mystery coolant leak identified

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Keep in mind, as OAT drops so does coolant level.

Only bad leaks leave a puddle. But one of the nice things about Toyota "red" or "pink". They leave behind a colorful dry crusty at any leak. In searching, make sure to check ever inch of head gasket along with both front and rear weep holes. Don't forget to inspect heater cores as well.

Old radiator cap along with sticky thermostat, may result in loss at overflow of reservoir. In this case; level usually stops dropping as reservoir nears the low line, unless engine is really overheating.

Overnight pressure test of coolant system can revealing.
 
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@PabloCruise , this did solve my coolant leak. As I stated above if you are removing your intake, replace all of the gaskets for the heater bypass both front and rear. Take a good look also around the front bypass mount location for any red crusty leaks which could point to a gasket leak. You will have to remove the intake to replace the front bypass gaskets. Also check all of your lines running to the rear heater system.

One thing also, have you drained your system, replaced your radiator or flushed it out recently? The reason I ask is in my experience when I changed my radiator I had to top off my overflow a few times after running my rear heat. There must have been air trapped in my system even after running the truck for some time.
 
No recent cooling system parts replaced!
But I know what you mean, getting a good “burp” out of the cooling system can be tricky. I like to use this big funnels that go on the radiator inlet to help, as well as elevating the front end as high as I can.

I will investigate the front and rear bypasses and see if that is where I loosing coolant.

Thanks!
 
Best way to make sure "burped". Check radiator level after 8 hr cold down with front elevated. Keep doing this until it will not take any more coolant after a cool down at least twice in a row. Reservoir should also hold above low line on coldest morning.
 
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2001LC said:
Keep in mind, as OAT drops so does coolant level.

Only bad leaks leave a puddle. But one of the nice things about Toyota "red" or "pink". They leave behind a colorful dry crusty at any leak. In searching, make sure to check ever inch of head gasket along with both front and rear weep holes. Don't forget to inspect heater cores as well.

Old radiator cap along with sticky thermostat, may result in loss at overflow of reservoir. In this case; level usually stops dropping as reservoir nears the low line, unless engine is really overheating.

Overnight pressure test of coolant system can revealing.
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I am not overflowing from the res, she has chronically needed a little "top-off" since I got her. They did the radiator and heater T's before I got her, but I would be fine changing coolant and T's to fix this little coolant loss.

EDIT: We got the truck 3 years/~50k miles ago. Coolant flush and heater Ts ~60k miles ago. Timing belt and water pump ~70k miles ago.
 
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PabloCruise said:
I am not overflowing from the res, she has chronically needed a little "top-off" since I got her. They did the radiator and heater T's before I got her, but I would be fine changing coolant and T's to fix this little coolant loss.
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If you've looked closely and still can't find. Your welcome to come by (South Denver). I'll take a look any see what I can find. PM if you like to.
 
2001LC said:
If you've looked closely and still can't find. Your welcome to come by (South Denver). I'll take a look any see what I can find. PM if you like to.
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That is so cool of you! Thank you! Little sister lives down in the Centennial area, so that is a definite possibility.

Thank you, you seem to have a very deep knowledge of how to best maintain the 100/470 series Cruisers.

I will switch to PM.
 
I got as far as cleaning the garage floor and getting visual of a leak on the floor about the size of a silver dollar. It felt a little slippery - like coolant.

The leak was under the driver side A arm, and I think it came out the junction between the metal and plastic skid plate. So it would make sense to drop the skid plates for better visual.

Then, during the week the retractor stopped working on the driver seat belt! So I have not driven the truck the rest of the week.
 
This is good news. By this I mean it indicates an externally visible leak.

Skid plate removed will make easier to inspect, but you can inspect for wet and/or red flaky dried coolant with it on:
Radiator hose.
3 small hoses on front of engine. (The throttle body, water inlet to oil cooler coolant hoses).
Water by-pass joint front (both sides)
Water inlet.
Radiator.
Water pump (Weep hole at bottom of timing chain cover. (look through oil filter hatch or radiator drain hatch to see weep hole))
All those can be seen with skid plate on.
One hard to see that rarely leaks goes from block to oil cooler. Mirror is helpful here.
Head gasket can be inspected with mirror. But really helps to have all shielding off.

