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Discussion Starter #1
Ok ever since I rebuilt this motor I have been loosing a little fluid from the overflow after every drive, and I can put the relief on the cap while its hot and it shoots air into the overflow followed by fluid. After it cools it sucks back the fluid and its always a little lower than before.

So heres what I have done, Replaced head gaskets, no change! replaced intake, no change! Leak down test on the radiator and it was great, No leaks revealed! I did find the overflow tube was letting in a little air but fixed that and the problem is still there!

So heres what I seen today, while the car was runnng and on ramps I was looking under it for leaks and couldn't find anything. so while up top I decided to give it a little throttle and noticed the fluid level will drop and recover in the radiator with a wrap of the throttle, I think this is normal. Also notice the car does not get any bubbles in radiator at idle. BUT if i hold it at a higher rpm it will get the occasional bubble out the cap, and the harder I wrap on it the more bubbles I get. Absolutely no water in oil, no water in tailpipes or sweet smell at all.

Only thing I know left to do is get one of those test for the radiator fluid that checks for combustible gases, and do a compression test, or maybe a leak down on each cylinder! I have never done these and am wondering if they can tell me the problem???? I know if I find combustibles in the fluid what it is. but If I dont what in the world can I try. I am sick of this thing and ready to burn it but have way to much money in it.
 

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Sounds normal to me! That tank on the outside of the radiator that is hooked up to the tube at the cap is known as a expansion tank because as the fluid heats it expands, as it cools it contracts. As you drive it self adjusts to the temperature of the fluid and the ambient temperature. Hook it all up keep an eye on it and forget it. I would not check to level until the engine is completely cooled off. As long as there are no leaks into the engine oil, compression areas and no leaks to the outside world, all will work out. If the water level eventually gets too low then I'd suspect something may be getting out of the system. If your concerned about air in the water try getting the front of the car up high so the air can migrate to the highest point in the system, the top of the radiator. Try parking on a hill.

It would probably be helpful if you mention cap pressure and if there have been any modifications to the cooling system.
 

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Discussion Starter #3
I think its an 11 psi cap, nothing stock on the radiator setup, 2 core griffin radiator, edelbrock high flow water pump, high flow stat, If I just "let it go it will eventually loose enough water in the overflow that I have to refill it" That may take several drives, but I still believe there is a problem when I KNOW the system is burped and I am still getting bubbles but only under throttle. I think my damn block is cracked or something.

Anyone know a good combustible leak test brand and where to get it???? Are the test strips any good???
 

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Discussion Starter #5
I have one and will install it, Please explain how this may help my problem???
 

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It could be venting under normal operating conditions ??

I really agree with the other comments.
If you aren't getting a drip on the floor and your oil doesn't look like a milk shake and you don't have any steam out the exhaust... I wouldn't consider it a problem unless I go through a gallon or two of water without it stopping.

How did you burp it ??


Sent from AutoGuide.com Free App
 

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Only fill the over flow to about half way up or at the very least, an inch or so below the filler neck level or it's going to over flow til it gets to that level. Mine gets down to the exit hole after several drives, especially in summer when it's hot. I think, like sumfoo1, it's normal. Unless it's down to the exit hole level after only 3 or 4 drives.
 

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I think its an 11 psi cap, nothing stock on the radiator setup, 2 core griffin radiator, edelbrock high flow water pump, high flow stat, If I just "let it go it will eventually loose enough water in the overflow that I have to refill it" That may take several drives, but I still believe there is a problem when I KNOW the system is burped and I am still getting bubbles but only under throttle. I think my damn block is cracked or something.

Anyone know a good combustible leak test brand and where to get it???? Are the test strips any good???

Steve, WHAT makes you think you "Have to re-fill it"??

Did you have an overheating issue?

ALL of the things you thought were "normal" ARE normal :)

The fluid level will be adjusted to the needs of the car it's self but running it.

Let the level go, then drive it and observe the temp gauge. If the temp gauge goes up and down or flat lines to cold, THEN you have issues, if it maintains a respectable temperature throughout operation "Even though you don't think the tank has enough coolant" You will be fine. :)

FE

P.S. I'd go with no higher than 15 psi cap personally.
 

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Discussion Starter #9
The thing is I know its loosing water and I know its getting air from somewhere inside the motor or throughout the cooling system. Every time after I stop from a short drive it has accumulated air in the radiator and once it cools down its lost a little more water from the overflow!! I will make a few marks on the overflow and keep a record of the length of time driven and how much it looses once it cools off. I keep the tank about half full.

It just seems like there shouldn't be any air mysteriously appearing air in the radiator after its been burped and driven several times after every drive. Or air bubbles coming out of the radiator fill cap when the engine rpms are a little higher.

