A few days ago, in the extreme cold here in Detroit, my truck leaked out the anti-freeze and started running hot. I was only a half-mile from home so I got home and parked it. It was too cold and snowy to work on it but I popped the hood and could not tell where the leak was coming from.

Flash ahead to today. I just got home from work and it's much warmer out (20 degrees I think) so I put a gallon of 50/50 mixed anti-freeze and water in the radiator and started the engine. The gallon almost filled up the radiator to the top but not quite. I left the cap off for awhile but the water started rising in the radiator so I put the cap on.

After about 10-15 minutes the engine warmed up and I guess it let the anti-freeze flow through the engine and start warming up. The top of the radiator got warm so I guess water was flowing through the engine. After a few minutes I saw anti-freeze dripping on the ground at the right-front corner of the truck. I traced it to this: there is a one gallon plastic jug that the radiator overflow hose goes into. That jug had holes in the bottom of it and anti-freeze was overflowing out of the radiator, through the hose, into the jug and onto the ground.

My questions are these: Is my radiator cap bad and do I need to replace it? I see no other reason for the cap to let water overflow into the overflow jug.

Thanks for any help.

Dennis

 

Probably not necessarly bad, but if you were going to replace it many of the older Fords did not come with a coolant recovery tank. Does yours look original, you stated it was a 1 gallon jug? If you do replace your cap there are caps for coolant recovery system and caps for without. It may be possible that your coolant slushed up in your radiator in the extreme cold then when your thermostat opened hot coolant was returned to top tank n had no where to go - so got pushed out overflow. Many times coolant is not good enough high concentration for extreme cold. I would check that and run a winter front ( piece of cardboard, etc.) in front of radiator.

 

i had a similar issue when I imported my F150 to Australia from Montana, went from snow country to 40 Degrees Celsius and it was leaking. I ordered a coolant overflow tank form LMC and fixed the issue perfectly.

Cheers

 

A decent parts store should be able to pressure test your cap and tell you if it's bad. If not, I'd suspect a leaking head gasket. That would let compression pressure enter the cooling jacket and push coolant out. Hopefully you just have a weak cap.

 

overheating and overflowing are two different issues.........when the engine gets too hot, it will probably blow out coolant, but not ALL coolant overflow issues are caused by too much heat. If it hasnt done this before, and it happened in extreme cold, id be concerned that Voca may have diagnosed it. Radiator caps are rated for certain pressure levels before they release pressure and allow coolant to flow into an overflow tank, go to a parts store, and caps will be available from maybe 7-15 lbs pressure rating, cant remember exact numbers, pressure wise.......its possible your thermostat isnt working properly as well. A GOOD parts store should be able to look up what pressure Rad cap is specified for your truck, and same for temperature rating of your thermostat

 

The overflow tank is just a plastic anti-freeze container.

I wasn't going to drive the truck this winter (or any other) but decided that after 3 mild winters maybe we were due to catch a cold one. Because of this (deciding late in the year), I didn't flush out my cooling system and change it to the proper mix of anti-freeze & water. Basically I don't know the mix in there so maybe what you say is what happened.

I just went out and re-filled the radiator again with a 50/50 mix and needed a little extra water to top it off. I again left the cap off and ran the engine for about 10-15 minutes. Again some coolant flowed into the overflow bottle, not a lot, maybe a pint. After about 15 minutes I put the cap on the radiator and within a minute or two the engine temp started to rise. There is a numbered temp gauge. The temp never went over 180 degrees. I left the engine running for 15-20 minutes longer until I was certain there was no problem.

After I put the cap back on no water came out the overflow into the bottle. It is a 16 p.s.i. cap also. All hoses and everything are hot as they should be and everything seems as fine as it was before this problem. By the way, the temp is in the 40's right now I think so maybe this has helped.

Obviously I need to buy some brand new anti-freeze and drain and change out the stuff that's in there. Fortunately I have a 3 day weekend off.

I do have one more question though if anyone can help with an answer: On one of the heater core hoses there is a y-connection and a hose comes off and goes to the lower radiator on the drivers side and is clamped on there. What would be the purpose of this split-off hose?

P.S. The truck came from California and runs cool in the hottest weather. It has never overheated in the worst heat here.

Dennis

 

Thanks for any ideas and advice. I just filled the radiator and let the engine run for 30-35 minutes and everything is normal again. No issues. Temp never went above 180 and nothing overflowed once I put the cap back on.

I definitely need to drain & change out the coolant this weekend so it's the proper mixture.

I'm glad it's not a head gasket and it's not even a bad cap

Thanks again for the advice.

Dennis