermarket one, but after reading as much as I can on the issue, I'm going with your advice and buying one from Toyota. Thanks, when I get it squared I will let everyone know what the problem ending up being.

shimmy

So I went and bought the OEM thermo from Toyota, cost 40 bucks with the gasket and tax. Replaced that and at least one of my problems is solved. The aftermarket stat that was in there had to be stuck open, and it was installed with the jiggle valve at 3 oclock as well. The new stat lets the truck warm up very fast, it was taking 15-20 minutes before it would and would run rich the whole time, now it warms up in 3-5 minutes and runs great, and will shift into OD as soon as its warm.
I still have a bit of air gurgling through my heater core, its much better than it was, but I figure I just need to bleed the system better. I need to get it on a steep hill I think, My property is flat so I can't do it here.
Does anybody know if I put it on ramps if that will be high enough to get that pesky last bit of air out? Thanks

justin_4runner

yeah getting the front on some ramps should help do it,

shimmy

Just an update to where I'm at here with this. I'm still having the slightest gurgle through the heater core. It seems to be one of those problems where nothing is totally clear as to why.

So far I've burped the system, flushed the heater core which was perfectly clean both ways, replaced the heater control valve which had a broken nipple, replaced the thermostat with a Toyota OEM, and also found the runner had the wrong pressure radiator cap and replaced that with a Toyota one as well.

Still have some air in there somewhere, but it is much better than it was. I can't seem to get it out, so I'm moving on to the next steps. Going to first put a block tester on it later today and see one way or the other if I have a leak in the head gasket, although I don't have any other obvious symptoms at all, it still could be a very small leak and I just want to find out one way or the other at this point. If that test shows nothing I will then pressurize the cooling system and see if I have a pin leak somewhere. After that I'm out of ideas.

So hopefully after today I will know more.

shimmy

I put the Napa block tester in the radiator, the fluid stayed perfectly blue, so no combustion gasses present, which is a relief, however I still have air gurgling through the core and no answers.

It did improve much after replacing the stat, but still just a little, so maybe I'm just not getting it all burped, I dunno. I'm hoping to pressurize the cooling system over the weekend to see if that shows me anything, its testing my patience a bit because nothing is obvious at all, one of those type of pains in the butt.

shimmy

I'm officially out of answers on this gurgle. I can't figure it out. I've replaced the heater control valve, t-stat, cap, block tested for combustion gasses, pressurized the cooling system, its holding pressure fine, I even flushed the whole system and put new coolant in it. I've burped the bitch until I'm blue in the face and the facking gurgle will not go away. I'm not losing coolant either, the heaters both work great.
I'm out of ideas. Can a partially clogged heater core cause swooshing, gurgling? The last thought I had is that the nipple on the inlet of the heater control valve was broken off, and I'm not sure I recovered the broken piece, or all of it, I'm wondering if that is jammed in on of the tubes of the heater core? The gurgle happens on acceleration and stops after 2000 rpms or so. If you sit there and rev the engine it will do it, if you rev again quickly after dropping to idle it will not, it has to sit at idle for 10-15 seconds before it will do it all over again. I was thinking that maybe that little chunk of plastic is stuck in the core, under pressure on acceleration it may be pushed to the side, then floats back when back at idle long enough. Damn if I know, I'm grasping at straws here really, but since everything is working just fine there is no way I'm going to pull out the core just to have that not work either, nothing is working!
Anybody got any other ideas?

RBX

I know for a fact I have junk in my core from th PO putting a sealant in the coolant. Mine makes the same noise, so I turn up the tunes!

Richard

mine makes the same noise at idle , also heat from the vents starts to blow cold till I get the rpms above idle 11-1200 rpms

jdamore

Mine is gurgling also, I just had a new engine put in a couple months ago ..so new therm. coolant and all. My Heater doesn't blow hot until over 2k rpm's also... So last weekend i went to put in an amp and lifted passenger side carpet... SOAKED with coolant.. So right now I've got most of the dash ripped apart heading towards the core.. ..I had the same symptoms.. so watch out!