'88 FJ62 - Mysterious Coolant Leak (2 Viewers)

[boredfast]

I have been at wit's end trying to chase a mysterious coolant consumption issue.

Several months ago I noticed my reservoir tank had been at the minimal mark, I assume staying at a level that the pickup can no longer take in radiator fluid. I filled it up with Toyota Red 50/50 and thought nothing more of it. Fast forward to a few months later (I drive around every few weeks or so, my rig only coming out for special weekends or camping trips), and I noticed the level back down at the minimal mark. I had probably put about 500-800 miles on the truck before popping the hood again and checking. Filled it up again.

I got alerted to this because on my last time offroading, I luckily noticed my temp gauge creep quickly up to HOT (230-240*F) and then fall back down slowly. It never got towards the hot mark again. Later that weekend, got under the truck, and noticed the lower hose from the water pump had some dried red coolant on one of the clamps. I assumed a leaky water pump and trying to confirm my suspicion, I drove the truck around more frequently and at freeway speeds (+30 min drive times) to ensure I was fully up to temperature. I am not seeing any new moisture on the lower hose or clamp area, and no other areas have dried coolant. The reservoir dropped another 1cm off the max line.

Things I've done:

1. Pressure tested the cooling system with a rental tool up to 15 psi. I followed the instructions and did it while the car was cold. No leaks found after holding pressure for about 15 minutes. The kit did not have the right fitting for my cap to test, but since the overflow tank is receiving coolant when the car is warm, I can assume(?) the cap is working properly.

2. Ran the rear heaters during the diagnostic and "driving aroung" stage. No coolant found on interior of the truck (none that I can find), and no coolant on the lines going to the rear heater.

3. No coolant weepage when the car is hot from the breather tube on the overflow tank.

4. Checked the dipstick for coolant or watery looking oil. Nothing that I can find, but I am planning to do an oil change this weekend and a blackstone analysis to rule that out.

5. Condition of the upper and lower hoses seem to be in good shape.

6. According to the PO, water pump, thermostat, radiator all replaced 8 years ago (about 20k miles ago)

Any ideas on things to look for? I am about to throw it at a shop and have them pull everything off to sort this truck out, but if I can avoid spending $1200~ to do that, then I would much prefer to play out all my options.

 

[MTB Land Cruise]

My 89 is kind of doing the same thing. Did a complete flush and pressure test last sept., no leaks, temperature good. Filled with Green 50/50 made short trips every couple weeks and no issues. yesterday, i noticed Low coolant in the reservoir and radiator needs coolant too. I'm waiting for some green coolant to arrive so i can refill and see what happens. my mechanic said its normal to loose some coolant (in these older LC's) via evaporation, especially after a full flush, but how much is not clear. So, i'm going to add more a check consumption and levels for the next few weeks. I'll advise if it fixes the issue.

 

[OSS]

It's disappearing so slowly that it isn't a significant issue. Don't worry about it.
Just keep track of it . If it gets worse, get the oil tested for combustion by products

 

[boredfast]

My 89 is kind of doing the same thing. Did a complete flush and pressure test last sept., no leaks, temperature good. Filled with Green 50/50 made short trips every couple weeks and no issues. yesterday, i noticed Low coolant in the reservoir and radiator needs coolant too. I'm waiting for some green coolant to arrive so i can refill and see what happens. my mechanic said its normal to loose some coolant (in these older LC's) via evaporation, especially after a full flush, but how much is not clear. So, i'm going to add more a check consumption and levels for the next few weeks. I'll advise if it fixes the issue.

Let me know what you may find... I've probably gone through 2 full tanks of overflow. I don't think this is normal.

It's disappearing so slowly that it isn't a significant issue. Don't worry about it.
Just keep track of it . If it gets worse, get the oil tested for combustion by products

I forgot to mention after my 40 min freeway drive yesterday, the coolant level is another 1cm down this morning after the truck cooled.

