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Running Hot - 351Windsor

2K views 11 replies 6 participants last post by  MHenricks 
#1 ·
I put my Mustang on the road to go to a show last weekend. It was a 400 mile trip that went quite well with the exception of the engine getting uncomfortably warm. It did not overheat, but pushed to normal limit. As the temp went up, oil pressure dropped - not below the normal range, but a significant drop from idle pressure. Driving at lower speeds (30 - 40 mph) brings everything back to normal. I have a 3 core radiator, 160 thermostat and 2900 cfm electric fan and shroud. I'm a bit stumped on this. Any help out there will be appreciated. Thanks!
 
#5 ·
Originally posted by nova69:


It did not overheat, but pushed to normal limit.

As the temp went up, oil pressure dropped - not below the normal range, but a significant drop from idle pressure.

Driving at lower speeds (30 - 40 mph) brings everything back to normal.

I have a 3 core radiator, 160 thermostat and 2900 cfm electric fan and shroud.<hr></blockquote>

Are you saying that the engine over heated at road speed? Usually this is an indication of restricted air flow (or coolant flow).

I am assuming this radiator is aluminum and fairly recent as to not have any restictions in the core. Is the electric cooling module assembly too large to allow proper air flow through the core?

What rear end gears are you running? Standard or automatic?

Are you using quality hoses or one fits all (flexible)? Water pump type?

As stated, the lower radiator hose may be collapsing at higher RPM's. If you raise engine RPM's while looking at the hose, do you see any signs of collapsing?

You might want to consider an engine oil cooler if pressure drops. Also an automatic trans cooler (if so equipped) to take some of the strain off the cooling system.

Make sure timing is correct and the system is properly sealed and vented.

What year MUSTANG is it and what type of drivetrain did you install?
 
#7 ·
The radiator is a standard brass unit, 3 core. The cooling fan is a 16" Permacool inside a shroud. I have an automatic transmission without a separate cooler. Rear gears are 2.80, so RPMs really don't get that high. It does have a Comp Cams XE with 477/484 lift. The engine components (oil pump, water pump, etc) are all stock, as was the rebuild kit. I've heard that my 160 thermostat may be a contributor by not allowing the coolant enough time in the radiator to work efficiently, so I'll try the 180. Hoses are all new. Hell, everything is new! I might also take the electric fan out and go back to the Flexalite.
 
#9 ·
Yeah I would try the flex fan, its what I run now with the 4 row and it works fine. THe only thing a 180 degree thermostat would do as apposed to the 160 is it would open up 20 degrees later allowing for a quicker warm up period. Thats about all it would do. I would stick with the 160 if i were you, engines generally make more power with these cuz they run cooler. (given an adequate cooling system)
What the thermostat actually does is that it opens and closes at a specific temperature. When an engine is fist started cold, the thermostat is completely closed. This means that all of the coolant inside the engine circulates only the engine block, intake, and water pump, completely bypassing the radiator. The thermostat slowly starts to open as the temperature goes up allowing more fresh cold coolant into the car so it won't overheat. The thermostat is completely opened at 160 or 180 depending on which one you use to circulate throughout the entire cooling system. Say its a cold day, or you have a really good cooling system. The thermostat opens when it gets to the right temp. then the air cools the water off too much so it goes below the specified temp. Then, the thermostat starts to close again as to not have a rough running cold engine. You see, all it does is allow the engine to operate at the specified temperature and warm up quicker.
 
#10 ·
Is the radiator fairly new and of a reputable manufacturer? Like I said before, overheating at road speed is usually an indication of restricted air flow across the radiator or plugged core (when you put your hand to the front of the radiator, the center seems to be cooler than the edges) or restricted coolant flow (or an engine mechanical problem).

The brass downflow is not very efficient. The cooling fan and shroud may actually be causing the air flow restriction.

You need to save your duckett's and buy an aluminum cross flow with the appropriate cooling fan assembly coupled with a high-flow aluminum water pump. A mechanical fan draws too much HP, clutters the engine compartment and is not needed at road speed.

Seeing as how the core support opening is so small on the MUSTANG, you might want to consider modifying the opening to accept a later cross-flow and cooling module assembly (later MARK VIII).

Isn't increased performance grand? :)
 
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