Has anyone ever seen this before. I’ve heard a lot of people say it’s because of bad coolant seals but it’s not coming out the top of the AST tank it’s coming out of a molding joint. Should i just replace the tank or do you guys think it could be bad coolant seals.

The coolant is coming out of the highlighted joint when the car gets hot. Has anyone seen this? Bad AST tank or is it bad coolant seals?

 

One of the most infamous parts for failing, and one, if not the 1st mod anyone should do to their FD...replacing that plastic time bomb.

There are plenty aftermarket ASTs made of aluminum that wont fail. I'll bet you can find one in this site's 3rd gen for sale forum for around 100 clams.

 

Do you think it’s just a bad tank or do you think it’s caused by bad coolant seals?

 

I'll bet it's the tank if you still have the almost 30 year old OEM one. They really are notorious.
Cheap and easy to replace.

 

Trust me, replace it. Mine blew on the road, HUGE mess in the engine bay, coolant EVERYWHERE, horrible time cleaning it all not to mention getting towed home.
my seam blew in the exact same place, literally blew in half at the same seam.

 

Like Natey stated it is most likely your AST tank. For one they are not supposed to leak and two you didn't state any symptoms of bad coolant seals.

Coolant systems are considered closed systems that work in conjunction with pressure and vacuum (for a lack of a better word). So when your car heats up the coolant expands and it dumps in your overflow tank, when it cools back down it sucks it back into the engine. When coolant seals start to go a common symptom is unexplained coolant loss. The reason is coolant ends up seeping past the coolant seals which ends up being evaporated in the combustion chamber. You search but can't find any leaks and yet you are low on coolant no matter how many times you refill. Another symptom is thick, and I mean very thick white smoke out the tail pipe upon cold starts (coolant is burning off) but this isn't the normal white smoke that all cars get from water condensation in the exhaust. Nope it is unmistakable, so don't get nervous when you go look at your car (because I know you will). Like I said there is no denying it. Another symptom is coolant being dumped out of your overflow tank due to exhaust gasses being passed through via the bad coolant seals. Usually in this scenario the coolant doesn't get sucked back in from the overflow tank because there is air in your coolant system. But this issue is not exclusive to coolant seal failure. Because other issues can cause air to be trapped such as: An improperly burped coolant system or a bad AST (that ends up sucking in air). But like I said, you didn't mention any symptoms like that so go replace your AST and go back to enjoying your car.