Help! Overheating issues after new head gasket, can't figure it out

[4runner15]

I recently just changed my head gaskets out and put everything back together.

Head Gasket symptoms starting to show...

I've started it up however am having overheating issues. The top hose gets hot however the bottom send hose stays cold, even after 20-30 minutes of idle. This tells me that the thermostat is not opening up. Here are a few possible reasons i found on yotatech and t4r:

1. Big air pocket in the cooling system?

I've sat there for 30 minutes with the radiator cap off and heater up. It's not bleeding in this standard method. I'm going to jack up the front end of the car, but not sure if these will do much. Considering getting a coolant bleeder to test it out.

So i popped open the top hose at the radiator side hoping to use the hose as a funnel to pour coolant in this direction however, it was already full with coolant. So i thought, maybe i need to release some air, therefore i opened the hose that connects to the heater control valve. I squeezed the top hose and saw coolant coming out of that rear hose i unplugged for air. Doesn't this mean that there's coolant sitting in the top half, at the manifold? I'm going to take out the thermostat and see if i can the same results, coolant to come out of the thermostat hole. Is this is good approach?

Can there be a giant air pocket in the heater core?

2. Thermostat jiggler not in 6 o'clock position.

Can this really affect the cooling system this drastically where idling for 20 minutes won't get it to open?

3. I put the head gasket on wrong.

This is probably the worst situation if so because that means i have to do it all over. Any way to know that i did this for sure before i start ripping it apart? Someone from Yotatech who did this incorrectly said there's an L on the bottom of the gasket if you're looking up while lying down on the driver side. Looking for any reason to rule this out....

 

[BlackCat914]

I recently just changed my head gaskets out and put everything back together.

Head Gasket symptoms starting to show...

I've started it up however am having overheating issues. The top hose gets hot however the bottom send hose stays cold, even after 20-30 minutes of idle. This tells me that the thermostat is not opening up. Here are a few possible reasons i found on yotatech and t4r:

1. Big air pocket in the cooling system?

I've sat there for 30 minutes with the radiator cap off and heater up. It's not bleeding in this standard method. I'm going to jack up the front end of the car, but not sure if these will do much. Considering getting a coolant bleeder to test it out.

So i popped open the top hose at the radiator side hoping to use the hose as a funnel to pour coolant in this direction however, it was already full with coolant. So i thought, maybe i need to release some air, therefore i opened the hose that connects to the heater control valve. I squeezed the top hose and saw coolant coming out of that rear hose i unplugged for air. Doesn't this mean that there's coolant sitting in the top half, at the manifold? I'm going to take out the thermostat and see if i can the same results, coolant to come out of the thermostat hole. Is this is good approach?

Can there be a giant air pocket in the heater core?

2. Thermostat jiggler not in 6 o'clock position.

Can this really affect the cooling system this drastically where idling for 20 minutes won't get it to open?

3. I put the head gasket on wrong.

This is probably the worst situation if so because that means i have to do it all over. Any way to know that i did this for sure before i start ripping it apart? Someone from Yotatech who did this incorrectly said there's an L on the bottom of the gasket if you're looking up while lying down on the driver side. Looking for any reason to rule this out....

If you rule out airpockets, I think it's safe to say you have the headgasket on wrong and are blocking cooling passages.

 

[4runner15]

If you rule out airpockets, I think it's safe to say you have the headgasket on wrong and are blocking cooling passages.

Any suggestions on how to fully bleed the system. Like an ultimate way to do it?

 

[4runner15]

I've seen people use this but not sure if it's the "ultimate" way to bleed it. I know shops use it too. Should i get one or is there another solution before i spend 30-40 bucks?

 

[Singtoe]

Sounds like a defective thermostat to me.

 

[agloukhoff]

How are you monitoring your coolant temperature?

I mean, are you actually overheating or are you basing this on radiator hoses being hot?

Are you blowing hot air out of the heater?

At this point I would go buy 8gal of distilled water, drain your coolant and try running on nothing but distilled water an NO thermostat. Find a way to monitor actual engine temp. If you reach 210F on water, go on vacation cause you're gonna need a break before redoing your gaskets.

