# How much coolant in burp tank?



## Jim Frye (Mar 16, 2011)

Pages 10-16 thru 10-18 of the OM. Cold is not warm. Although, some folks that have been dealing with the AF smell issue claim that the actual level should be below the mark on tank when cold. Read the Antifreeze Smell threads here for more information on coolant level.


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## obermd (Mar 3, 2012)

Look closely at the coolant tank and you will see an arrow on the tank near the front left corner of the tank. It's a little over an inch long and the shaft is about a third of an inch wide.


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## MetallicaMatt (Mar 26, 2012)

I see the little arrows pointing to one of the molded hash marks, pretty high up, is that considered "cold" level? The manual said nothing of where to fill other than how to fill it.

My fluid level is probably 1/4 - 3/8" above the top of the hose. This seems pretty low. I'm a little concerned that the level is low, especially for a new car? 

Or am I missing something?


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## obermd (Mar 3, 2012)

At that level, I would have your dealership fill it to about halfway between the top and bottom of the arrow. Then you need to keep an eye on it to ensure it stays there. At the level your coolant is at you risk pulling air into the cooling system.


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## MetallicaMatt (Mar 26, 2012)

I have some dex-cool in the garage, just throw some of that, with some bottled water (50% mix) and I should be good to go, correct?

i.e. avoiding the dealership since the car will be hot by then


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## obermd (Mar 3, 2012)

I know it's a 50/50 mix but I don't know if you need distilled water or not. Personally I would take it to the dealership just so they can document that your coolant was low.


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## 70AARCUDA (Nov 14, 2010)

...the first picture in this posting on the subject shows you what you want to know:

http://www.cruzetalk.com/forum/10-engine-technical-discussion/10307-coolant-level-tracking.html


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## MetallicaMatt (Mar 26, 2012)

very helpful. I think I'll stop by the auto store tomorrow and just buy the pre-mix 50/50 Dexcool and top it off....might be the best bet. My car will be nice and hot by time I get to the dealership.


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## obermd (Mar 3, 2012)

In any case, keep an eye on your coolant level. Mine dropped for about the first 14,000 miles. It's been stable in the 10K since then.


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## MetallicaMatt (Mar 26, 2012)

I totally forgot. I had to have my radiator replaced after a semi threw a tire tread into it. That would explain it. Off to the autoparts store tomorrow!


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## obermd (Mar 3, 2012)

Ouch. I'm glad you didn't get hurt. In your case I would definitely fill the coolant and then watch it. I'd also watch for leaks under the car (the one benefit of the engine shield slash job) to make sure everything got properly tightened after the radiator replacement.


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## MetallicaMatt (Mar 26, 2012)

Yes, luckily I walked away okay. This happened way back in the fall, so no leaks. I'm guessing it just wasn't topped off all of the way or there was some air.

I haven't had the engine shield slash job done, but no leaks in the garage.


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## NickD (Dec 10, 2011)

Could read the cold hot lines on my 2012 coolant reservoir, with a bright light. Augmented those lines with a black marker pen. Did come full from the factory, but checking it a week or so later, was very close to the bottom. Was concerned but have a bottle of 100% Dexcool, hate that 50-50 mix crap.

While other liquids are far more concentrated to save on shipping cost, these idiots are adding water to it. And charging a stiff price for it. A gallon of distilled water is still around 69 cents. In my neck of the woods, should be using a 60-40 mix.

After a year, still at that full mark, and this is not a new problem ever since they decided to get rid of that radiator cap. No way to get rid of that air in the system, but will do it by itself, after driving it for awhile. You can't no longer change coolant and say you are done, takes several hours of watching it after you think it full.

One think you notice on sticker prices besides drastically increasing prices each year are additions, like such things as a license plate bracket.

One thing you don't see are deductions, like no more radiator cap, lubrication drains, zerk fittings for key lubrication spots, or even AT dip sticks.


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## MetallicaMatt (Mar 26, 2012)

I agree, the cost of 50/50 Dexcool is insane. Did you fill to the very top hash mark of the burp tank? Doesn't leave much room for when it gets hot out to me, but I didn't design the thing.


