Over the past 6 months or so my radiator has lost antifreeze. I cant find a leak anywhere and hoses look fine. Any ideas where to look for a possible leak site. Im going to have to do a flush pretty soon myself is there anything i can add that would seal up the radiator from any hair line leaks. Thanks for any input. Also how much antifreeze do i need to fill our radiators up. Ive heard two different answers ive head (2) 1 Gallon containers and ive heard (3) 1 Gallon containers then the rest with distilled water. Also has anyone tried one of those off the shelf flushes that you put in fill with water run your truck then empty and refill with antifreeze. Thanks for any tips.

 

It could be a pin hole somewhere or maybe a loose cap. They do sell stuff to seal pin holes, you just have to be careful with what you use. Hooefully someone will chime in with suggestions. Ive only used bars before and had ok results but it was an old truck that wasnt my daily driver.

 

2 things here

1. It might be one of your side tanks on the rad. My passenger side tank developed a small leak and it turned into a nice puddle when the system became pressurized. Ended up just replacing the whole thing.

2. If your truck came with an oil cooler or oil filter relocation system then check near the block where it bolts up. Many people find the leak there due to poor gasket design. My 97 as the SD style oil cooler so i can not use normal F-150 style gaskets but i think you might be ok.

Note: Careful with using Stop Leak, some of those products like to gum up a cooling system worse than Dex-cool. i have seen water jackets and t-stats clogged beyond repair from too many bottles of that stuff to stop leaks. When i was working for an auto parts store a lady came in for her 5th bottle of the stuff (she used the big head gasket repair bottles). Ended up being a broken T-stat housing and she clogged the water jackets so bad she need a complete tear down to clean it all out.

 

Check under your floor mats and see if the carpet is wet to rule out a leak in the heater core.not that it can be ruled out completely, but if it's wet you know there could be a leak there.

 

Checked the floor mats and they are dry. I will run by a radiator shop and have it pressure tested. Is that something i would have to leave till it cools or can they do it anytime whether its hot or cold.