95yoyo

Hi all first post here... anyways I have a 95 pickup 22re 4x4 that I've been having coolant puking issues lately. Started off about a week ago with a surging idle and temp gauge climbing high. I changed thermostat, new hoses, fresh coolant and a new cap just because. Well the that thermostat was junk so I swapped it out for a superstat thermostat. Temperature was good but started puking coolant out the overflow tank. So I did some research and I swapped out the auto part store cap for a factory Toyota cap. All is well for a couple of days until this morning 🤬. I get a few miles from home and it starts the funny idle, temp gauge is climbing up fast so I pull over and shut it off. Coolant has been puked out again but radiator is barely warm. I let it sit for about 15mins and drive it back home and it runs perfectly fine 🤷‍♂️.

Any suggestions on what to do would be greatly appreciated!

Timing chain, head gaskets, water pump and radiator has been replaced probably 10-15k miles ago.

maxvp01

It's possible your fan clutch is bad (attached to the front of your water pump).

Symptoms of this would be stopped at a light your temp will start to overheat, but once you start going down the road it will cool down slightly

This was the problem with my buddy's 01 dodge Dakota, his hasn't seemed to burp coolant out the overflow since we changed it and it no longer overheats.

Jimkola

First thing I'd do is block test it. The chain parts stores have one in their loaner tools.

95yoyo

I feel the fan clutch is good because itll run all day idling without overheating issues.

I called the Toyota dealer and they had a thermostat in stock so I went and picked it up and swapped them out. There is a pretty big difference between the two thermostats. Its running right now as I type this completely normal. Very hot heat so maybe with fingers crossed that this is the culprit.

95yoyo

Update, first run around town was flawless! 🤞 ran for about an hour. The overflow tank didnt fill up and heat was super hot.

2ToyGuy

Toyotas had a small difficulty with the original thermostat Toyota used. The temp would go pretty high before the thermostat would open, It's the way the system's designed. The bypass that feeds the heater core returns to before the thermostat, so it is constantly feeding cool water onto the back of the thermo, keeping it closed until the water temp from the engine it's self get's up high enough.
Toyota fixed the problem with what's called a two stage thermostat. It looks like a regular thermostat, but with a little "sub-thermostat" on the flange. This opens at a cooler temp than the main part, allowing the engine water through in enough volume to keep the temp from going high, before the main part opens up.

If you had a single stage thermo in, the system would go high before it can open, especially in a hot environment. I used to live in Yuma, Az, so I'm very familiar. Naturally, when it goes high, yes it will dump more out into the recovery tank. If you had the recovery tank pretty full before you started, yeah, it would dump overboard. The normal fill line is just over 1/3 of the way up the tank, allowing plenty of room for expansion during warmup.

Another thing to look for is to make very sure the system is "burped" properly after you work on it. I, personally, just park on a steep incline, namely my driveway, with the radiator cap loose, heater temp set to full on, and run the truck until I'm certain it's good and hot. Hot enough I'm sure the oil is warmed up as well as the rest of it. With it nose high, it makes sure the radiator cap is the high-point in the system, making any air in the system go there, and out. Once it's cooled back down, I add any water needed back into the radiator, dill the recovery tank to the line, and away I go.

BYW, when you use the Toyota red coolant, make sure you only use distilled water, if you need to mix it. 50/50 is the best over-all, all around ratio. Having said that, in a constantly hot environment, like Yuma, going to a 60/40 water, or even 70/30 water, will cool better. Just make sure there's enough coolant to keep the boiling point up. If you're someplace that is hot in the summer, but cold in the winter, stick to 50/50 mix.
Of course, if you get premixed, it's a moot point.

I hope something in here is slightly helpful, anyway...
Pat☺

95yoyo

Very good information! Gonna keep a check on for a few days but I feel pretty confident about it now. Thanks for the replies!

RAD4Runner

We have a thread on the two-stage thermostat on the forum, with part numbers.

Lesson learnt this past couple of weeks for me: Whenever you drain, change coolant or disturb the cooling system, burp it.
Here's my burping setup: Gallon jug with just right size mouth sealed against radiator opening with wetsuit material and held down with cord so I'm free to do other things. Make sure you have estimate to put enough coolant in jug because it will get sucked into radiator when thermostat opens.
Part 1 while coolant still cold and thermostat closed.

Part 2 When thermostat opened (I bare caught it.) Watch how air bubbled up then some of the coolant got sucked into the cooling system.

