weird flathead issue,need expert advice!

hombres ruin

hombres ruin

Well-known member
hi guys here is the situation,1950 8BA,offy heads,copper head gaskets,offy regular dual manifold and dual holley 94s,aluminum radiator with distilled water and water wetter,and i use brad penn oil.I have 7,000 miles on a rebuild.I have loss of water from the rad,no overflow tank and i run a 7lb cap.The water seems to dissappear when the car is parked for a time ,i have no white smoke from the engine,i did but drove it and it dissappeared and hasnt returned.I do not over heat and the temps are spot on. I did a block test for a blown gasket a couple of weeks ago and it was negative,i have no bubbles in the rad and the oil looks ok,its not brown its slight green/grey because the oil i use is green.Now i did a block test again today and the fluid turned green,yes green not yellow,i did this 4 times to make sure, and it turned green on all occasions.does green mean a slight leak?..what should i do? should i retorque the heads and drain the rad and do a leak test again? could it be a loose head bolt,although on inspection i see no leaking bolts at all? could it be the copper gaskets?..experts what do you think and what would you do?...thanks guys
 
homb,
I'd switch to the GraphTite head gaskets. The copper head gaskets with
alum heads and an iron block really promote galvanic action. The GraphTite or
Best Gasket equivalent are pretty forgiving too. Speedway 910-15848.
Charlie ny
 
thanks charlie, i have heard that the iron block,copper, and aluminum heads act together and cause electrolysis.How could this cause a problem,by causing a leak,an opening? an uneven surface?
 
The flathead radiator system is not a recovery system like we have in todays vehicles. So when the flathead gets to operating temperature water is pushed out the overflow till it get to the level it can handle with out overflowing(water expands). As if cools down the water level drops leaving a space in the radiator.This is a normal condition
 
habbott thanks for the advice,i have an after market aluminum rad,but i am loosing a gallon of water,i have bought an overflow tank and will install it,but its the positive leak test that worries me
 
I wouldn't worry about green TK check test this can be caused by contamination of the check fluid eg radiator water, condensation .Does you tester have 2 fluid levels or just a single level?
 
hombres ruin said:
habbott thanks for the advice,i have an after market aluminum rad,but i am loosing a gallon of water,i have bought an overflow tank and will install it,but its the positive leak test that worries me
Click to expand...
Do you lose a gallon of water every time you drive it or does it lose a gallon and then remain at that level?
 
habbott,by it turning green means something is going on for sure,i did the leak test 4 times and each time i rinsed the tube out with clean water,there was no contamination i can see.It has one fluid level....Flatjack,i loose a gallon once i have driven it and then parked it and come back say n about 3 days to drive it again and its down a gallon.I drove the car with correct rad level for 30 mins to the paint shop,left the car there for two weeks in which it was worked on and not driven ,came to collect it ,checked the rad and bingo down a gallon again
 
But if you don't refill it, does it go down another gallon the next time you drive it? If you are losing a gallon of water when it is just sitting and it's not external then you would surely see it in the crankcase or in a cylinder. I think you are losing the water out the overflow while driving it.
 
flatjack,i always re fill it when its low so i cant answer that question,others i have spoke to have said what you said and that its going out the overflow when driving,i thought it was a crappy rad cap but i changed it and it did it again,so i am putting a recirculating expansion tank on there in the hope it solves that problem,but the positive leak test is what concerns me,and should i retorque the heads????
 
I would have to agree with flatjack9 to loose this much water it would show in the oil or out the exhaust. If it was a combustion leak then the TK would be yellow real quick. Check the radiator cap is sealing inside the radiator neck if not sealing you will get a siphoning effect while driving. (Air passing the overflow tube ). I would also do a head re torque as well to make sure.
 
Do you have an original radiator? If you do they take a 1" deep radiator cap, when you drive it the water goes out the overflow and you can't find a leak. If you put a new cap on it is for a 3/4" deep neck that is your problem? Check it out.
 
get one of those rad test hand pump with the gauge on it pump it up to 7-10 lbs & see if it stays there if the gauge drops you have a leak some where
 
hi bossy i have a after market aluminum rad,i see no leaks any where from the pumps or the rad.The cap is new 7lb stant brand.Habbott the cap seems to be sealing well to see water in the oil what would i look for since i have water water wetter and run brad penn oil which is green,when i look at the dip stick i see a golde green color once the engine stops and settles after i run it i see a greyish color but not a chocolate milkshake color like others have said it appaers as.i will do a head retorque as well
 
Im going to post a question that i think is rudimentry but here goes... Do you have a puddle or mark on the floor? Evidence of it coming out the expansion tube?

A 7lb cap seems like too much. 4lb is better in my opinion.

Do what flatjack said and drive it after it goes down. Obvisiusly not letting it over heat. Check again. If it remains the same you have your level with a 7lb cap.

Doesnt copper turn green when it corrodes or oxidies. Just thinking out loud. Sorry for some of the spelling.
 
REtorque the heads, change the cap and ck with your comb leak kit again.
If losing a gallon on short fills and oil level NOT changing, it's either going out the over-flow or thru the exhaust. Fighting basically the same thing on my A after a hard run. Good luck.
Paul in CT
 
Hi tinker. No I don't have a puddle under the car. But now that you mention it the drivers side head closest to the rad and below the water neck, where the head seals to the block, I notice some green oxidation and what look like water weeping marks, that could be where it need to be sealed ... Hi Paul.. Yep will do that and keep you posted
 
Have you tried some Barrs leak or other stop leak? I seem to remember being told to use that after a re-build and with every radiator flush on a flat head. I fought what I thought was low level in the radiator until someone on here years ago said these old cars will determain how much coolant they want and need. Haven't checked it since pulling it out of storage and it hasn't overheated this hot summer. I know the level is below the tubes when cold.
 
hombres ruin said:
flatjack,i always re fill it when its low so i cant answer that question,others i have spoke to have said what you said and that its going out the overflow when driving,i thought it was a crappy rad cap but i changed it and it did it again,so i am putting a recirculating expansion tank on there in the hope it solves that problem,but the positive leak test is what concerns me,and should i retorque the heads????
Click to expand...
Wouldn't hurt to retorque. I would not believe that test. I've got a friend with a 35 Ford, rebuilt engine and had a problem similar to yours. He also had an aluminum radiator. He had a positive test, so took the engine out disassembled it and brought it to me to check. Found no problems, reassembled it and ran it in my test stand. It puked water out the overflow in no time. About drove my nuts looking for a problem until I changed the radiator to a stock one that I had and - voila- no more overflow. The aftermarket radiator could not handle the flow. Junk.
 
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