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Discussion Starter · #1 ·
Hello all. A little background before asking the coolant question.......A month ago I had intermittent coolant loss leading to the red triangle and "coolant level low-stop safely" message. The independent traced it to a leaking thermostat housing and replaced it. A few days after the service my wife was driving the car and she received the coolant level low message. She called the shop and they asked her to top it with H2O (according to her the level was at the minimum mark on the reservoir). They told her it most likely was an air pocket from the recent flush and fill and it "burped." For three weeks it has been fine and levels have held.

That was until last night. I drove 4 hours from NH to NY and 5 minutes from home in NY (almost 4 hours into the trip) the coolant level low message appears on the dash. I checked the level this morning after it sat all night and the level was hovering at the minimum mark. As I removed the reservoir cap this morning there was pressure released and the level raised between the MIN and MAX markers on the reservoir. I decided the level was good enough for the short errand I was running and drove off. 10 minutes down the road the message re-appears. I brought it home, let it cool again, this time for only approximately two hours and starting removing the cap and the same happened; the level raised as pressure was relieved.

Question one....is there still air in the system and if so why would it surface three weeks later after the initial burp? Question two.....I need to drive back to NH tomorrow and will most likely need to top off from time to time. I don't want to run the car with low levels but at the same time I don't want to over-fill. Where is the coolant going? The ground is clean and the oil dipstick and filler cap doesn't suggest any intermix of coolant and motor oil.
 

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Get the coolant system test pressurized to see if there is any leaks that you cant see, if there is no signs of leaks buy a block tester to check if you have a crack in your cylinder liner which could explain the coolant disappearing. Fill the coolant to max and let it get to temperature, shut down the car and let it cool a bit, open cap and squeeze the big hose next to engine gently and watch for bubbles coming out of reservoir, this should bleed air out of the system and drink a bit of coolant, refill to 1cm under max. If you are still losing coolant after bleeding all the air out you are losing coolant somewhere, either a leak or a cylinder crack.

PS: When i flushed my coolant the system only burped once and went from max to min on the first drive, light went on and i refilled to max, bled the system when i got home and never had to add add more coolant 2 weeks after the flush.
 

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If its a cracked cylinder, usually most of the water is blown out the cap as the system is over pressurized instead of passing through the crack into the cylinder.
 

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Discussion Starter · #5 ·
Thanks Stealthy and Haunt. Stealthy, the car is, zzzzzzzz, completely stock and has 182,000 miles. Haunt, three weeks ago when it was at the indy they did a pressure test to chase down the leak but didn't find any. They didn't catch the thermostat housing until they parked it and later came out to find coolant all over their parking lot!

I will try your suggestion and press any air out tomorrow morning. Here is hoping it is just a little air in the system and that is it.

Thanks again.
 

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If its a cracked cylinder, usually most of the water is blown out the cap as the system is over pressurized instead of passing through the crack into the cylinder.
There's also the coolant that leaks into the cylinder when the car is off and causes misfires when starting. Have you been having any hard starts or white smoke on start up?

Check for leaks around the radiator end-caps. It's a common coolant leak area, but the behavior you are describing with the coolant levels doesn't seem to indicate a radiator leak. When you said you opened up the cap and there was pressure, was this sitting overnight or was the engine still warm/recently driven?
 

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Get the block tested before going into any conclusion, you can borrow a block tester from your local auto parts.
 

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Discussion Starter · #8 ·
The car is at the shop (independent) who is familiar with it and I am waiting for the diagnosis. A fellow Swedespeeder has posted similar symptoms, and while I am hopeful, I am expecting bad news. I haven't had a misfire on starting which gives me a little hope but most of his symptoms are identical to mine. There was a question asked on whether the coolant level raised as the cap was opened when the car was cold or hot and the car was cold; it sat overnight in freezing temps.

My next post will be in the classifieds..... :D
 

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I doubt the head is being pulled... That would be a waste of time and money. A car with a cracked block can drive. A car with no head cannot.
 

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Like houndogger says, if money is tight and/or you need to have the car to drive, the leak by the crack can be lived with for a while as long as you lay off the boost.
 

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Discussion Starter · #11 ·
Thank you for the tips and heads up on this issue. If the indy tells me they can't trace it I will offer the suggestions provided here. The general consensus and my gut tells me there is a crack(s). Will the cylinder sleeves be the best (and perhaps only) option for the fix? I'd prefer to keep the motor if it is not toast.
 

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You guys are nuts. These cars have several other places that will crack and leak coolant long before a cylinder. The radiator is plastic, the reservoir is plastic, the cap is plastic, all are known leak points. On a stock car these are way more likely than a cylinder crack.

Step 1, top up coolant to max to see if it's a consistent leak. You can't really overfill, as any excess will burp out the reservoir cap by design.
Step 2, look for evidence of coolant leaking anywhere else.
Step 3, replace reservoir cap
Step 4, replace reservoir.
Step 5, replace all hoses.

All of these are way cheaper than tearing into the motor looking for major engine failures. These cars routinely go hundreds of thousands of miles without cracked cylinders, what are you guys smoking?



Reminds me of a friend who was freaking out with a persistent air leak code in his Audi. he replaced the MAF 3 times, then assumed he blew a turbo. When he finally dug in to the motor to investigate, it was simply an intercooler hose clamp that wasn't tight enough and popped off. It's far more likely to be a simple problem than a major one.
 

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Are you convinced you are actually losing coolant? It take some time to really purge all the air out of a cooling system especially if it wasn't filled properly. Air will always get trapped in the high points of the circuit which is often the heater core and hoses, but depending on the circuit design it can also get trapped in the radiator and engine passages. It's best to fill the system, rev the engine up for a while with the cap off the bottle (should be done on a cold engine). Once the engine starts coming up to temp, the thermostat will open and coolant will begin to flow through the radiator. The bottle level will likely fluctuate. Continue to rev the engine for a while with the cap off. Again, the level in the bottle will fluctuate. It's helpful to squeeze the upper radiator hose a few times. Once the level stabilizes, you can put the cap back on the bottle and drive normally. If you continue experiencing coolant loss, then you likely have a leak. To identify an internal leak, go get a combustion gas tester from your local auto parts store... they rent them. You will need to buy a bottle of the test fluid ~$10. If it changes color, you have an internal leak and can be fairly comfortable thinking it's a crack block. If it doesn't, your leak is external and the pressure tests done above simply haven't pinpointed it... in which case, they should be done again.
 
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