I also believe that when I initially got the toyota red to top off the first time, the radiator level seemed OK.

 

[Kleatus]

Take a close look around the head, especially on the drivers side on top where it is congested. Sometimes cracks can open up with temp and pressure and there are some spots up there coolant can sit and boil off without making a visible "leak." You will have white crusty deposits though if that is the case. Same with the engine block itself. Mine leaks out of several cracks in the water jacket when hot, and coolant runs down to the oil pan flange and evaporate as it travels, never really reaching the level of a "leak" that makes a puddle. In normal use, I loose a cup or two every couple weeks. Been this way for years.

Here is a shot of where mine is visible (it only gets this bad when temps are way too hot)

 

[boredfast]

Take a close look around the head, especially on the drivers side on top where it is congested. Sometimes cracks can open up with temp and pressure and there are some spots up there coolant can sit and boil off without making a visible "leak." You will have white crusty deposits though if that is the case. Same with the engine block itself. Mine leaks out of several cracks in the water jacket when hot, and coolant runs down to the oil pan flange and evaporate as it travels, never really reaching the level of a "leak" that makes a puddle. In normal use, I loose a cup or two every couple weeks. Been this way for years.

Here is a shot of where mine is visible (it only gets this bad when temps are way too hot)View attachment 2609874

Thanks, I'll check that tonight.. I definitely hope I don't find that.

 

[MTB Land Cruise]

@boredfast, Got my coolant delivered earlier today. added about a quart to the radiator and filled reservoir to limit line. Drove about 20 miles, temp. good and holding. No leaks, no level drop(s)..... after sitting a few hours. Like others indicate, some coolant loss is common, unless obvious leak is detected. Good idea to keep extra coolant in garage or in LC for quick top offs. Good luck.

 

[John McVicker]

If it were me I would do the pressure test again AND somehow get a proper fitting cap.

It’s going ‘somewhere’ and it’s important to find out where...so that you can address the issue. At the rate you are leaking a good pressure test is your best bet.

 

[EscapeWagon62]

I may be way off base so apologies if thats the case.
Filling to the limit line when cold actually causes an overfill situation snd your overflow tank will vent that out while you are driving.
When you fill to the low line, then fully warm the truck up it should come close to the high line.
Actual level line in your overflow tank will go up and down a bit when fully cold based on ambient air temp.
If you had a leak in the system, you would find drip puddles under your rig after parking or at least drips on your frame/undercarriage.
Go look for some of those EXCLUDING below your expansion/overflow tank

 

[John McVicker]

Ah yes, @EscapeWagon62 ...you are correct.

 

[ToyotaMatt]

I have been at wit's end trying to chase a mysterious coolant consumption issue.

Several months ago I noticed my reservoir tank had been at the minimal mark, I assume staying at a level that the pickup can no longer take in radiator fluid. I filled it up with Toyota Red 50/50 and thought nothing more of it. Fast forward to a few months later (I drive around every few weeks or so, my rig only coming out for special weekends or camping trips), and I noticed the level back down at the minimal mark. I had probably put about 500-800 miles on the truck before popping the hood again and checking. Filled it up again.

I got alerted to this because on my last time offroading, I luckily noticed my temp gauge creep quickly up to HOT (230-240*F) and then fall back down slowly. It never got towards the hot mark again. Later that weekend, got under the truck, and noticed the lower hose from the water pump had some dried red coolant on one of the clamps. I assumed a leaky water pump and trying to confirm my suspicion, I drove the truck around more frequently and at freeway speeds (+30 min drive times) to ensure I was fully up to temperature. I am not seeing any new moisture on the lower hose or clamp area, and no other areas have dried coolant. The reservoir dropped another 1cm off the max line.

Things I've done:

1. Pressure tested the cooling system with a rental tool up to 15 psi. I followed the instructions and did it while the car was cold. No leaks found after holding pressure for about 15 minutes. The kit did not have the right fitting for my cap to test, but since the overflow tank is receiving coolant when the car is warm, I can assume(?) the cap is working properly.

