460 radiator burp

jupoa · 01-21-2011, 08:02 PM

Do radiators "burp" occasionally for no reason?
I found about a cup of fluid under my 97 460's radiator after I had arrived at a campground about three days before. I hadn't noticed it on the first or second day and it looked fresh. The bottom tray of the radiator was wet with fluid but I could not find the source. There were a couple of open ended 1/2" tubes stubbed through the bottom of the pan that the fluid may have come from. The plastic reservoir was still between the max and min lines.
The trip there and back was uneventful with ambient temperatures around 60 degrees and the stock temperature gauge drifting between 1/4 and 1/2 full scale depending on the load as usual. When I got back home there was no leak.
Can anyone explain this? Will it lead to problems?
Thanks for your help.

Wanabee FTer · 01-21-2011, 08:20 PM

I would suggest doing a radiator pressure test. It's possible that a hose or connection may be leaking slightly. When you park and the engine cools down you may be getting a temperature sensitive leak. Usually a pressure test of the cooling system when the engine is cool will allow the leak to show up. I have seen water pumps leak only at certain temps before they go out, but not sure about that on a Ford product.

justimagination · 01-21-2011, 11:05 PM

.....Check clamp on lower radiator hose, and also check where the hose goes into the burp tank. I know that would not show up on the lower portion of the radiator area, but will affect the level in the burp tank, since you mentioned it was between the upper & lower marks. I finally put a small clamp on the hose going into the burp tank which solved a small leak problem there.
I would also check the radiator cap(when cold) as it will sometimes have a small leak and let the antifreeze trickle down the radiator winding up in the bottom area below the radiator. JMHO, good luck.
David G.

Midniteoyl · 01-22-2011, 01:25 AM

Change the radiator cap...

jupoa · 01-22-2011, 09:01 PM

Good suggestions all around. Thank you.
As it happens, there was a trail of fluid down the front of the radiator from under the radiator cap attachment nipple. It did not dry up due to being under the rubber firewall waterproofing sheet. It may have come from the radiator cap, the overflow tank attachment hose or the short connector hose between the tank nipple and the radiator cap assembly.
Anyway, it's all going to be replaced and redone.
Thanks again to everyone.

Happy Trails

jupoa · 01-27-2011, 09:32 PM

Just as an aside to the other radiator issue, while checking out the leak, I noticed the face of the radiator was covered with lint looking stuff. The problem with cleaning it off was that there is only about 1 1/2" between the face of the radiator and the back of the AC condenser coil. If you look at it from the front, you might mistake the face of the condenser coil for the face of the radiator because it is about the same size and shape and mounted just in front of the radiator.

There is no access to the face of the radiator through the top or sides, just the bottom. I tried blasting the condenser coil with water from a garden hose hoping that enough pressure would come through to clean the radiator but no luck. I opened the dog house and blasted the radiator as best I could from the back and that helped but didn't get most of it. I finally had to fashion a cleaning tool from an old wide soft bristle brush and a scrap steel handle. That works, but it must be done from directly underneath so wear eye protection.

BTW, how do they pressure test a radiator? I tried to find a radiator cap with an air fitting but no luck. How many PSI do they use? Where and how do they input the pressure?

Thanks again for your tips.

Happy Trails

Midniteoyl · 01-27-2011, 09:44 PM

Pressure testers...

radiator pressure tester - Google Search

justimagination · 01-27-2011, 09:54 PM

Quote:

Originally Posted by jupoa

Just as an aside to the other radiator issue, while checking out the leak, I noticed the face of the radiator was covered with lint looking stuff. The problem with cleaning it off was that there is only about 1 1/2" between the face of the radiator and the back of the AC condenser coil. If you look at it from the front, you might mistake the face of the condenser coil for the face of the radiator because it is about the same size and shape and mounted just in front of the radiator.

There is no access to the face of the radiator through the top or sides, just the bottom. I tried blasting the condenser coil with water from a garden hose hoping that enough pressure would come through to clean the radiator but no luck. I opened the dog house and blasted the radiator as best I could from the back and that helped but didn't get most of it. I finally had to fashion a cleaning tool from an old wide soft bristle brush and a scrap steel handle. That works, but it must be done from directly underneath so wear eye protection.

BTW, how do they pressure test a radiator? I tried to find a radiator cap with an air fitting but no luck. How many PSI do they use? Where and how do they input the pressure?

Thanks again for your tips.

Happy Trails

........I have never seen a radiator cap like that, they don't exist. Drive to your local WalMart auto service center and they will pressure test it as well as your cap, it takes a special tool. The cap pressure should be around 15 lbs, good luck.
David G.

Jagtech · 02-09-2011, 08:22 PM

This sounds exactly like my rig. My '97 F53 has an unexplained coolant leak, about 1/2 cup periodically, which I haven't been able to locate the source. Also, the same "lint" problem; I got about 90% of it out using compressed air. It must have really reduced the cooling capacity of the rad!
Did you ever definitely locate the source of your leak?

Wanabee FTer · 02-10-2011, 08:53 AM

I noticed a small leak on my f53 also. I pulled away the rubber boot from the left front side of the radiator and found the source at one of the heater/bypass hose connections. I't so tight of an area to work on, I haven't tried to tighten it yet. The leak is very slight so it's not a priority concern right now.
hope this helps.

KC1BUD · 02-10-2011, 01:59 PM

One of the possible hazards of not replacing your radiator cap every few years happen to me. Blew about 8 inches of the seam of the end tank out. I was going about 55 on the freeway at the time, Quite a bang. Back then all it took was time to solder it back together, I am not sure what would be the fix other than replacement for a lot of these new plastic and aluminum radiators.

jupoa · 02-21-2011, 10:30 PM

Finally got around to replacing the radiator cap on my 460 and from the looks of it, it may have been the problem (see OP). The rubber washer under the cap part, not the spring loaded center part, was full of cracks around the perimeter. I don't understand how that could have caused my problem, but it is the only defect I've found.

A curious thing, the local auto parts store gave me a 13 psi cap but the one I removed was 16 psi. It's probably doesn't matter because my 460 has never even come close to overheating since I put a full Bank's system on it. Still curious about the correct psi though if anyone knows.

Happy Trails