Head gasket leak?

Looking for suggestions in which direction to go with this. Back story is I did a coolant flush a week ago and noticed infrequent bubbles from radiator after bleed. I’m at 200k miles now with no misfire, no CEL, no white smoke or sweet smell. No loss of coolant and engine essentially runs flawless at this point. I want to catch a potential problem before I overheat it and warp a head or burn out a valve.

I went for a leak down test and cylinder 1 is 18% and 2 is 20%, all others are 15%.

The tech didn’t note where the leak might be from but said it’s “in spec” and said head gasket looks good. I’m following up with them to get more info on their findings since they didn’t note any other details about leak.

 

Get a coolant test that turns color if there are exhaust gases in the coolant. Cheap and easy to do. If no color change, your head gasket is AOK.

Not sure what those percentages mean....they should be in PSI. If you paid for a test, you should get wet and dry numbers...otherwise, what's the point?

 

I did a block test, fluid stayed the same color but there aren’t a lot of bubbles


As far as I know, the leak down measures percentage lost under constant pressure vs a compression test (wet or dry) measures psi attained during crank.

 

Oh, I see. Sounds like a healthy engine. Just don't allow it to overheat.

 

The last time I did a coolant change, I used a vacuum coolant filler. It pulled all of the coolant from the system and was able to test for any leaks by being able to hold a vacuum. Then, it fills the system super fast without a mess. No bubbles once the system has been burped.

I think that some of the older Toyotas do have a bleed valve on the thermostat housing to manually burp the system.

 

I seem to be having the same issue with mine, keep having to put coolant in the radiator after every week or so. Already replaced radiator and did a coolant test and looks fine. Truck runs fine no white smoke no gunk in the oil no misfire thinking possible water pump but I don’t see any leaks from it. Were you able to get yours figured out?

 

Mine is a 2004 V6 176K miles and I was only using water when it ran down the freeway, not around town. 1/2 of the coolant reservoir gone in 600 miles. Ran great, no white smoke, missed fired upon startup a couple times after running on the freeway in 6 months. Block test showed the fluid did not change color. Radiator/system pressure test showed 25 lbs of pressure down to 0 in 10 minutes so I knew I had a leak somewhere. No pink coolant leaks on outside of engine, I even took the skid plates off. No water in the oil. When I did the Head gasket job last week the gasket showed the leak was in the narrow spot between 4 and 6 cyl. As I read most are there. It is a big job. Mine was a very slow leak that slowly was getting worse. Sorry to say I think yours will too. I use mine as a 2nd car and as an overland and trail vehicle out in the wilds of Utah so last thing I needed was for it to get bad when out in the middle of nowhere.

 

The newer models (after 06) don’t usually have HG problems unless it was overheated and a head warped or something. Why do you think it has a leak? Sounds like you’re chasing a problem you don’t have.