I'm leaking anti-freeze at almost all the hose connections. Not a lot but it's dripping from from almost all of them on and off. It's driving me crazy.

I installed a used engine over the winter and I bought ALL new hoses and a new water pump. I flushed out the engine and replaced the freeze plugs. When I first started it it leaked at a couple hoses and I was able to tighten them up and stop it. Then it leaked at another hose and I tightened it. Then another, and then back to the ones I tightened already. I've used a ratchet to get them tighter and I'm afraid I am getting close to busting the hose clamps. But they are still leaking! And now I took the car out for a drive last weekend and found anti-freeze inside on the carpet so I'm thinking my heater core is leaking too...lol.

I've never had these problems with coolant leaks like this. What the hell am I doing wrong?

 

Make sure you are using the right size hose, I just hade the same problem and I did know there where two different sizes coming from the heater core, I just bought all 3/4 hose and it takes two different sizes, 5/8 and 3/4 so no matter how much I tight that clamp it still leaked where I put 3/4 hose instead of 5/8, got the right and problem solved, I too tough my heater core went bad,,

 

X2 on checking the hoses, I have found I often need to clean up the outlets the hoses fit onto, often there is corrosion and pitting on them.
One cure in really bad cases is to put jointing compound (rtv silicon) on them before fitting the hoses.
Overtightening the hoses won't help, you will distort the hose if you overdo it, and possibly weaken them. Don't forget they only have to withstand maybe 15 lb/in pressure with perhaps spikes of 25 lb/in.


Roger.

 

You installed a used engine ,that sounds to me like it may be the problem.Maybe you have to much cooling system pressure ie head gasket?Nick

 

Sounds like a build up of too much pressure, if the heater core is leaking no pressure their, what psi is your rad cap ? If your hose diameters are correct scuff the inside of the hoses a little with emery cloth.

 

What type of clamps are you using? I've found that the tower style clamps sometimes tend to leak. People are sometimes afraid to tighten hoses too much. Also as some have said above the mating surface tends to corrode and pit making it hard to get a good seal.

 

What are the temps where you live? What mixture of coolant are you using? Should be 50/50..

 

Make sure the fitting is clean, smooth, and free of heavy rust. Make sure they are not bent or dimpled either. Make sure to position the clamp about 1/8 to 1/4" past the barb on the fitting.
They should seal fine without any RTV and with only moderate tightening.

 

First, thanks for the replies.

The hoses are indeed 3/4 and 5/8 so they are the right sizes. The upper and lower radiator hoses are brand new AC Delco hoses. So all the hoses are for sure the right size. I am using worm gear type hose clamps. The radiator cap is rated at 16lbs. Anti-freeze is 50/50 mix. I'm pretty sure the hose barbs were clean but I would have to take the hoses off to check them out for sure. It was not leaking with the previous engine which used the same radiator, heater core and thermostat housing.

I don't understand this statement "You installed a used engine ,that sounds to me like it may be the problem.Maybe you have to much cooling system pressure ie head gasket?Nick"

The engine was a used running engine I never removed the heads. I just flushed it and replaced the freeze plugs. It is a 1966 330 4 bbl. The previous engine was the original 1967 330 2 bbl. How would I check the cooling pressure?

I have put in mechanical gauges and on a cool day the engine hits a little over 190-195 before the thermostat seems to kick in and then it drops so it appears that is working correct also.

Like I said I'm confused as to why I am have having this problem. I've never had to tighten the hose clamps this much and I don't want to ruin the clamps or the hoses by over tightening.

 

Oh and the radiator cap is new also. I do not have an overflow reservoir.

 

You've got to have some crud on the hose nipples.

Either that or the new cap is way screwed up and is raising your pressure too high.

Most chain auto parts stores have radiator pressure testers you can borrow, and it should be easy to bring the cap to the store and test it on their loaner tester.

