Help me- rental car coolant question

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I rented a pontiac g6 in california, the coolant recovery bottle is part of the cooling system and is pressurized so that if it ever looks low when hot you can not add coolant (to the recovery bottle) when its hot. Are all new cars like that? my 2004 toyota has a vented coolant recovery tank that you can add coolant to at any time. is this a GM thing? pressure cap on the coolant bottle? the pontiac lost 1/2 inch of coolant each 500 miles (comparing cold levels)
 
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Meh, I would just wait until it's cold, top off with some water and keep driving it... It's the rental places problem, not really yours. Water will keep you going until you can get it back to them. It's not just a GM thing to have a pressurized tank, my VW does too.
 
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Pressurized overflow tanks are very popular with European cars. I think it's not as good as non-pressure reservoir in Honda or Toyota and most Japanese cars.
 
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You can add coolant anytime. It will depressurize as you open the lid - not like old cars where the cap would bubble fluid out on you.
 
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 Originally Posted By: Drew99GT
It's a rental, don't be gentle. I'd forget about the coolant and do a burnout.
 
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 Originally Posted By: Drew99GT
It's a rental, don't be gentle. I'd forget about the coolant and do a burnout.
It's ok... It's a rental and I have the "damage insurance"! Who says you can't make a u-turn over a concrete divided island?
 

JHZR2

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 Originally Posted By: HTSS_TR
Pressurized overflow tanks are very popular with European cars. I think it's not as good as non-pressure reservoir in Honda or Toyota and most Japanese cars.
And most American cars too? I don't know... we have original hoses and radiators even after 25+ years in our MB and BMWs and the mileages are as follows: 228000, 238000, 209000, 117000, 85000. Our integra and previa couldnt/cant even seem to keep a radiator for 100k! May be related (in terms of presurization, air bubbles, changes in the chemistry), or not...
 
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 Originally Posted By: JHZR2
 Originally Posted By: HTSS_TR
Pressurized overflow tanks are very popular with European cars. I think it's not as good as non-pressure reservoir in Honda or Toyota and most Japanese cars.
And most American cars too? I don't know... we have original hoses and radiators even after 25+ years in our MB and BMWs and the mileages are as follows: 228000, 238000, 209000, 117000, 85000. Our integra and previa couldnt/cant even seem to keep a radiator for 100k! May be related (in terms of presurization, air bubbles, changes in the chemistry), or not...
Behr radiators vs Nippondenso and Toyo rads. Although @ 200K the Behr is on borrowed time.
 
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 Originally Posted By: edwardh1
I rented a pontiac g6 in california, the coolant recovery bottle is part of the cooling system and is pressurized so that if it ever looks low when hot you can not add coolant (to the recovery bottle) when its hot. Are all new cars like that? my 2004 toyota has a vented coolant recovery tank that you can add coolant to at any time. is this a GM thing? pressure cap on the coolant bottle? the pontiac lost 1/2 inch of coolant each 500 miles (comparing cold levels)
Just note that its low on coolant and then add some after it's cooled off. So long as there's coolant IN the surge tank, you're guaranteed that the block is completely full. Being low doesn't hurt anything unless the surge tank becomes empty, then air is going to be drawn into the engine itself. FWIW, there's not set pattern of which vehicles use pressurized surge tanks and which ones use conventional overflow tanks, even among individual manufacturers. Old (80s) Jeep Cherokees used surge tanks, then later switched to conventional overflow tanks. Chrysler LH cars (1993 and later) use surge tanks, but PT Cruisers use conventional overflow tanks. Both systems work. The big drawback to the surge tank type is that the tank has to be pressure tolerant. Its big advantages are that you always get an indication of coolant level, and fresh coolant is always circulated through the surge tank. With a conventional overflow tank, you can have a situation where an air leak in the hose from the radiator pressure cap to the overflow tank will prevent the radiator from ever drawing coolant back out of the overflow tank, so if this happens you can be VERY low on coolant but the overflow tank level will still be normal. Its always a good idea to periodically check the actual radiator level in systems with an overflow tank, or squeeze a radiator hose with the engine cool and confirm that the level in the overflow tank changes when you squeeze.
 
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