95yoyo

Truck is still acting right however I believe I need to burp it again. I have a gurgling noise coming from the dash area especially when cold. 🤦‍♂️ never have I had this much trouble out of a cooling system.

cgeorge

Yeah, you need to get all of the air out or you'll hear air going through your heater core. I change my coolant about every 18 months and it is a process to get all of the air out. The instructions that Pat gave above will do the trick. I bought this and it also works well:

2ToyGuy

Yup! "Gurgling" from the heater core, IE behind the dash someplace, is a sure sign of air in the system.
If you can, park it on a fairly steep hill, nose high. Ramps work well too. Pull the front wheels on the ramps, so the radiator is the highest point in the system. Pull the radiator cap, just loose, not off, so that any overflow while warming up will go to the recovery tank, hopefully .
Let it run from dead cold to fully warm. It can take a while, due to the bypass allowing some cooling whether the thermostat is open or not. Let it run 15 min at least, with the temp control for the heater full hot, to allow the water easy, high volume flow through the heater core.
With it set up this way, the temp gauge may get pretty high. Keep an eye on it, and if you think it's going to go too high, IE above the white arc on the gauge, turn the heater control to full cold. It will allow the hot water to get to the thermostat, opening it. You can check the flow through the radiator by simply touching it. If it's hot, the water is flowing through an open thermostat. If it's cold, the thermostat isn't open, yet. Be careful, the radiator can get pretty hot. Be very cautious.
Once you get good flow through the radiator, set the heater control back to full hot to get any air OUT of the heater system. The temp gauge may go up a little from where it sits with the heater set to cold, but not a lot, and will eventually settle down.
Shut it down, and once it's good and cold again, say 1/2 hour or so, open the radiator cap, and see if the water in the radiator is down below the filler neck. It probably will be. Top it up, make sure the recovery tank is only as full as it should be.
Something that may help as well is a "water wetter". It lowers the surface tension of the water, to allow any trapped air to break loose and come out into the system. Most auto parts stores, like Autozone or whatever, carry the stuff. It's a cheap addition to the water to make sure it's touching every possible part of the engine water should be touching. It prevents air from getting trapped in small corners that exist in every engine. It was a big help in mine, anyway.

Good luck to you. This can be a frustrating problem, but if you just persevere, you can get it taken care of.
Pat☺

95yoyo

Ok this is officially driving me insane. Cranked truck up with front end as high as I could get it, loosened cap with heat wide open. Everything was going good then it starts to do the surging idle thing, no heat and I could watch the temp gauge climb. I shut it off, radiator and hoses are still cold to the touch. So I fire it back up and temp gauge goes down immediately and heat starts working again. So I let it run for probably 25-30 mins with heat wide open and it does perfectly fine. What am I missing here? Suggestions would be greatly appreciated.

Oh and just a few minutes ago I drove it up the road and still have the gurgling noises 🤦‍♂️

2ToyGuy

I don't KNOW that the surging idle is related to the cooling system, but I could well be wrong. That's often related to the o-ring on the idle speed adjustment screw on the Throttle Body. Screw it all the way in, and count the turns as you do. 2 1/4, 3 1/2, whatever. Best to replace it, but anyway, check it for any damage, nicks, cuts, brittleness, anything. You can get new o-rings at most auto parts stores, just match up size, and slide the new on, making sure it's seated in the correct location on the screw. Screw it down to the stop again, then back out to where it was originally.
BTW, if the idle is too high, when you apply the brakes, the ECM cuts the fuel to the injectors, and once the idle gets down below the proper RPMs, it allows fuel again, then when the RPMs climb, cuts the fuel, etc etc. See the possible trouble going on here?
Idle RPM should be about 800, or so, with the truck warmed up all the way, brakes off.

Anywho, on to the cooling system, again. Did the temperature gauge go above the white arc on the gauge, or did it just start to climb? Remember, especially with the heater full hot, the single stage thermostats allow the temp to climb up pretty high before they open. When you shut it down for a bit, the hot water sat on the thermostat long enough for it to open, then when you started it up, the water flowed through the radiator correctly, allowing the engine to cool down.

Did you try shutting the heat down, IE setting it back to full cold, while the engine was running, and watching the gauge? Did it make the gauge drop again, or stay high? Bear in mind, it takes a second for the thermostat to pop and allow the cool water in the radiator to flow. It can go through a number of cycles of warm, cool, warm cool, as the thermostat "hunts" for balance between how open it should be, and how warm the engine is running. It can be kinda stressful, thinking the engine is about to overheat, with all the attendant problems that entails. Only really worry if, and only if, the gauge goes up and touches the red. THEN shut it down, and let it cool off.

If you want, try letting the engine warm up with the heater set to full cold, then, once the thermostat has popped and settled down to a specific temperature, radiator and it's hoses nice and hot, turn the heater to full hot, to allow the air out.

