Bronco Forum - Full Size Ford Bronco Forum banner
1 - 20 of 23 Posts

·
Registered
Joined
·
73 Posts
Discussion Starter · #1 ·
During the winter my radiator started leaking. Being proactive I changed out the thermostat, water pump, heater core, rad lines, and heater hoses. I was driving from Northern PA to the East side of D.C. 3 weeks ago and it started getting hot. I stopped and felt the upper rad hose had a lot of pressure on it. I changed the thermostat. That was about halfway through my trip. When I got to D.C. I had talked to a friend and he told me to check the fan clutch. It was bad so I changed that out. The new thermostat was bad as well. I pulled it out and it wasn't opening all the way until I jammed a screwdriver and pried on it, I felt it give and it opened all the way up. So, I put another new one in. Anyway if I sit and let it idle it will not over heat unless I turn the A/C on. If I am driving on the highway 70-75 mph with the heat on it will run around the far side of the m and sometimes into the a in normal. I have to watch my speed and adjust as I am going to keep it reasonable. I have used the chemical set from Fisher's Auto to see if there was any carbon monoxide in the water and it is not showing any. So I assume I don't have a bad head gasket but I don't feel I can rule it out, since it may be blocking some water passages. I have not flushed the system so there could be build up in the block as well. I have been on travel for work for the last 3 weeks so I haven't been able to do too much to it. I am going to limp home this Friday and see if I can either find time to work on it Friday/Saturday or drop it off at the local shop and ride my bike back down here. Any ideas on how to troubleshoot this problem better?
 

·
Registered
Joined
·
273 Posts
Did you replace the radiator or use stop leak? You should probably get a mechanical gauge and see what the temperature really is. It may be something as simple as a faulty sending unit.
 

·
Registered
Joined
·
1,634 Posts
fwiw: To check you thermostat you can boil some water with a temp-gauge stuck in the water. If you have a 195deg stats for example, once the water get's to 195degs or so, the stats should start to open. That's the correct way to check your thermostat.

btw, did you flush your engine block? I had todo this to mine FSB due to the lack of coolant not being used. The upper, lower,radiator hose all had scaling. I ran 2 different brands of engine flush for about 4 days thru the engine after changing the radiator which btw had rust sediments on the lower end. Now my FSb runs cool and the thermostat opens on a few ocassion when sitting idling.

Also I've worked on cars that had crappy coolant and their water pump fans blades where rusted away and even worst the lower hose was clogged.

So check both of these areas also.
 

·
Registered
Joined
·
73 Posts
Discussion Starter · #4 ·
Had a guy hookup with Mac Scan tool and put a mechanic's thermometer in radiator. Definitely a different temp but that was before the third thermostat. Electronic sensor and dash gauge agreed with temp, thermometer was 20* lower than them. So thermostat was not letting water flow. New radiator NOOOOOO Stop Leak..
 

·
Registered
Joined
·
73 Posts
Discussion Starter · #5 ·
Any ideas, please help if you see something that may be overlooked.
 

·
Ex Navy Nuke
Joined
·
5,421 Posts
Did you replace it with a 1 row radiator? I've seen several older Ford trucks that overheat(including my own) when going fast or going slow with the a/c on. For some reason the 1 row radiator just isn't enough to cool it. Doesn't hapen to all of them but it does to some. If you have a new radiator bigger than a 1 row then I would assume something else. If the fan clutch went bad then the new water pump bearings could be bad.
 

·
Registered
Joined
·
73 Posts
Discussion Starter · #7 ·
I don't think it was a one row but it has been 6 months or so. It was however, the same physical size as the one I pulled out of it.
 

·
Registered
Joined
·
273 Posts
meweehaa said:
Had a guy hookup with Mac Scan tool and put a mechanic's thermometer in radiator. Definitely a different temp but that was before the third thermostat. Electronic sensor and dash gauge agreed with temp, thermometer was 20* lower than them. So thermostat was not letting water flow. New radiator NOOOOOO Stop Leak..
The gauge in the dash does not give you a numerical reading so I don't know how it could agree with any thermometer but if you are comfortable with the results, I won't argue.

Did you get the correct radiator for your application? I have heard of heater coils being partially clogged and not allowing enough heat to be transferred to the air to heat the cab. Maybe something similar happened in your new radiator. Are you running the correct mixture of water to antifreeze?
 

·
Registered
Joined
·
9 Posts
It sounds like you have enough pressure, but I'll throw this idea in anyway. Have you checked/replaced your rad cap. I had similar symptoms on a used car I bought many years ago. Thought I tried everything until someone mentioned the cap. It had the wrong one. I've since learned that the springs on the cap can go bad over time and not allow full pressure. Just an idea. Good luck.
 

