The Cooling System Troubleshooting thread

[llamavan]

And yes, replace the radiator cap first. Simple, cheap, and quite possibly the culprit.

Gwen

[Knibbzy]

Hey guys so an update on the cooling system for my 1994 Toyota Spacia 4YEC Engine, Replaced the coolant radiator cap and filler neck to overflow coolant hose and installed a aftermarket coolant gauge, been driving the car and my coolant does not get above 90 degrees Celsius / 194 Fahrenheit and when warm stays between 77 - 87 degrees Celsius / 170 - 188 Fahrenheit so I think its safe to say the cooling system is running fine and I have no overheating problems or issues and I dont see any green coolant on the floor or driveway and when warm the overflow is full and normal and when its cools downs retracts back. Also cool feature about the water temp/coolant gauge is I can set a static temperature to give me a warning if the car is starting to overheat and it will start beeping.

Here is a video of the coolant gauge after a road test:
https://www.youtube.com/shorts/jvz8wP6aHJU

[Knibbzy]

So my cooling issues are still persistent, its winter here in Australia so we have been getting cold mornings and cold afternoons, the coolant gauge allows me to see what my temps are at, short trips it has been fine stays around 80 to 90 degrees celsius, but the other day I got stuck in a traffic jam 1 hour of stop starting driving, then turns out a semi truck was broken down between a 4 way traffic light intersection which blocked all directions I had to do a u-turn and drive onto the freeway to get home a 40 minute detour, when on the freeway I was travelling 100 km/h for 20 mins my temps kept creeping up to 95 to 100 degrees, then when I got off the freeway exit and was stopped at the traffic lights the temps kept creeping up to 105 - 107 degrees and went up and down until I got home. I am gonna do these things:

- Replace Thermostat
- Flush Cooling system see if any gunk is stuck in the radiator, possibly take radiator out depending how lazy I am
- Replace upper and lower radiators hoses
- Replace Coolant Sensors

I am also wondering how does the viscous fan work and what detects the fan to kick in, I dont really hear my fan kick it and suspect that maybe its not working, is it a sensor or is the oil in the viscous coupling that makes the fan kick in when it gets to hot.

[timsrv]

Check out this thread: https://www.toyotavantech.com/forum/...upling)-Thread

[Knibbzy]

After many confusing months and my cooling system giving me woes and problems, I have finally figured out why my cooling system was losing coolant every so often and my overflow would be near to empty.

It was good I replaced these components with new parts in time for summer here in Australia that is coming up this will give me reassurance that my van will survive summer, so I am not to bummed that I spent money on these things such as my:

- Radiator Cap
- Thermostat
- Water-pump
- Upper and Lower Radiator Hoses
- Overflow Hose from water outlet to overflow reservoir
- New Toyota Long Life Coolant (Toyota Red)

Now for the final reveal what was making my car lose coolant, THE WELCH PLUG/FREEZE PLUG ON THE LEFT SIDE OF THE ENGINE BLOCK, The second welch plug on the engine block had built up coolant around it and corrosion and there was a trail of coolant going down the block all the way back to my gearbox I had a look and yep when the car was warm and running, there was coolant weeping out of the welch plug, so I have finally figured it out after many months, for the time being I have just gooped some Toyota Black Sealant on the welch plug until my new ones come in from Toyota to be replaced, luckily its the second one so I can have somewhat easy access to the welch plug and can replace it with not to much struggle fingers crossed. So guys and girls check your Welch/Freeze plugs to if you have replaced everything on your cooling system and your car is still overheating or losing coolant.

All The Best
KNIBBZY