80 series - Help with cooling system (1 Viewer)

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Ghost LC

Ghost LC

Joined
Jul 23, 2020
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Hello all,

I have a 1994 LC. I’m a noob.

Truck has been overheating. I have to fill coolant directly into the radiator before I drive. I looked underneath and thought I found the issue. Lower radiator hose, looked like the source of the leak.

I replaced the lower radiator hose. Drained coolant in process.

Filled overflow, and I think I didn’t put enough into the radiator, it was not topped off for sure.

This is where I made the mistake I think. I turned the truck on and went to the post office. Started overheating.

Did I not put enough coolant in the radiator or was it because of the air let in to the radiator? Or something else

Old hose pic attached

Thanks everyone!

BA3D919E-0C1D-48CA-B473-8A6CEE9664F1.jpeg
 
The radiator should be full, and the overflow tank should be filled about 2/3rds. Don't be surprised if after getting it to temp ad the system cooling down that the overflow may be low or empty. Air in the system expands and bubbles into the overflow tank when the engine is hot - purging the air out of the system. When the system cools it creates a vacuum that pulls the coolant from the overflow tank back into the system. Once the air is purged the overflow level stays pretty static.


Just cause it is mud I have to say it - it is probably your headgasket. Welcome to mud. Also just incase you don't know - don't mix coolant colors. If it has toyota red use that, if it has prestone green use that.
 
Likely both. Assuming you drained the radiator from the petcock on the drivers side bottom lower left side and removed the passenger side lower hose when replacing it, you most likely did not have enough coolant in the system when filling just the radiator and the coolant overflow bottle. You needed to fully fill the radiator after changing the lower hose and start the vehicle and let it run until the thermostat opened, thereby replacing the coolant lost in the block. You would need to continue to fill the radiator until it appeared to be full at the top of the radiator. Assuming you still have your rear heater it helps to run the vehicle with both the cabin heater and rear heater turned on high. This helps to circulate the coolant through the heater cores and remove any air trapped in the system as well. A good last step is to use ramps, a hill or a curb to make your radiator cap the highest point in the cooling system to help burp the air out of the cooling system. Once that is done top off your radiator and overflow bottle and put the radiator cap back on. Drive it, watch your temp gauge for what it is worth, turn the vehicle off, let it cool down, and then recheck the coolant system under the hood (both radiator and overflow bottle). Top the system off if necessary.
 
I did not open the petcock, only what was drained when replacing the passenger side hose.

I’m unfamiliar, is there a thermostat in the cap?
 
This seems a lot more doable. I’m not sure about opening the cap after the engine has been running.

Thanks, I’ve lurked for while. But I want to start doing the work myself.
 
cahill said:
The radiator should be full, and the overflow tank should be filled about 2/3rds. Don't be surprised if after getting it to temp ad the system cooling down that the overflow may be low or empty. Air in the system expands and bubbles into the overflow tank when the engine is hot - purging the air out of the system. When the system cools it creates a vacuum that pulls the coolant from the overflow tank back into the system. Once the air is purged the overflow level stays pretty static.


Just cause it is mud I have to say it - it is probably your headgasket. Welcome to mud. Also just incase you don't know - don't mix coolant colors. If it has toyota red use that, if it has prestone green use that.
Click to expand...
This seems a lot more doable. I’m not sure about opening the cap after the engine has been running.

Thanks! I’ve lurked for while. But I want to start doing the work myself.
 
