Just wondering how to tell if you need to replace the head gasket and how much it would cost?

A few ways to tell your head gasket is toast are: Loosing coolant, high amounts or small. You can tell this by keeping an eye on ur coolant overflow tank AND getting a buddy to watch ur exhaust when u stomp on it and see if it puffs out white smoke [burning coolant].

Another way to tell but not as accurate is if the car overheats a lot. This could also be a thermy, fan relay not engaging, or many other things but overheating is another sign of head gasket failure.

If you dont mind spending a couple bucks, bring it in and get a "compression test" done, then can quickly check if you are loosing compression due to bad gasket or cracked head.

I replaced my own head gasket over a weekend, it is very expensive to get done by a mechanic. Hope this helps, good luck!

cost wise your looking anywhere from 500-900 est. bucks depending on where you go to have someone do it. Besides that, ^^^ nailed everything else that I would have said.

i think i messed my head gaskets too, but if im ridding like that can that affect my car.. and how long would it take to change them myself.? also how much would a compression test cost?

If u want a definate answer just bring er in and get a compression test, takes like 15 mins.