2. Ran the rear heaters during the diagnostic and "driving aroung" stage. No coolant found on interior of the truck (none that I can find), and no coolant on the lines going to the rear heater.

3. No coolant weepage when the car is hot from the breather tube on the overflow tank.

4. Checked the dipstick for coolant or watery looking oil. Nothing that I can find, but I am planning to do an oil change this weekend and a blackstone analysis to rule that out.

5. Condition of the upper and lower hoses seem to be in good shape.

6. According to the PO, water pump, thermostat, radiator all replaced 8 years ago (about 20k miles ago)

Any ideas on things to look for? I am about to throw it at a shop and have them pull everything off to sort this truck out, but if I can avoid spending $1200~ to do that, then I would much prefer to play out all my options.

THIS added TECH LINK BELOW to this particular conversion , should be poured over in detail by anyone interested ,

Understanding 3FE Cooling System

Good Morning Gentlemen, I was referred here from the Pirate4x4 forums, hope someone has some insight here: So, I've been working on a client's Land Cruiser for a little while now. The engine has received quite a bit of attention over the past year because it was neglected for a while. Its been...

forum.ih8mud.com

 

[boredfast]

If it were me I would do the pressure test again AND somehow get a proper fitting cap.

It’s going ‘somewhere’ and it’s important to find out where...so that you can address the issue. At the rate you are leaking a good pressure test is your best bet.

I do have a proper fitting cap, I just could not find an adapter to test the cap with the kit I had, and based on my research so far, I have no reason to believe the cap is leaking (nor can I find any evidence of it doing so).

I may be way off base so apologies if thats the case.
Filling to the limit line when cold actually causes an overfill situation snd your overflow tank will vent that out while you are driving.
When you fill to the low line, then fully warm the truck up it should come close to the high line.
Actual level line in your overflow tank will go up and down a bit when fully cold based on ambient air temp.
If you had a leak in the system, you would find drip puddles under your rig after parking or at least drips on your frame/undercarriage.
Go look for some of those EXCLUDING below your expansion/overflow tank

That's interesting, because my assumption is that in a cold car, filling anywhere between the Min-Max lines should not result in overflowing coolant unless the car pegs out at 240+etc.
I have a suspicious amount of surface frame rust near the front frame rails near the overflow and radiator plumbing that may have been the result of cooling issues during the PO's time.. who knows. So far, I have spent 15-20 mins after shutting down the car laying and waiting for a puddle or a drip to form. I also check in the morning when the car is fully cold and find nothing.

THIS added TECH LINK BELOW to this particular conversion , should be poured over in detail by anyone interested ,

Understanding 3FE Cooling System

Good Morning Gentlemen, I was referred here from the Pirate4x4 forums, hope someone has some insight here: So, I've been working on a client's Land Cruiser for a little while now. The engine has received quite a bit of attention over the past year because it was neglected for a while. Its been...

forum.ih8mud.com

View attachment 2610129

View attachment 2610130

Thanks ToyotaMatt, but I have done a serious amount of reading on this forum and have seen both microfiches for potential resolutions to my problem.

Does anyone know if their heater lines and other cooling connections have this amount of dried crud on them (attachments)? It seems abnormal but they are not wet after driving nor after sitting... im really stumped.

 

[John McVicker]

Semantics...when I said proper fitting ‘cap’ I meant proper fitting adapter on the pressure tester in order to locate the leak that you say you have. Your red coolant should help you find the leak and it will simplify your search once you have it under pressure.

 

[boredfast]

Semantics...when I said proper fitting ‘cap’ I meant proper fitting adapter on the pressure tester in order to locate the leak that you say you have. Your red coolant should help you find the leak and it will simplify your search once you have it under pressure.

Not sure if we're talking about the same thing.