Also, did you feel the heater return hose coming out of the firewall while the engine was warming up? With the heat set to full hot, you should feel the return hose get pretty warm, pretty quickly. This tells you whether the water flow through the heater core in the cab is correct, restricted, not there at all, whatever. The heater supply hose, that feeds the control valve, should get very warm, or hot, pretty quickly, even with a relatively cold engine.

When you installed the thermostat, did you place the little air bleeder "jiggler valve" on the flange at about 12 o'clock? IE, it should be pointed at the firewall, not the radiator. If you decide to get a two-stage thermostat, place it in such a way that the smaller part is at 12 o'clock.

Burping the cooling system can take a few cycles to get all the air out. Patience is your greatest tool.
I have no patience. That's why I quit medical school. Badum-bump! ​​​​​​
Stupid joke, sorry...
Pat☺

95yoyo

So I've noticed that everytime it has that funky idle the thermostat craps out. But anyways I let it get over 3/4 on gauge before I shut it off. Heat was nonexistent, radiator and hose was still ice cold. Fired it up a few mins later and all was normal. Hot heat and after awhile of idling the radiator was warm.

Today I drove it over to a friend's house a few miles away. Truck performs flawlessly. Normal idle, hot heat and temp gauge stayed at the normal range. Gonna try to flush it once more and burp it again. I will admit that I installed the thermostat with the valve at the 6o'clock position towards the radiator... but surely that wouldn't affect it that much? Definitely gonna turn it towards the firewall when I flush.

2ToyGuy

What do you mean by "the thermostat craps out"? it breaks in some way? It won't open no matter what? It won't close under any circumstance? As usual, I'm confused...

You didn't wait long enough. Like I said, if the gauge isn't above the white arc, you're still golden. The thermostat was still closed due to the cold (relatively) water return from the heater system flowing onto it. That's why the radiator and it's hoses were still cold. No high-volume flow from the engine of nice hot water, since the thermostat is still closed. No way from hot water from the engine to get to the radiator. Yet. Did you try closing the heater down to cold, and seeing what the gauge did?
I've seen mine go up nearly to the top of the white arc on the gauge, with the heat set full hot, before the thermostat opens, especially after flushing. After a while, once all the air is out, it goes up to about 1/2 on the white arc, before dropping down to about 1/3 deflection, again, cold day, heater hot. If I start getting it going, like 50 MPH in 4th, before it's all warmed up, it can get up to about 3/4 or higher on the gauge before the thermostat opens, even with all the air out. Scares my wife no end, especially after we had the top tank on the old 3-core all-aluminum we had, blow off one day. Now, she starts bugging me if it goes above about 1/2

Right. When you shut it down, the "cold" water from the heater stopped flowing onto the thermostat, thus allowing the hot water the engine has been generating to sit on the thermostat, causing to open. Just like hot air, hot water rises, and the thermostat stops it from getting up to the radiator. Thus the thermostat has hotter and hotter water from in the engine block applied to it, until it's enough to open it, even sitting with the engine not running.
Since it was open, the hot water from the engine was now allowed to flow through the radiator and it's hoses. Once the hot water opened the thermostat, it stayed that way, due to the high volume of hot water from the engine flowing over the thermostat, much more volume of hot engine water than the cool water from the heater, and all became "normal".
After a little while, the water stabilized at the correct temperature, the engine warmed up, and thus, good heat out of the heater. Before, the engine wasn't warmed up, so little heat from the heater. See? Si...

You might be surprized. The water can flow in peculiar ways, leaving a bubble of air stuck at the 12 o'clock position, with no way to get out. It's can be a pretty long bubble too, extending back from the thermostat housing down the lines. If you have a mechanic's stethoscope, you can sometimes hear the water sloshing where there's air in the system, even in the engine, or intake manifold. There's a bunch of small heater hoses going to various parts of the intake manifold, including the Throttle Body. Easy places for air to get stuck.

When you drove to your friend's house, you were running the engine at higher RPM's than sitting there idling in the drive way. You're also running the RPM's up and down, accelerating up through the gears as you go. All this adds up to enough changes going on to pop the thermostat sooner, even with the heater going, allowing all systems to function properly. Running the engine under load like that, IE moving the entire truck around, also causes it to heat up faster. Couple that to the varying RPM's and so on, the thermostat pops correctly, again, I wager it was later than if the heater had been set to full cold, and would have indicated lower on the gauge than if the heater was maxxed hot. IE: Heater full hot, gauge will go higher and consistently read higher on the gauge once the thermostat opens up. It just didn't have time to go very high on the gauge while you were driving than if the engine warmed up slowly at idle, sitting still.
I bet after that little drive, the recovery tank was lower than when you started out, once everything was totally cold again. I wager you bubbled out some air on your trip. Maybe not ALL the air in the system, but some of it. Does the heater core still gurgle, at all, any more?

