My '96 Ford Bronco w/351 V8 is consistently running in the 215F to 225F coolant temp range. Those values are from the ScanGuage2; the dash gauge reads A to L (NORMAL on gauge face - !%$@!% Ford gauges!) and never past L. I'm not losing any coolant and the temp is very stable, just higher than I would expect cruising easy with air temps in the 20s. The radiator seems to be in good shape: no crud visible through the fill and the fins are straight on the outside. Is this something I can just keep an eye on and swap the t-stat when the weather is better or should I get on it right away?
Coolant - How hot is too hot?
- Thread starter calvin1
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my Mazda 3 runs at 190F or 88Celcius as per my ScangaugeII. 215 doesn't seem too much hotter.
Originally Posted By: c3po
Have you thought about running an aftermarket gauge, also where is that Scanguage taking the temp from, is it from the cylinder head, usually if the temp is taken from the cylinder head it will be hotter than anywhere else.
ScanGauge is getting the temp from the stock sender the ECU uses. The ECT screws into a fitting that is just after the water pump. It isn't in the head at all.
Have you thought about running an aftermarket gauge, also where is that Scanguage taking the temp from, is it from the cylinder head, usually if the temp is taken from the cylinder head it will be hotter than anywhere else.
ScanGauge is getting the temp from the stock sender the ECU uses. The ECT screws into a fitting that is just after the water pump. It isn't in the head at all.
Originally Posted By: calvin1
Originally Posted By: c3po
Have you thought about running an aftermarket gauge, also where is that Scanguage taking the temp from, is it from the cylinder head, usually if the temp is taken from the cylinder head it will be hotter than anywhere else.
ScanGauge is getting the temp from the stock sender the ECU uses. The ECT screws into a fitting that is just after the water pump. It isn't in the head at all.
Here's another thought, do you have an infrared gun, these are great to have, you can aim it at different places in your engine and get instant temp readings.
Originally Posted By: c3po
Have you thought about running an aftermarket gauge, also where is that Scanguage taking the temp from, is it from the cylinder head, usually if the temp is taken from the cylinder head it will be hotter than anywhere else.
ScanGauge is getting the temp from the stock sender the ECU uses. The ECT screws into a fitting that is just after the water pump. It isn't in the head at all.
Here's another thought, do you have an infrared gun, these are great to have, you can aim it at different places in your engine and get instant temp readings.
That does sounds a little high. Perhaps your coolant temperature sensor is a little off? I'm not sure what temperature T-stat your application should have, but I'd think it should probably be under 195 (but definitely under 205). And so 195 is what you should be seeing on your scan guage.
I would check the coolant level and condition, which you say you have. Check T-stat, and consider checking your coolant temperature sensor. If you know the outside temperature and your engine is dead cold, does the scan guage read the same temp? Also does your intake and coolant temp read very close?
I would look into it because maybe your T-stat is going out and you don't want to overheat the engine.
I would check the coolant level and condition, which you say you have. Check T-stat, and consider checking your coolant temperature sensor. If you know the outside temperature and your engine is dead cold, does the scan guage read the same temp? Also does your intake and coolant temp read very close?
I would look into it because maybe your T-stat is going out and you don't want to overheat the engine.
Originally Posted By: mechanicx
That does sounds a little high. Perhaps your coolant temperature sensor is a little off? I'm not sure what temperature T-stat your application should have, but I'd think it should probably be under 195 (but definitely under 205). And so 195 is what you should be seeing on your scan guage.
I would check the coolant level and condition, which you say you have. Check T-stat, and consider checking your coolant temperature sensor. If you know the outside temperature and your engine is dead cold, does the scan guage read the same temp? Also does your intake and coolant temp read very close?
I would look into it because maybe your T-stat is going out and you don't want to overheat the engine.
The t-stat should be 190f. On the Ford f-series (bronco is pretty much a rebodied f-series) the dash and ecu use different coolant sensors so I'm getting readings at the high end of normal from two different sources. BTW, yes, the reading from cold is the same as the outside air temp.
IR gun: don't have one, don't want one but it sounds like the right tool for this job so I might ask around about borrowing one.
That does sounds a little high. Perhaps your coolant temperature sensor is a little off? I'm not sure what temperature T-stat your application should have, but I'd think it should probably be under 195 (but definitely under 205). And so 195 is what you should be seeing on your scan guage.
I would check the coolant level and condition, which you say you have. Check T-stat, and consider checking your coolant temperature sensor. If you know the outside temperature and your engine is dead cold, does the scan guage read the same temp? Also does your intake and coolant temp read very close?
