200 ci Overheating....Help Please !?!

[MercuryMarc]

I had my fan start at 190 and turn off at 170 (the turn off point is not adjustable separately - just 20 degrees below the on setting), and I had a 180 degree thermostat. Since the fan temp switch was mounted to a "T" fitting between the thermostat and the upper radiator inlet, the fan would turn on and never turn off!!! That was because the thermostat would close at 180 and then the hot fluid would remain at the "T" and would not recirculate, and never get below the 170 lower switch setting. I solved the problem by swapping in a 160 degree thermostat and setting the switch to kick in at 200 and off at 180 (it is variable between 170-180) but that way I won't get struck in an endless fan cycle. Pics of the above sete up availiable on the link mentioned in my previous emails.
Now I am not sure if I have selected an optimal operating temp but, doggone it, I am not going to overheat in a parade again!!!!!
Marc in SF
63 Comet Ragtop
200 ci/C4
etc...

 

[Anonymous]

High Capacity radiator has been ordered, and will be installed with a new carb spacer (which I'm sure won't lead to a vacuum leak).....

If that, and proper timing does not work, I'm not sure what I'll do.....

 

[Anonymous]

It should cool fine with the standard radiator especially since it is new. Before springing for another radiator, I would spend a little more time on the distributor and making sure you are getting enough advance. The distributor that I boutght from Autozone had an adjustable vacuum advance. I found that it was screwed in almost all of the way. Probably it was set this way to be conservative so that it did not cause 99% of the cars to ping. I backed out the adjustment and was able to get another 10 degrees of vac advance.
Doug

 

[PutPut6]

While removing the head off my 6, I took the thermostat housing off and found the thermostat had 3 small holes drilled in it. Thought that was an interesting find. I've never had any trouble with over-heating.

 

[ludwig]

I had a serious overheating problem on a long grade close to home. I also was having some timing and fuel mix issues. After reading a couple of strings here on timing and carb adjustment I finally got the mix and timing just right. In fact , the mix was as important as the timing because I think I had a lean condition. When that was cured and the timing was right the overheating stopped.
You need a good dwell tach. Don't do it by ear. That was my mistake.

 

[ski4evr]

Lots of good info. I use to drive a 65 Mustang coupe with a 302 in it. I never noticed the engine ever getting that hot (i.e. I could drive it for a while, pop the hood, touch the radiator and not scream). My 200, however, gets wicked hot (the radiator that is). I've flushed the system and verified/replaced the thermostats with little or no improvement in the radiator can't touch this factor.

The temp gauge in the dash always reads in the bottom third (towards cold). I now it works since I watched it scream up to Hot when I gunned it one day. I was in Las Vegas (110 F) in the summer. I was sitting at a stop light testing out the carb (autolite 1100) that I rebuilt and the timing was set correctly (finally). I was very pleased at this point and decided to gun it from a full stop to see what would happen. The car's front end raised about a foot, a loud thunk occurred and steam started billowing out from the front of the car. When I gunned it, the passenger side motor mount broke free (rubber part) as well as the transmission mount (rubber part as well), and the engine raised up knocking the upper radiator hose off of the radiator. This is when I verified the function of my temp gauge.

That was a long day.

Where is a good source for a fan shroud (if I keep the water pump driven fan)?

Where is a good source for an electric fan if I go that route?

Ski

 

[MercuryMarc]

I got my 14 inch fan on eBay - just type in "14 Fan" and there are tons listed. I ended up getting mine for about 30 bucks, but you can spend up to 120. The one I purchased is similar to the Tornado Derale version (http://www.derale.com/electricfans.shtml). I went for the largest fan that would fit - limited not only by height and width but also depth. Hope that helps.
Marc in SF
63 Comet Convert
200 ci /C4

 

[Anonymous]

I would definitely check out your timing. Usually a few degrees of advance is what works best for me. How are the points? Consider converting to a pertronix ignition setup for stock appearance and no more fussy points.

To get a good feel for the timing on your car, ride in the fast lane of an interstate with the window down, and listen to your car's sounds echo off the guide-rail. Listen for tell-tale pinging, pull over, and whip out your wrench and adjust it until the pinging goes away. This is how I got my timing to satisfy me.

A worthwhile preventive measure might be to check the condition of your oil pump. Maybe the sump head has some gunk on it and your oil pressure guage isn't being accurate.

Also, check and see if your carburetor is running too lean. A lean engine runs hot, and a rich engine runs cool. This is a problem I chased for a while on my car.

Finally, consider swapping down to a 160-degree T-stat. I swapped a 160 into my car, and since then, I've never seen the temperature go above the middle of NORMAL on the guage, even in summer traffic.