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## Robby (Mar 1, 2013)

I'm going to assume you are commenting on the radiator no longer having a cap (IE radiator cap omission)

So, to clarify, the radiator cap (pressure cap) exists.....but it is located on the surge tank.
This design has been used on various cooling systems since the late 50's. (I point to Corvette in this case)
It also is used on my 1995 and 1996 Impala LT-1's.

Regardless, I continue to believe the surge tank operation is being confused with a coolant overflow tank, such as found on my 1996 Blazer.
Vehicles that use a overflow tank have the pressure cap mounted on the radiator and any expansion of coolant is directed through a hose to the tank.
When the vehicle cools after shutdown, the coolant is drawn back into the radiator through negative pressure.
The overflow design purpose is to keep the actual radiator full at all times, maximizing efficiency and, by having no air in the core section, the coolant won't gel.

The surge tank, as found on the Cruze in this discussion, is simply a remotely located place for coolant expansion to take place and, because it has air space, there is no overflow bottle required.

Therefore, as long as the level is above the hose inlet, at the bottom of the tank, when cold, it is considered 'full'
The airspace above the level is required so the cooling system pressure will remain below 20 psi.
This is the caps designed relief pressure.
If one was to fill the surge tank to its maximum 'HOT' level, and the coolant is not at 210 degrees (variable) the now very small airspace remaining will reach and likely exceed 20 psi before the engine is fully warmed up.
This will result in the cap releasing pressure, venting just ahead of the fresh air inlet and 'viola!'.....you now join the 'I smell coolant crowd'

I keep the coolant level 1/2" above the lower tank hose checking it first thing in the morning.
I have operated the vehicle with a pressure tester installed......results were surge tank pressure at that starting level never exceeded 14 psi......a nice sized buffer zone against cap venting.

My experience and $.02.........the 'FULL HOT' arrow means just that.......never exceed the tip of the arrow under any circumstance.

Rob


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## MetallicaMatt (Mar 26, 2012)

So the arrow's indicated towards the top of the tank are for "hot"? Not cold? Seems like a bad idea to open the cap to top off the tank when the system is at operating temperature. 

So as long as I have some margin above the hose, 1/2" - 1", I should be okay and not spray coolant all over my engine compartment.


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## Robby (Mar 1, 2013)

MetallicaMatt said:


> So the arrow's indicated towards the top of the tank are for "hot"? Not cold? Seems like a bad idea to open the cap to top off the tank when the system is at operating temperature.
> 
> So as long as I have some margin above the hose, 1/2" - 1", I should be okay and not spray coolant all over my engine compartment.



Thats what I'm saying.....
That darn arrow is IMO probably the primary cause of the coolant oder problem........misinterpetation of the meaning, 'Full Hot'

I even caught my dealer taking the level up to the arrow during pre-deliveries (not on mine) and after considering my discussion, went back out and dropped the levels to avoid potental future owner complaints.

Rob

Rob


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## MetallicaMatt (Mar 26, 2012)

Since I'm already 1/4 - 3/8" above the hose, could I just add some purified drinking water to get it to 1/2" to 1" above the hose? Or do I need demin? 

Assuming it's still mixed for the right temps, I can check that


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## jblackburn (Apr 14, 2012)

Robby said:


> I'm going to assume you are commenting on the radiator no longer having a cap (IE radiator cap omission)
> 
> So, to clarify, the radiator cap (pressure cap) exists.....but it is located on the surge tank.
> This design has been used on various cooling systems since the late 50's. (I point to Corvette in this case)
> ...


Yes sir. You've hit the nail on the head. 

Since reducing the level, no smell AT ALL from my tank. In fact, I only had a a smell when the level was brought up to that arrow. 

As long as you've got coolant above the bottom hose (like the car was shipped from the factory) you should be just fine. 


