When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
1999 TA automatic. Temp shot up yesterday...the overflow tank was totally empty. Underneath the battery was wet, so I pulled it and the tank. I filled the tank up with water and flipped it upside down thinking that it may have been cracked or damaged in some way...water started leaking from the top of the coolant tank (see pic). I pulled the half rubber/half metal hose out and it slipped out really easily...I suspect that the rubber grommet is just old and has softened causing a bad seal between it and either the tank or the metal hose.
Can I buy just the rubber grommet?
Should I just try to find a used tank and hope that the grommet in that one is OK?
Would a new tank come with the rubber grommet?
Thanks in advance!
The tank leaks from here when filled with water and flipped upside down The metal hose slips in and out of the rubber grommet very easily and feels loose
Last edited by jdoostil; Apr 3, 2019 at 07:11 PM.
Reason: fixed text
That grommet is not available through GM, nor will you get a new one if you order a new bottle (the grommet was a separate item). I tried to get one of these about 5-6 years ago from the dealer and they were already not available at that time. To the best of my knowledge, nobody is yet reproducing these. However, I've found that a PCV grommet from a Ford application (don't remember the specifics, this was many years ago and done for a friend's car) can be made to work. I found this piece in the "Help!" section of a local auto parts store.
Having said that, the overflow bottle should never be under pressure nor turned upside down during normal operation; that grommet is mostly there to prevent dirt and debris from entering the tank, not to prevent coolant escape or make a pressure-tight seal. If it's leaking from around the grommet during normal operation, then either the tank was overfilled to begin with, or it became overfilled due to some problem with the cooling system.
Having said that, the overflow bottle should never be under pressure nor turned upside down during normal operation; that grommet is mostly there to prevent dirt and debris from entering the tank, not to prevent coolant escape or make a pressure-tight seal.
+1 Nothing is wrong with the grommet here. That being said, the battery tray should not be wet, so either:
- There is a leak higher up in the hose.
or
- There is a source of gas in the coolant system forcing coolant out of orifices it shouldn't flow through.
If you can't track this down by manual inspection, then some coolant dye and a compression test should be conclusive as to what is going on.
I recently replaced the hose on the coolant bottle. Used a Dremel tool cut the hose at the aluminum piece shown in pic ( under battery). Worked like a charm... As the other guy said.. you won't find a new one anywhere!! I scoured the internet for one.
1999 TA automatic. Temp shot up yesterday...the overflow tank was totally empty. Underneath the battery was wet, so I pulled it and the tank. I filled the tank up with water and flipped it upside down thinking that it may have been cracked or damaged in some way...water started leaking from the top of the coolant tank (see pic). I pulled the half rubber/half metal hose out and it slipped out really easily...I suspect that the rubber grommet is just old and has softened causing a bad seal between it and either the tank or the metal hose.
Can I buy just the rubber grommet?
Should I just try to find a used tank and hope that the grommet in that one is OK?
Would a new tank come with the rubber grommet?
Thanks in advance!
The tank leaks from here when filled with water and flipped upside down The metal hose slips in and out of the rubber grommet very easily and feels loose
These tanks are non-pressurized....it’s just a simple potable water type of tank. It should leak through the grommet. It’s all loose fitting items. Just like the cap, it has vents built in....water coolant will spill out easily.
Do what i said above and just use the rubber hose......no need for the metal pipe. Just make sure to measure the rubber hose so it’s about 1-2 inches from touching the bottom. It’s doubtful such a hard material like heater hose would perfectly push up against the bottom inside of the tank and seal to the bottom.....so just make sure it’s measured to hang 1-2 inches from the bottom.
If the hose hose is really lose in the grommet....simply get the hose where you want it.....then wrap duct tape around the house at the top of the grommet so the cannot slip into the tank any deeper.
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.
7 Most Reliable High-Performance Engines GM Has Ever Built
Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.
Overflow tank leaking from the top 