- Eric

 

That's strange indeed, especially with new AC Delco hoses, I put new hoses on although mine were made in Mexico, I had to scuff the inside of the rad hoses to get mine to stop leaking a little with 3 row rad and an 18 psi cap. I used triton hose clamps. I'm not sure as to the head gasket comment either. If the heater core was leaking I can't see to much pressure building for the system to be leaking at the hoses. Has the heater core now been replaced? Re-check the cap possibly.

 

Ok, now you mentioned you replaced the radiator cap,on your first post no mention of that,just engine and hoses.Nick

 

Carefully check the radiator and heater core nipples for damage and dents from previous clamp overtightens, or from someone prying off the old tower clamps. I had this damage to my heater core and had to replace the core. Someone long before me had use RTV and then the clamp but it had always oozed.

The nipples at the water pump can be cleaned with a wirebrush (one in a drill or dremel works great if you have the room). Sandpaper will work too.

 

If all of your connections are leaking then it's 1 of 2 things. Serious overpressure in the system, or your just not tightening the clamps enough. The heater core can be a symptom of the overpressure or just a coincidence due to age. With a new cap rated at 16#'s it should blow out the overflow preventing overpressure. Your temps seem fine.

 

Very well could be as Eric said, serious overpressure, especially if the PO dumped a lot of block sealant in the used motor he sold you. That would suck!!!

 

I have not replaced the heater core yet. I was thinking about bypassing it until I can get around to it. Under the dash is kind of a mess and I want to take out all the heating and cooling stuff to figure out what is missing and what needs to be replaced but I still want to be able to drive it while I mess around with that.

Anyway, when I bypass the heater and remove it I will take that time to recheck everything.

 

You have all summer. Do you have a/c?

 

It is an A/C car and everything appears to be there but it does not work currently. The controls are messed up and are stuck/jammed. The compressor belt is not on at the moment but it spins freely. This is part of the reason I want to get under the dash and clean it up and see what's messed up.

 

Here's a question I've not seen asked yet, and I ask from experience.

Are you sure it's actually leaking from where you think it's leaking?

I just last week had the radiator in my '73 wagon overhauled after discovering that the seal between the tank on the right side and the radiator had opened slightly. But I would have sworn on a stack of bibles that the leak was from where the lower hose attaches to the tank as the leak appeared to be coming from directly under that connection point. I removed and reattached the hose and retightened the clamp, but no luck. I then thought it might have been a leak around the nipple itself where it emerges from the tank. But nope, not that, either. The radiator shop did a pressure test, and the leak point was obvious.

I don't buy that your problem is just dirty or corroded hose connection points. I could see this if just one hose leaked. But all of them at the same time? Not likely. And I also believe that you know what you're doing when you go to tighten hose clamps. They're likely tight enough.

I've not seen any mention that the radiator itself was examined/repaired/replaced as part of this engine swap. I would pull the radiator and have a shop test it.

 

The best cooling (heat transfer) occurs with 100% water. Antifreeze / ethylene glycol has a lower heat capacity than straight water. It will depress the freeze point significantly and raises the boiling point marginally but reduces the heat capacity and heat transfer, therefore reducing cooling capability. 50/50 is really needed only in climates that experience sub-zero temperatures. Well, I should mention that it provides corrosion resistance, but that's irrelevant to this discussion.

 

You also mention that the heater core started leaking. Yes, this could just be coincidence. But maybe not. You could have an overpressure problem that's causing your system to spring leaks like a Three Stooges plumbing job.

The OTHER thing that was suggested to me by the radiator shop that fixed mine was to get rid of that 16 psi cap, put a 13 psi on instead, and prolong the life of my radiator. He said that leaks like the kind my radiator had are commonly caused by overpressure. Yes, that's a 16 pound system, and a 16 pound cap should work fine. I haven't actually done this yet, but it's an interesting suggestion from a guy who sees and fixes leaky radiators for a living.