If unsure of any of these location, ask, I'll post pictures.
 
Thank you!
I will check those first.
My first priority is the seat belt. If it is not an obvious fix, I will need to get it out for 24 hour repair. This is my wife’s truck, so I need to have it up and running.
She is out of town, so I have some time, but I also need to take care of our boy, so my time is divided.
 
Can't help with that! I've never had the issue, but I'll bet someone in mud has.
 
Just wanna ressurect this thread as I am in the same situation. I have been having some coolant loss ever since i got my 2001 land cruiser. I brought it to an auto shop for a pressure test and discovered a leak in the lower section of the radiator. Fast forward to yesterday and I got a denso radiator installed. Before leaving the auto shop the coolant level was above the full line while the engine was hot. Last night before i slept it went down to the FULL line. This morning after not driving the truck for at least 8 hrs it went and inch below the full line. Drove it for 15miles at least and it went back to full but never went over to where it was yesterday before i left my mechanic. Is it normal for the coolant level to go down? If so, then how much every month or year should coolant go down and how often should you top the reservoir off.

Also, been reading how to burp it and people have their own way doing it. Should i top it off while the engine is cold or hot? Take note this is within a 24 hr perior.

20200301_143951.webp


20200301_163505.webp
 
YetiCruiser14 said:
Just wanna ressurect this thread as I am in the same situation. I have been having some coolant loss ever since i got my 2001 land cruiser. I brought it to an auto shop for a pressure test and discovered a leak in the lower section of the radiator. Fast forward to yesterday and I got a denso radiator installed. Before leaving the auto shop the coolant level was above the full line while the engine was hot. Last night before i slept it went down to the FULL line. This morning after not driving the truck for at least 8 hrs it went and inch below the full line. Drove it for 15miles at least and it went back to full but never went over to where it was yesterday before i left my mechanic. Is it normal for the coolant level to go down? If so, then how much every month or year should coolant go down and how often should you top the reservoir off.

Also, been reading how to burp it and people have their own way doing it. Should i top it off while the engine is cold or hot? Take note this is within a 24 hr perior.

View attachment 2226442

View attachment 2226444
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Yes, as stated earlier in the thread, it's totally normal to have to top off your coolant a couple of times after refilling the system. Air trapped in the system will work it's way out and be displaced by coolant. There will be fluctuations between hot and cold, but those should be fairly consistent once the air is all burped out.
 
Eyedaho said:
Yes, as stated earlier in the thread, it's totally normal to have to top off your coolant a couple of times after refilling the system. Air trapped in the system will work it's way out and be displaced by coolant. There will be fluctuations between hot and cold, but those should be fairly consistent once the air is all burped out.
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So is my cooling system fine/normal?
 
YetiCruiser14 said:
So is my cooling system fine/normal?
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You have no evidence of a problem at this point. Top it off the first few times you drive it as the air burps out of the system. If you keep having to add significant amounts of coolant aftera few days, then maybe you have a leak.
 
Anyone have any input on the attached image? Been smelling coolant a bit lately. System is overly maintained, recently flushed , new OEM radiator.

KIMG2440.webp
 
Cleaned up area and seems like a fresh leak, will keep an eye on it.

If this continues to seep what do I expect if removed to fix, is there a seal or the black sealant that's used in other areas of cooling system?
 
Mike NXP said:
Cleaned up area and seems like a fresh leak, will keep an eye on it.

If this continues to seep what do I expect if removed to fix, is there a seal or the black sealant that's used in other areas of cooling system?
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That is the location of the thermostat. The thermostat o-ring appears to have failed. Pick up a new OEM coolant, thermostat and o-ring and replace. You could also check to make sure three bolts that hold housing on are tight to spec.
 
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