Coolant Low on a 2018 4runner

My boyfriend and I were doing the 60k mile tune up last night and noticed that the coolant was low. Any thoughts on why it’s low and what could be wrong?

 

Was the truck running, off, hot or cold?

 

Fill it even with the full line and monitor. Get back to us with results after 100-200 miles, no need to worry yet.

 

It was cold.

 

don’t check it with the vehicle running. Check it with the vehicle off and cold. With it running, the coolant is circulating in the system, not in the reservoir

 

We had it on for roughly two minutes to turn the car around. I’ll check it again with it off and cold. Thanks!

 

That’s not enough time to have any change in reservoir level.

The cooling system is a closed system with the radiator cap working like a relief valve. When at operating temp the fluid is hot and has expanded a little. This is why you will se a slight level change in your reservoir when the engine has run a while.
As the coolant drops in temp, some fluid will pass back to the radiator via the reservoir back through the cap.

This is why I say fill to full line (engine cold) and monitor. After about 200 miles you will see if the coolant level is dropping when you check level at ambient temp before running the engine an extended period of time.

 

What’s the logistics on filling coolant? Does it have to be the exact same brand used before?

 

Yes there is a Toyota specific coolant, and the Zerex Asian Red formula. Both come in a 50/50 ready to use formula. 50/50 means equal parts coolant and water. Zerex is cheaper and usually at any parts store. Walmart might have it as well.

 

Regardless, it is better to check the level correctly before dumping a bottle of coolant into it.

 

100%

 

I’m going to say this because safety and all. not everyone thanks about it...


Do not take the radiator cap off after the engine has been running.

 

Hello,

Noticed my 4runner had basically the same level you posted in your photo. 2020 with 48k miles.

Did you ever find the issue? I added coolant in the meantime to the "Full" line as stated in the owners manual using the 50/50 Toyota blend.

Monitoring overflow reservoir for now.

Thank you!

 

Any update?

 

Yes! no blown head gasket............ luckily.

Reservoir is staying at the correct level and I have not had to top it off. I found another thread on a forum, this person was looking at 5th gen 4runners on dealer lots and all of them had low coolant levels - source: "https://www.toyotanation.com/threads/coolant-levels.1682052/"

Only thing I have noticed now is a little big of spillage but there are others that have also reported this when using the car off-road.

Did you notice your coolant level was low or why do you ask? just curious.

 

Bought a used 4runner with coolant as same level. No symptoms, runs great. I saw a few posts of 5th gen that had low coolant for some odd, unexplained reason.

 

My 2018 is always at or below the “L” line. I recently drained and replaced with one container of oem Toyota 50/50 mix. 4Runner is running fine in this Texas heat.

 

Are you saying regardless of the fill level, it just returns to at or below L and stays there?

 

I follow the “Viking” on YouTube. He’s a Toyota mechanic and has a small YouTube channel. He did an episode a while back on coolant change. I bought my 4Runner new in 2018. Even though I’ve been to Utah and Colorado several times I only have 35000 miles on it. I’m getting ready to go to Idaho and figured a coolant change would be a good idea. I followed the Viking’s guide exactly. Didn’t think anything else. Then I was under the hood doing other stuff and noticed the low coolant level. I started to get paranoid so I checked the volume of the Toyota coolant container and because my local auto store wouldn’t take the coolant it’s still sitting in my garage the coolant I drained. Both are approximately the same. So instead of going and buying a new container for just a few ounces, I started being conscious of my temp driving around in 100° stop and go traffic. It’s been a few weeks now with no issues.

 

Ok. I bought a used 2011 with the same level as you pictured here. Seems a few people have this same amount for some reason.

 

I should find out where he works. Based on things I've seen in his videos, he lives about 12 miles down the road from me.

 

Probrably nearby Toyota dealer.

 

It’s probably low because the system wasn’t completely burped, either from new, or from the most recent coolant change. I wouldn’t leave the resevoir below the low line, even if you were able to make a long trip without a problem.

Fill it to the max line, and monitor. If it’s completely burped, the coolant level should stay the same.
If it doesn’t the system is leaking out coolant somewhere.

 

Full when cold. Surprising how long these systems can hold onto air.

 

Wait, are you saying it’s full when cold, but drops below min when warm?

 

Bought a 2007 4Runner a few months back with a coolant reservoir that looks exactly like this. Runs and drives fine!

Any updates on this?

 

Top it up to max line and drive for a few days to see if the level falls. Inspect when the vehicle is cold.
If it does, you have a leak. If it does not, you are sorted.

 

I drained my radiator and put in 1 container of Toyota oem fluid that I purchased from the dealership. I then drove 5600 miles following the continental divide trail. With absolutely no problems whatsoever. My coolant level in my reservoir stayed the same‍♂️

 

Awesome! Thanks for the quick response. I'll do the same if mine drops again. Did you follow the Viking Garage tutorial for flushing the coolant?