Curious about something

[jeffjeff]

Just wondering , I have a 97 Taurus 3.0 . The antifreeze resovoir full line is about a third of the way down the tank. What could happen if someone filled it to the top and ran it that way, would it damage engine, like maybe blow the head gasket or anything else like the radiator? or just blow out the cap?

[shorod]

As your engine heated up, the coolant will expand and overflow out of the reservoir/overflow tank. The hot coolant will then need to vent out of the tank, causing steam to roll from under your hood most likely.

Might I ask why you would want to fill it all the way? Unless you have a leak in your system, you should never need to fill it beyond the "full" mark.

-Rod

[jeffjeff]

Originally Posted by shorod

As your engine heated up, the coolant will expand and overflow out of the reservoir/overflow tank. The hot coolant will then need to vent out of the tank, causing steam to roll from under your hood most likely.

Might I ask why you would want to fill it all the way? Unless you have a leak in your system, you should never need to fill it beyond the "full" mark.

-Rod

Well awhile back I took my car to a muffler brake shop, to get antifreeze flush , my radiator leaked temporarly at the seal, lost enough antifreeze that I guess boiled somewhat and knocked off some rust in engine , turning antifreeze muddy looking. Guess the rust particles plugged up the leak. Anyway they said we'll have your car in , in about 10 min. well an hour and a half later my car was still sitting out front , I got pissed and left and called there corporation about it and they said to go back and they would flush it for free. Well I automatically knew not to go back but I did , u know how if you complain and they get chewed out they probably gonna screw with your car somehow. Well my reservoir tank was only about a inch below full line and while I was standing there watching he filled it all the way to the top and over , then put the cap on let it run for awhile and took cap off , of course antifreeze started gushing out and he said you got a blow head gasket , thats not suppose to do that, u got exhaust gases blowing out through here. I said well you overfilled the tank is why it doing that. anyway he wouldnt do a flush said it wouldnt do any good till I got the head gasket fixed. Well months later after replacing reservior cap and the leak stopped the tank level has been staying right at the full line. so no blown head gasket like that a-hole was trying to say, course he got out of that free flush. but just wondered if he was trying to make the head gasket blow by purposely overfilling the tank, it was so obvisous that he overfilled it, he just poured it in real fast. not a little at a time like anybody normally would do.

[shorod]

You should be fine for now. The gushing out was most likely due to heat rather than compression forcing coolant out. In his defense, some Taurii were known for blown head gaskets. However, it would not be caused by overflowing the recovery tank.

-Rod