I did have the proper adapter to test the cooling system. But when testing my cap, I could not find an adapter in the kit that had the same inner diameter bore as the radiator cap I have on. So when I applied pressure, air just leaked around the cap as it could not form a tight fitting seal. Hell, this isn't an OEM cap so maybe I'll try swap that out and see if it fixes any.

 

[ToyotaMatt]

you mention above installing Factory Toyota RED 50/50 ?

are you installing it straight or with the addition of Distilled water too ?


if you have ANY type of a cheap low cost aftermarket cap , this alone can be your entire problem and 100% of the cause

related to the ALL or a high number of the various symptoms you outline above , and you might never see a leak live or

any notable moisture what so ever ?


i have seen versions of this mystery coolant consumption problem in my own fleet of Toyota;s over the years and on my clients vehicles when still operating my own shop several times too

during my time at the dealership level , if any toyota came in any type of after market RAD cap , that was a company policy
to raise a red flag and ask that to the list of service recommendations , the writer would later pass on to the service customer


back then , installing a NEW OEM Toyota Radiator Cap , all were made then by Parts maker NipponDenso and had the ND cast logo stamp on one of the ears only paid .1 hours , YEA that's right .1 of a 60 minute hour ,,,,,,

a full and compressive by the book to cover your butt cooling system inspection generally always paid a solid 1.0 or a full hour of technician labor time

so , typically the average dealership service customer does NOT want to spend much of any level of money servicing there Toyota vehicle , they came in motivated by low cost oil change coupons and service specials , a $99 Major Tune up etc ...

this concept of reality gave way to simply hating , and frowning all aftermarket parts not installed at the factory or replaced using real toyota genuine parts at that dealer or another one the customer used a vacation for example ....

i saw my share horror stories and still do occasionally a wide range of Pep Boys grade toyota vehicle parts , so that's
why i frown upon them the way i do as a Unacceptable alternative ever in any way shape or form period !


i am going to take a Leap here and suggest this might just be your issue , and the reason you never see a leak visually is because any slow leak from a faulty cap , is sucked into your fan blade and ATOMIZED instantly into a dry powder and dispersed down the road as you drive

it would be extremity helpful if you posted a wide range of general perspective engine bay photos that include the entire engine bay from all 3 sides , few from drivers fender , then overhead grill front , finally the passenger side too ..

this way the big picture can be assessed , NO pun intended


some times with a land cruiser i need to step back and look at the big picture , and not focus on the small details like old crusty coolant GRUNGE seep from the use of FULL Strength ONLY factory RED fluid , NO distilled water added ......


as for the final chapter on the radiator cap topic :

ONLY source this part # and cap for your 1988 FJ62LG-PNEA

16401-54750


made in Japan by OEM parts maker TOKAIRIKA or the old skool T and R looking bird casting logo on the LH ear of cap face .......


good luck , i hope a simple high quality cap is the remedy here.......




one last thing , DO NOT BUY this cap part # anywhere else but your local toyota dealer ship in person


there are loads of good counterfeits on ebay right now and places online claiming to have your lowest cost oem PARTS DEAL........

straight up serious .

 

[EscapeWagon62]

I do have a proper fitting cap, I just could not find an adapter to test the cap with the kit I had, and based on my research so far, I have no reason to believe the cap is leaking (nor can I find any evidence of it doing so).

That's interesting, because my assumption is that in a cold car, filling anywhere between the Min-Max lines should not result in overflowing coolant unless the car pegs out at 240+etc.
I have a suspicious amount of surface frame rust near the front frame rails near the overflow and radiator plumbing that may have been the result of cooling issues during the PO's time.. who knows. So far, I have spent 15-20 mins after shutting down the car laying and waiting for a puddle or a drip to form. I also check in the morning when the car is fully cold and find nothing.


Thanks ToyotaMatt, but I have done a serious amount of reading on this forum and have seen both microfiches for potential resolutions to my problem.

Does anyone know if their heater lines and other cooling connections have this amount of dried crud on them (attachments)? It seems abnormal but they are not wet after driving nor after sitting... im really stumped.

