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Discussion Starter #1
Once again I call upon camaro.net members to help out where others have failed to answer......I got a brand new radiator, a powerful CFM fan with a relay and have been having a problem with the radiator puking fluid. Here is the deal. It is a brand new aluminum radiator, 16 lb cap and electric fan. I replaced the radiator because the old one had alot of crap in it and after a flush it still would not hold fluid without puking it out. Upon replacing it I noticed that there was NO THERMOSTAT. So I put in a brand new thermostat(180) , Brand new aluminum radiator and kept the fan( it is a airride 2450 cfm fan). Now the car will still puke out fluid and I have to top it off after EACH 20 minute trip on the highway. I put a catch can on it so it wouldnt puke all over the underside of the car but it still is puking out fluid. I have a 302 in a 65 mustang. The fan kicks on at 160 and the car never goes over 185 in traffic or on the highway. One thing I did notice is that I seem to have this problem more so at higher RPMS(HIGHWAY DRIVING) I know this is not normal. I have had more than a dozen old muscle cars and never had this problem. Any help would be greatly appreciated! Thanks in advance!!

Mark
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Engines always puke coolant out when they are completely filled with coolant. Older cars with no recovery system just puke it out until the right level is reached. Ones with a recovery system allow the ejected coolant to be sucked back in when the engine cools.
 

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I'll x2 that. If it's not running hot let it puke to the level it wants.
 

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The guys are right, about 2" down from the mouth of the filler is about right. Hot water (coolant) expands as it gets hot. With the cap on that expansion creates pressure in the system, the cap keeps it in check up to it's rating then it releases pressure and pukes. By leaving room for expansion the pressure doesn't build beyond the caps rating and so spills...
 

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Discussion Starter #5
OK I can see that BUT.... When I pop the cap off the radiator. The top tubes of the radiator are completely uncovered. When I pour coolant in it takes about 4-5 seconds for the water level to start to appear above the coolant tubes then I stop filling it. When I took a 20 minute drive on the highway I left the coolant jug attached to the overflow tube. When I got home it had filled the jug about 3/4 of the way to the top! seems like an aweful lot of coolant to be puking out. Like I said I realize about overfilling it but you have to at least be sure the tubes inside are covered? Right?

Mark
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Sounds like your pressure cap is bad then...
Same thing happened to me a few months ago with my Aluminum Rad. I took a close look at the seal on the cap and the surface of the filler neck.
The surface of the filler neck was gouged and wouldnt let the cap seal.

Either a bad cap or a cap sealing problem would be my guess.
 

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Discussion Starter #8
Well thought of one more thing it MIGHT be? A blown head gasket?? Only reason I say this is that when the rpms climb, the temp range on the highway climbs with it. Gotta figure I am doing about 3K on the RPMS and traveling at 70 MPH with the electric fan blowing full blast. So the temp climbs to a high of 195 at 70-80MPH. Then as soon as I let off the throttle and let the car cruise down to about 55-60mph it goes down to 185... When I am sitting at a light coming off the highway it goes down to 181...



So could I be right in assuming that the excess pressure created from a blown head gasket could be causing the temp to rise to such a high level on the highway AND causing the pressure to build in the radiator to exceed the 16lb cap causing it to puke out radiator fluid? If so how do I test for a blown head gasket so that I can either confirm or rule out it all together? I know if I see white smoke it is a good indication but I do not seem to see any during startup and I cant really tell when Im traveling down the highway?



Mark

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195° is not hot at all for an engine. It takes more power to run at 80 mph than at 60 mph, so the engine generates more heat. The system heats up until heat balance is achieved.
You can reduce the apparent rise in engine temperature by increasing the coolant flow through the radiator, increasing the air flow and/or reducing the air temperature.
Do you use a stock water pump and pulley system?
Is your electric fan blocking the flow through the radiator at high speeds?
 

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Mark water boils at 212 degs at sea level and is lowered by 2 degs for every 1000' of altitude. Pressure raises the boiling point and for every pound of pressure the the boiling temp is raised by 3 degs. With a good 15lb cap it should take about 250 deg water temp in your radiator before it boils over. If your cap doesn't hold any pressure it would boil over at 212 degs. Keep in mind that's water, anything else you add to the radiator will alter this.

Pressure test your cap and radiator and you can look for signs of water getting into the combustion chamber by white smoke out the exhaust and you'll see little bubbles coming up in the radiator when the engine is running.
 

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Discussion Starter #11
OK Thank you.. but how do I pressure test the radiator cap and the radiator? Is there some home test kit I can get to do this?
 

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If you're heating up running 70mph, I would say that the electric fan running is actually becoming a restriction. Is your fan thermostatically controlled to turn off once the radiator is cool? You said your Mustang comes on at 160 but does the other one you're having a problem with turn on and off properly?

