Hello,

ever since I changed my coolant, I can't get to top off the level. After I full it up, I drive for a ride and then when I stop the car, it leaks a shitload of coolant form the oveflow tank area. when the car cools down, I need to pull hard on the filler cap in order to remove it, because it seems to be sucked in.

so my coolant level is always low in my AST, but my oveflow tank is more than full. if I add more coolant in my AST or filler neck, it all leaks down the overflow tank after a drive, and doesnt seem to get sucked back in when the motor cools down. My ast cap is brand new too.

I was thinking the hose between AST and overflow tank might be twisted, belt or plugged, but I checked and it's not. it's not broken or leaking either.
I have no cooling problem either, the car doesnt overheat or anything. I don't get the "add coolant" buzzer either because I still have enough coolant in the system, I just can't full it completely or it all leaks out.


Lately I also noticed some black goo (oil?) on the overflow tank dipstick. I thought about a dead water seal... but my exaust doesnt blow any white smoke and I see no bubble in my coolant when the car is running. it does have somewhat of a hot starting problem though...

any imputs?

 

If it only started happening after you changed your coolant and replaced the cap, then I would suspect the cap even though it is new. It is cheap to replace along with the line going to the over flow. Try those first and see what happens.

 

I'm no master mechanic, but the AST is an air separator tank and it shouldn't be full of coolant or it can't do its job, to separate air from the coolant.

Sounds like you have overfilled the system and it is pushing out the excess coolant. You should check the coolant level while it is cold at the radiator or at the coolant reservoir (what you are calling the overflow tank). If you take the cap off of the reservoir and look at the dipstick, you'll see a series of marks on them. Do not fill above these marks or the reservoir will overflow. It will also overflow I believe if you put coolant in the AST.

See the attached PDF for how to check the coolant.

 

You really can't overfill an engine... You do want it full of water. When the engine warms up and the coolant expands due to temperature it gets pushed out via the overflow tube. When the engine cools down the engine pulls the coolant back into the engine...

 

could have the two caps mixed up happened to me the cap w spring should go to ast

 

I'm not that stupid, I know how to check coolant level lol

I didnt mess up with caps either, the one with the spring is on the ast.
as I said, the coolant reservoir is way too full, but if I check through the filler neck or the ast, the level is pretty low. even if I did overfill it, after I drive and get the engine hot, it spills on the ground, but the problem is that the coolant in the reservoir doesn't get sucked back into the system

I'll change the cap and the hose, see what happens.

what about the oil in the coolant reservoir, can anything else than a blown coolant seal cause that kind of situation?

 

Check the entire line going from the tank to the ast and make sure you can blow both ways. There could be a restriction that only lets it go out and not back in...

 

Do you have any gurgling after shut down when the engine is hot?

Have you sucked all but 1/3 or so of the fluid out of the overflow res. and then topped off the filler neck?

I had a similar problem (after radiator flush per the ASM/FAQ hints...pulled block plug and all) where the over flow res. pissed after shut down. Level at filler neck would always go way down after cap removal. Continued until I emptied overflow to 1/4 or 1/3 of capacity. I let engine cool overnight, removed radiator cap and topped off with water, slapped cap back on a ran her like I stole her. No more pissing, no more gurgling. Overflow level has never exceeded the "Full" mark since. To scared to remove the rad. cap and see if any fluid is left