filling catch can?

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Johnny Mac

Johnny Mac

www.blueprintengines.com
FABO Vendor
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a few weeks ago my 408 stroker started boiling over. the passenger side of the radiator was boiling, the driver side was cold..so i replaced the thermostat. and the cooling issue went away...car runs very cool now, but its doing something it hasn't done ever before? Im getting several ounces of fluid in my overflow can every pass down the track....my overflow has been dry for 3 years? and never ever had any fluid in it until this boiling over occured before i swapped thermostats. and now although running very cool...i'm still getting fluid passed the cap. i replaced the cap from a 16 to a 20 and seems to make no diff.
any ideas?
 
One side of the rad is hot and the other side is cold ??

Sounds like your radiator is plugged.
 
yellowdartdave said:
One side of the rad is hot and the other side is cold ??

Sounds like your radiator is plugged.
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new 2 core all aluminum aftermarket radiator, crossflow...everything up to the thermostat was hot, after was cold...so the water pump was pushing everything to the hot side, and it was being stopped at the t-stat..this boil over happened after very little warming of the engine. so ichanged the tstat, runs good and cool now, all the hoses and both sides of rad heat up, but not excessivly. but now getting the fluid in the overflow.
 
maybe this would have better been asked in small block tech...i took cooling to mean cooling system...not a/c
 
have you checked the rad with motor running and the cap off to see if your getting bubbles in the rad.or run the rpms up to around 2000 or 3000 with cap off and let off it and see if water comes puqueing out.if so could be a blown head gasket.???? thats happend to me the same way....Artie
 
also a new crate engine.lol....soo hoping its not a head gasket...especially since the car is running very well and not overheating at all... i'd think that it'd smoke and boil, and overheat if it were a head gasket?

you're saying let it run at idle up to temp with no cap and watch to see if the fluid moves?
 
johnnymac2k6 said:
also a new crate engine.lol....soo hoping its not a head gasket...especially since the car is running very well and not overheating at all... i'd think that it'd smoke and boil, and overheat if it were a head gasket?

you're saying let it run at idle up to temp with no cap and watch to see if the fluid moves?
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i already swapped 3 caps out...and anyways that doesn't matter because its a head gasket for sure, water in oil. air in the cooling system, and water out the exhaust....real high quality crate motor boat anchor i picked up here. they don't know it yet but they will be refunding every cent i have on this thing.
 
umm the catch can is supposed to cycle... that kinda the point lol

the radiator gets hot so the fluid expands.. then the now extra fluid gets pushed into the overflow...

when i cools it will suck it back in...

when you put a high cap on it it has to reach that pressure before it can vent...

your suposed to fill the overflow half way cold and then just let it do its thing...

helps get rid of air also...
 
805moparkid said:
umm the catch can is supposed to cycle... that kinda the point lol

the radiator gets hot so the fluid expands.. then the now extra fluid gets pushed into the overflow...

when i cools it will suck it back in...

when you put a high cap on it it has to reach that pressure before it can vent...

your suposed to fill the overflow half way cold and then just let it do its thing...

helps get rid of air also...
Click to expand...

First off it's an overflow catch can. not a recycling one. that i have never had fluid in ever. If the cooling system was functioning properly it should never push fluid past the cap. i tried multiple 16's and even a 20 to no success. I'll also point out that it was pushing off hoses.

Now to the reason why it has nothing to do with a bad cap or clogged radiator. you can see above in my last post, water in the oil/exhaust..on top of the fact that i can watch it air bubble out the radiator with the cap off, on top of multiple oil leaks from excess pressure. points at a head gasket. The troublesome Piece of S this thing has been since day one, Its going back to the vendor for a refund plain and simple. Im tired of Effing with it. I bought a engine to drop in and go, not to pull it 3 times since racing season started.
 
johnnymac2k6 said:
First off it's an overflow catch can. not a recycling one. that i have never had fluid in ever. If the cooling system was functioning properly it should never push fluid past the cap. i tried multiple 16's and even a 20 to no success. I'll also point out that it was pushing off hoses.

Now to the reason why it has nothing to do with a bad cap or clogged radiator. you can see above in my last post, water in the oil/exhaust..on top of the fact that i can watch it air bubble out the radiator with the cap off, on top of multiple oil leaks from excess pressure. points at a head gasket. The troublesome Piece of S this thing has been since day one, Its going back to the vendor for a refund plain and simple. Im tired of Effing with it. I bought a engine to drop in and go, not to pull it 3 times since racing season started.
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damn i hope u get ur cash back or at lest a good motor keep us posted and if the vinder dont do ya right let us know who it was that way he dont get any on emore
 
johnnymac2k6 said:
First off it's an overflow catch can. not a recycling one. that i have never had fluid in ever. If the cooling system was functioning properly it should never push fluid past the cap. i tried multiple 16's and even a 20 to no success. I'll also point out that it was pushing off hoses.

Now to the reason why it has nothing to do with a bad cap or clogged radiator. you can see above in my last post, water in the oil/exhaust..on top of the fact that i can watch it air bubble out the radiator with the cap off, on top of multiple oil leaks from excess pressure. points at a head gasket. The troublesome Piece of S this thing has been since day one, Its going back to the vendor for a refund plain and simple. Im tired of Effing with it. I bought a engine to drop in and go, not to pull it 3 times since racing season started.
Click to expand...

i did miss in you post about the oil in water... but i have to disagree with this...
if your cooling system IS working properly it will push extra coolant out because the system is full and once it hits over a certain pressure it vents... no what your saying if that wasn't true the coolant would just stay in the bottle?

if so when the system cooled the hoses would collapse, the radiator could possible implode (plastic tank)...

the overflow tank started to make a sealed system, no air, originally they just vented to the ground so it would heat up and vent the extra coolant, then cool and suck in air, allowing the engine and everything else to start rusting faster...
 
what i'm saying is that with my other engine, a moderate 318. my overflow NEVER once got a drop of fluid in it. The cap held the water in the radiator without a problem...the only reason it'd need to vent is excess pressure....so the setup i have now. if the radiator gets too much pressure...so much that its pushing hoses and filling my CATCH CAN, (which is obviously not correct or normal) then yes. the fluid has nowhere to go. it does NOT recurc. it just sits in the catch can after being pushed past the cap.
also as said before i have a race, ALL ALUMINUM radiator. its not a plastic tanked one that needs to expand and collapse.
the pressure builds in a cooling system due to heat..this is why hoses expand, and also why you can't open a cap when the coolant is hot. The radiator cap holds the pressurized fluid in the system which also keeps it from boiling (producing gas that leads to even more volume expansion) in a closed system the expansion is kept to a minimum b/c the water cannot boil. this is how a car runs above 212 degrees w/o boiling over.
if you have a small air leak, or a bad cap. then the pressure can slowly escape, which leads to the water boiling and expanding rapidly. which leads to fluid being pushed out of the cap.
now again if you're filling a catch can on a regular basis...you either have a small leak via a cap or hose. a clog somewhere, or a bad T stat. or worst case scenario as in mine. a leaky head gasket that is allowing cylinder head pressure and heat to work its way into the cooling system.....more pressure and heat than the cap is rated for, filling the catch can.
sorry for my long winded explanation of how i think the science works...anyone can feel free to correct me, and i mean no "schooling" here, just stating how i have always understood it and i believe im correct.
 
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