1HDT Coolant into Overflow - What am I missing? (5 Viewers)

perrobravo

SILVER Star
Joined
May 21, 2012
Messages
618
Location
San Diego, CA
Looking for help solving a new problem with my 1HDT. After replacing the head gasket for unrelated reasons, the truck consistently pushes coolant into the overflow when driven under load. I've read every burping thread, searched extensively for ideas, have tried a dozen things, and have run out of ideas. Any help would be appreciated!

Observations:

Truck starts immediately, runs great, and pulls very well through the rev range
No unexpected smoke from the exhaust (just a puff of black on startup)
Engine temps (measured by factory gauge) normal, never budge once up to temp
EGTs in check, never exceed 1200F (most of the time far lower), reasonable AFR through rev range
No visible water or oil leaks
~320k on the odometer
New GTurbo green wheel (boost set to max ~23)
Injectors and injection pump rebuilt (timing set to factory spec)
PDI front mount intercooler
Torfab airbox and aneroid pin
EGTs in check, has never exceeded 1200F, reasonable AFR through rev range

Problem:

Under load (i.e. uphill, high speed, pushing a bit harder than just driving to the local dealer to buy more coolant), coolant is pushed into overflow and doesn't get drawn back into the radiator when the engine cools. A couple times, the overflow overflowed and dumped coolant onto the ground. Most often it simply fills the overflow, but I haven't been pushing it to avoid making the problem worse.

Tests completed:

Checked for bubbling of coolant in radiator...none other than usual flow of water once thermostat opens
Oil and coolant appear clean visually (no milkiness or other bad signs)
Oil tested by Blackstone (no indication of coolant making its way into the oil...I specifically asked them to look)
No sign of compression gases in coolant (using 2 different test kits in both overflow and radiator)
Cooling system holds pressure (tested to 16psi)
Compression at sea level (on cold engine) 510-525psi (maybe a bit high, but could be my cheap gauge isn't as accurate as it should be)

Work done recently:

Head resurfaced, tested for cracks (none)
Valves cleaned up, new OEM stem seals, lash set to factory spec
New OEM head gasket (the right one based on the number of tabs on original)
New OEM head bolts torqued per FSM instructions
New OEM radiator and radiator cap (0.9bar)
Coolant drained and flushed (including block and heater core...which seemed very clean)
Rear heater deleted
New 50/50 mix of Toyota red coolant
New OEM thermostat (installed with the jiggle thing at the top per the FSM)
Used Venturi compressed air/vacuum coolant fill tool with front end on ramps, truck on an inclined driveway, heater on

I'm hoping this is simply an air pocket somewhere in the engine, but I've tried multiple times to burp the system and haven't read too many stories of people struggling with this on this engine. I don't want it to be something I screwed up when replacing the head gasket, but also don't know what else to test to confirm/deny this. I wouldn't love doing the head gasket work again, but would IF I was confident doing so would fix the problem.

Anyone have ideas? I know there are quite a few folks here deep into 1HDT engines, so maybe some specific tips or something I'm missing? @Onur @SNLC @torfab @Loober ?

And a picture, just because

9backinafton.jpeg
 
Joined
Jul 5, 2013
Messages
859
Location
San Diego
hmm almost sounds like a blockage not allowing the coolant to circulate, and the water pump is forcing it out where it can. Ruling air bubbles out, whats the condition of the radiator. How do the hoses look, any signs of them collapsing. Sounds more like cooling system related rather then anything caused by the engine. If you were to keep driving it would keep pushing more out?
 

perrobravo

SILVER Star
Joined
May 21, 2012
Messages
618
Location
San Diego, CA
hmm almost sounds like a blockage not allowing the coolant to circulate, and the water pump is forcing it out where it can. Ruling air bubbles out, whats the condition of the radiator. How do the hoses look, any signs of them collapsing. Sounds more like cooling system related rather then anything caused by the engine. If you were to keep driving it would keep pushing more out?

Thanks for the reply, Nick. The radiator is new, fresh from Toyota. I replaced it hoping that was part of the problem. No sign of hoses collapsing. All have been replaced within the last year or two with OEM. Heater blows hot when turned on.

When the coolant pushes into the overflow I've poured it back into the radiator after the engine cools. I'd guess if I didn't do that it would continue to overflow. Not wanting to risk overheating, I haven't pushed/tested that too much. That said, there have been times when I've had to add more than the full overflow canister to get the radiator full again. Frustrating.
 

perrobravo

SILVER Star
Joined
May 21, 2012
Messages
618
Location
San Diego, CA
How well was the head checked when you did the H/G? It sounds like a cracked head that opens up as it expands. Is the fan clutch working ok?
Thanks for your input, @roscoFJ73 !