Good luck...
Rob

 

[ski4evr]

Thanks for the link MercuryMac

Ski

 

[Anonymous]

Guys These engines didn't do this when they came out of the factory, why would you need to add fans, larger radiators, lower temperature stats, ect, ect. As far as I know the Mustang was never known for having an overheating problem. Go back to basics. What causes the heat and why is it staying in the motor??

My motor was completely rebuilt, super cleaned the water passages, and I still had an overheating problem. The gauge would get to about half way then the faster I went the higher the temp would go. Sitting at a light the temp would go up. I had a stock distributor and a stock carberator. I made three changes (actualy 4 if you count the headers) at the same time that I'm not sure which moved the temperature down to 1/4 or less on the gauge. The Holley/Weber 2 barrel, the dizzy to Electronic, and my guess as being the main issue, changing the water pump from a cheap pressed metal impeller with a huge gap between the impeller and the casing, to a cast iron one with a clearance measured with a feeler guage. Now I still have some issues with the dizzy, I think my total is to high (55d) and my curve is to steep (seems to advance to quickly, around 1500 rpm) but the temperature is way down at all speeds.

The major issue with most engines is a buildup of crap in the water passages. Even a thin layer will cause a retaining of heat and a reduction of flow. I've flushed systems for 15 mins. with clear water flowing, then reversed the flow and watched brown pudding flow for another 15 mins. With a reduction in flow and a water pump that has a possibility to not force water into the passages (path of least resistance thing) a good portion of the heat isn't going to get to the radiator and the crap in the passages will hold it there. As a suggestion pull the temp. sending unit and see if the water is clean there. Low flow rates will allow the crap to buildup as well. By the way Heater Cores are more succeptable to clogging becouse there a secondary system to the main radiator, meaning there flow rates are lower therefore flow is lower and the particles get "stuck" there.

As has been pointed out if the timing is off the heat is increased as well. Verify the dizzy is working correctly, the system is clean and take a look at the water pump design. The cheap ones are crap and I'm of the opinion may be a high possibility for overheating problems. Just looking for a good discussion on this subject.

Steve

 

[addo]

It's good to bring up that aspect of the "barrier" of corrosion inside the parts. I have seen one blasting place successively pull the brass plugs, in order to channel the flow of abrasive for maximum effect. It's my belief a lot of rebuilders are inattentive to this aspect of corrosion, and removal.

Adam.

 

[CobraSix]

hyper brings a good point. Any 200 in stock form should have no cooling problems. Most of our cooling problems are corrosion oriented. 3-row, AL, low temp thermostats, electric fans, flex fans, etc all basically hide the real problem (unless you routinely drive in 100*+ temps). I had the same issue, I flushed my engine 5 times. Each time, it would end clean, 1 week later, I'd flush again and it would be muddy again. My problem ended being my radiator was extremely corroded. But before that was found, when I bought the car I had a carb with a vacuum leak that causes some overheating, and I had timing that was way off.

Check you cooling system, check your carb, check your timing. IT's one of those issues. You shouldn't need anything fancy. My car with a 3 row (yes, I did go 3 row, because it was actually cheaper) will never go past the thermostat temperature, even on 95+ days idling in traffic. the 3 row is the only thing I have that is not otherwise stock. I dropped my flex fan and went back to stock fan, and still won't overheat at all.

Slade

 

[Anonymous]

Thanks for all the tips guys. I'm replacing the carb spacer / gaskets this weekend, and swapping in a new NPD 3+ row "desert" radiator.

Both, along with timing, as possible roots of the overheating.

Full report to follow. I really hope this takes care of it!

 

[Anonymous]

PutPut - Thanks for the reply. I head through Niceville on the way to the Destin area each year. Great place you live! BTW, I've heard that you can drill a small 1/8" hole in a thermostat to allow for "burping" of excess gas from the cooling sytem. I think that's what's up with yours.

 

[Anonymous]

Yes, hole drilling in t-stats is an old '60s trick. Sometimes, the curves in the aftermarket radiator hoses (especially the bend-it-yourself types) go too "high" and can cause a suction problem for the water pump - especially if it's a cheap, sheet-metal-impeller type. The water flow then slows down because of the air bubbles that collect in the "high spots", and the heat goes up. Finally, the bubbles end up behind the t'tstat, preventing the coolant from contacting the thermal piston in the t'stat, and it doesn't open as soon (or as far) as it should. Drilling little holes lets the bubbles pass by easier and reduces the heating, but finding out where they come from in the first place is the real fix.