Manual gauge shows 210 220 when driving at 65. Has Proform electric fan, 3 core radiator from Mustangs Unlimited, new thermostat. Any ideas. Also pops through intake, misfires when it reaches this temp. Thanks
Overheats at cruise speed
- Thread starter 93notchback
- Start date
Usually, overheating at cruising speeds indicates that the radiator is either not working efficiently, or it's not getting enough airflow over it. Do you still have the plastic radiator airdam in place under the front of the car? If not, that's your problem right there.
Backfiring and such, though, sounds like something else is wrong in the system - vacuum leak, timing being off, etc. ...
Backfiring and such, though, sounds like something else is wrong in the system - vacuum leak, timing being off, etc. ...
Does the water pump have any coolant leaking from the weephole(s)? If not, the only chance it's the water pump is if the impeller popped off, which I've never personally seen or heard of, myself. If the water pump bearings seized up, you'd be seeing/hearing/smelling the fan belt squealing like a pig, or at least the pump bearings would be noisy as all hell and the water pump pulley would be wobbling all over if it were that bad.
Does the coolant actually boil over, or is the evidence of overheating mostly in the coolant gauge reading? Are you going by what the factory temp gauge says, or an aftermarket piece? Sometimes the factory sending unit gets wacky and tells lies - factory gauges, in general, just suck.
Just curious, have you verified that the electric fan is still working properly? I know this doesn't matter at speeds above 45 MPH, because the wind running through the radiator goes at a rate faster than the fan, alone can pull it, but it might be a contributing factor if the car starts heating up at lower speeds and it can't cool down enough for whatever reason at highway speeds.
How old is the radiator? Has it been flushed within the past year or two? Are you sure you're running a 50/50 coolant-to-water mix (and not straight antifreeze)?
Sorry for all the questions, just trying to cover all the bases.
If the water pump bearings seized up, you'd be seeing/hearing/smelling the fan belt squealing like a pig, or at least the pump bearings would be noisy as all hell and the water pump pulley would be wobbling all over if it were that bad.Does the coolant actually boil over, or is the evidence of overheating mostly in the coolant gauge reading? Are you going by what the factory temp gauge says, or an aftermarket piece? Sometimes the factory sending unit gets wacky and tells lies - factory gauges, in general, just suck.
Just curious, have you verified that the electric fan is still working properly? I know this doesn't matter at speeds above 45 MPH, because the wind running through the radiator goes at a rate faster than the fan, alone can pull it, but it might be a contributing factor if the car starts heating up at lower speeds and it can't cool down enough for whatever reason at highway speeds.
How old is the radiator? Has it been flushed within the past year or two? Are you sure you're running a 50/50 coolant-to-water mix (and not straight antifreeze)?
Sorry for all the questions, just trying to cover all the bases.
put the radiator in it 2 days ago. brand new 3 row. Bottom hose has a wire in it. Has an aftermarket gauge instead of the factory. Doesn't run hot at idle. just after going bout 10 15 miles is starts going up. when it goes to bout 220, car starts to miss and backfire through the cold air kit then shuts off. sits bout 20 minutes it fire back up
when it warms up take the cap off and look in and you should be able to see if the water is moving through the top of radiator. if its not,the thermostat probably is not opening or its not installed correctly.did you put a new radiator cap on it?also i heard that some types of antifreeze eats away the fins on the waterpump.i'd start checking the easiest things though.you can also take it to a radiator shop and do a pressure test on the radiator,which would reveal pin holes that you wouldn't be able to see.
LiquidGT
Member
The first things I would do is check the timing and pull the codes. Then get a radiator pressure tester and check the system and the cap itself.
As suggested...
Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.
Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.
See Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical
If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.
89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.
There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.
What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems.
Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.
Or for a nicer scanner see EQUUS DIGITAL FORD CODE READER (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.
Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.
Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.
See Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical
If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.
89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.
There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.
What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems.
Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.
Or for a nicer scanner see EQUUS DIGITAL FORD CODE READER (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.
i have a scan tool to check the codes, but the car is an 87 that has had a granetelli MAF conversion harness put on it with an 89 model ECM put in it so it won't communicate with my code reader. 
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