View attachment 2610280

View attachment 2610281

View attachment 2610282

View attachment 2610283

I do have a proper fitting cap, I just could not find an adapter to test the cap with the kit I had, and based on my research so far, I have no reason to believe the cap is leaking (nor can I find any evidence of it doing so).

That's interesting, because my assumption is that in a cold car, filling anywhere between the Min-Max lines should not result in overflowing coolant unless the car pegs out at 240+etc.
I have a suspicious amount of surface frame rust near the front frame rails near the overflow and radiator plumbing that may have been the result of cooling issues during the PO's time.. who knows. So far, I have spent 15-20 mins after shutting down the car laying and waiting for a puddle or a drip to form. I also check in the morning when the car is fully cold and find nothing.


Thanks ToyotaMatt, but I have done a serious amount of reading on this forum and have seen both microfiches for potential resolutions to my problem.

Does anyone know if their heater lines and other cooling connections have this amount of dried crud on them (attachments)? It seems abnormal but they are not wet after driving nor after sitting... im really stumped.

That is not normal.

That is not normal. I ran into this as well and it was due to corrosion/buildup on the hard line, specifically on the lip/buldge that helps keep the hose on. I pulled the hose off, used some sandpaper to clean it off and applied some rust reformer with a Q-tip.

 

[Gretsch]

I may be way off base so apologies if thats the case.
Filling to the limit line when cold actually causes an overfill situation snd your overflow tank will vent that out while you are driving.
When you fill to the low line, then fully warm the truck up it should come close to the high line.
Actual level line in your overflow tank will go up and down a bit when fully cold based on ambient air temp.
If you had a leak in the system, you would find drip puddles under your rig after parking or at least drips on your frame/undercarriage.
Go look for some of those EXCLUDING below your expansion/overflow tank

@EscapeWagon62 is right on here. Mine does this. I used to worry about it and spent a bunch of time chasing leaks that didn't exist. The level on mine goes up when hot and down when cold. This should be pretty normal with the expansion and contraction of the coolant as it heats and cools and if your cap is working properly. Since mine returns to about the same place each time, I stopped worrying about it and moved on to bigger things. Since you have visible evidence of coolant leaks on some of the heater lines with still factory hoses on them, I would prolly start by replacing those lines and see if your issue is handled.

Does anyone know if their heater lines and other cooling connections have this amount of dried crud on them (attachments)? It seems abnormal but they are not wet after driving nor after sitting... im really stumped.

You shouldn't see residue like that anywhere. If you do, its coolant leaking out. As coolant leaks it dries quickly as you drive, which is why its so hard to see and why you need the pressure test to see them. A slow leak like that would prolly dry quickly enough for them to not look wet. Those are factory hoses so any of those are ripe for replacement on one of these trucks. I would start here by replacing those hoses, and then pressure testing your system again, and look at those spots with the crud on them to see if you see visible leaks after replacing them. One of the first things I did on my truck was go through and replace most all the old rubber on it. Takes some time but will make your truck much more reliable. GL and HTH.

 

[John McVicker]

Again, do a proper pressure test...OR keep going in circles.

 

[SteveH]

Does anyone know if their heater lines and other cooling connections have this amount of dried crud on them (attachments)? It seems abnormal but they are not wet after driving nor after sitting... im really stumped.

The pix you show has an original hose with an original Toyota clamp. 25 year old hoses weep a bit and sometimes rupture. Regardless of what you think of your radiator cap, I would install a new one purchased from a dealer. I would also round up some various hoses and start replacing all the OEM ones.

 

[2mbb]

I agree about getting a new cap. They are cheap and it's and easy fix.

Another place to check that is easy, is the overflow hose that runs between the radiator neck and the overflow tank. I developed a leak in mine such that fluid would be pushed into the overflow tank, but not get sucked back into the radiator--air would get sucked in. Your conditions sounds different, but you could have leak under pressure instead of vacuum. Also make sure the overflow tank cap is configured properly.