I would look into it because maybe your T-stat is going out and you don't want to overheat the engine.
The t-stat should be 190f. On the Ford f-series (bronco is pretty much a rebodied f-series) the dash and ecu use different coolant sensors so I'm getting readings at the high end of normal from two different sources. BTW, yes, the reading from cold is the same as the outside air temp.
IR gun: don't have one, don't want one but it sounds like the right tool for this job so I might ask around about borrowing one.
Your 351 can run pretty warm and still be ok. 215-225 is "normal". 230 I'd start watching it and @ 240 get it into the wind.
What are you doing when it's running 225? Idling in traffic, cruising or pulling a hill?
What are you doing when it's running 225? Idling in traffic, cruising or pulling a hill?
Assuming the cooling system is OK, which is a stretch on a 14 yr old Ford, Mebbe the engine is running a tad lean? Vacuum leak could do it too. A 195' thermostat should be fine for this rig
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That it does it with varying outside temps makes me believe it's the thermostat. Maybe an IR gun to the radiator and other parts would provide useful data. If the thermostat is keeping it warm the rad will be cool. If it's really close to overheating the rad will be hot and the fan clutch should grab, blowing hot air you can feel outside the driver's door.
Could also be a fan clutch on the way out. It's running hotter than it should. My father has the same engine in his 96 F150 and it never runs that hot. He's kind of ocd like I am though so the coolant has been flushed and a new OEM thermostat gets put in about every 40k. He also replaces all the hoses every 3 years if I remember correctly.
If it was my vehicle... I'd flush the cooling system and replace the thermostat with an OEM. Thenn if it's still running warmer than it should replace the fan clutch.
If it was my vehicle... I'd flush the cooling system and replace the thermostat with an OEM. Thenn if it's still running warmer than it should replace the fan clutch.
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fan clutch: it feels like it should - spins by hand with resistance - but I don't have the strobe that the factory manual uses for its test
driving conditions: nothing strenuous, not loaded or towing and it's the same in town or on the interstate
rad temps: the top hose is never blazing hot, easily handled
I guess I'll change the t-stat and see what happens.
driving conditions: nothing strenuous, not loaded or towing and it's the same in town or on the interstate
rad temps: the top hose is never blazing hot, easily handled
I guess I'll change the t-stat and see what happens.
These ford T-stats are notorious for being bad - Do you have a stant in there? I had a 4cyl Contour that was overheating and the ford dealer was doing scanning and checking sensors and pressure checks and they give me the car back and say its ok. Then it overheats again. I pulled the T-stat myself - put it in pyrex cup of just boiled water - and it only opened about 1/16" and didnt close either. Got a new one - tested it in a cup of just boiled water - and it opened up fully. Unfortunately, while they were messing around without a clue - the HC blew!
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Now: I would DEF give the old unit a test when you pull it out, then, give the NEW unit a test before it goes in. Just boil some water pour it into a big pyrex measuring cup and drop in the t-stat and watch it blossom (or not). OTW you have partially blocked rad core and/or eroded water pump impellers soft collapsing hoses. Have these been serviced or r&r'd recently?
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Now: I would DEF give the old unit a test when you pull it out, then, give the NEW unit a test before it goes in. Just boil some water pour it into a big pyrex measuring cup and drop in the t-stat and watch it blossom (or not). OTW you have partially blocked rad core and/or eroded water pump impellers soft collapsing hoses. Have these been serviced or r&r'd recently?
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Originally Posted By: ARCOgraphite
These ford T-stats are notorious for being bad - Do you have a stant in there? I had a 4cyl Contour that was overheating and the ford dealer was doing scanning and checking sensors and pressure checks and they give me the car back and say its ok. Then it overheats again. I pulled the T-stat myself - put it in pyrex cup of just boiled water - and it only opened about 1/16" and didnt close either. Got a new one - tested it in a cup of just boiled water - and it opened up fully. Unfortunately, while they were messing around without a clue - the HC blew!
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Now: I would DEF give the old unit a test when you pull it out, then, give the NEW unit a test before it goes in. Just boil some water pour it into a big pyrex measuring cup and drop in the t-stat and watch it blossom (or not). OTW you have partially blocked rad core and/or eroded water pump impellers soft collapsing hoses. Have these been serviced or r&r'd recently?
That's good advice about testing your t-stats in boiling water; I always do that too. I don't have any idea about what is in there now. I just bought it and it has 190k so who knows. The top rad hose and the heater hoses look good: no cracks or bulges. I haven't taken a good look at the lower one yet but will tonight.