Could the high flow water pump be causing cavitation and making air bubbles??? i am going to do a combustion leak test this weekend. If I have combustibles in it i may burn it. if not I may not worry about it and drive it until it shows its face, "if it ever does"

Also the car runs good temps, but at highway speeds it tends to run a little warmer. I am praying the test doesn't show combustibles but I feel as if it is. I want to say the overheating at speeds may be I may be moving the water to fast with the griffin 2 core, edelbrock high flow pump, and high flow stat, I may need to find a larger 3 V pulley for it to slow it down some. I also had a problem with blowing out the intake gaskets and dumping water in the oil before I replaced the old intake. I think I warped it while installing the motor with the trans bolted on and at bad angles with the attaching bolts. if it blows these I know there is a much deeper problem, or I have to much PSI from the pump or a leak.
 

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If you have installed a aluminum radiator I would assume the manufacturer has recommended the cap psi to be used. But as a rule of thumb the higher the pressure the lower to water temp will be to a point. You don't want a pressure so high it starts damaging the system. Also I would not worry about the level of the water in the overflow container as it will change with the outside ambient temperature. Only open the system when it is completely cooled to see what the level is in the radiator. It should be down an inch or two from the cap. Just relax, drive it and watch it. NEVER open or vent a hot system!
 

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ANSWER the Q bro :) DOES IT OVERHEAT?

I dont' care how low the water level goes, if the car don't overheat or get too hot then it's FINE!

NO the water pump cannot CREATE air bubbles, it simply pushes air around when it's going through it.

The ONLY reasonable explanation for air getting into your system, WHILE it's under pressure is a blown head gasket or a cracked head.

So please don't worry about the level UNLESS it overheats to starts to overheat. 215 to 218 is the beginning of the overheating mark for most run of the mill FE's.

If it don't get that hot, there is really nothing to worry about....

Lastly.... A combustion gas test kit can be found at any "good" mechanic shop, and you can likely get one from Napa or A major auto parts chain.
 

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These guys are all on the right track, but it seems you have a modified system. >>> How about a complete description, or better - a few good pics of your setup? <<< In the mean-time:

  • The original system was designed to self-level with coolant 1 to 2 inches below the cap of the top radiator tank.
  • Your proper cap pressure rating is dependent on your thermostat rating - what is it?
  • Original systems did not have catch-cans or reservoirs for their self-leveling systems.
  • While most purging of steam or excess coolant happens after warm engine shutdown, it can happen any-time during or after operation.
  • Air bubbles caused by pump cavitation collapse and disappear immediately after leaving the impellers. They are not permanent, lasting only microseconds.
David
 

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does the fluid remain green /orange ? or is it turning brown ?

If the cap is to light it lets fluid bypass to easy and causes problems. Run atleast a 15lb cap.


Everyone always thinks there car run's hot or to hot ect .... if its not 220+ its fine. 250 is hot and needs to be figured out ..
 

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Discussion Starter #14
answering the questions!!!

No it never overheats!!!!

My cap is a 13 psi!!!!

Done a combustibles test and good news, absolutely no combustibles in the fluid. the fluid is blue and turns yellow when combustibles are detected. Fluid stayed blue!!!!!

I did not realize these cars ran an inch or two below the cap! I was looking for it to stay perfectly full with the overflow. I am going to eyeball it for a few weeks and report back. BUT i am positive something is putting air in the system even though it does not run over 195.

Here is a question off subject. It the car runs hotter when I am following closer to someone at highway speeds does this mean its not getting enough air across the radiator, and has anyone ever made a lower air dam for these cars. seems like my bumper blocks half my radiator.
 

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Discussion Starter #16
I am thinking about putting a desert model 4 core factory style radiator back in. I think its flowing to fast. "not looking into getting into a war about that" Here are a few pics, maybe yall can see the flappers and all for added flow at highway speeds, it did help. She never runs warm at slower speeds with the fan on.










 

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Discussion Starter #17
3300 cfm 600 hp rated fan with shroud and high speed vents/flappers on the shroud, close to me is 3 to 4 car lengths behind them with factory drum brakes. I can immediately tell on the temp gauge when I get to close at speeds it will rise pretty fast. Back off a few lengths and runs cooler lol. The cooling system on this old car has give me fits lol
 

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What temperature is the fan set to come on? What temperature is it set to turn off? What's the antifreeze ratio?
 

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Discussion Starter #19
stat is a 180 fan comes on around 185 190 and it shuts off pretty fast and stays off a good while, Ratio is about a 1/4 concentrate and 3/4 water. Its been in and out so much I cant give you an exact amount of it.
 

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What temp is it set to turn on and off??

The coolant looks a bit anemic to me. Should be 50/50 mix to cool properly, add some water wetter.

Is the fan controlled by a thermostat connected to a relay?
 
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