Coolant level drop.

I have a 1997 Tacoma with the 2.4L. I changed the oil today and while I was in there, I checked the radiator. I was down a quart or so and the overflow tank was almost empty. The oil looked fine though and there was no sign of it being watered down and there wasn't more than 5 quarts. No smoke from the tail pipe and the over flow tank wasn't getting air bubbles. It has been around 10,000 miles since I checked it last, but I know this was the first time I noticed the issue. Where would the coolant go? This is the third truck I have had with this motor and I have never had this happen before. The only thing I can think of is that I somehow evaporated it, maybe when I was carrying two canoes on the topper for a couple of hours. The truck never got hot though and there don't appear to be any other issues.

Any thoughts?

 

I would check all of the hoses to make sure there aren't any small leaks anywhere.

Unfortunately you probably have a leaking headgasket and are in fact burning small amounts of coolant. My truck was using very small amounts of coolant over time like you described and it continued to get worse until the headgasket failed completely.

 

I was losing it through the cap. It looked fine, no evidence of leaks, but a new one solved it.

 

How hard is it to do the HG on these? This one has 221,000 on it and I want to keep it. I also have a Land Cruiser, so I can drive that if I need to think about the HG on the Taco.

 

I will keep an eye on it and if it goes down again, I will get a new cap. I hope it's this simple.

 

It's nice to get lucky once in a while.

 

this is another good thing to check! you can have your existing cap pressure tested or just replace it for $10 or so for peace of mind

 

I am going to try the cap. It does seem a bit loose and I am pretty sure it's 19 years old, it still has the Japanese characters below English translation of not opening while hot. I actually did open it hot and nothing happened. I bet that is it.

The truck purrs, but I do also hear a light tapping noise at idle and I am wondering if it's not the timing chain slapping around. If I up the I idle just a hair, it goes away, so I don't think it's a rod knock. I could change that too, if I end up doing the HG. I have had it for about 40,000 miles and plan to keep it. Any remarks on that?


It's completely rust free, it has been well maintained and it still gets 30 MPG on the highway, and I live in far northern WI. Fluid Film does work, in case anyone wondered... any thoughts on that other issue?

 

Get the cooling system pressure tested. Or buy a pressure tester and do it yourself.

 

Is there a kit where you can test for CO2 in the coolant and do a pressure test?

 

https://www.amazon.com/s/ref=nb_sb_...+tester&sprefix=Cooling+system,automotive,292

https://www.amazon.com/s/ref=nb_sb_...n:15684181,k:cooling+system+combustion+tester

 

I had a coolant leak in my old truck and this truck. The coolant would evaporate from the heated engine and I hope yours is that simple too. Good luck, Mark

 

Could be a small hole in the upper part of the cooling system (hose or radiator or housing).
If thats the case, when hot and under pressure, you might be able to see or hear the steam venting.

 

Or you could take it to a professional who already has the tools and experience required to diagnose the problem quickly... Just a suggestion. And just FYI, coolant will NOT evaporate from a properly sealed cooling system.