Sent from AutoGuide.com App


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## Jim Frye (Mar 16, 2011)

I completely agree with Robby's description, but it leaves me begging the question: *What is the purpose of the molded in arrow on the surge tank?* Is that the maximum HOT level? And why isn't there a better description of it in the OM? Maybe it's a design flaw that needs to be corrected (the "Certified Engineering Fix)? Also, checking the fluid level every morning seems a bit extreme, or high maintenance, for a current automotive design.


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## Robby (Mar 1, 2013)

MetallicaMatt said:


> Since I'm already 1/4 - 3/8" above the hose, could I just add some purified drinking water to get it to 1/2" to 1" above the hose? Or do I need demin?
> 
> Assuming it's still mixed for the right temps, I can check that



IMO, if your first thing in the morning level is where you say it is, add nothing.
For grins, you might want to look at the level avter about a half hour of driving in stop and go to get a feel for how much expansion takes place.....just to learn how it works.

If you must add something, you are only talking a few ounces here......A shot of straight Dex-Cool undiluted would be OK.....the current 50/50 mix might become 55/45 and that would disappear after it circulated anyways.....right back to 50/50.

Rob


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## Robby (Mar 1, 2013)

Jim Frye said:


> I completely agree with Robby's description, but it leaves me begging the question: *What is the purpose of the molded in arrow on the surge tank?* Is that the maximum HOT level? And why isn't there a better description of it in the OM? Maybe it's a design flaw that needs to be corrected (the "Certified Engineering Fix)? Also, checking the fluid level every morning seems a bit extreme, or high maintenance, for a current automotive design.


THAT is what I keep trying to get across.......the manufacturer has provided a arrow but is not making it clear enouph, to even the mechanics servicing the car, that this is a level that is NEVER to be exceeded.

IMO, a 'Full Cold' marker is all that would've been necessary to prevent all these odor concerns.......and, yes, an engineering oversight from the standpoint of easy misinterpetation. 

Rob


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## obermd (Mar 3, 2012)

Robby - thanks. The Cruze is the first car I've run across where the tank didn't say "Full Cold" and "Full Hot" on it. I would still ensure there is at least an inch of coolant above the main return line, especially if you live in an area with steep hills. No need to run the coolant levels so low that air gets into the system because you're going up or down hill before the engine warms up.


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## Robby (Mar 1, 2013)

Heh heh............,

That'd be one heck of a hill to uncover the inlet.....I think at that angle there would be much greater concern than coolant level, aye?

Rob


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## Jim Frye (Mar 16, 2011)

Additional thought on the coolant level issue and the molded arrow on the tank. I wonder if the original design included the rather high operating temperatures we've seen reported? i.e. the higher the coolant temperature, the more expansion volume needed in the surge tank.


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## Robby (Mar 1, 2013)

Jim Frye said:


> Additional thought on the coolant level issue and the molded arrow on the tank. I wonder if the original design included the rather high operating temperatures we've seen reported? i.e. the higher the coolant temperature, the more expansion volume needed in the surge tank.


Although I have read reports of rather high operating temp, it really isn't that high for a coolant mix under pressure.....just a bit more than is often seen on other vehicles.
I suspect this is why the Cruze utilizes a 20 psi pressure cap rather than the more commonly found 16/18 psi relief design.
But again, a ten degree increase in operating temp would not likely even be visable from a expansion viewpoint.

Regarding operating temperature......I do not know where on the head the sending unit (not sensor) is located and it must be remembered that the temperature being reported is at that mounting point and is not necessarily the actual temperature.

For example, small block Chevy V-8's generally have the sender located on the outside of the left cylinder head casting......between two exaust ports..arguably one of the hottest points in the entire cooling system.
If you were to install the sender in the crossover water passage in the intake manifold, just beside the thermostat, you will find the coolant to be 10 to 15 degrees cooler.......so, begs the question: What temperature is it operating at?

Eventually the answer I settle on is 'Who cares as long as it is within its design parameters'........that being it is not overheating, temp lights aren't being triggered and the gauge is where it should be....somewhere between 3/8's to 6/8's needle travel.......if it gets higher I look into it, otherwise I refuse to cause myself brain damage worrying about something that is of no concern.


Rob


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