PS. Know how you feel. I'm frustrated as hell as well having just dropped an engine in only to have it throw a low oil pressure light.

 

[4runner15]

How are you monitoring your coolant temperature?

I mean, are you actually overheating or are you basing this on radiator hoses being hot?

I'm basing it off of the temp gauge on the cluster. It rises above half way and can keep going especially if i put it in gear or drive it. If sitting in park or neutral, it'll stay at the below-half-way mark.

Are you blowing hot air out of the heater?

Yup, as hot as vegas weather. That means the coolant is circulating through the heater core right?

At this point I would go buy 8gal of distilled water, drain your coolant and try running on nothing but distilled water an NO thermostat. Find a way to monitor actual engine temp. If you reach 210F on water, go on vacation cause you're gonna need a break before redoing your gaskets.

I will do this. I'm gonna get some distilled water. Tired of wasting my money on coolant. Already went through 3 bottles. So what is the main point of running distilled water and no thermo? What will this tell me if it hits 210 degree? Is it suppose to be lower, say 180-190? I thought that the coolant will help it stay down.

One observation that i'm curious to try later is to take out my thermostat and see if the coolant sitting at the radiator hose goes in. It should, right? Being that i released air from the bottom, gravity should carry the water down and out the thermo hole. If it doesn't, than i got bigger issues and need to go on vacation.

PS. Know how you feel. I'm frustrated as hell as well having just dropped an engine in only to have it throw a low oil pressure light.

The problems continue. When will i get to lift and off-road this thing. I'm already going to miss the toyota meet at Pismo this weekend.

 

[agloukhoff]

I suggest investing in either an ODB2 scanner or an Ultraguage to get exac temps. Those dash gauges are terrible, although to be at the 2/3rds mark you're probably around 220F which is certainly not where you should be.

I suggested distilled water because it's $1/Gal and will not leave lime and calcium deposists in your engine. Pure water has better cooling capacity than coolant, so if anything, you should see better temps with it when testing. (Frankly, you can run tap water, just don't do it for long especailly if you got hard water in your home. I've done it plenty of times, just alway flush with distilled after.)

The purpose of coolant is to lower the freezing point, raise the boiling point and prevent electrolysis. Some coolants have additives that do more but that's the basic 3 that matter.

The fact that you got hot air blowing out of the vents means that your water pump is working fine. So that's out of the equation.

At this point, if you overheat with no thermostat, you will have no possible points of failure left.

And yeah, you can take the thermostat out, flat out hook up a garden hose to the top rad line and flush the engine. I've spent hours doing just that on Tyrone before I gave up on wishfull thinking and tested for combustion gases in the coolant...

That won't tell you much though as it doesn't prove that coolant is circulating through the entire engine.

 

[4runner15]

And yeah, you can take the thermostat out, flat out hook up a garden hose to the top rad line and flush the engine. I've spent hours doing just that on Tyrone before I gave up on wishfull thinking and tested for combustion gases in the coolant...

Thats the thing though... if there's a coolant still in the radiator hose even after i take out the thermostat, will it mean that the coolant is not passing through the engine? Can this determine that i did indeed put my HG in the wrong way?

 

[agloukhoff]

And yeah, you can take the thermostat out, flat out hook up a garden hose to the top rad line and flush the engine. I've spent hours doing just that on Tyrone before I gave up on wishfull thinking and tested for combustion gases in the coolant...

Thats the thing though... if there's a coolant still in the radiator hose even after i take out the thermostat, will it mean that the coolant is not passing through the engine? Can this determine that i did indeed put my HG in the wrong way?

Hmm - honestly, no idea. I don't know if a gasket install wrong would block all holes or just some.

I will say this though, I had no issues pouring gallon after gallon of water into my engine through the top out of the garden hose without it backing up.

 

[thor999]

Replace the thermo and ensure it is in proper position! Dumb question, is your fan running properly? I assume you are attempting these fixes while the vehicle is parked, thus no decent airflow across the rad. Do you have a rear air control? If so set it to high (heat) and massage the rad inlet hose while operating to properly burp the system (cap slightly unscrewed)... also feel across the fins make sure the rad is getting HOT and properly dispelling heat.

