overflow capacity

EDIT: And the answer is.... About 32oz or 1 qt. Seemed like it could have even been 36 oz but I couldn't precisely measure. This is the cold fill to hot fill difference, NOT the overall capacity which definitely exceeds 2 qts.

I have an odd question, I was wondering if anyone knew the difference in the amount of fluid from cold fill to hot fill. I don't necessarily need the total capacity of the entire overflow tank (tho that could be helpful too) just how much the fluid expands. I'm looking to replace the overflow tank with something more pleasing to the eye and I've found sizes ranging for 16 oz to 2 qts. Too small would be a problem cause it could run dry and suck in air or not hold enough and either spray out (vented type) or possibly build excess pressure (unvented type). Obviously bigger would hold more fluid and would give more of a margin for error in the event of a small leak but would be harder to fit. Was hoping someone on here might know but if not I could always pull off the stocker and measure...

I don't think it's critical how much it holds, as long as it's not drastically smaller than the OEM tank. I doubt it would suck dry or overflow unless you used a really small one. Try to keep with one that looks about the same size, or a little smaller.

I was kinda hoping you'd jump in on this AA, you always have good advice and ideas. I'll give you the story. I'm looking to put a cia in my 97 gtp which would require relocating my overflow bottle to fit. I have the option of switching to the 99+ factory bottle (very ugly) or going aftermarket. The 99+ bottle would mount on the passenger side strut tower and makes it more difficult to work on anything in that area (plus its damn ugly!). Most aftermarket offerings seem to be in the 18-24 oz range, which sounds tiny but may be big enough. The stocker is bigger than it has to be to give a safety margin. Those of us that check fluids regularly don't need as big a safety net but it still needs to meet a minimum size. I was looking at a weapon r catch can which is pretty, afordably priced, works in the factory vented style, has a sight glass, and has a fill cap, but the largest they offer is 24oz. I've seen others from canton at one qt, which is definitely big enough but may be more difficult to find space to mount. My intention was to mount it on the radiator support but there's no a huge amount of room. I will of course take measurements before buying anything but I was hoping someone might have some ideas or suggestions. Since the question was just general knowledge and not grand prix specific I thought I'd ask here, since many on the gp boards are know-it-all jerks. If I have to I will pull the bottle off my riv (both engines are l67's so it should be very similar I would think)and measure how much fluid it takes to go from cold fill to hot fill. Thanks in advance for any info. Oh and AA I just realized I'm not sure I posted this in the correct section, its hard to know where its gonna go from an old cell, so feel free to move as necessary.

I'm putting this in the "Everything Else" forum because it's a GTP, and the overflow is different than the Riviera's.

Check this out: http://www.pfyc.com/GP3009.html

Worth $50?

That IS the ugly factory style overflow for 99+. In 97-98s they had the bad idea of mounting the overflow directly behind the headlight and right infront of the airbox, so your airbox gets heatsoaked easily. At $50 its very overpriced, even ZZP sells it for $40 and they're usually overpriced. The aluminum ones from weapon r go for around $65 and the 1qt from canton is about $115. I know the 99+ style will work but I'd rather something more appealing to the eye and I'd rather mount in out of the way on the radiator support. Guess I'm gonna have to pull the overflow off the riv and see how much it holds. Since the riv has a bigger radiator I would think it would need more room for expansion so anything that's big enough for the riv will be fine on the gtp. Thanks for trying AA you're always a big help. Once I have the measurement I will post up my findings in case anyone else can use it.

Quote :

Guess I'm gonna have to pull the overflow off the riv and see how much it holds. Since the riv has a bigger radiator I would think it would need more room for expansion so anything that's big enough for the riv will be fine on the gtp.

I'd agree with this 100%. Another thing you could do is call PFYC and ask the capacity of the '99 tank that mounts to the strut tower. I know you think it's ugly, but I like the idea. Thinking about whether or not that would work for the Riv!

That's not a bad idea... But I doubt they could tell me the hot/cold difference, which is really all I need cause any more is just extra reserve, but they could probably tell me the overall capacity which is a start. I'm sure it could be made to fit in a riv, you would just need to find where it sits best and drill. Pfyc says 2 sheet metal screws are needed (not included of course lol) but from what I hear you also have to put a third screw in the bottom to keep it from swinging out into the belts thru hard turns. Its smaller than the rivs with less capacity but should still be plenty big enough. One word of warning tho... Its veeery visible mounted on the strut tower so a brand new white bottle may be ok but a crusty old yellowed one would stand out and look bad. Thanks for putting my feet on the right path AA.