I have a 66 Mustang with a 302 and a 600 Edlebrock carb. The motor it's self is bone stock nothing special. I was first having problems with it running hot before now it's worse. Before it was a 14" pusher electric fan and a 18" flex fan on the water pump. It used to climp a little in traffic and over heat on the high way. Well now I traded my problem with the another. :bang: :bang: :bang:

Now she is running 190 degree on the high way but when I stop it shoots to 230 really fast and will not stop untill I get the car moving. I installed a new 3 row radiator with a 16" electric puller fan. The thermistate is a 160 degree and I even installed a lower sprung radiator hose. :flame2: :flame2:

I was kinda worried about using only an electric fan. I just figured that it should be able to cool a stock motor. What are my options here I really wish now I would have went with an aluminum after the discussions on the other topic. What can I do to bring the temp down now that I went this route? :scratch:

Any suggestion no matter how bizarre would be great thanks guys.

 

apropos of something, you should be using a 180* t-stat.

did you build your engine? head gaskets on correctly?

have you tested your radiator cap?

fan shroud?
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It's a crate 302 motor. I didn't build it myself. I alos don't have fan shroud. How do I test the cap. It's got a 13lbs one on it now. Will it help to go to better cap and what kind? :scratch:

 

Hmmm, this is a toughy. I was in a similar situation with my 060 overbored 289, but after a new radiator and puller electric fan, all my problems were solved. This leads me to think it isn't the components. Is there any way you have an air bubble in the system that isn't allowing the coolant to flow? I know it's a goofy thing to trouble shoot, but short of a wonky head gasket, I'm not sure what the culprit could be.

 

bleeding the system is a good idea

Honestly, I dont know how to 'test' a rad cap, but if its not holding pressure that will lower the boiling point of your coolant. If its a brand-new cap it is prob OK, but if you reused one or its older, its a cheap check to try a new one. 13-15 lbs is about right.
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In addition to the above, here are a few things to try

Try running without a thermostat just to see if it makes a dif. There have been many failures of New t-stats so just rule that one out. Also, with the t-stat out you can verify coolant flow to make sure the pump is pumping
Double check your timing.
Do you have an auto trans? If so, make sure it is full of clean fluid. Also make sure the heat exchanger for it is clean.

 

Did you have any overheating at idle prior to the electric fan addition?

First thought would be that your fan isn't big enough. Is it possible to swap the engine-driven fan back on as a test?

Basic Overheating Troubleshooting.

 

It ran a little hot but as soon as you got moving it was fine, but ,it would never get past 210 sitting at a light. I had alot of problems running hot on the highway the faster you went the hotter the car ran.

Now I traded problems. Runs fine on the freeway then super hot in traffic. :bang:
I guess I'll try replacing the cap and thermosate tomorrow and see if it changes. :scratch:

 

OK, we've got a "before" & "after" thing going here. It didn't overheat in traffic "before", but it does "now". Are we talking last week, last month, last year???

What are ALL the changes that were made?

Typically, if you overheat during driving, you have a coolant flow issue - water pump/radiator. If you overheat at idle, you have an AIRFLOW issue. If you installed "... a new 3 row radiator with a 16" electric puller fan. The thermostat is a 160 degree and I even installed a lower sprung radiator hose.", you probably fixed the radiator and/or lower hose problem that WAS the problem before. However, the electric fan may not be large enough to move the volume of air needed at idle. With the car running and hood closed, does the fan stink enough air to hold a dollar bill against the GRILL (not against the radiator, but the grill!)?

 

I'm gonna go way outside the box here and say you need to check your timing. From the sounds of it, you have plenty of cooling capacity. You say that you run 190 degrees on the highway. If you have flow, there should be plenty of air to cool that engine at highway speeds, even with that little fan.

Have you done anything to the timing? Are you running Pertronix, MSD or points?

 

I ran a timming light on it and it's right on spec. I have eletronic moduel instead of points.

 

LOL, gotta love the swear filter!!! I said, "...does the fan s u c k enough air...". The filter apparently changes s u c k to stink. LOL! I gues I should say "does the fan PULL enough air..."

Anyway - 67shelby said "If you have flow, there should be plenty of air to cool that engine at highway speeds, even with that little fan. " As I understand things, you ARE keeping cool on the highway. It only heats up when not moving. That indicates to me that you have sufficient cooling ability, just not enough airflow when the car is stopped.