Correct me if I'm wrong but since I'm getting plenty of heat in the cab doesn't that mean that the water pump is good?
These ford T-stats are notorious for being bad - Do you have a stant in there? I had a 4cyl Contour that was overheating and the ford dealer was doing scanning and checking sensors and pressure checks and they give me the car back and say its ok. Then it overheats again. I pulled the T-stat myself - put it in pyrex cup of just boiled water - and it only opened about 1/16" and didnt close either. Got a new one - tested it in a cup of just boiled water - and it opened up fully. Unfortunately, while they were messing around without a clue - the HC blew!
-
Now: I would DEF give the old unit a test when you pull it out, then, give the NEW unit a test before it goes in. Just boil some water pour it into a big pyrex measuring cup and drop in the t-stat and watch it blossom (or not). OTW you have partially blocked rad core and/or eroded water pump impellers soft collapsing hoses. Have these been serviced or r&r'd recently?
That's good advice about testing your t-stats in boiling water; I always do that too. I don't have any idea about what is in there now. I just bought it and it has 190k so who knows. The top rad hose and the heater hoses look good: no cracks or bulges. I haven't taken a good look at the lower one yet but will tonight.
Correct me if I'm wrong but since I'm getting plenty of heat in the cab doesn't that mean that the water pump is good?
Well, It means it can pump enough to flow the heater core which is a bit smaller than the radiator
The water pump impeller gets eroded over time and the pumping capability drops off as they age. The t-stats an easy and cheap changeout - so I'd go there first - and you'll have the rad cap off when topping the rad and you can (sorta) see how well she's flowing through there. Have someone rev the engine when the stat is open and the rad cap is on and see if the lower hose collapses when revved. Eeve a slightly Soft hose and deteriorated anti-collapse spring (Slinky) in the rad hose core can cause a bunch of trouble. Since you're in the cold, you may want to block off 1/2 the radiator - a good stat will barely open or flow the rad when its cold. I was born in Indianapolis. We got 10degF and sunny today in NH.
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That is high.
A sensor or thermostat are the likely culprits.
A sensor or thermostat are the likely culprits.
Originally Posted By: calvin1
My '96 Ford Bronco w/351 V8 is consistently running in the 215F to 225F coolant temp range. Those values are from the ScanGuage2; the dash gauge reads A to L (NORMAL on gauge face - !%$@!% Ford gauges!) and never past L. I'm not losing any coolant and the temp is very stable, just higher than I would expect cruising easy with air temps in the 20s. The radiator seems to be in good shape: no crud visible through the fill and the fins are straight on the outside. Is this something I can just keep an eye on and swap the t-stat when the weather is better or should I get on it right away?
I run a scangauge2 in my Jeep....it is much more accurate than the factory temp gauge.
Does this truck run a thermostatic fan clutch or electric fans? Either way, make sure the fan clutch is engaging properly or make sure the fan(s) are coming on when they should be.
My '96 Ford Bronco w/351 V8 is consistently running in the 215F to 225F coolant temp range. Those values are from the ScanGuage2; the dash gauge reads A to L (NORMAL on gauge face - !%$@!% Ford gauges!) and never past L. I'm not losing any coolant and the temp is very stable, just higher than I would expect cruising easy with air temps in the 20s. The radiator seems to be in good shape: no crud visible through the fill and the fins are straight on the outside. Is this something I can just keep an eye on and swap the t-stat when the weather is better or should I get on it right away?
I run a scangauge2 in my Jeep....it is much more accurate than the factory temp gauge.
Does this truck run a thermostatic fan clutch or electric fans? Either way, make sure the fan clutch is engaging properly or make sure the fan(s) are coming on when they should be.
That sounds high for your vehicle. I could be that the radiator isnt cooling the water significantly enough prior to it going back into the motor. Lots of crud builds up in those things over time. I have noticed in some fords that the radiator seems undersized as far as rows and design. I wouldnt doubt that your radiator is just suffering from normal type buildup.
The thermo may not be fully opening due to crud and deposits.
The thermo may not be fully opening due to crud and deposits.
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It finally got warm enough for me to swap out the t-stat and all is well. It shows a consistent 185-190 on the scanguage. It looks like the cooling system is all 100% original. The top hose had an imprint on it that I couldn't see until I had it off: 10/31/1995 - 14 years and 195k miles. I think I should go by the PO's house and let him know he got his money's worth! 
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