Engine Temp Issues

[Bob Gaines]

Bob, this isn't the first time we are at odds with each other  over the 160 degree thermostat use, and I imagine it won't be the last time. Our positions are very unlikely to ever be modified by what the other guy is saying.

So lets shake hands, and come out swingin'

with limited running time, like in a parade, yes a 160 might help.

But in 99.99% of all cases, once the thermostat has fully opened, the engine doesn't care if it's a 160 or a 190. Overheating at that point has nothing to do with the thermostat, (and you know it). 

Thermostats only set the low point of an engine temperature, never the high point. That's been true since the first one was used, long before either of us was around to observe the results.

Z.

Well you have moved from never ever   to conceding that it works in some situations. That is the point I was trying to make by suggesting it wasn't prudent to eliminate that switch all together as a possible remedy in some cases (not all).  I rest my case your honor.  

[SFM6S087]

Suggestion. Take off the radiator cap and look into the tank to be sure the baffle is still there. If someone worked on that radiator and left the baffle out it will cause the engine to run hotter than normal.

To  give you some numbers to compare with, I used a temp gun to check the engine in my 6S087 a while back. Here are the results after driving around for 30 minutes, then parking in driveway, opening hood & checking temps with a Fluke temp gun with engine still running.

Outside temp = 73F
Thermostat housing = 185F
Radiator top tank = 185F
Radiator bottom tank = 178F
Driver's head (front) = 188F
Passenger's head (front) = 187F

The engine has been rebuilt with mild bore & stroke.

The gauge needle was pointing at the P in TEMP on that particular day. I later learned the voltage regulator for the instrument panel was faulty. After replacing that regulator the needle now points at the M (or lower) most of the time.

Steve

[shelbydoug]

OK. So now when someone asks you what your engine runs at you can tell them M. 

The only worse engine temp monitoring I've seen is in a Pantera. First of all the sender doesn't even match the gauge, next the normal operating temp hot is over 220F and the gauge only goes to 230 so people freak out when they see the gauge getting pegged.

Incidentally, 185-187 is way to cool. You're gonna' have sludge city.

The Mustang system tends to have air pockets simply because it doesn't use an overflow tank and as a result you can't fill the radiator to the top so it can make the gauge erratic in that it absolutely does rise and fall 10 degrees while in use. That's absolutely true.

I don't see where a 160 thermostat lowers the operating temp of the system. It just opens the system operation earlier. In a hot climate with 15-20 minute drives you will see the difference.
Take it on the road and drive across Texas in the summer and you won't see any difference.

If you want comfort, have a shop make up a full three core radiator with the stock tanks. Just keep it away from Gaines eyes in Concourse judging. You can't have both a happy life and a happy Concourse Judge. Those things are mutually exclusive.

[zray]

"..........Well you have moved from never ever   to conceding that it works in some situations. That is the point I was trying to make by suggesting it wasn't prudent to eliminate that switch all together as a possible remedy in some cases (not all).  I rest my case your honor.  

I do love a parade.


Z

[Greg]

Bob, this isn't the first time we are at odds with each other  over the 160 degree thermostat use, and I imagine it won't be the last time. Our positions are very unlikely to ever be modified by what the other guy is saying.

So lets shake hands, and come out swingin'

with limited running time, like in a parade, yes a 160 might help.

But in 99.99% of all cases, once the thermostat has fully opened, the engine doesn't care if it's a 160 or a 190. Overheating at that point has nothing to do with the thermostat, (and you know it). 

Thermostats only set the low point of an engine temperature, never the high point. That's been true since the first one was used, long before either of us was around to observe the results.

Z.

Well you have moved from never ever   to conceding that it works in some situations. That is the point I was trying to make by suggesting it wasn't prudent to eliminate that switch all together as a possible remedy in some cases (not all).  I rest my case your honor.  

Zray, that isn't quite right.  What a 190 deg thermostat does is allow the fluid to stay in the radiator longer which cools through convection due to the forced air.  Now before you doubt and come out swinging :-) think about what I am saying, the coolant is cooled and isn't free-flowing into the engine block because the thermostat is a barrier and the coolant is forced via the increased pressure into the engine.  In your theory that once the thermostat is opened, it doesn't matter would be true if the thermostat opened to the diameter of the inlet or the hose, but it doesn't. A 190 deg thermostat will always allow an engine to operate cooler which is why I am sure FORD spent many $ evaluating it in the 60's. 

