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-   -   Closing in on overheating issue (http://mustangforums.com/forum/classic-mustangs-tech/697071-closing-in-on-overheating-issue.html)

wgc68nyc 06-20-2013 05:05 PM

Closing in on overheating issue
 
Over the last weekend I finally spent some Amex points on amazon and got a second spal fan. Ive been running too warm at highway speeds (60 and above) and despite having flushed the coolant system and fiddled with timing it still ran warm. I got a 14in pusher (9amp) to go in front of my A/C to help with the hipo Spal 16in (22amp) puller on the radiator. The difference was big....at idle the engine would cool with both fans running to the point the termostat temp dips below 180 which is when it will close. This was in 80+ degree weather. This helped me conclude concern I have:

- There is too much space between the AC condensor and the radiator (almost 2 inches+)

Essentially air takes the easiest path and would go through and around the condensor. The puller was only pulling whatever air came through the condensor hence why despite its power it would not cut it. With the second fan force air through the condesor at a high velocity the rad stayed cooler.

Want further proof? The 14 pusher fan was almost more effective at idle by itself than the 16in puller.

I still run on the warm side on the highway but hopefully with the use of some spacers I can sandwich the rad and condensor to the point they are almost touching which should yield better results.

Also....I regret getting a higher stall converter....at 60mph im at 2100rpms which means in all likely hood I am still getting a bit of slipping. The trans cooler I have has helped but first chance I get I am going back to a stock which is honestly what my car is cam'd for anyway. MPGs have suffered too.

wgc68nyc 06-20-2013 05:06 PM

On a side note could I be running too lean on the highway based on a bad carb adjustment? I have a Edel perf 500 and a pertronix 2.

jonward786 06-20-2013 05:38 PM

If you're getting hot on the highway it could be a sign you're thermostat is stuck open. I'd start there. Putting another fan in front of the radiator will not solve your getting hot at highway speeds problem. At high speeds, that airflow coming into the radiator should be more than adequate to cool. You only really need a fan while not moving or moving slowly. What you should do is properly utilize your puller fan. I'm guessing you are just hanging it from the radiator like ive seen a lot of people do around here. Treat your electric fan just like mechanical fan and use a shroud that covers the entire radiator. Here is what I use with my 68's radiator:
http://www.northernfactory.com/HIGH_...NG/1968/Z40069

wgc68nyc 06-20-2013 05:49 PM

Quote:

Originally Posted by jonward786 (Post 8235005)
If you're getting hot on the highway it could be a sign you're thermostat is stuck open. I'd start there. Putting another fan in front of the radiator will not solve your getting hot at highway speeds problem. At high speeds, that airflow coming into the radiator should be more than adequate to cool. You only really need a fan while not moving or moving slowly. What you should do is properly utilize your puller fan. I'm guessing you are just hanging it from the radiator like ive seen a lot of people do around here. Treat your electric fan just like mechanical fan and use a shroud that covers the entire radiator. Here is what I use with my 68's radiator:
http://www.northernfactory.com/HIGH_...NG/1968/Z40069

The champion 3 row rad I had came with a aluminum shroud but it seem to run cooler without it. I am guessing if I had more room to back the fan off the rad and shroud it then it would work better I don't have the space. The other option would be to mod the support and try to move the rad forward against the condenser but now we are talking cutting and fab'in some bracket.

Here it was with the shroud but with the fan inside which probably had a negative effect

https://lh3.googleusercontent.com/-5...0/finished.JPG

Unless I move the rad forward I have 1/2 inch to the pump which I discovered is likely from a 70 or later as it is a driver side outlet. I dont know if those pumps stick out further but I can only get 2more inches at best.

I guess I have to hope bringing the condensor back helps.

The Alien 06-20-2013 06:01 PM

I want to say something really but really stupid so, my apologies in advance but...

did you check the fan wires? is it running on the right direction? the airflow should be the same as the driving airflow.

I'm sorry about that but I didn't understand well if the fan was originally mounted on reverse or not :)

wgc68nyc 06-20-2013 06:03 PM

Quote:

Originally Posted by The Alien (Post 8235028)
I want to say something really but really stupid so, my apologies in advance but...

did you check the fan wires? is it running on the right direction? the airflow should be the same as the driving airflow.

I'm sorry about that but I didn't understand well if the fan was originally mounted on reverse or not :)

Don't feel bad....at one point I wondered myself but no they are right.

The Alien 06-20-2013 06:10 PM

Quote:

Originally Posted by wgc68nyc (Post 8235030)
Don't feel bad....at one point I wondered myself but no they are right.

without being there I could guess many stuff that maybe you already checked but the first thing I have in my mind is the waterpump,

You had this problem when you replaced the radiator or there was something else before?

wgc68nyc 06-20-2013 06:15 PM

I am tempted to replace the pump but I use to run cool after the rad was installed but before the AC....should probably just pony up and do it. I dont know if she was ever burped correctly so I will try to do that as well and check with the cap off to make sure the impeller is pushing well.