Make sure you are using a non-vented cap if you do not have a true recovery system. Vented is for a closed cooling system with recovery tank. Running a non-vented cap with just an overflow hose, the fluid level will be a couple of inches below the filler neck since the extra space is for the fluid to expand. It will push out whatever you overfill. Make sure you don't go over 50/50 on your antifreeze mix or the boiling point will just get lower.

You can get your cooling system pressure tested at just about any auto shop for probably a half hour labor charge.
 

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I think your fan is blocking airflow at speed. It should not even be on if you are doing 70, what kind system is it using to turn on and off the fan? Also try letting it puke out and continue to drive it. If it stops puking and never really gets hot (stays under 210) just cruising around town then the rad level has "self adjusted"
 

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Discussion Starter #15
Well Ive done some driving and hooked up a coolant jug with the hose submerged. When I do some highway driving it just keeps puking fluid out into the jug. When the car cools down it will not suck the fluid back in and the cap still has pressure on it. I let the car sit for 24 hours and when I went to undo the cap I found that there was still pressure under it. The car will now hit the 220 mark when I drive it and then slow down off the highway. I am assuming this is due to a very low level of fluid in the radiator. The radiator is far beyond "finding its level" I dont think it is the radiator cap since the car should suck the fluid back into the radiator when it cools. It is not and the cap still has pressure when I release it a day later... I really am starting to wonder if it is a head gasket problem but I have NO milky oil on the dipstick or in the radiator. I do however smell rad fluid when driving at high speeds with the temp rising but dont see any white smoke.. What is the BEST way to test for a blown headgasket? Someone said to hook air up to each cylinder and see if air bubbles come up in the radiator. If this is true then how much air pressure do I need to apply to each cylinder and do I need to make sure BOTH VALVES are in the closed position when I run this test?? I guess I just want to rule the head gasket out all together if I can or at least know what I am in for....

Thanks
Mark
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Have a shroud? A lean mix too much timming at hwy speed a bad rad. cap. I dont see head gasket here. How does it idle after hwy speeds a LIL rough? . If you can use an infra red temp prob. that could tell you more.
 

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Mark,

Are you running a vented or non-vented cap? Vented is for use with a recovery tank, non-vented for regular overflow tube.

I would start looking into worn out vanes on the waterpump if it hasn't been replaced in awhile.
 

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If there is still pressure in the system 24 hours later, that says to me that something other than expanding water is causing your problem. If it was just hot water expanding, you are right there should not be any pressure in the system after it has cooled down.

I would start searching for a head gasket problem, try idling with the coolant level low and check with a flashlight for bubbles coming up through the rad. If you want to use compressed air, yes you need to make sure both valves are closed, just use whatever pressure your tank is at, 150 or 125, whatever. Or if you have access to a smog test machine the probe over the open radiator cap with engine running will read hydrocarbons (raw fuel)

Oh, and a blow head gasket does not always allow coolant and oil to mix, it might just be blown between the cylinder and the water jacket.
 

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Discussion Starter #19
If there is still pressure in the system 24 hours later, that says to me that something other than expanding water is causing your problem. If it was just hot water expanding, you are right there should not be any pressure in the system after it has cooled down.

I would start searching for a head gasket problem, try idling with the coolant level low and check with a flashlight for bubbles coming up through the rad. If you want to use compressed air, yes you need to make sure both valves are closed, just use whatever pressure your tank is at, 150 or 125, whatever. Or if you have access to a smog test machine the probe over the open radiator cap with engine running will read hydrocarbons (raw fuel)

Oh, and a blow head gasket does not always allow coolant and oil to mix, it might just be blown between the cylinder and the water jacket.
OK I will check that out. This is my plan of attack although I will have to wait till friday to do it due to lack of time...

1. Pressure test the cap and the cooling system.
If the cap is good but the pressure drops, then I know I have a leak either externally, internally or both. If externally I will fix and retest. If I am still losing pressure then I will have to check internally. If it holds pressure then I will have to check flow problems... IE waterpump vains or thermostat sticking etc...

2. Pressurize all cylinders with both valves closed and look for bubbles coming up in the radiator. If bubbles are coming up then I can bet on a blown head gasket. If bubbles are not coming up then I will also run the motor and see if bubbles are coming up then. If not then.

3. I will get a block tester?(If someone knows the proper name Im all ears!!! please) its that tester that tells you if you have hydrocarbons in the coolant by the color changing?

4. If that all checks out then I will start looking for a flow problem. Maybe the waterpump is not able to keep up anymore, maybe the system needs a thorough flushing and cleaning, maybe the therostat is all clogged up(although it is new). I guess I could also check the upper and lower rad hoses to see if there is a major temp difference too. Only problem is the car really doesnt get out of whack unless I bring the RPMS up on the highway.

So what do you think? Is there a better way to go about it to trouble shoot this problem? I hope to GOD it is a flow problem and not a head gasket problem Thanks for the input I really appreciate it.
 

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Just a thought but the thermostat is not upside down is it?? Sister in law had a six banger Mustang that got hot on the freeway, it was because the thermostat was in upside down..
Here's hopin..

Bill
 
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