Topic: 1966 Mustang overheats

[Garret]

Car has new Ford Racing 340HP, 302 crate engine, Keisler 5 speed and factory air.  180 thermo with a northern 2 row aluminum radiator with 1" tubes.  The inlet and outlet on the radiator are both on the passenger side.  It has a milodon high vol. water pump.  3,000 cfm 16" electric fan.  V belt.  All parts are new.
Please help, any ideas?

[Soaring]

I assume you flushed the system well before putting all those aftermarket parts on it.  You seem to be pumping the fluid through the system too fast for it to cool down sufficiently in the radiator before entering the system again.  That pump may be too much for the setup. 

[Garret]

It was all done at the same time.  Project was finished in October of 2009, problems did not show up until weather got hot in April 2010.  Car runs good until I get in stop n go.  A/C makes it worse so I added a 2,700 cfm fan in front of the condenser, helps but will eventually heat up?  On the Hwy it runs fine.

[Soaring]

I still think you are moving the liquid too fast through the system, or your 2 row rad is just too small for that big assed engine. 

[Garret]

Do you think I should try a 195 thermo?  I have been looking at the Griffin radiators $550.00, 1.25" coils and the core is .5" thicker, would hate to spend the $ and have the same results.  I see you have a 03 Mach.  I almost bought one with 12K miles for $17,000.  Had a deal and the guy wrecked it the next day, then I bought this possessed 66.  It hates me.

[Soaring]

 No, the 195 thermostat  won't help. I don't know much about that aluminum rad you bought.  The Griffin is the top of the line regarding aluminum rads, but I don't think that is your problem.  What else have you done to resolve the heating problem? Have you added Water Wetter to the system? What is your mixture of anti-freeze and water?  Did you flush out that engine? 

[Garret]

I have tried royal purple ice with water, just water, 50/50, all ant-freeze.  Right now it has water and royal purples ice.  I was thinking of trying water flow restrictor  discs, it is a kit with 3 sizes from small to large.  I think you take the thermo out and place the disc in, about $10.00.  I will contact Northern to see what the radiator is rated for and let you know.

[Soaring]

That sounds like a plan.  Do you have a shroud on that radiator? If not, then that is your next step.  You need to get as much outside air coming through that rad as is possible.  Check to see if your hoses may be collapsing in you.

[68 Shelby KR500]

You mentioned a 16" elec fan, I assume this came in its own plastic housing/shroud? Its mounted on the water pump side of the rad? If so its a PULLER  correct?

[Garret]

This is true.

[Soaring]

You mentioned a 16" elec fan, I assume this came in its own plastic housing/shroud? Its mounted on the water pump side of the rad? If so its a PULLER  correct?

Thanks for chiming in and welcome to the site  '68 Shelby KR 500.   This is the kind of stuff we desparately need on here, so thanks. 

[68 Shelby KR500]

Garret,
This thread seems to share a similar problem, perhaps restrictors may be worth looking into? Perhaps that HP water pump is flowing too much...? Food for thought.
http://www.mustangv8.com/forum/classic-mustang-technical-forum/68-mustang-with-a-87-302-overheats/

See you Saturday.

[Soaring]

I have heard success with drilling a small hole in the thermostat that will allow a small amount of fluid past the thermostat before it opens, but don't quote me.  I still think the fluid is not staying in the radiatior long enough to cool properly before entering back into the block. 

[66GTKFB]

There is a difference between "High Performance" and "High Volumn" water pumps. A stock 289 water pump has 8 blades inside the pump. My HP 289 reves higher so it has six blades. That is lower the volumn of water. There is a good possibility you are passing too much water. This may seem contrary to normal beliefs but that's a possibility.
Jim

[Garret]

I am thinking of trying water flow restricter plates.  Could the addition of a pcv valve make it heat up?  It is really the only thing I changed recently.


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[Soaring]

No, the pcv valve won't make a difference regarding over heating. 

[Jeff73Mach1]

What pressure cap is on your radiator?  If it is a low pressure 7 pound cap that could contribute to your problem.  Try a 13 or 16 pound cap.

[Soaring]

The 13 lb. rad cap is the norm.  That's what I have on mine.

[Garret]

I have a 16 pound cap.  I had a 13.  The 16 improved it, but it still heats up after about 20 min.  I think the caps range from 13 to 18lbs., higher pound pressure for higher H.P.  The cap is good no leaks.

[Jeff73Mach1]

Let's get back to the most basic of issues here.

You say it is overheating-what makes you think it is overheating?  If it is boiling over, then it is overheating (obvious enough)

If you rely upon factory gauges, then your gauge accuracy is the first thing I would suspect.

an infrared thermometer aimed at the radiator near the inlet, the outlet, along the inside edge of the cylinder head, and at the side of the block (well away from any exhaust component will give you some very accurate numbers.  They tend to cost about 20-30 bucks and are a valuable tool to have.

How hot is too hot is another issue to consider.  an engine running at 210 degrees is just fine.  220 is still okay.  When coolant temperatures get higher than that it is time to start worrying.

AC condensors give off a lot of heat-if you are running an electric fan, make sure it is wired to come on whenever the ac is activated regardless of temperature.

a 195 degree thermostat will not help-a 160 degree thermostat might help, but once it is open, the thermostat is letting water circulate.  a lower temp thermostat will keep the engine cooler initially, but once it gets past being able to operate at that range, it will simply stay open and then when the engine heat created is greater than the cooling systems capacity your car will reach the same ultimate temperature.

are you running a coolant overflow tank?  If not, adding one can help by increasing the systems capacity-if it is installed in a manner that allows it to draw coolant back into the system when is needs it.  To work, it cannot suck air (meaning that the tank always needs to have some coolant in it to cover the tip of the return hose.  A coolant return tank is not going to lower temperatures-but it will make sure that after getting too hot, that your system isn't running low on coolant.

Finally, you have to get air out of the system.  What you are looking for is the highest point in the cooling system.   If this is not the radiator cap, you may need to bleed or burp the system.  Sometimes it is the thermostat housing and occasionally it is the heater core.  wherever it is you need to loosen it til it leaks and run the car with the radiator cap off, filling the system til it overflows at the high point, then tighten it up and cap off the system.  Air in the system will cause lots of cooling/overheating problems.

Reducing engine compartment temperatures by wrapping the exhaust might help and a finned large capacity oil pan (make sure it is baffled) can help as well.  An external oil cooler that is NOT in front of the radiator will help.

With a pusher and puller electric fan, I doubt the pusher is adding much and it may be restricting airflow.  If you do not have a "cap"
 fabricated between the radiator and condensor, then the fan will try and pull air through that gap- which does not cool the condensor as well which in turn means it radiates heat back to the radiator.  Sealing the gap between the two should include the top sides and bottom.

or like me, you could just avoid stop and go traffic when the temperature outside is over 90 if you can't get the engine temperature down to an acceptable level.