Toyotas4life said:
Likely both. Assuming you drained the radiator from the petcock on the drivers side bottom lower left side and removed the passenger side lower hose when replacing it, you most likely did not have enough coolant in the system when filling just the radiator and the coolant overflow bottle. You needed to fully fill the radiator after changing the lower hose and start the vehicle and let it run until the thermostat opened, thereby replacing the coolant lost in the block. You would need to continue to fill the radiator until it appeared to be full at the top of the radiator. Assuming you still have your rear heater it helps to run the vehicle with both the cabin heater and rear heater turned on high. This helps to circulate the coolant through the heater cores and remove any air trapped in the system as well. A good last step is to use ramps, a hill or a curb to make your radiator cap the highest point in the cooling system to help burp the air out of the cooling system. Once that is done top off your radiator and overflow bottle and put the radiator cap back on. Drive it, watch your temp gauge for what it is worth, turn the vehicle off, let it cool down, and then recheck the coolant system under the hood (both radiator and overflow bottle). Top the system off if necessary.
Click to expand...
I did not open the petcock, only what was drained when replacing the passenger side hose.

I’m unfamiliar, is there a thermostat in the cap?
 
Yeah, check (replace) the thermostat. Sounds dodgy.
No, it is inline with the piping of the coolant system.
Search for threads on it. The pics will show the way.
 
No Tstat in the cap, the Tstat is in a Tstat housing, but if your radiator cap is some no name aftermarket cap, replace it with a new Toyota cap.

To find the Tstat you can follow the lower radiator hose toward the engine; it will be hose-steel pipe-hose, then a cast aluminum pipe held in place by three 12mm nuts.

So if you still get overheating with a full radiator/cooling system you can remove those nuts (cold engine), pull back on the Tstat pipe and hose and yank the Tstat out of the housing. Then one way to see if the vehicle is still overheating is to leave out the Tstat and button the pipe/housing back up, fill with water (temporary) and drive the vehicle. It should run a bit colder than normal with the Tstat removed, but if the vehicle still overheats you have bigger problems. If it doesn't overheat with the Tstat removed then replace the Tstat with a new correct Toyota Tstat and refill with 50:50 coolant and distilled water.

If you're going to flush your cooling system (good idea if the coolant looks dodgy/rusty) be sure to also open the block drain. That's located on the left side of the lower engine block; straight in from the left wheel well. If you kneel down and line up about with the 1-2 O'clock position of the tire (wheels straight ahead) and look straight in that's where you'll find the block drain.

1FZFE block drain plug location.jpg
 
Last edited:
As cahill mentioned above, replace Toyota red coolant with red, or green anti-freeze with green. Do not mix the two! Also, if it is red, make sure you you get the red for the older Toyota vehicles such as the 80 series and not the Toyota pink used in newer vehicles. If it still continues to drink coolant and you don’t seek any leaks or coolant under the vehicle after a driving cycle, then as Cahill alluded to start checking for a head gasket leak which is fairly common with the 80 series at some point in their life.

With mine, a 96 LC, the first sign was disappearing coolant which as it progressed manifested itself by a gurgling sound and bubbles in the overflow bottle after driving it caused by the exhaust gases mixing with the coolant. Another tell tale sign is a large amount of white smoke coming from the tail pipe upon a cold start. However, the white smoke tends to dissipate once the engine comes up to operating temperature. You can also check on the inside of your oil cap to see if it appears clean/dry or has a brown/milky looking sludge inside the cap.

Hope for the best, just a leaking radiator hose and cooling system refill and topoff. However, if it continues to drink coolant with no visible leaks, then prepare for the worst “a blown head gasket”.
 
No, never open the radiator cap on a hot engine as that is a good way to scald yourself. I was talking about a coolant refilling and air burping procedure on a cold engine startup. Sorry, I didn’t make that clear in my previous response.
 
Okay so I filled the radiator fully. Started and we are good so far.

I’m attaching pictures of some relevant info if anyone sees anything

Thanks everyone for helping. Trying to prepare for a bday trip with the gf this weekend.

A51B7E30-DBF9-482E-BB77-6BA28DCBC6B5.jpeg


767A1A9C-E8E5-400E-919B-6C716713B601.jpeg


8923EBF5-6C95-4A6F-AD27-1AEC676E82B0.jpeg


94C19835-6A59-40C8-AC18-3F58E206744F.jpeg


8379CF2D-A1B5-4696-AE99-B02E2694DE85.jpeg
 
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