No need to flush it again, you'll just be back to the beginning. Just burp it again. See what happens
BTW, did you pick up a bottle of water wetter? that stuff really works to help get air out of the system. It lowers the surface tension of the water, so any air is encouraged to flow around the system, and hopefully out the radiator cap, more easily. It keeps the air from getting stuck in little nooks and crannies all engines have in their cooling system.
Pat☺

95yoyo

Ok so... since I burped it last Friday and it puked coolant out the overflow tank in the driveway it has been flawless. Radiator is staying full however the overflow tank is just above the low line. I haven't added anything at all. I've had heat on full blast, A/C on and I can't make it do it again. Fixed? Maybe? 🤞🤞. I did not mess with thermostat either so it's still at 6'clock position.

Could the puking issues be letting air out of the system too? This has been a learning experience for me to say the least and I appreciate all the help!

Jimkola

One thing nice about the old 22R# system is you could lightly squeeze the upper radiator hose while the engine was running and water circulating. If there were air bubbles you actually feel them as they go by.

2ToyGuy

Yes, definately. That line on the overflow tank isn't the "low" line, it's the max fill line. THAT is where the water level should be, with the engine dead cold. Much ore, and as the engine expands with the heat, it forces water out of the system into the recovery tank. If you have the water in the recovery tank much above the line, yes, it WILL puke it out the overflow tube, onto the ground. The coolant system contains X amount of fluid, and when the engine expands as it heats up, it has to go someplace, since water isn't compressible. Does that help?

Another consideration is that air spaces allow the water to boil off into steam wherever there is air. Steam expands a LOT more than the steel and aluminum of the engine. Thus, it pushes more fluid into the recovery tank. Thus, if you start with the fluid level in the recovery tank AT the line, and you still have air in the system, when everything cools off again, the fluid will be BELOW the line, since the steam forced more fluid out of the system than the engine alone would, see? Si!

That will also work to tell you if there's air in the system, especially the radiator or upper parts of the engine or intake.
With the engine dead cold, and not running, squeeze the upper radiator hose, pretty hard. If it compresses very much, air in the system. If it will only squeeze a little bit, no air. Water isn't compressible, after all. Basically, if you can squeeze the hose 1/4 of it's diameter, or more, air. It may even squeeze less than a 1/4, if the system is properly full of water. And no air in it.

If you can squeeze the hose flat, and the water in the recovery tank goes up when you do, you need a new radiator cap, or you are a strong SOB

Good luck!
Pat☺

95yoyo

Well here we go again... 🤦‍♂️🤦‍♂️🤦‍♂️🤦‍♂️ I've drove this truck for a week and half with no issues until this morning. Same scenario as before except it didn't technically run hot or spit coolant out. Gauge ran about 3/4 and overflow tank got filled up above the full mark along with the weird idle. The thing that I've noticed here is that it only does this when the weather is colder. Last week was definitely above average temps but this morning was cold and rainy. Thoughts or suggestions? Gonna try to burp some more because I can still here some gurgling when I crank up first thing.

RASALIBRE

This does sound like air in the coolant system, either trapped air that needs burped, or pressurized air from a failing head gasket or water pump cavitation.

For burping:
You need to either buy the product in the amazon link posted above/below or build radrunners container.
If you buy the amazon linked product (available many places) it comes with instructions, super easy to use, no mess, and extremely convenient.
1. You want to jack the front of the truck up so that the radiator cap is higher than the heater valve on the firewall.
Radiator cap=highest point of coolant system.
Easy to do if you have that no spill coolant funnel, because when it’s installed and filled to the line it becomes the highest point.
2. Install whatever radiator filling funnel contraption you have.
3. Pour coolant to mark on funnel or similar to where rad had it o his.
4. Start the truck heat on high. Let truck get up to temp. Once thermostat has opened, you’ll notice bubbles in or a surge in the coolant.
5. Hold engine rpms to 2000-2500 for a minute or two minute increments. Pinch and release repeatedly the upper radiator hose during rpm increase. Pinch and release repeatedly the lower radiator hose in between rpm increases or during if you have a helper.
***You need to do this for a while! 15-20 min hell 30 min if needed/wanted. (Won’t hurt, but probably not necessary)
During this time you will see bubbles come through the coolant in the funnel and you will see the coolant level rise and fall in the funnel.
If the bubbles and coolant level never stop changing/happening, this is indicative of problems other than just trapped air.
6. Once you’ve notice no more bubbles or coolant level change:
pinch and hold the upper radiator hose
insert plunger/stopper into funnel
release upper radiator hose
remove funnel
add coolant to overflow tank if needed.