I'm curious about anyone's thoughts on this radiator cap switch. I looked it up, and the boiling point of pure water varies by about 6 degrees F in going from 13 psi to 16 psi. At 13 psi (which is actually 13 psig or 14.7 + 13 = 27.7 psia), the boiling point is 246 F. At 16 psi (30.7 psia), the boiling point is 252 F. I would imagine that the boiling point of a 50/50 coolant/water mix, which would be higher to begin with, would vary by about the same amount over the same pressure range.

Is this enough to be concerned about?

 

Boiling point elevation, in general, is not the only reason for the 16psi pressure.
It's also because it will reduce micro-boiling right at the interface between the heads and the water, which interferes with heat transfer.

That being said, I have done this experiment, albeit unwittingly.
My heating system seemed to have a little leak. Not a big deal, and it did hold pressure, but it always seemed that coolant would slowly disappear.
I picked up a new cap and tried it out, and DAMN! if I didn't suddenly have water spraying out of the radiator core in a couple of places after a drive around town.
I pressure tested the new cap and it was dead-on at 16psi.
I pressure tested the OLD cap, and it was releasing at about 7psi (though it was a 16psi cap).
Lesson learned. The crappy cap was acting as a Band-Aid to the crappy radiator.
Replaced the radiator and all was well.

- Eric

 

I'm pretty sure that it's leaking at the hose connections and not the radiator itself. Especially since it leaks at more than spot. After looking at it a little closer it's possible my heater core is not actually leaking but still leaking at the hose fitting as it does sit inside the firewall slightly so it could be just leaking from the hose point there. The radiator was not tested but it was not leaking with the old engine. I also never ran the car with the new engine with the old radiator cap. The seal was really dry rotted so I just replaced it. I bought the 3/4 to 5/8 adapter to bypass the heater so I may try that this weekend.

One thing I forgot about and I will check when I drain everything is the inlet fitting that goes in the intake manifold. The new engine had a straight nipple but the old engine had a water valve instead because it is an A/C car. The old nipple was a bear to get out and when I got it out it was completely blocked inside where no water could flow through it. I'm pretty sure just the fitting was clogged and not the manifold but I will check that also.

I may replace the radiator this summer anyway. It looks like the original one and it's a little banged up. Does anyone know if the radiator was the same for a 67 330 250hp car and a 66 330 310hp car? Rock auto shows the same radiator for both but they are only replacements so I'm not sure. Also, is the SPECTRA PREMIUM from Rock Auto worth it or any other recommendations? It's not a show car or race car just a driver.

 

Update:

I finally got around to working on this. I removed the heater core and bypassed it. I checked all the hoses and clamps and re-tightened them. I also added an overflow tank. It's not the cleanest job I've ever done but neither is the car...lol.

The heater core was definitely leaking and it looks like it has been for a very long time. The car is in pretty good shape as far as rust goes but the passenger side floor pan and carpet are the worst. Now I know why. It has been leaking for a long time before I had the car. The floorboard is rusted out pretty bad and the sill plate is completely corroded through at a couple spots. I had thought it had just leaked water at some point but I'm sure it was coolant now. The heater core was bulging and you could easily see where it was leaking. A lot of the brackets and screws were completely corroded and had to be pried off and broken to get it apart. It looks like someone might have attempted to fix it and gave up. Lucky me!

Anyway I took it for a long ride and even had it out on the highway stopping at several places and checking for coolant leaks. So far there is none. I will keep an eye on it and see how she does over several drives but so far so good. It even felt like it ran better. I can't imagine why. I did tighten the alternator and power steering belts but that's about all I did besides the heater core.

Oh, did I mention how much I hate working with coolant?!?!?! Somehow it always ends up all over me and everywhere else too.

 

Sounds great! Glad you fixed it. And sorry to hear about the floorboard.

- Eric

 

Heater cores are always fun. Glad your getting it squared away.

 

LEAKS of any kind be it coolant, oil, or transmission fluid, can make you lose your religion! Glad you have yours figured out.

 

And there she is!

 

Oh yeah, time for a new one.

 

that thing is toast!!!