Coolant Boiling on '87 F150
10-11-2013, 08:52 PM
#1
Coolant Boiling on '87 F150
Hey, I'm new to the forum, but I need a little help with my truck.
I recently bought an '87 F150 (4.9L I6, 2WD, 3 speed automatic) as my first car. I don't know jack about vehicle maintenance, but from what I gathered here, I managed to fix a busted U-Joint, Neutral Safety Switch, and the gas tank which had a huge hole rusted through it. Now I've encountered a new problem, and I don't know where to start troubleshooting.
Since I've gotten it, I've heard a gurgling coming from it when I shut the engine off, and when I drove it on the interstate. I recently drove it about 50 miles one way to a nearby town, over some pretty steep hills for a good bit of that, and I noticed a small amount of smoke coming from the engine. I pulled over, popped the hood, and saw it was some oil burning off the top of the engine. I checked the oil levels and they were completely normal. That didn't worry me as much as the coolant, as it was boiling. I popped the radiator cap and let the pressure out until it stopped boiling and the cap stopped hissing. Not knowing what else to do, I closed the hood and proceeded to head home. On the way home I watched the temp gauge pretty closely, and it got hotter than normal, all the way to the edge of the normal range, but never outside what the truck labels "normal". Also, the temp would drop when I started coasting. I stopped about 10 miles from my house for an event for about 4 hours, and then started my drive home. Only a few minutes in, the temp started climbing pretty rapidly again. I pulled over, popped the radiator cap, let the pressure out, and then finished my drive home, again with the temp at the edge of the "normal" range.
Does anyone know what this could be? I think it could be a bad radiator cap, but I'm a highschool student working part time, so I'm hesitant to blow the money on that only to find out that isn't the problem.
I had a similar problem with a 1997 Honda Accord I borrowed before I bought this truck, but when I checked the coolant, it was completely empty. Once I filled it up it ran just fine.
I recently bought an '87 F150 (4.9L I6, 2WD, 3 speed automatic) as my first car. I don't know jack about vehicle maintenance, but from what I gathered here, I managed to fix a busted U-Joint, Neutral Safety Switch, and the gas tank which had a huge hole rusted through it. Now I've encountered a new problem, and I don't know where to start troubleshooting.
Since I've gotten it, I've heard a gurgling coming from it when I shut the engine off, and when I drove it on the interstate. I recently drove it about 50 miles one way to a nearby town, over some pretty steep hills for a good bit of that, and I noticed a small amount of smoke coming from the engine. I pulled over, popped the hood, and saw it was some oil burning off the top of the engine. I checked the oil levels and they were completely normal. That didn't worry me as much as the coolant, as it was boiling. I popped the radiator cap and let the pressure out until it stopped boiling and the cap stopped hissing. Not knowing what else to do, I closed the hood and proceeded to head home. On the way home I watched the temp gauge pretty closely, and it got hotter than normal, all the way to the edge of the normal range, but never outside what the truck labels "normal". Also, the temp would drop when I started coasting. I stopped about 10 miles from my house for an event for about 4 hours, and then started my drive home. Only a few minutes in, the temp started climbing pretty rapidly again. I pulled over, popped the radiator cap, let the pressure out, and then finished my drive home, again with the temp at the edge of the "normal" range.
Does anyone know what this could be? I think it could be a bad radiator cap, but I'm a highschool student working part time, so I'm hesitant to blow the money on that only to find out that isn't the problem.
I had a similar problem with a 1997 Honda Accord I borrowed before I bought this truck, but when I checked the coolant, it was completely empty. Once I filled it up it ran just fine.
10-11-2013, 10:07 PM
#2
Update: I checked the coolant levels at the radiator and they were low. I put two and a half gallons of coolant in and am about to test drive it. It was still full in the reservoir. It might be a clogged line or bad water pump.
