Possible antifreeze leak on my 2008 Tundra SR5 4.7

I just got a 2008 Tundra SR5 4.7 with 188k on it. Noticed the coolant was low. Topped it off, popped the hood and noticed it was getting low again. The res tank was almost empty after sitting overnight. (These pics were taken over a period of a day) The temp gauge has been normal and hasn’t seemed to be overheating. Me and my mechanic buddy looked and couldn’t find any wet spots on any tubes or wires in the engine bay. There was a small amount of thin white smoke coming from the exhaust when the truck is in park and you rev the engine suddenly. The smoke disappears quickly. (No white smoke just sitting in idle. Only when you rev it in park) We took it for a drive and I stepped on the gas and we saw no thick white smoke coming from the exhaust when we stomped on the gas. What could this be and has anyone else had similar issues. Have an appointment at a shop for them to look at it themselves. Hope it’s not bad since I just got the truck :/

 

Sometimes those radiators will have micro cracks along the top plastic, which open up when driving. Might be something to check if nothing obvious.

 

I would say it sounds like a head gasket leak, but I believe you said that you topped off the coolant and came back the next morning and the level was lower without ever starting the vehicle. Interesting. In my 3.4L 1st gen it ended up unfortunately being a head gasket, but maybe some 4.7L owners will have more insight.

 

I’m worried it’s a gasket. Not seeing much white smoke out the exhaust. A tiny bit when it’s parked and I rev the engine..but it’s not thick white smoke like I’ve heard will happen with a head gasket. But when I’m out on the road and I step on the gas hard to rev it, I see no smoke at all. So I’m confused for sure.

 

If I remember correctly with my situation I never had any type of thick white smoke it was very mild and would typically only happen during a cold start in slightly colder weather. I don't recall ever seeing white smoke once driving at any point. Then again, the 3.4Ls are more known for head gasket problems so hopefully that's not the case with your 4.7. Are you getting any misfire codes? P0300-P0308?

 

I would also browse the YouTube channel "Toyota Maintenance." He has a lot of videos regarding the 4.7L engine, but I'm not sure if he has one specifically for coolant loss. Might be worth a search.

 

Any coolant coming from the engine valley between the engine and trans when parked at an incline?

 

I haven’t sent it up for any codes yet. Did you happen to open the radiator cap and look at the fluid? Just did with mine and the color looked like what my antifreeze is. Was told a tell tell sign of a blown gasket is a brown chocolate milk type color when you open the radiator cap.

 

I never had any of that. My coolant looked normal. I would just loose a lot of it and have to top it off often. I never had any overheating either. I think those are likely signs of a more severe head gasket leak. I will also idle rough and have the misfire codes that I mentioned. If it is determined by a mechanic that you have a head gasket lead you might be able to try some sealant solution that you put into the radiator, but that is often seen as a temporary fix if it does work.

 

Ugh… okay. Thank you for the replies

 

No problem. Theres definitely a chance it can be something else, but this was just my experience with my 3.4L