Slowly loosing coolant

Hey everyone, my 2007 5.7 Tundra slowly looses about half an overflow resivor of coolant about every 8 months or so. Last year i did some heart surgury to fix the valley plenum leak (3 days, what a great time), i see nothing obvious and it's so slow, is this "normal"? should i be looking somewhere besides the top & bottom of the engine? thanks-o-bunch for advice!

 

I’d pull an oil sample and send it to Blackstone.

 

no milkshake oil either, nothing appears out of ordinary

 

How often do you change the oil? If it takes 8 months to lose half the overflow I wouldn’t expect a milkshake. Ruling out a HG leak would be worth the $35 for me.

Do you ever smell any coolant when you shut it off?

 

Oil change is same frequency, no smells since I did the valley pan fix. Interesting, I like your thought process, thank you!

 

Coolant leaks are inevitable. Check for pink crusties (dried coolant) all around the radiator and the water pump (behind the serpentine belt). Mine was leaking from both.

Since I replaced both the radiator and water pump, coolant levels have not changed. Good luck.

 

First post, I think. My leak turned out to be the radiator cap had broken off at the bottom. This caused the antifreeze to be gradually pushed out of the overflow tank. Easy to check. Bill

 

My radiator cap is all sorts of not right, but i have a custom all aluminum radiator that doesn't take OEM caps.... oh what tangled webs i've weaved

 

'ColdCase' OEM on the Left side; OEM from Amazon on the right.

 

My 08 does almost the exact same thing. Every few months I have to top up the overflow. Seems to happen more in winter when it's very cold out. I found some crusty pink trail running down my bellhousing but I haven't investigated any further. I suspect/hope it's just a heater core hose leaking at the firewall. Hopefully not the heater core itself lol

 

07 5.7 with 132k doing the same thing...Temp stays @ under half.. no milkly oil, no smell, no smoke, radiator doesnt bubble with truck running... no codes with my autel maxisys.. no leaks of anykind except the cam towers on both sides... just did all the fluids from front to back except the coolant because the radiator was done a couple of years ago

I'v been marking the coolant res and watching it.. it will lose a inch or 2 in a tank of gas... thinking about pulling my plugs and checking for clean ones and bore scoping the pistons

Just degreased the engine bay for a hour today in prep if i have to work on it...... Does anyone have the part number for the correct radiator cap? Im seeing 2-3 different part numbers depending what 5.7 rads I look at in what vehicle I want a toyota one