 

Just for the record, spec timing is rather enimic, usually in the 6* BTDC range. Your car is a 66' and you say you have a crate 302, so which "spec" are you following, the original guide for the 289 that would normally be in a 66' or the spec that that the crate motor came with? Timing should vary with every combination of parts and you should give your car as much as it likes. I have very simple basic mods on my 302 and it likes 16* BTDC, that's 10 over spec designation so I would suggest you at least try it. The best thing is to slowly advance it until you start to hear a ping than back it off, that will be what YOUR car likes.

BTW, I have never been a believer that an electric fan can do a better a job of cooling than the stock balde and shrowd setup. Unless you are constantly sitting in traffic in a very hot climate and using AC often, you may be better off switching back.

 

Thanks for the suggestions great stuff to try. I'll let you know what happens with it.

 

Sorry Cloney, I don't know where I was going, I got interrupted 3 times (I'm on 2 this AM) and don't quite know where I was going. So, I'll start over.

I think the first part of the post is what confused me: Anyway, there are three ways heat leaves an engine:

1) Through the cooling system.
2) Through the exhaust.
3) Through the air surrounding the engine.

It sounds like while #3 is present, everything is ok. So the problem is either #1 or #2 aren't doing their jobs or something else is causing the heat to be a problem so #1 and #2 alone can't do the job in conjunction with each other (which they should). So....

1) The cooling system isn't adequate.
2) The exhaust is plugged or restricted in some way.
3) The engine is producing more heat than normal.
4) Something is making the engine work harder than it should.

There are many problems associated with #1, including a plugged system (have you done a good flush lately), bad thermostat, bad cap, etc. A good professional cleaning could help solve the problem if you have a plugged or restricted flow problem. Sometimes, the flushes we can buy aren't good enough. The problem could well be that the electronic fan isn't adequate like Pakrat states. A three row radiator should be more than adequate to cool this engine.

We haven't addressed #2, but I would think if there was a real problem with a restricted exhaust there would be other problems. However, make sure Axle Foley didn't put a banana in your tail pipe. (If your not old enough, you might not get that one).

Number 3 presents the fact that it is possible that the engine is producing more heat than normal. Something we often overlook. It is possible that an engine can be running "adequately", but severly out of time. I recently helped a buddy start a fresh 428 CJ in a 68KR and even though it was running excellently, it was firing early and the heat gauge went through the top. It was running near spec (6 BTC) but was one tooth off. I agree with Pakrat:

Timing is influenced by different things that make the specs change. Find out what your car likes, but be careful. Make sure that dizzy isn't too far out of line to hit the "sweet spot". If it is, move it back a tooth and try again....

So the last one, something is making the engine work harder. You need to make sure the automatic transmission fluid level is good if you have an automatic and make sure there isn't any brake drag that is causing load on the engine that could be a problem. Long shots I know, but you have to make sure to consider everything.

I have one more "theory" I'll explain and then I'll quit ranting. The new electronic ignition modules like Pertronix make the older engines run hotter. You gap your plugs wider, run hotter coils, etc. for these modules. That causes two things IMO, that are somewhat related to the question at hand. The first is that you need a better cooling system than a stock engine would need without the electronic ignition, and the other is that you need to use different oil (with a higher flash point). I worked for a year on my 65 trying to find out where the oil was going until I changed from 5W30 to 10W40. Low oil, low viscosity, etc. can cause an engine to run hotter. Probably not enough to cause the problem itself, but it can be a contributing factor.

There you go, 9 interruptions and almost 1 1/2 hours from start to finish. No wonder these posts don't make sense....

 

great post, Lorne! Tons of good sense there.....
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OK guys this is the nail is the coffen for me. I ran test on the motor this after noon. I pulled the cap off and let the car warm up. It seems that the thermosat is opeing correctly and I have nice flow BUT, I saw something I wish I hadn't. Bubbles many little white bubbles. I guess the problem at hand is Head Gasket. :bang: :cry: :bang:

Well pull out the stops it's compression testing time. I'll let you know what I come up with. It probly involes pulling one of the heads when it's over and done with.

Oh the pain of it all

 

Is the oil milky????

 

abnormal bubbles? Just because you have bubbles doesn't mean there is a blown head gasket. Some amount of bubbling is normal, IIRC.

 

I took the car to a radiator shop today to preform a presure test and see if there any exahust gasses in the anti-freeze. I also checked the oil this morning and the oil looks clean and I'm not blowing any smoke. I guess I'll see what the shop tells me hopefully what is wrong with my cooling system.