Greg

[zray]

Zray, that isn't quite right.  What a 190 deg thermostat does is allow the fluid to stay in the radiator longer which cools through convection due to the forced air.  Now before you doubt and come out swinging :-) think about what I am saying, the coolant is cooled and isn't free-flowing into the engine block because the thermostat is a barrier and the coolant is forced via the increased pressure into the engine.  In your theory that once the thermostat is opened, it doesn't matter would be true if the thermostat opened to the diameter of the inlet or the hose, but it doesn't. A 190 deg thermostat will always allow an engine to operate cooler which is why I am sure FORD spent many $ evaluating it in the 60's. 

Greg

I never said a thermostat opens to the diameter of the hose.

I did say a 160 and a 190, when fully open, have the identical effect on the cooling system, which is, zero. As pointed out already, at the point a thermostat is fully open, it's up to the rest of the cooling system to keep the dad blame thing from overheating.

Not many mechanics today were taught by a mentor, or mentors, as through as mine were, RIP, Uncle Hobart, and Leroy Y. 

To diagnose a cooling problem, don't start at the thermostat, or radiator, or water pump. To have a methodical approach, always start where the heat is generated. In our case this will be the cylinder head and cylinder block. Does the head have heat holding deposits, or other issues ? If not, proceed to the engine block. The block is without doubt, the MOST overlooked component of the cooling system. Having a professional flush your engine block always always will cure an overheating issue. Not a home flush either.  But a real, take out the freeze plugs and really get the crap out.

Who teaches this anymore ? No one I know.

Z

PS  but to the OP's issue. I don't advocate the use of Evans, so I'm not up to speed on diagnosing overheating when Evans is used.  No help here.

PPS  the only thing a 190 has going for it is that it will get the motor hot enough to burn off sludge making moisture in the oil . That's it. And that's plenty of difference, enough a difference that I'll never put a 160 thermostat bandaid on a car and think I've fixed something.

[Dkutz]

I don't think anyone suggested "Burping" the system.  They tend to get an airpocket around the thermostat area.  You can get the air out by elevating the front of the car either by jacks or hill.  Warm up the car first so the thermostat is open then try that.  Otherwise try all the other suggestions you were given. 

I had similar problems, had the rad flushed and checked the thermostat with no luck.  I went to a larger mechanical fan, HD water pump, and a fan shroud.  No more Issues.

[SFM6S087]

What is the optimum engine coolant temperature for warmed up and running 289HP?

Steve

[Greg]

PPS  the only thing a 190 has going for it is that it will get the motor hot enough to burn off sludge making moisture in the oil . That's it. And that's plenty of difference, enough a difference that I'll never put a 160 thermostat bandaid on a car and think I've fixed something.


[/quote]

Zray, we do agree on a few points but you aren't 100% complete.  I agree that the higher operating temperature promotes moisture evaporation in the oil, but the 190 deg thermostat allows the coolant to be regulated at 190deg so it stays in the radiator longer for better coolant regulation.  I also agree that the OP could have a blockage not allowing enough flow which would obviously cause an issue. 

[Greg]

What is the optimum engine coolant temperature for warmed up and running 289HP?

Steve

190-200 degs

[J_Speegle]

I don't think anyone suggested "Burping" the system.  They tend to get an airpocket around the thermostat area.  You can get the air out by elevating the front of the car either by jacks or hill.  Warm up the car first so the thermostat is open then try that.  Otherwise try all the other suggestions you were given. 

And by making sure you use a thermostat with a air bleed hole and orientate it towards the top once installed (just works a little better that way. 

[shelbydoug]

What is the optimum engine coolant temperature for warmed up and running 289HP?

Steve

190-200 degs

The optimum operating temperature of an engine is determined by the oil temperature, not the coolant temperature.

Engine clearances are optimized for that. You need an oil temperature of 210 to 220 F. Whatever the coolant temperature that results in is whatever it winds up at. The actual coolant temp is going to vary during normal operation.

