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Discussion Starter #1
Ok guys this is my second domestic vehicle and to be honest I am really starting to regret it. So here is a brief history. I bought it less than 2 months ago it leaked oil so I replaced the intake gaskets and vc gaskets. During that broke bolts then broke ez outs then removed head installed a new head, fired it up all is well. Warmed it up no heat temp gauge isnt rising and the resvoir is overflowing. Let it cool open rad cap let it sit over night refill same issue sob. Think great hg is gone so I do a exhaust gas check in the coolant test came back negative. yay. Remembered when I first got it heat sucked and the temp gauge was funny so I decided to replace the thermostat. Now the temp gauge is acting more normal usually running right in the middle but still no heat but I do get a warm blast of air every now and then and the overflow still fills up. So any suggestions on what to do or check would be wonderful.
 

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After you refilled the radiator, did you let it warm up with the radiator cap off? Sounds like you've got air trapped in the system, especially the statement "get a warm blast of air every now and then". Try letting it run with the cap off and it will probably "burp" itself. The air in the system expands and pushes the coolant out, that's what may be happening with the overflow filling up.

Good Luck!
 

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do like the above post states with one exception runit let it get warm and shut it down allow to cool , then top off bottle and repeat continue to do this untill the bottle and radiator are at the proper level then replace the cap and run it till warm then let cool and check the fluid , you should be good at this point if not top it and run it but be sure to check fluid level periodically untill it has completely gotten all the air out of the system.
 

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Charlie don't surf..
'92 Ford Bronco XLT
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This may be a stupid question, but are you sure you put the thermostat in the right way???

Also like Mikey said, you definitely want to burp the system to get any residual air out..just remove the radiator cap (while the engine is cold), start it up and let it come up to operating temp then observe the coolant level in the reservoir, and watch for bubbles. continue to add coolant until it's leveled off and you don't see any more bubbles.
 

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Discussion Starter #5
Yup I am sure the thermostat is installed right. I have done all that about 20 times and im still having issues. Getting ready to scrap it pretty soon heh.
 

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definitely sounds like air in da system. if you dont want it i'll drive down from Bradford County......:thumbup
 

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For cooling system maintenance, see post #8 HERE.

Have you tried reverse flushing the heater core? The heater core could have sediments in it blocking hot coolant from passing through it. Post #6 HERE explains how to do it. Read the entire thread. It has a lot of good info.

Keep us posted, and good luck.
 

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could be a bad thermostat. I just replaced mine...shoulda gone with a napa tstat...my new tstat goes 3/4 of the way before opening and spends more time closed than open
 

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Discussion Starter #9
So I did everything everyone said with no luck. Still having the issues. Some more info is it will idle fine in the driveway for a half hour or more I will get some heat but not much. I think the issue is fixed I take it for a drive heat goes away and overflow overflows. If I have the cap off while its running the coolant will surge up and down about 3/4 of an inch until it eventually just raises to the top and slows overflows out of the coolant fill. If I rev it with the cap off it will suck the water in to where im guessing the bubble and after I let off of the gas it will promptly shoot out of the radiator about an inch. The time that I felt like I was making some progress was when I took the heater core lines off prefilled the core and lines connected it all up left it idle for about half an hour. I got the best heat out of it temp gauge was fine all semmed well. I left it sit for about 2 hours too cool and refill when I popped the cap off it still had pressure and spit coolant out when I popped the cap. It was all downhill after that. So any new fun and exciting suggestions?
 

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OK, let's look at this logically. The cooling system is only supposed to have coolant in it (duh). Your cooling system has some air in it. When refilling a completely empty system, some air can become trapped, you have taken the steps to "burp" the air out of the cooling system.

But you have air in it still, so somehow there is air getting in the cooling system (and that air is pushing the coolant into the overflow bottle)

Do you have any coolant leaks? Especially in the lower hose area of the water pump? That's where the water is "sucked" into the pump, and it might be possible for a small leak to suck air into the cooling system. (But it would probably leak out when the system was pressurized.)

So, my next guess, is that you have a head gasket that has a very small leak from one of the combustion chambers into the cooling system. As sad as that sounds, there is air somehow getting into the cooling system. You said you had a coolant combustion test done, so it's a long shot, but maybe repeat the test? Any chance that the "new" head you replaced has a crack?

IIRC, the head gaskets have "front" marked on them, any chance that you have blocked off a water passage by mis-installing the gasket(s)?
 

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Discussion Starter #11
Thanks for the quick reply. I have not found a coolant leak anywhere. Another reason I dont think I do is my system will hold pressure for hours with no problem. I guess I could do another test but those things usually pick up the exhaust gas pretty easily. I guess its possible that it could have a cracked head but I knew the engine it came off of and it had no issues that would suggest that. I also know that I installed the hg correctly. Thanks for the suggestions.
 

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Just for grins, have you changed the radiator cap? The cap allows coolant out at about 13 PSI, when the coolant cools, it will allow the coolant back in through the hose connected to the overflow.
Maybe also check that little hose that goes to the overflow. It also could allow air back into the system, maybe it's allowing air in when it should be pulling coolant in from the overflow.
 

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I was going to suggest the backwards head gasket too. If the head(s) have a lot of miles on them they may need a surface. They get pitted around the water jackets and let coolant pass, but you'd probably see it in your oil first. Did you replace your radiator hoses? For the price even cheap aftermarket hoses are better than old ones. You should also throw a $14 dollar rad cap on there too to rule out the overflow problem! I usually spend the cash and buy a new thermostat when I flush my coolant, and replace the lower hose just because it sits in the coolant full time. I use 50/50 premixed stuff, fill it to the top, start her up, let it run and "slowly" squeeze the top hose starting from the therm housing to the radiator, and add coolant as it drops down and warms up. Unlike some, I always have my heater on vent, full blast, and leave it that way till I'm done. It takes 10-15 mins to slowly work the air out, then I top off the overflow, and take her for a drive around the block. You may have got a bad thermostat, or it slipped down as you tightened the bolts, or the little "jiggle valve" may not be at the top? It could be a lot of things, but it doesn't sound too bad, definitely sounds like "trapped air" but make sure the overflow is full and take it on the freeway, watch the gauge, bring some coolant, and run her with the windows down, heater cranked, and work that air out...........:thumbup -Kevin-

Oh, and the thing about the coolant surging up and down, then overflowing out of the radiator, it's perfectly normal. Mine does that every time I change my coolant and I have never had any overheating issues. I've done this the same way, with numerous vehicles since High School, and always had the same results. It's probably just an "air" thing....
 

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"Unlike some, I always have my heater on vent, full blast, and leave it that way till I'm done." - on your '96, the water circulates through the heater all the time the engine is running. There is no valve that shuts off the water flow. Heater output is controlled by air door functions.
(Take a look at your heater hoses.)
 

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Discussion Starter #15
Yup I slapped a new rad cap on the thing as well. I am also pretty sure I got the thermostat seated properly and I know I got the valve on the top. I havent checked the rad hoses yet because they look pretty new to me so I figured I was pretty good to go. Maybe if my next time burping it doesnt fix anything I will drain the system and flush them. I already flushed all the upper hoses just not the main rad hoses.
 

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Sorry to hear that, but after all the other troubleshooting, it wasn't a surprise.
(if there's a good side to any of this, it should come apart this time without breaking any bolts)

Good Luck
 

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Discussion Starter #18
Time for an update. I installed a new head and hg and the overflow doesnt overflow now woohoo. I still had just about no heat so I decided to try flushing the heater core out really well before replacing it and wouldnt you know now I have heat. About time this pos works like it should haha.
 
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