 

[4runner15]

Hmm - honestly, no idea. I don't know if a gasket install wrong would block all holes or just some.

I will say this though, I had no issues pouring gallon after gallon of water into my engine through the top out of the garden hose without it backing up.

If you let the thermostat out, do you think the coolant you poured in would've came out that housing?

Replace the thermo and ensure it is in proper position! Dumb question, is your fan running properly? I assume you are attempting these fixes while the vehicle is parked, thus no decent airflow across the rad. Do you have a rear air control? If so set it to high (heat) and massage the rad inlet hose while operating to properly burp the system (cap slightly unscrewed)... also feel across the fins make sure the rad is getting HOT and properly dispelling heat.

I definitely need to check that it's in proper position. But i'm not sure if this would cause these occurrences. But yes, i will try this first since it's easiest.

Yes it''s in park and on flat driveway. The fan works fine, spins and i can even feel the gusts of wind while starring over the motor.

What's a rear air control? I massaged the top hose plenty i feel. I end up just squeezing more coolant out the top of the radiator.

I think the last time i touched the radiator, it wasn't too hot. It was cool. Especially the bottom of the radiator. I'll double check this too but what does it mean if it's cool? Not dispelling heat? Doesn't it just mean that there isn't flow of water going through the radiator to the bottom hose and back into the engine?

 

[FancyPantsMcGee]

pop quiz!
If coolant isn't going through the cylinder heads properly, will the coolant bypass pipe allow it to ..bypass them?
If so, then I dare say there is only 1 way to find out if the HG's are installed upside down or switched...
However:
If coolant must go through the heads; then you could pull the TS and unplug the fan and idle it up. the entire radiator will get hot.
If it doesn't get hot quick(esp. the bottom) you have radiator blockage or the HG's are incorrect.
Sound logic?

 

[thor999]

If you let the thermostat out, do you think the coolant you poured in would've came out that housing?



I definitely need to check that it's in proper position. But i'm not sure if this would cause these occurrences. But yes, i will try this first since it's easiest.

Yes it''s in park and on flat driveway. The fan works fine, spins and i can even feel the gusts of wind while starring over the motor.

What's a rear air control? I massaged the top hose plenty i feel. I end up just squeezing more coolant out the top of the radiator.

I think the last time i touched the radiator, it wasn't too hot. It was cool. Especially the bottom of the radiator. I'll double check this too but what does it mean if it's cool? Not dispelling heat? Doesn't it just mean that there isn't flow of water going through the radiator to the bottom hose and back into the engine?

I'm hoping for radiator blockage then!!! :driving: By rear air control I mean does the back seat have it's own air controls (on/off and cold-hot dial), located on the backside of the console, between the seats? If so, crank that up high heat when "burping" the system.
NOTE: if you completely remove the thermostat, it is my understanding that the coolant system will not function properly and can result in further overheating! No, I do NOT have a source to quote on the web, this is wisdom from a 30yr Merchant Marine Master Engineer I had the opportunity to work with once. I would replace the thermo w/ OEM and ensure proper orientation, at least it is the cheapest rule-out.

 

[4runner15]

pop quiz!
If coolant isn't going through the cylinder heads properly, will the coolant bypass pipe allow it to ..bypass them?
If so, then I dare say there is only 1 way to find out if the HG's are installed upside down or switched...

So are you saying that if I installed the HG incorrectly, it will block for certain and not get passed that bypass valve?

However:
If coolant must go through the heads; then you could pull the TS and unplug the fan and idle it up. the entire radiator will get hot.
If it doesn't get hot quick(esp. the bottom) you have radiator blockage or the HG's are incorrect.
Sound logic?

I just got back from the garage and did this. I took the thermostat out and poured water into the top radiator hose. Water flowed out the thermostat housing. Does it mean i rule out the head gasket being in wrong? I don't want to get my hopes up just yet. Final test is to boil my tstat to make sure it opens. Doing this now..