Hmmm. Interesting question. I don't know anything about how to magnaflux, but the shop which came recommended to me claimed the results were good...no cracks or other obvious problems. @Onur warned me that a cracked head was a possibility before I originally removed it, so I was pretty clear with the shop that I wanted to ensure no cracks.

The fan clutch works great. I considered changing the fluid, but found it was in great shape so simply reinstalled and made sure all the belts were properly adjusted.
 

perrobravo

SILVER Star
Joined
May 21, 2012
Messages
618
Location
San Diego, CA
I take it that it wasn't pushing fluid out before the hg problem?

Correct. No cooling system problems before. I originally replaced the head gasket to fix oil leaking out of the back between the block and head. the good news (I guess) is that problem has been solved!
 

ToyotaMatt

Factory Focus-Point Mind-Set Approach
Supporting Vendor
GOLD Star
Joined
Aug 12, 2007
Messages
19,727
Location
EAST COAST
Website
vintageteqparts.com
Correct. No cooling system problems before. I originally replaced the head gasket to fix oil leaking out of the back between the block and head. the good news (I guess) is that problem has been solved!


was the top of the Cylinder Block checked for warpage with a straight edge and a FLAT strip type feeler gauges like the FSM shows and calls a LIMIT ?

the big X pattern and along the sides and the flats or Horizontals ?

this would smoke out any pitting or depressions around the metal compression rings on the head gasket or LOW points that may now be allowing combustion pressure

and gasses to escape with coolant giving it the propellent to breach the over-flow like u describe ?

like this EXAMPLE ONLY diagram :



1628987523584.png
 

Squash

SILVER Star
Joined
Dec 8, 2006
Messages
1,659
Location
Sudbury, Ont. CA
Try a new rad cap and check the hosing from inside the overflow to rad. There is a suction tube in overflow which can fall off.
Hopefully it's that simple...
Just remember that anything with tires or a bikini will cost you time, money and grief!
 

perrobravo

SILVER Star
Joined
May 21, 2012
Messages
618
Location
San Diego, CA
was the top of the Cylinder Block checked for warpage with a straight edge and a FLAT strip type feeler gauges like the FSM shows and calls a LIMIT ?

the big X pattern and along the sides and the flats or Horizontals ?

this would smoke out any pitting or depressions around the metal compression rings on the head gasket or LOW points that may now be allowing combustion pressure

and gasses to escape with coolant giving it the propellent to breach the over-flow like u describe ?

like this EXAMPLE ONLY diagram :



View attachment 2759086

Unfortunately, I didn't do this to the extent I now wish I had. If the block is warped, I suppose the theory would be that the head was also, but then after machining they no longer mate up together well...at least under load? @ToyotaMatt , any thoughts on how likely this may be for this engine in particular? Appreciate your input.

@Squash , thanks the reply. The radiator cap is new (have tried at least 3 caps) and the hoses on the overflow are all in place and clear. And for sure this bikini-wearing 80 is costing me time, money, and grief. And it has been worth it!

@crave reFleXion , thanks for your input as well. I did tests for combustion gases in the coolant using two different test kits. I tested directly from the radiator and in the overflow canister, specifically after the coolant had been pushed there. I also separately tested when the engine was cold. All tests were negative (magic liquid did NOT change color) which I took as a good sign.


The machine shop that did the head work suggested I try a higher pressure radiator cap. Anyone have a strong opinion either way on this idea...and maybe a part number? The cap currently on the truck is an OEM 0.9 bar version.
 

ToyotaMatt

Factory Focus-Point Mind-Set Approach
Supporting Vendor
GOLD Star
Joined
Aug 12, 2007
Messages
19,727
Location
EAST COAST
Website
vintageteqparts.com
Unfortunately, I didn't do this to the extent I now wish I had. If the block is warped, I suppose the theory would be that the head was also, but then after machining they no longer mate up together well...at least under load? @ToyotaMatt , any thoughts on how likely this may be for this engine in particular? Appreciate your input.

@Squash , thanks the reply. The radiator cap is new (have tried at least 3 caps) and the hoses on the overflow are all in place and clear. And for sure this bikini-wearing 80 is costing me time, money, and grief. And it has been worth it!

@crave reFleXion , thanks for your input as well. I did tests for combustion gases in the coolant using two different test kits. I tested directly from the radiator and in the overflow canister, specifically after the coolant had been pushed there. I also separately tested when the engine was cold. All tests were negative (magic liquid did NOT change color) which I took as a good sign.


