That's the overflow cap

 

"Surge Tank" is actually the correct name for the overflow that you are referring to.

 

It maintains pressure on the cooling system and performs the same function as a cap mounted directly to the radiator. No different. The tank this cap screws onto is pressurized during vehicle operation.

If it malfunctions, the cooling system is directly affected.

 

Surge tank cap, coolant recovery tank cap, radiator cap, same difference.

 

They are not the same!

Surge tanks and radiators are pressurized, and they each require a pressure cap in order to maintain the pressure at a specific amount.

Coolant recovery tanks, like those used on cars in the 70's, 80's and 90's, are NOT pressurized. The coolant contained in them is at atmospheric pressure, and their simple unpressurized caps only serve to keep the coolant from sloshing out of the top.

 

As far as function I agree, however the old "coolant recovery" tank design evolved into the more modern day "surge tank" which is actually a dual purpose tank which functions as both a coolant recovery tank as well as a remote (away from radiator) pressurized reservoir for coolant. Being remote it also allows designers to make radiators more compact and mount lower giving greater flexibility in front end designs with lower, sloping hoods and/or smaller grills, etc and serve as the fill point for coolant as well.

Further, depending on which source is being used to look up parts, i.e. dealer, factory, aftermarket auto parts etc, the terms radiator cap, coolant recovery cap and radiator surge tank cap are in fact commonly used interchangeably.

Even GM dealer network terminology refers to the tank itself as a "engine coolant recovery tank" (primary) as well as "surge tank" (secondarily). Same for the cap, but if you go to some of the common auto parts sources like RockAuto.com for example the cap is widely categorized and referred to as a "radiator cap".

http://parts.nalleygmc.com/showAssem...category=19395

www.rockauto.com


2002 CHEVROLET CORVETTE 5.7L V8 : Cooling System : Radiator Cap Wiki Price Alternate
No parts for vehicles in selected markets.
GATES Part # 31544 OE Type Radiator Cap; Threaded Coolant Bottle Cap (Closed System) - 18 psi (SAE Range 16-20 psi)
18 psi Pressure Rating

$4.56
Add Part
STANT Part # 10257 OE Type Radiator Cap; Threaded Coolant Bottle Cap (Closed System) - 18 psi (SAE Range 16-20 psi)
18 psi Pressure Rating

$4.65
Add Part
ACDELCO Part # RC87 {#25713160}
CAP,RAD SURGE TK 18 PSI (Only 12 Remaining)


2002 CHEVROLET CORVETTE 5.7L V8 : Cooling System : Coolant Recovery Tank Wiki Price No parts for vehicles in selected markets.
ACDELCO Part # 10430189
TANK,RAD SURGE





So when speaking about C5s (in this case) it's just as correct to use these terms interchangeably. That's the point I'm making. No different than "sway bar" (both functionally and technically incorrect) and "anti-roll bar" or "e-brake" and "parking brake". The terms are used interchangeably and refer to the same thing.

 

wow that was the most attention a cap has ever had lol

Telling someone to look at a radiator cap is going to point someone to a radiator.

The surge tank or Expansion Tank is also referred to as over flow tank

And a surge tank or expansion or over flow tank is not a radiator so the cap is definitely not a radiator cap.



lol

http://www.vetteweb.com/tech/vemp_12...stem_hot_mods/

 

Unless the "someone" is a parts man at a dealership, or an aftermarket AP store. Same is true for numerous online auto parts sources as well. And a "sway bar" is not a sway bar either.

 

Asking for an AC actuator wont work at the parts guy as well..

But at least the Tire guy always knows what you want.

 

One can hope.

 

Um without a t stat many cars overheat My 84 C4 overheats without a t stat what happens is water doesn't stay in the radiator long enough to cool off. Do all your testing with the T stat in place.