Make - Toyota
Model - Hilux
Year - 2016
Mileage -28000 Miles
Tranmission- Automatic
I’m experiencing some weird behavior with my coolant. My vehicle contains an expansion tank system and a radiator without a cap.
i noticed the coolant was below the Low level and topped it up using Toyota Original Long Life coolant as recommended by my owners manual.
After driving for a day the coolant dropped back to the same level and remains stable at that level when cold ever since.
I assume if there was a leak or blown head gasket I would continuously be loosing coolant, but it just remains stable at that level below low.
I have topped of three times after and confirmed the same behavior.
any ideas ?
What the heck it's not overheating change the radiator cap and pray it's just that being weak
Just because a Toyota dealership serviced it almost guarantees that they didn't do it correctly.
You need to find the source of the leak (if there is one) first. Any puddles or drips? White smoke out the exhaust?
No puddles, drips or white smoke out of the exhaust. Oil isn't milky coloured either.
When was the last time the system was flushed and refilled? You may have air trapped in the system, most notably, the circuit to the heater core.
I recently bought it used. The seller told me flushed all the fluids including the coolant 3100 miles ago.
How to go about getting that air out?
Park the vehicle facing up hill. Run the engine with the heat setting on High. This will force any trapped air to the top of the system and into the recovery tank.
The level the water settles at in the expansion tank is based on how much water gets pushed out when the coolant heats up. So if the level settles at Low, then the coolant is expanding more than expected. Some possibilities are;
- non-standard expansion tank for that engine/radiator
- less space inside the coolant system. So this could be rust, sludge or a blockage. I had my radiator cleaned once just because I had it out, and they told me it was 40% blocked. I had no symptoms.
- air entering the system via the suction side of the water pump. Bearing or gasket in waterpump or anywhere with negative pressure. Normally this would display as a leak when cold and not running, but stranger things have happened.
- compression gases entering the coolant. You can test for this with chemical indicator.
- faulty seal on radiator. Water can get pushed out when hot, but suction is not maintained to draw it back in when cooling
- coolant boiling as it gradually loses it's properties over a couple of years. Get an accurate test of the water temperature, not just a C -> H gauge on the dash. Hilux temp gauge is actually built to be less responsive so drivers did not get concerned with the rapid fluctuations that occur in those engines. For example my exhaust gas temperature can go from 620°C to 200°C within a kilometre, so coolant can fluctuate wildly as well.
So as people have said; eliminate air, ensure fresh coolant additive, ensure no rust (should be clean water and coolant additive, no rust), have radiator cleaned internally and externally, test for compression leak gases in coolant, check parts (radiator, tank, etc) are original spec, and pressure test the system for leaks.
Don't add a coolant sealer unless all is well apart from a leakage that would be difficult to repair. Do add a rust inhibiting antifreeze that raises the boiling point, but do that after flushing the cooling system clean. The rear heater circuit adds a few complications if it is at fault.
Just wondering if this was ever solved?I too have a 2016 hilux that was recently loosing coolant and it shut down my heater and blew a head gasket .I bought it brand new 7kms on the odometer and have had it serviced every 15,000kms can not figure out how there was airpockets in coolant when i never touched the motor ever as Toyota always serviced it...has anyone els had problems like this with their new trucks?
