Surprize surprize, cooling issues

[67FEfastback]

This is a 'stang, but I assume some of the cobra guys have dealt with cooling issues, once or twice.

I have already done a whole bunch of troubleshooting
replaced a bad thermostat
replaced a bad fan clutch
replaced a bad rad cap

The good news is that I did not boil over. It got very hot a few times
The bad news is that it's fall weather here and very cool outside 10 C +/-

My car is heating up a lot in stop and go city traffic.

Seems to cool of at speed better.

I have a big block rad, shroud, and big block clutch fan (now working I think)

I was thinking of adding an electric pusher fan - what do you think?

Should I consider a big aluminum radiator?

The New MR gasket high flow thermostat failed. I replaced it with a stock type thermostat. I have a 16 lb rad cap and overflow tank with an edelbrock aluminum water pump.

The fiberglass hood that I have, does not have the cut outs (louvres) in the top.

[undy]

..just out of curiosity, is it a fresh rebuild?

[Bill Wells]

how accurate is your temp gauge ?ie, , you said it ran hot but did not boil over . one school says if it doesnt puke, it is not hot .

what fan do you have and what year mustang ? 67 - 390 ?

on my 65 Mustang with .040 bored K code modified motor I have the stock radiator and hi-po shroud but added a 6 blade clutch fan - which really helped cool it down ( 4 blade was standard ) . On my 57 TBird i added a 6 blade clutch fan replacing a stock 4 blade and a large back up electric pusher fan with automatic thermostat - those old 312 Y block early birds all run hot, no longer runs hot.

the many Mustang parts suppliers offer a variety of high output aluminum radiators that are an easy bolt in - but I would not jump too quick before you determine if the engine is really running hot - and you can somewhat test /compare your gauge by buying or borrowing an infra red heat thermometer and shoot various engine areas to see what the temps really are . also, double your anti freeze to make sure it is fresh and at a 50/50 level - too much anti freeze will make it run hotter too . good luck . bill

[DAVID GAGNARD]

Originally Posted by Bill Wells

how accurate is your temp gauge ?ie, , you said it ran hot but did not boil over . one school says if it doesnt puke, it is not hot .

what fan do you have and what year mustang ? 67 - 390 ?

on my 65 Mustang with .040 bored K code modified motor I have the stock radiator and hi-po shroud but added a 6 blade clutch fan - which really helped cool it down ( 4 blade was standard ) . On my 57 TBird i added a 6 blade clutch fan replacing a stock 4 blade and a large back up electric pusher fan with automatic thermostat - those old 312 Y block early birds all run hot, no longer runs hot.

the many Mustang parts suppliers offer a variety of high output aluminum radiators that are an easy bolt in - but I would not jump too quick before you determine if the engine is really running hot - and you can somewhat test /compare your gauge by buying or borrowing an infra red heat thermometer and shoot various engine areas to see what the temps really are . also, double your anti freeze to make sure it is fresh and at a 50/50 level - too much anti freeze will make it run hotter too . good luck . bill

all of the above and I would add a few things to check........

1. do you have under drive pulleys????? If so, go back to stock pulleys, underdrive pulleys are for race use only......

2. 50/50 anti freeze and water....

3. you may want to drill 2 or 3 small holes in the flange of the thermostat for extra water flow, but before you go that route, get the car up to temp and then let it idle and remove the cap and see just how much water you have flowing........at idle it should come out the flues and inch or so, at fast idle on up, it should really shoot out a couple of inches, you'll see a big difference in flow....
on my street Mustang and race Mustang, I run the same thermostat and water pump, street car has stock pulleys, race car has underdrive pulleys, difference in flow at idle is like night and day, no comparison, race car rarely idles much, always running at speed, so it's not an issue.........

4. get a mechanical temp gauge, and check it in your house with the sender in a pot of water on the stove, you can check it to 212 degrees, once you determine if it is accurate, run the car and get it up to temp, remove the radiator cap and insert the sender into the radiator and see what the temp of the water is coming out of the engine going into the radiator..............this will tell you a lot.....

Had a buddy with on old big block Trans Am, factory gauge would peg out after some idling, checked the water temp in the radiator with a known good gauge and it never got over 195.......factory gauge was not accurate at all, he changed it and all was well in the world again............

good luck....

David

[PANAVIA]

Also check plug gap and timing and arc of timing throughout idle to 3000 rpm.

retarded timing can cause a heat problem with FEs.

--Steve

[FWB]

is that your car at the bottom of your post? if so the fog lamps you have in the grill have been noted as a cooling problem since their inception in 1967
the 68's didn't get them because of that very issue. this is not saying it is the only reason, but it is contributing to it. the unibody construction of the car makes it difficult to remove the heat under the hood. the radiator, original big block design will be inadequate for a performance application, consider it was there for a car with a 390 or 428 with factory cam and factory exhaust manifolds. add a cam and headers and you have more heat.
where is your timing set? is the motor stroked? try removing the fog lamps to see if there is any improvement, if so you could then assume it is an air moving problem and then address the fan issue, after that try to upgrade the radiator. been through this a couple times with big block mustangs. it always sucks to say the least.

