killagt

iTrader: (3)

I check coolant almost every 2 week, and recenrtly it getting really cold out side, I alway want to change to 180* for winter, but have not time atm. Anyway I note I loose half cup of coolant recently. mabe 4oz of coolant. How much coolant loose a year is consider normal ? i mean does coolant get low in winter time ? thanks

LS6427

iTrader: (2)

No, coolant should never ever go away if everything is sealed properly. I don't think I opened my radiator cap for a good 3 years straight when my car was brand new and bone stock for its first 3 years of being bone stock. It was 100% topped off.

I bet your starting to lose coolant out of the cap. You shouldn't take your radiator cap off that often. I'm NOT sure, but aren't we supposed to get a new cap each time we open it....according to the manual?

If I were you I would go get a new Stant cap with the pressure relief lever on it....they are great, and they cost like $3.50. Mine has been rock solid for like 5 years now.

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killagt

iTrader: (3)

U might be right about the cap, cause I saw some thing look like it been leak from cap. Ty I hope that the problem ^^

wssix99

iTrader: (5)

I'd suggest not getting the Stant cap and going with a GM one. The original cap has a vacuum release (in addition to the pressure relief) which protects you from a vacuum build up that can crack the plastic parts of your radiator.

How many miles do you have on the car?

killagt

iTrader: (3)

114k miles, only gm sell that cap ?

wssix99

iTrader: (5)

As far as I know, you can only get the cap through a dealer.

You could also have a leaking head gasket, etc. - but 4 oz isn't really a large amount and your miles aren't too bad - so I hope that's not it.

ae13291

iTrader: (8)

go with a GM one the stant cap wont look right under the hood

senicalj4579

iTrader: (41)

IDK about loosing coolant, sounds like either a leak (which you need to find) or head gasket.
As for the colder t stat, idk where you are from. Imo I wouldnt ever use a cooler t stat in winter. These engines are desinged to operate at least 190. This time of year my temp sometimes dip to 186 (just for a min) at highway speeds with the stock stat.

killagt

iTrader: (3)

update, after changing the cap, coolant been stay full ^^. BTW im using 3 dollar stant ^^.

killagt

iTrader: (3)

Ok guys, TBH cause of wat he say I been kinda thinking about it lately, Is this true I need to get GM one ? how much does gm cap cost ? thanks

LS6427

iTrader: (2)

All I can say is my Stanat cap is rock solid after 5 years....and my Stanat cap has let coolant go into my overflow tank on more than one occassion. Its an ~18psi, if the pressure rises above that the sprintg loaded cap gets pushed up and pressure is released.

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killagt

iTrader: (3)

Im using just regular under 3 dollar car, that have no pressure release **** thing, it cost 7 dollar, but I just go with cheap under 3 dollar one, I just pop the cap this morning and saw coolant still full. Look good quality, but the guys above say it have vacum release and pressure release on gm cap. I dont want to keep using my stant cap and if it over pressure and crack my radiator.. should I keep this under 3 dollar cap or get new gm one ?

wssix99

iTrader: (5)

Need? No. But if GM designed a special cap - someone in the past must have related issues...

LS6427

iTrader: (2)

Like I said....I'm past 5 years with mine. I've had temps way past 230* many times sitting in traffic down here in 100*+ summer heat with the AC blasting......I know I had many many overpressures...........my coolant blows into my overflow tank. I know this because I never put anything into my overflow tank so the coolant thats in there blew into it from pressure relief.

The cap is ~18psi, the pressure leaving the radiator just pushes that cap open and releases the pressure..........I don't see how you can possibly have an overpressure situation that can cause a crack.....UNLESS you have a 25-30psi cap (or whatever) and the pressure cannot get pushed out.

As long as you have an 18 psi cap....you cannot build pressure much beyond 18 psi before the cap pushes open and spits out coollant into your overflow tank.......and you need a ton more than 18 psi to cause any issues in the system. 19psi doesn't crack anything.....I would guess it would have to go well into the 20's..........

Up to you....get the GM one if you want to.

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killagt

iTrader: (3)

ty for rely. I feel kinda better now. I guest I keep the stant cap.

wssix99

iTrader: (5)

I believe the GM cap has both a pressure release (like the Stant) and a vaccuum release. (which protects against cracking)

I looked at the system and the only way I can think a vacuum can occur is if the overflow tube gets clogged and the coolant in the radiator contracts as it cools.