possible blowby into the radiator

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joecool

joecool

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I'm becoming more convinced after reading many forums on the causes of antifreeze dripping from under the rad cap when it's not even hot yet. It's sounding like it might be from a bad head gasket or warped head. I just rebuilt the heads changing all the bent valves after a incorrect timing belt replacement job bent all of them. It ran great for about two weeks or more than the dripping started even when it wasn't hot.
Has anyone used any chemicals that are made for these leaks? One I heard is clear and has no solids, don't know if that works. And are these permanent enough as I'm planning a 6000 mile trip in August. Help please ! Joe
 
Hold on back up the cart!

Blown head gasket causing dripping from the cap?
That's not right.

I have been in and out and up and down with this cooling system and auto systems.
Dripping from the cap sealing surface (not the hose fitting) is a cap to radiator lip seal problem (wrong cap maybe) not a blown head gasket.

If you have a leaking (blown) head gasket you will see fairly steady bubbles in the recovery tank.
Without exception this is the case with this engine and cooling system design.

Now if your getting drips of coolant coming out the hose fitting with the hose disconnected that is normal and is caused by coolant expansion as it heats up.
This is true to an extent.

If you've replaced the cap and this started, put the old one back on.
With it running and warming up you may see a few bubbles if there is air in the system as that air is pushed out by the expansion.
You should not see bubbles once the engine is warmed up to fan temperature.
 
i agee with dan ...idont think its a blown head gaskit either ...not yet .....you need to say more ...if its not getting hot on long runs i mean real hot as in to hot to run i dont think its a head gaskit.....it could be the re4covery hose is stoped up going to the recovery tank ....while your at it takr the water pump spout bolts off and check the impeller for play ...with the kill switch on use the starter to check its spinning....if all that is good check and its still doing it go after the thermostat take it out and run it and see if it still dose it ...me personaly i dont run thermostats i want full flow all the time ....

i agee with dan its probably the cap or plug hose ...if your going to take a long trip you need to check this cooling system out and get to know it ...i wouldnt be putting any mirical crap in there at all ....good luck joe :mrgreen:
 
No thermostat? :shock: Is that a common thing ? I always thought you needed it in there..Please educate me..
 
If it's leaking from around the rad cap itself, I'd agree with it being a bad/incorrect cap. You just replaced it, if I remember right, and that's when you saw the leakage....kinda points to the cap being the problem. Unless...somehow, the lip on the radiator got messed up, and is not allowing the cap to seal. The only time I have EVER seen a leak from there, it has been a bad cap. Even with a bad head gasket, the added pressure would cause the cap to "puke" into the overflow/reservoir tank, not from the cap seal. :mrgreen:
 
As other folks said, try replacing the cap first. They're cheap from NAPA and only a few dollars.

If it WAS a head gasket after all, I wouldn't trust my bike on a long trip with a fix-in-a-bottle. They just don't work.
 
second NEW cap and it still leaked. Tested it for blown head gasket with Chemical block leak tester and no gasket leaks apparently. I have and will always use thermostats because when coolant gets back to the hot motor too quickly without the thermostat to slow it down and cool it off in the radiator, it over heats.
I took out some antifreeze so it just covers the cooling fins inside and the leak has stopped. But the bottle is almost full if it need to draw on any.
We'll see what happens now. I'm also changing that pesky 7 volt regulator behind the gauges as it was making both gauges bizzerk.
 
Two camps on the thermostat. Joe's camp believes removal of it aids in cooling and in old motors like these there is evidence to support that claim.
Second camp believes that the thermostat is needed to allow the motor to warm more quickly and to impede coolant flow enough to allow the radiator to cool it before it returns to the motor. Newer motors absolutely require a thermostat to slow the flow or they quickly overheat.
 
Wow, first I ever heard of removing the thermostat like that, I suppose the bike will warm up alot faster.. Could be the idea behind removing it.. I would think the thermostat would work in concert with the fan switch...I don't know though because I'm not an expert...I only wish to learn.. :Egyptian: :hihihi: And I like taco's
 
littlebeaver":1swne6t2 said:
And I like taco's
Click to expand...
:smilie_happy:

Me too!

Removing the thermostat won't make the engine warm up faster, rather the reverse.
I am of the leave it in group since I've seen too many problems in older cars when it's removed, slow warm up, hot spots, but that's off topic in this thread.

joecool, you said the bottle is full. Are you saying the reservoir is full?
If it is full because the radiator has expelled so much to fill it then that points to combustion pressure getting into the cooling system. It's normal expansion and contraction for the coolant level to rise as much as 2 inches then drop back down to it's cold level once the system is cold. It should never overfill itself, unless the engine is overheating and the coolant is boiling out.

It's odd the problem remains with 2 new caps.
When combustion is getting into the cooling system it will run warmer than normal, that is one sure sign but you haven't said it runs abnormally warm and blok check says no exhaust gas in the coolant so the cap and filler neck are suspect.
 
That's a odd problem Joecool, I'm sure you checked the rim of the radiator opening for smoothness or maybe tiny cracks, I'm thinking it's not sealing tight somehow or maybe it is but there's a crack just below it maybe.... I'm sure it's not the hose connection just below the cap because you said it was at the cap.. I hope you find it or figure it out.. good luck :eek:k:
 
Joe you mentioned draining the radiator down to the fins stops the drip.
That's only because the coolant isn't as high as the cap like that which won't last more than a few heating/cooling cycles, because while cooling the radiator is filled to top from the recovery tank.
Also, the system is designed to run air free to reduce corrosion.

I think what's likely happening here is the old cap was releasing it's pressure very early which meant the cooling system was running at a much lower pressure.
Now with a new cap (13 lbs) the system is up in pressure like it should be.
When under pressure any little chance for a leak will show up.

Don't try any block sealer, the stuff doesn't work and will only lead to blocked passages and taking your money.
I've tried them so trust me on this.

Run your finger around the cap sealing surface. It should feel very smooth and even.
You may just have to pull the radiator to fix this.
A shop can pressure test it.
 
I agree with cmonSTART . I wouldn't leave on a 6000 mile trip with a band aid fix like bottled stop leak. It has to be fixed right or I wouldn't go. Major breakdowns on the road are just too expensive. Where are you going on your long trip? And I thought I was brave planning a 1780 mile trip this summer.
 
Is it possible that it's leaking from the hose that goes to the reserve tank connects to the radiator (just below the radiator cap)?
When I was rebuilding mine, I neglected to check / replace that hose. The hose had a tear at the radiator connection and coolant leaked from there.
 
I'd take a close look at both caps (old and new) compare them closly. did someone maybe put a differnt cap on and strech or somehow distort the filler neck?
does the new cap tighten all the way to the stop?
is it easy to turn to the stop?
caps should be fairly tight, snug fit.

if its the same cap, and both rubber seals are in good condition.. then maybe someone had "tweeked" the old cap slightly to make it tighten on the outer seal a bit better.

keep us updated on your progress.

I run a thermostat and have never had a reason not too.
only in our race cars did we ever go without a thermostat and even in those we ran a restrictor in its place to slow the coolant in the radiator.
 
seems to be fixed by just lowering the coolant level to just above the fins.
 

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