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AudiTurbo
07-19-2014, 05:30 PM
So, I just bought a new doron coolant tank for my 98 1.8t and today it started leaking out of the overflow nipple. I am
Using my factory cap (which didn't fit to well) and it's still leaking. I thought I might of put to much in the tank but it went down (below min) so I put more coolant in and let it run for a while (cap off at this time). When I put either of the caps on it would leak a lot out of the nipple. Do you think this is the cap or the tank?
Thanks

BrucexL33
07-19-2014, 06:14 PM
Sounds like you need another clamp for the overflow nipple.

AudiTurbo
07-20-2014, 06:54 AM
There is no hose that goes on that piece though. Does it always overflow a little when you leave the cap off while running then put it back on?

SquishyPanda
07-20-2014, 09:01 AM
Shouldn't there be? Mine has a hose there.

Turbo_B5
07-20-2014, 09:02 AM
Pictures would help.

AudiTurbo
07-20-2014, 10:31 AM
I'm talking about the nipple at the rear of the tank. Back by the level sensor. Where would the hose go to?

BrucexL33
07-20-2014, 11:04 AM
We have no idea what you're talking about. Like King_Life said if you want some help please post pictures.

Turbo_B5
07-20-2014, 11:08 AM
A picture says a thousand words.

AudiTurbo
07-20-2014, 12:28 PM
There is only 3 ports on the tank and the other 2 have a hose going to them. I just went ahead a took it back and bought one from ecs tuning. When I put the old tank back on it didn't leak and it acutally made the hissing noise when taking the cap off
http://i.imgur.com/nEid6qy.jpg

buckeyexx
07-20-2014, 01:46 PM
Mine actually leaks a little bit there also. I was wondering myself what would cause this because mine is fairly new. I was leaning toward the cap not venting correctly.


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AudiTurbo
07-20-2014, 01:57 PM
That's what I thought it was, but I even used my OEM cap on the new tank and it still leaked. Put the old tank back on and is fine now.
The tank was advertised as non-pressurized, so I think that was the problem

buckeyexx
07-20-2014, 03:50 PM
I threw mine out because it was cracked along with the cap not thinking I would have issues. My temp will stay in the middle but will occasionally rise above to just before the next mark and fluctuate. I don't know if it has anything to do with the tank and cap or not.


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27litres
07-20-2014, 05:10 PM
The tank was advertised as non-pressurized, so I think that was the problem
Never heard of a non-pressurised tank. As the system requires pressurisation to function efficiently, a non-pressurised tank would certainly be a problem!


Mine actually leaks a little bit there also. I was wondering myself what would cause this because mine is fairly new. I was leaning toward the cap not venting correctly.
Correctly filled, the tank will not leak. If it does, you have a problem.
The key to the cap sealing correctly is the o-ring. This seals against the inner ring of the two under the cap - the outer is the overflow which drains to the small pipe (AudiTurbo's nipple) everyone seems confused about.
The cap does not 'vent' as such. It is a pressure cap. It has spring pressure which will allow the cooling system to pressurise to 22psi (nearly 1.5 bar), before releasing any excess pressure via the overflow. The only reason for it to overflow if functioning correctly is if there is air in the system, or the engine is not cooling correctly.
Any leaks or overflows at the expansion tank, I would immediately look to the o-ring on the cap (new cap is easiest solution), or a problem with the expansion tank (cracks in the inner pressure neck under the cap are common). Again, tank replacement is easiest (well, only really!) solution.

Just remember that when the engine is cold, the coolant should be sitting at the minimum mark on the tank. The maximum mark is for when it is hot (when it expands, thus 'expansion' tank). If you fill it to maximum cold, it will push that excess coolant through the overflow, which you may then confuse as a problem - which it isn't!

AudiTurbo
07-20-2014, 05:12 PM
Yeah this is the one I took back
http://shop.advanceautoparts.com/p/dorman-oe-solutions-non-pressurized-coolant-reservoir-603-703/22149143-P?searchTerm=coolant

Mad Cow
07-20-2014, 07:23 PM
Just remember that when the engine is cold, the coolant should be sitting at the minimum mark on the tank. The maximum mark is for when it is hot (when it expands, thus 'expansion' tank). If you fill it to maximum cold, it will push that excess coolant through the overflow, which you may then confuse as a problem - which it isn't!

I always assumed the tank is designed to still have enough room for expansion even at the max mark. I personally like to keep mine right around the level where the 2 halves of the tank meet, that seems to be right in the middle of max and min.

ricekikr
07-20-2014, 08:08 PM
Assuming everything else is normal. And try a cap that fits properly.

Did you bleed the system?

Do you have any engine issues? Overheat? Cracked head, piston rings etc could be overpressuring system.

27litres
07-20-2014, 11:36 PM
Just remember that when the engine is cold, the coolant should be sitting at the minimum mark on the tank. The maximum mark is for when it is hot (when it expands, thus 'expansion' tank). If you fill it to maximum cold, it will push that excess coolant through the overflow, which you may then confuse as a problem - which it isn't!I always assumed the tank is designed to still have enough room for expansion even at the max mark. I personally like to keep mine right around the level where the 2 halves of the tank meet, that seems to be right in the middle of max and min.
I used to fill mine to the max mark, and after a week I would check it and it would be back down at the min. So I'd fill it again... Lots of coolant later I left it at the min mark and it stopped using coolant!
So I read the fill instructions in either the owners manual or my Haynes, and it said "fill to minimum mark on coolant tank" or words to that effect!

Mad Cow
07-21-2014, 08:12 AM
I used to fill mine to the max mark, and after a week I would check it and it would be back down at the min. So I'd fill it again... Lots of coolant later I left it at the min mark and it stopped using coolant!
So I read the fill instructions in either the owners manual or my Haynes, and it said "fill to minimum mark on coolant tank" or words to that effect!

Now that I think of it, that's exactly what happened to me, I just assumed there was still a bit of air in the system and it drew in some coolant with it when it vented. It seems to be doing just fine sitting at the middle though.