The Alien 06-20-2013 06:23 PM

yep it seems a air bobble somewhere.

even with the AC off you have overheating?
I never saw this engine and on the picture I'm not sure to see if the compressor is using the same water pump belt

The Alien 06-20-2013 06:27 PM

another thing: the ac condenser has the honeycomb as the same orientation than the radiator right?

wgc68nyc 06-20-2013 07:07 PM

Quote:

Originally Posted by The Alien (Post 8235059)
another thing: the ac condenser has the honeycomb as the same orientation than the radiator right?

The pic is pre AC installation so none of it is picture. Here is a video of the gap. The trans cooler has been moved and this is pre fan #2


The Alien 06-20-2013 07:23 PM

Quote:

Originally Posted by wgc68nyc (Post 8235082)
Here is a video of the gap.


ah ok, thank you now I can see.

mmm three mass radiators... yep maybe it could be a problem.

is it overheating whatever the AC is off or on right?

I don't know if you have the plastic undercover, if so you could redirect a bit of airflow between the condenser and the radiator.

By the way, for what I understood, it's overheating only on certain speeds but not on idle right?

wgc68nyc 06-20-2013 07:26 PM

Quote:

Originally Posted by The Alien (Post 8235088)
ah ok, thank you now I can see.

mmm three mass radiators... yep maybe it could be a problem.

is it overheating whatever the AC is off or on right?

I don't know if you have the plastic undercover, if so you could redirect a bit of airflow between the condenser and the radiator.

By the way, for what I understood, it's overheating only on certain speeds but not on idle right?

Runs warm at higway speeds with ac off or on. At idle so slow speed with both fans the temp drops rapidly. Dont know what you mean by plastic undercover but I have blocked off some gaps.

The Alien 06-20-2013 07:44 PM

Quote:

Originally Posted by wgc68nyc (Post 8235090)
Dont know what you mean by plastic undercover but I have blocked off some gaps.

Sorry for my English tech terminology :)

on the bottom of the engine bay, usually there is a plastic cover to close the engine bay from outside. this part is fundamental for the aerodynamics on the cooling airflow. But I'm not sure if these models still have this.

BTW you need to follow up two path: one is to check the waterpump but now that I see the radiators I could follow up better this one.
it seems at high speeds, it creates a turbulence that slow down the airflow creating a counter pressure. I know it sounds too much sophisticated but it's easy to change the radiator effect using a wrong airflow

if you have a car thermometer with in/out temp, you can use it to put the sensor before the ac condenser, between and after the radiator to see if it's something related to that or if it's something on the pump.

wgc68nyc 07-01-2013 12:10 AM

So a quick update

Did a oil change and went all out and got Royal Purple. Car runs slightly cooler but still gets around 200-205 in 80 degree weather with humidity doing highway speeds. The dual fans work great. With both of them off the engine cools to the point that I hit the temp where thermostat would close.

Burped the coolant a few days ago on a hill...waited till the the therm opened up and ran it. Coolant expanded almost to the point where it overflowed. Dont know if I should have done it for longer. Could it be overfilled? I have a overflow thingy but its always empty.


Couple of thoughts/possibilities:

- Timing could be off? She runs very smooth and has a Pertronix 2 with the resistor wire bypassed.

- If my termostat was in backwards wouldn't the highway pressure be pushing the termstat closed or partially close?

- Could the carb be tuned to thin? Again we are talking in the 2100-2400 rpms and it take a while for the heat to build (does not overheat but AC is off)

- I had my torque convert stall speed increased (2200 I think) so probably getting some slippage? Trans temp in the deep pan rarely goes over 150 and I have a cooler but could the slippage be causing extra heat.

- Heat builds quicker on uphills which couple with a hipo oil pump and a regular pan could the engine be pumpin the oil too quick while the rest slides to the back? Again it seems a little weird that I would need a baffle for street driving.

- I still thing the primary issue is probably the AC condensor blocks the air and there is too big a gap. Anyone with AC please let me know how close you have your condensor to the rad. I can move them together but its going to be a pain.

67mustang302 07-01-2013 01:42 AM

What's wrong with 200-205? That's fine, most new engines run around 215.

If the temp keeps climbing up in hotter weather or going up hills and can't be kept under 230, then your radiator either sucks, is clogged, or is damaged.

I run ~200* when it's 20* outside.

wgc68nyc 07-01-2013 10:18 AM

Quote:

Originally Posted by The Alien (Post 8235059)
another thing: the ac condenser has the honeycomb as the same orientation than the radiator right?

Compressor has its own belt

PICS HERE
https://picasaweb.google.com/1025608...eat=directlink

I do not think the fins match and again there is like a 2inch space between the rad and the condensor

I should mention I have two temp gauges

The center one is coming from a port right at the thermostatand will creep up to 210ish (maybe go over) without the AC on highway driving (I have a switch so it can read the trans or the coolant)

https://lh4.googleusercontent.com/-W...0/DSC01588.JPG

The normal gauge which come off the manifold closer to the carb will end up 75-80% to the hot side which is why I am concerned it is running warm but not overheating.

https://lh3.googleusercontent.com/-F...0/DSC01587.JPG

I am concerned in 95 degree weather it will be worse and forget about flipping the AC switch.


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