Fred

Originally Posted by 67FEfastback

This is a 'stang, but I assume some of the cobra guys have dealt with cooling issues, once or twice.

I have already done a whole bunch of troubleshooting
replaced a bad thermostat
replaced a bad fan clutch
replaced a bad rad cap

The good news is that I did not boil over. It got very hot a few times
The bad news is that it's fall weather here and very cool outside 10 C +/-

My car is heating up a lot in stop and go city traffic.

Seems to cool of at speed better.

I have a big block rad, shroud, and big block clutch fan (now working I think)

I was thinking of adding an electric pusher fan - what do you think?

Should I consider a big aluminum radiator?

The New MR gasket high flow thermostat failed. I replaced it with a stock type thermostat. I have a 16 lb rad cap and overflow tank with an edelbrock aluminum water pump.

The fiberglass hood that I have, does not have the cut outs (louvres) in the top.

[67FEfastback]

Thanks guys, a lot of helpful info in your replies.

Yes - new motor, standard stroke, aluminum heads, 040 over but lots of thickness on the sonic test.
Standard pullies

I am going to try and water down the antifreeze. I am certain when I replaced the thermostat, that I am over the 50/50 mix.

The timing is not too advanced, It may be retarded though, but I cannot confirm, without a timing light. I am concerned that the vacuum advance is too much, though (MSD 1 wire dizzy)

I checked the radiator. I believe it is a standard 3 row radiator, not the HD 4 row, I'll have to suck some antifreeze out the top to count the rows.

[xlr8or]

is the water pump a standard or reverse rotation?

[undy]

Just a thought.. A reversed head gasket is easy to do. If the head gasket's reversed the coolant's return path is compromised and for no other apparent reason the motor will overheat at the drop of the hat. ..not trying to insult anyone's engine rebuild capabilites. I know of a 428 FE that this happened to.

Dave

[67FEfastback]

A couple more steps tonight.

I drained an amount of coolant. I am going to replace it with water to get the mix closer to 50/50 (that should get me very close)

While I was at it, I removed the thermostat and drilled the three small holes in the top. At the very least that should help purge the system.

I am going to check the timing and look at the vacuum and mechanical advance as well

Water pump is edelbrock standard rotation. The heating up of the car is steady in traffic. Once it moves (air flow) it starts to cool back to normal. When I step through the gears it heats up fast, then goes back to normal if I back off (after a short while)

If the weather is decent again this coming weekend, I'll test it out again.

[Bill Bess]

Hey, just a thought....because I had all these problems with my FE Cobra. I changed everything as you have and guess what, it was the brand new temp. gauge that was bad.
Check your motor with an infered gun when the gauge is indicating very hot and then you'll know. You can buy one at Summit for $35.00 or find a shop with a gun.
Start with basics...is it really hot?

Best Regards, Bill

[67FEfastback]

Thanks for your suggestion, Bill.
All of you responses have helped me get this close to a conclusion.

I filled the balance of coolant up with distilled filtered water. That should get me to around 50/50.

I left the rad cap open and ran the engine up.
Slightly over 1/2 on th temp guage, no flow.
Ran it a bit more. Shut it off.

I figure the thermostat was not even opening.
When I restarted I did get coolant flow, until the temp went down a little, then it stopped again.

Even at 3/4 mark on the gauge there is not too much flow.

So it is not likely that hot.

The only thing I'll need to do is to be wary of the stop and go traffic scenario,
It was obviously heating up, more than it was able to cool down.

I think I'll still look at a larger rad and possible pusher fan, for the summer time heat. It's better that I have too much cooling capacity, than not enough and struggle in the summer.

What do you guys think about size and combinations of pusher fans?

[DAVID GAGNARD]

Me thinks your factory gauge is not all that accurate.... I would get a mechanical gauge and stick it somewhere in the car temporarely and see what the reading are on the street........

Your thermostat will not open till it reaches it's temp rating, sometimes it seems to take forever..........
BTW: I ALWAYS check a new thermostat in a pot of water on the stove to make sure it is working properly.........

Some years ago I added a 12" pusher fan (temporarely mounted) to the front of my radiator for parades, it worked fine........ I would think anything from 12" on up would help, just make sure it is shrouded, I've also found the curved blade fans work better than straight blade fans...........

Over the years, I have expriemented with 4 radiators, 1/2 dozen electric fans, different pulleys and 3 water pumps on my 65 Fastback to get it where I could do the Forth of July parade here, (usually about 100 degress outside) with no problems.... I can now do the parade which last about 45 to 60 minutes.....first 40 minutes or so, temp stays around 180 to 185, then afterwards starts creeping up, by the end of the parade (50 to 60 minutes later), I'm about 190 to 195 degress, 2 miles down the road and I'm back to 180..........

David