10-11-2013, 10:11 PM
#3
USN Retired 1992-2012
Welcome to the forum. Let me say first, never attempt to take off a radiator cap off an over heating radiator. You can end up with severe burns. I received first, second, and third degree burns from a gaseous oxygen explosion while in the Navy, burns are extremely painful. Especially second degree. I know its coolant and not gas, but that coolant will make you regret the day.
In your case there are numerous problems that could cause the engine to overheat:
Is the radiator oily and covered in dirt preventing it from cooling the water?
The thermostat may be stuck closed or partially closed. First thing I would check as well as flushing the radiator.
Assuming it has a belt driven fan, does the fan freewheel easily when the engine is hot. Ensure engine is off, spin the fan by hand, if it spins more than one complete round, the clutch needs to be replaced.
Drain some fluid from the radiator so its about 6 inches from the top. Leave the cap off and run the engine. If you see water flowing from the flues fairly well, you know the thermostat is open and the flues in the radiator are not clogged, if the water does not flow at all, I'd say thermostat, if it flows partially I'd say have the radiator roded.
Worst case scenario, you could have a blown head gasket.
By the way, do not remove the thermostat and not put it back in. An engine can actually over heat without one because the water flow through the system is to fast, not allowing the water to cool.
Also, do not use 100 % coolant. Ethylene Glycol does not allow for the transfer of heat very well. 50/50 mixture should meet your needs.
In your case there are numerous problems that could cause the engine to overheat:
Is the radiator oily and covered in dirt preventing it from cooling the water?
The thermostat may be stuck closed or partially closed. First thing I would check as well as flushing the radiator.
Assuming it has a belt driven fan, does the fan freewheel easily when the engine is hot. Ensure engine is off, spin the fan by hand, if it spins more than one complete round, the clutch needs to be replaced.
Drain some fluid from the radiator so its about 6 inches from the top. Leave the cap off and run the engine. If you see water flowing from the flues fairly well, you know the thermostat is open and the flues in the radiator are not clogged, if the water does not flow at all, I'd say thermostat, if it flows partially I'd say have the radiator roded.
Worst case scenario, you could have a blown head gasket.
By the way, do not remove the thermostat and not put it back in. An engine can actually over heat without one because the water flow through the system is to fast, not allowing the water to cool.
Also, do not use 100 % coolant. Ethylene Glycol does not allow for the transfer of heat very well. 50/50 mixture should meet your needs.
Last edited by mrgooden; 10-11-2013 at 10:21 PM.
10-11-2013, 11:31 PM
#4
I checked the fan, turns normal. I'll check the thermostat in a minute but for now, that's the hose leading from the reservoir to the radiator. It seems to be leaking pretty badly and sprayed a good bit when I test drove it a few minutes ago. I don't think it's the head gasket, my dad had a Jeep Grand Cherokee that blew a head and it doesn't act anything like that one did.
Thanks for the advice, by the way. I really appreciate it!
10-12-2013, 09:00 AM
#5
USN Retired 1992-2012
I checked the fan, turns normal. I'll check the thermostat in a minute but for now, that's the hose leading from the reservoir to the radiator. It seems to be leaking pretty badly and sprayed a good bit when I test drove it a few minutes ago. I don't think it's the head gasket, my dad had a Jeep Grand Cherokee that blew a head and it doesn't act anything like that one did.
Thanks for the advice, by the way. I really appreciate it!
If you mean that small hose with duct tape on it, replace it. But that is the overflow hose, it pulls coolant from and puts it in as temperature/level changes in the radiator. It probably started leaking with all that fluid boiling out the radiator, I doubt repairing it will fix the overheating though, although it would be nice.
Richard
Last edited by mrgooden; 10-12-2013 at 09:07 AM.
11-04-2013, 05:15 PM
#6
Sorry for the long wait for the update, I haven't had internet for a while. I replaced the hose and filled the radiator and haven't had problems with overheating even driving my truck 150-ish miles in a day.
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mrgooden (11-04-2013)
11-04-2013, 10:29 PM
#7
Keep an eye for a stuck thermostat. Good to hear UR on the road again.