The machine shop that did the head work suggested I try a higher pressure radiator cap. Anyone have a strong opinion either way on this idea...and maybe a part number? The cap currently on the truck is an OEM 0.9 bar version.


i HAVE Indeed experienced this on numerous TOYOTA Engine Block TOP DECK mating Surfaces ..........

over the years

if this FSM Step by Step was missed of NOT DONE at all ?


then my opinion is this is the logical place to first start looking for your pressure gasses escaping w/ coolant thru overflow
 

perrobravo

SILVER Star
Joined
May 21, 2012
Messages
618
Location
San Diego, CA
i HAVE Indeed experienced this on numerous TOYOTA Engine Block TOP DECK mating Surfaces ..........

over the years

if this FSM Step by Step was missed of NOT DONE at all ?


then my opinion is this is the logical place to first start looking for your pressure gasses escaping w/ coolant thru overflow

Well, that's no fun. I was hoping to hear how this is never a problem on the most reliable Toyota engine ever, or something similar. Unless some other low cost/effort solution pops up, it sounds like I have my work cut out for me.

Anyone else want to offer up an easy solution...please?
 

Bama4door

Supporting Vendor
Joined
Sep 10, 2013
Messages
2,445
Location
Birmingham, AL
Did this problem start as soon as you put it all back together after HG replacement? I just picked up an HDJ81 with the same problem and haven't dove in yet. Your setup sounds similar to mine - Gturbo badboy set at 28lbs, OEM HG and bolts.

My plan of attack is to re-torque every head bolt one at a time and see if that helps. If not, I'm going to take the head off and put on ARP studs and a new HG.
 

ToyotaMatt

Factory Focus-Point Mind-Set Approach
Supporting Vendor
GOLD Star
Joined
Aug 12, 2007
Messages
19,727
Location
EAST COAST
Website
vintageteqparts.com
Well, that's no fun. I was hoping to hear how this is never a problem on the most reliable Toyota engine ever, or something similar. Unless some other low cost/effort solution pops up, it sounds like I have my work cut out for me.

Anyone else want to offer up an easy solution...please?


so guess what ...

i forgot i scooped up a nice 2H , 12H-T factory Engine FSM a few weeks ago ..............i have been slammed busy and spaced on this :rolleyes:


would you like me to post all the pages related to MY Theory on what your issue may indeed be ?

just say the word ...

kindly matt
 
Last edited:

ToyotaMatt

Factory Focus-Point Mind-Set Approach
Supporting Vendor
GOLD Star
Joined
Aug 12, 2007
Messages
19,727
Location
EAST COAST
Website
vintageteqparts.com
If the installer did not have a FSM like this I don’t see how they would know or if they did know the LIMIT specs ?

also

the head bolts tighten sequence is critical

I was a toyota master tech for 12 years at dealer ship level and was in my prime during the entire 3.0 3vZfe and 3.4 5vzfe head gaskets factory Dibical

I was told the slightest limit out close as a hair write up a new short. Block engine lower end

I must have replaced Over 50+ v6 toyota warranty engines in my career ?

Maybe more

I saw my share of private shops F up head gaskets Jobs

customer then brings lame repair to dealer to do it right

well they got new engines 99% of the time


those are the USA spec gasoline engine facts in trucks and 4 runners

and land cruisers too

I did warranty work on Fj62 platforms

wow what a time to be 21 again ….

I wish you best of luck here

If I can help in any way don’t hesite to ask or PM me

Matt
 
Joined
Apr 12, 2019
Messages
73
Location
The Dalles, Oregon
I have this one going on too. After a hard tow in a 30mph headwind this started, despite not overheating. I'm really hoping its a headgasket and not a cracked head. After about 3 hours of hard hilly driving, or even an hour sometimes, I'll have a completely full reservoir. It does pull it all back in to the engine however when it cools down, sometimes overnight, sometimes after a day driving around town and a full cool. If I'm just putting around town, even if it is very hot and the engine runs at a 85-90*C (normally I'd say it sticks between 80-85*C) it wont' fill the reservoir beyond a small bit of expansion and contraction. When the reservoir is full there is some bubbling from the radiator fill tube, which makes sense from the pressure and air that's displaced in to the radiator. I guess I'm just venting here... I hope I can get this sorted, and that it's not a cracked cylinder head.
 
Joined
Feb 7, 2019
Messages
173
Location
Down Under
Did this problem start as soon as you put it all back together after HG replacement? I just picked up an HDJ81 with the same problem and haven't dove in yet. Your setup sounds similar to mine - Gturbo badboy set at 28lbs, OEM HG and bolts.

My plan of attack is to re-torque every head bolt one at a time and see if that helps. If not, I'm going to take the head off and put on ARP studs and a new HG.
You can't retorque TTY (torque to yield) head bolts.
 

Users who are viewing this thread

Top Bottom