·
Registered
Joined
·
73 Posts
Discussion Starter · #10 ·
I understand the gauge in the dash has no numerical figure but if the scan tool says 210 and the thermometer sticking out of the radiator says 195 and the dash gauge is over at the "a" which one would you think it was agreeing with? Where are the heater "coils"? j/k
 

·
Registered
Joined
·
73 Posts
Discussion Starter · #11 ·
rowanart said:
It sounds like you have enough pressure, but I'll throw this idea in anyway. Have you checked/replaced your rad cap. I had similar symptoms on a used car I bought many years ago. Thought I tried everything until someone mentioned the cap. It had the wrong one. I've since learned that the springs on the cap can go bad over time and not allow full pressure. Just an idea. Good luck.

Had the cap checked. It was a 13lb. cap and it checked out fine. Thanks



Next? :banghead :banghead :banghead :banghead :banghead
 

·
www.easttn4x4.com
Joined
·
2,191 Posts
You probably haven't flushed out all the air in the system. Take the cap off and start it and let it get hot. Once the stat opens it should not boil over vigorously. If it does then that's the problem. Add water untill you can see it flow across quickly and doesn't try to boil over.
 

·
Registered
Joined
·
76 Posts
One thing many people overlook is the lower radiator hose.....make sure that at operating temp and moderate rpms, that the hose is not collapsing and consequently blocking coolant flow.........
 

·
Registered
Joined
·
73 Posts
Discussion Starter · #15 ·
Yesterday before I left from work I checked the reservoir and it was dry. I poppd the cap on the radiator and it seemed just about full. I filled the reservoir to the cold fill mark with 50/50 coolant/water. Then I drove it up and down the B/W pkwy with the A/C at max and doing about 70-75. It seemed pretty stable until I slowed/stopped. It did go up to the middle of M in normal which I think is still a little high. I do understand that it will get warmer after putting a good load on it and then as you slow/stop there is less airflow to cool the hot water/coolant. But I think I may be a little gun shy. Then this morning as I was going to work it climbed to the M and then backed off to between the Oand R. I assume this was when the thermostat opened. I thought the thermostat opening would be a gradual opening showing less dramatic temperature fluctuation. I did check the coolant level before I left the hotel and it seemed fine so I thought that whatever air was in the system had been purged but maybe there is still some more in there. Any new ideas?
 

·
Registered
Joined
·
273 Posts
Mine tended to fluctuate similar to what you are saying. At cruise speed it would hold a pretty constant temperature but in the city (acceleration and deceleration at the lights) it would fluctuate by a few letters. The belt chirped a bit at idle but only squealed when it rained. I replaced the tensioner and the belt to fix the chirping and now the temp constantly stays at the "n" in normal. I can only assume that the belt was slipping on the water pump or crank shaft pully.
 

·
Registered
Joined
·
867 Posts
DMGunn said:
One thing many people overlook is the lower radiator hose.....make sure that at operating temp and moderate rpms, that the hose is not collapsing and consequently blocking coolant flow.........
did you put the spring thing in the new hose or was there already one in it?
when i replaced my lower hose the new one didnt have the spring in it. so i had to pull the old on out, cleaned it and put it in the new hose.
also when you filled with 50/50, did you turn on the heater? when your truck is hot touch all the hoses to see if there hot, even the small ones.
 

·
Addicted to Junk
85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
Joined
·
16,558 Posts
i had this happen too once and it turned out that i was about two quarts low on my oil so that might be the problem possibly
 

·
Registered
Joined
·
73 Posts
Discussion Starter · #19 ·
hipropos said:
did you put the spring thing in the new hose or was there already one in it?
when i replaced my lower hose the new one didnt have the spring in it. so i had to pull the old on out, cleaned it and put it in the new hose.
also when you filled with 50/50, did you turn on the heater? when your truck is hot touch all the hoses to see if there hot, even the small ones.

The new lower hose had the spring in it already. The lower hose is warm but not as warm as the top so I can assume it is circulating.


I did not turn on my heater when I filled the reservoir. I didn't even have the truck running when I did that. So after I get back to the Hilton ummm I mean Holiday Inn I will turn on the heat and see if the heater hoses are getting warm as well.

Thanks guys.. more ideas are welcomed.

I will check my oil and see where I am at on that too.
 

·
Registered
Joined
·
16 Posts
also might want to check for little tiny bubbles ,, had the same thing happen to mine,couple weeks ago , tried and changed everything ,, no steam out the tail pipe either so i thought not a head gasket

then i let it get warm, without pressure took off the cap ,topped it off and sure enough little tiny bubbles ,rev it up and hold it,got hotter and bigger bubbles, mine wouldnt get hot setting or normal driving but push it or pull a hill and it was hot

my problem cracked head,, crack wouldnt open up enough to let cyl pressure in untill it warmed up ,and when it cooled down crack would shrink and not let water into the cyl,, faster you ran it ,hotter it got

check under your overflow tank and see if its been well over flowing , looks like dirty water streaks or rust streaks down the inner fender

best of luck and hope its not the same as mine,,
 
1 - 20 of 23 Posts
Top