Coolant Reservoir

[youngrider]

The coolant reservoir tank is not a totally sealed system in many vehicles, it has a vent on its cap. Because the coolant may expand up to 3/4 the height of the tank during normal operation, cracks or leak points at this level or below are bad, above this level, leaks paths may not be that critical.

But we have this GM car which I think has a totally closed cooling system, if ever it has a relief vent, it would only open at a certain elevated pressure. The reservoir tank cap is totally different from what I usually see, it is threaded, which I think can not be replaced generically.

[baludoy]

^that's why it made me scratch my head when i peeked under the reservoir cap of our fd because there were no rubber seals/gaskets underneath it (as opposed to the ek's). but since the ek's reservoir tank has it, i suppose it's there for a purpose & it's best to repair it

it won't look good but you can use sealant.

will the sealant hold for long? won't it be torn up by the resrvoir tank's threads bro?

[youngrider]

If you will use RTV (Room Temperature Vulcanization) silicone, buy the one with noozle cap so that you can place it more precisely. loosely tighten the cap initially until the RTV silicone is set then re-tighten the cap to its normal setting.

If the cap has a full-time open vent then the reservoir pressure is around the normal atmospheric pressure only, and the coolant will leak only if the level reaches the vent or leak points.

In cars which do not even have a radiator cap, with coolant refilling only possible thru the reservoir tank's cap, the coolant in the reservoir may be pressurized above the atmospheric pressure when the engine is running and any leak path is critical as the coolant may gush out as soon as the thermostat valve opens.

[baludoy]

^thanks for the tip bro