Ultimately you probably do best with a 50/50 mixture although you can get a little better boil over protection with a 75% anti-freeze mix.

When you look at a system that is presurized to 12-13 psi, you need to investigate why. When you look at the data on the coolant chart, boil over at that pressure with 50/50 comes in at around 242.

Anything under that number would be considered normal operating temperature. Simply put, that's how the engineering is on the engine.


289's are not generally a heat producing dynamo. They can create a good deal of anxiety for an operator but by comparison to a 428 in a Mustang chassis they are child's play.

You can't diagnose cooling if you are using a stock Mustang temperature gauge. I went through this 40 years ago. Put gauges in the car that you can read and are accurate.


At one point in the '70s I had a Boss 351, 11.0:1 cr, with Webers in the car. I found that a 70 Mustang 351 4v with A/C had a full 3 core radiator and bolted in. The lower hose nipple needed to be moved to the other side because of a different exit point on the water pump. NBFD.

That engine ran right in the 195-200 degree range water temp. Yes, cool. You really had to beat on it to get the oil temp up even with just a stock pan.

It had the block "boiled out" with the old, now unobtanium EPA banned stuff. Gunk never had a chance.


The old intakes without the rear water crossover are less susceptible to air pockets. The new ones with the rear crossover don't help cooling. Burping a Mustang is easy. You need to stand the Pantera on it's nose to do it without a pressure tester.

Buy a Stant pressure tester kit. You can test the cap and you can pump the air out of the system with it. It's really worth it's weight in gold and will go a long way in helping analyze WTF is going on inside the system.

[Greg]

What is the optimum engine coolant temperature for warmed up and running 289HP?

Steve

190-200 degs

The optimum operating temperature of an engine is determined by the oil temperature, not the coolant temperature.

Engine clearances are optimized for that. You need an oil temperature of 210 to 220 F. Whatever the coolant temperature that results in is whatever it winds up at. The actual coolant temp is going to vary during normal operation.

Ultimately you probably do best with a 50/50 mixture although you can get a little better boil over protection with a 75% anti-freeze mix.

When you look at a system that is presurized to 12-13 psi, you need to investigate why. When you look at the data on the coolant chart, boil over at that pressure with 50/50 comes in at around 242.

Anything under that number would be considered normal operating temperature. Simply put, that's how the engineering is on the engine.


289's are not generally a heat producing dynamo. They can create a good deal of anxiety for an operator but by comparison to a 428 in a Mustang chassis they are child's play.

You can't diagnose cooling if you are using a stock Mustang temperature gauge. I went through this 40 years ago. Put gauges in the car that you can read and are accurate.


At one point in the '70s I had a Boss 351, 11.0:1 cr, with Webers in the car. I found that a 70 Mustang 351 4v with A/C had a full 3 core radiator and bolted in. The lower hose nipple needed to be moved to the other side because of a different exit point on the water pump. NBFD.

That engine ran right in the 195-200 degree range water temp. Yes, cool. You really had to beat on it to get the oil temp up too even with just a stock pan.

It had the block "boiled out" with the old, now unobtanium EPA banned stuff. Gunk never had a chance.


The old intakes without the rear water crossover are less susceptible to air pockets. The new ones with the rear crossover don't help cooling. Burping a Mustang is easy. You need to stand the Pantera on it's nose to do it without a pressure tester.

Buy a Stant pressure tester kit. You can test the cap and you can pump the air out of the system with it. It's really worth it's weight in gold and will go a long way in helping analyze WTF is going on inside the system.

Doug, the water temperature (mixture, flow rate etc...) does regulate the engine temperature which in turn regulates the oil temperature.  I also think you are getting into the race engine world with what you have outlined and I agree.  For race engines, the oil temperature is the greatest factor.  These engines are nowhere near as precise as those which is why Ford didn't put an oil temperature gauge on them.   

[Side-Oilers]

I also agree with Doug and others who have said the stock Mustang gauge is not very accurate. Especially as old as they are now, and the fact that there aren't any actual numbers on the gauge faces.   Oh no, it's on "P" again.

Kind of like some women I've known in my life who've said something like "its broiling hot outside" whether the ambient temperature is 85 or 95 or 105 or...