Also, i ran the car without the thermostat and poured water. I noticed that the difference with no thermostat was that it took a long time to warm up, even the heater on full blast took at least 5-10 minutes to blow hot air. The lower hose finally got hot (obviously without the tstat). I think i even saw a few burps since i had to refill with some water. But this is all without the stat. Need to put the stat back in and pray.

I'm hoping for radiator blockage then!!!

This is possible but it wasn't clogged before. If it WAS blocked though, where would the blockage be? How do i check this for sure? Any test you suggest?

 

[4runner15]

Alright so i boiled the thermostats and they both opened up. I'll need to install these and give it another start tomorrow.

You can see the opening on the left side stat. It was the original one off the car. Definitely beefier than the one on the right side which i got at oreilly auto parts. The right one opened too, just can;t see it in this angle

Another shot of what the stat looks like open.

 

[FancyPantsMcGee]

I was literally asking that question myself, I'm hoping someone would know definitively if coolant must go through the heads. anyone?
This thread ends with the HG's being on wrong:
97 Overheating..Help - Toyota Nation Forum : Toyota Car and Truck Forums
If you can rule out your radiator, water pump and thermostat.. your symptoms do point towards a left right HG mixup. You would certainly not be the only person to have experienced it.
(I wish I had been reading your other thread all along, my bad. I ordered head bolts, timing parts, valve train parts from LCE and would vouch for them. I also used cometic mls headgaskets and recommend them as well. I too put a nick in my harmonic balancer/crank pulley. two actually. no biggie.) (I had cracks in both heads; cyl 3 and 4 respectively))

 

[4runner15]

Well, i put one of the thermostats in yesterday and started it up. The lower hose was still cold. So i know when i had the thermostat OUT, the lower hose got hot. I tested the thermostat above by boiling it and as you notice, it opened up. I poured water through the top radiator hose and it came out the thermostat hole so i know there is a flow.

Now, my questions are..

1) Perhaps the flow of coolant down to the thermostat hole does NOT prove and rule out that i may have possibly switched the gaskets. Anyone can confirm or know?

2) With the thermostat OUT, how did the lower hose heat up? Where did the hot water come from? Was it actually coolant circulating through from the top and going back into the motor via the bottom? If so, i would imagine that's a good sing. Or is it instead, the motor returning coolant through the bottom hose and somewhat mixing with the coolant in the radiator? How would i confirm?

3) I'm stumped on this one, if i know water is hitting the back of that thermostat (proved when i pour water through the top hose), wouldn't that coolant heat up and open the thermostat? Maybe it did, but is it possible that the water pump is not thrusting enough water through? I have an Aisin water pump that i replaced the old one with.

My thoughts and what i think i'll need to do:

- get a new thermostat and test it out again, put the jiggle valve at 12 o clock and see if that makes a difference.
- try driving the car without the thermo and see how hot it gets. If it is flowing coolant, it would stay cooler than normal temp, yeah?
- pour boiling water through the top radiator and see if my thermostat opens up while installed. I'm not sure what this will prove.
- replace my radiator and see if that fixes things. If it doesn't, i got a new radiator.. lol
- last resort is to tear the motor down to check if i switch my HG. I will be super pissed at myself if it was on CORRECT and it ended up just being something stupid and small i didn't check for. That's why i want to rule everything else out first.

 

[Singtoe]

Run it with the thermostat. If it over heats, it could be some head gasket or a plugged radiator.

 

[FancyPantsMcGee]

ok, I conferred with my FIL who works at a radiator shop.
This is his advice:
Check the radiator, since you had HG issues and your heads off, it's possible you got oil into your cooling system which could cause clogs.
-Flow water from your garden hose into the lower radiator hose and pinch off the top hose. observe flow out the top, if there is significant back flow out the bottom, you could have clogs.
-Bring the engine up to temp, clogs can be found as cold spots on the radiator.
-Start the truck with the hot air on high and watch your temp gauge, If you don't have hot air coincide with the temp gauge reaching warm; you have poor flow to the heater core. this could be indicative of HG blocking flow.
Do these with a properly installed new thermostat.
You can take your truck to a radiator shop and they can do all this for you. It might be worth it if you want peace of mind before you pull the heads again.
good luck boss.