Hey guys, I've been having a lot of trouble recently with my cooling system. It seems like every time I fix one problem, I'm encountered with another. Fortunately, it's usually something small, like a bad rad cap or a thermostat. Right now my current situation is a small leak somewhere in the system. From the location of the coolant I can see, I *believe* it may either be the AST or the lines associated with it. Now as an experiment, I'd like to completely remove both from the system temporarily to see if my coolant is still leaking. I'm using the regular FD filler neck cap, so there is no nipple on the top portion. Would it be a problem if I just ran the system for a short time with no way for the pressure to escape into the overflow? Could this potentially damage the coolant seals because of the exorbitant pressure?

Thanks for any useful responses! ~A-Rod

 

I think you should get the fixture for the sec gen and do away with the ast , burp the system and go for a ride .

 

Yes it would be a problem. The fluids expand when heated. Just like in chemistry class in high school. You need that 2nd gen filler neck so that the fluids can over flow to the over flow / coolant reservoir tank.

The best way to test the coolant system is to rent a coolant pressure tester from your local autozone. its usually free actually. Attach it in place of the filler neck cap, pump it up, watch for leaks.

Best to get new OEM hose clamps when you find the leaks. The screw type clamps eventually loosen up after a few heat cycles and leak.

 

yes this is a bad idea. things will break and you will cry. as stated above, fluids do expand when heated, and even if you have a coolant pressure gauge, it will be too late to stop by the time you notice it getting too high. if you know someone with a shop do a uv leak test or buy/borrow the equipment from an auto parts store and do it yourself.

 

If not mistaken, I've read about a number of people on this forum who have permanently removed the AST and had no problem. As a matter of fact, here is a "How to" link

http://robrobinette.com/coolant_tank.htm

 

Read this one too. http://www.fd3s.net/cooling.html#AST

Guess the question still stands...yea or nay on the AST. I'm keeping/replacing mine, but a short term gig for diagnosing a leak sounds like no big deal.

 

If you find yours is leaking and you do not want to remove it ,I have several used ones that I removed for customers that I can sell .

 

His question wasn't regarding keeping or eliminating the AST. It was:

"I'm using the regular FD filler neck cap, so there is no nipple on the top portion. Would it be a problem if I just ran the system for a short time with no way for the pressure to escape into the overflow? Could this potentially damage the coolant seals because of the exorbitant pressure?"

Best way to test for coolant leaks is coolant system pressure test.

 

Thanks for the responses guys. I'm probably just going to do away with the AST and buy the FC filler neck lid. I'd like to have the least amount of trouble points as possible, and this one seems to be giving me a hell of a time. Also, I'm not going to be "experimenting" in it's present condtion.

Does the FC filler neck lid come in metal, or only plastic?

 

I eliminated mine and now using the AST for a coolant overflow reservoir...The only thing I can say is that a lot of people block off the hose that comes out of the radiator to the filler neck, I kept mine so that way the air pockets still have some place to go, basically the filler neck acts as somewhat an AST

 

Here is a pic, even though I have a custom filler neck it still is basically the same thing, also notice the hose that comes out from the front which goes to the radiator.

 

Better read it again...in the original post he states

"From the location of the coolant I can see, I *believe* it may either be the AST or the lines associated with it. Now as an experiment, I'd like to completely remove both from the system temporarily to see if my coolant is still leaking.