must cap for the coolant reservoir be vented?

[p7387]

hi
must the cap for the coolant reservoir tank be a vented cap?
i have seen both types.

thanks

[enaberif]

what year is your truck? generally speaking yes its a open system with a overflow jug which has a hose that goes to the bottom of the tank to suck fluids back in.

[LTZ C20]

The cap for the coolant reservoir is just a plastic cap, no venting required. That is for models with a radiator with its own venting cap, which is what came in all of these trucks. A divorced coolant flow area and overflow tank.

Newer vehicles that use a surge tank that is directly tied into main coolant flow, the LS series engines for example, the radiator cap goes on the reservoir because the surge tank is included as one of the coolant areas that is under pressure. A married coolant flow area and overflow tank.

So no, your tank does not need to be vented. This is assuming your using a factory or somewhat factory setup.

[bd]

what year is your truck? generally speaking yes its a open system with a overflow jug which has a hose that goes to the bottom of the tank to suck fluids back in.

x2

All square body trucks that use the original style cooling system have a vented overflow tank.  That is, the overflow tank is open to atmosphere (hence, non-pressurized) via a u-tube that is cast into the overflow tank body or a vented cap, dependent on the year of manufacture.

The fully pressurized, closed cooling system mentioned by LTZ 20 occurred post-square body truck design.

[enaberif]

lol my overflow bottle was in ROUGH shape. I went to napa and picked up a universal bottle for 25 and mounted it in the stock location.

[LTZ C20]

I may have created some confusion for you p7387, everything Enaberif, BD and I have told you is correct. Where I may have confused you is, the cap and the bottle itself. As BD mentioned, the BOTTLE itself IS vented yes, with the U-shaped port on top opposite the cap, open to outside air. The CAP itself is NOT a vented item.

Your original question was about the CAP itself according to your first post. Unless you ment the whole bottle.

I hope all the info we provided answers your questions.

[bd]

The 1987 R10 used a "vented" cap.  The bottle itself was not vent.

[AZ87V10]

That's the same style cap that my 87 has! My dad's 89 K2500 had the same cap and so did my 91 S-10! Although my dad's 82 K20 had a different style cap that just snapped onto the overflow bottle. But it did have a molded in nipple above where the rubber hose from the radiator attached that was open to the air. I believe that describes the same thing that BD already mentioned. Hope this helps! Our cooling systems are pressurized, but our overflow bottles are not.

[p7387]

got it, thanks for the info