Cooling problems

[shelbymann1970]

Bob it's been going on since I have owned the car  bought it in 97 the engine was rebuilt and bored over .040 around that time.  I've been driving it a lot more these past years to where it's becoming more of a problem.  I'm getting sick of having to pull over in stop and go traffic to let it cool down.   It seems to me the fan is too far in the shroud.  I have a clutch and fan assembly a buddy gave me years ago from a 68 GT350 I wanted to try it to see if it improve my cooling but I wasn't sure if it would work. The measurements I took of the clutch assy would put the fan about 2/3's in the shroud.  Just trying to save some money with all that has been going on lately

My no-air uses the smaller radiator. I had the same exact problem as in it would run cool in HWAY driving but a little hotter in traffic and then stopped on Woodward during a cruise pulled into a parking lot with his gauge nearly pegged and puked antifreeze out of the overflow hose(had the radiator checked for leaks and such a week early at a shop). My solution was when I restored the car and in the process flushed the block and had the radiator re-cored. This solved my over heating problem. i can sit in traffic and it only goes a little over half way. Did it the other day sitting in my garage for over a half hour running for the first time in about 3 months. No more overheating. I'd look into the radiator. Gary

[KR Convertible]

The fan seems more suspect to me, if you are good at highway speeds and hot when moving slow.  Try a fixed fan as an experiment.  Do not buy a cheap fan clutch!  Ask me how I know.  If you want to stay with a clutch driven fan, break down and spend the money on a good one.  I went with Chris Brown's reproduction.  Looks and works great.

[Bob Gaines]

The fan seems more suspect to me, if you are good at highway speeds and hot when moving slow.  Try a fixed fan as an experiment.  Do not buy a cheap fan clutch!  Ask me how I know.  If you want to stay with a clutch driven fan, break down and spend the money on a good one.  I went with Chris Brown's reproduction.  Looks and works great.

Good positive info however 69/70 GT350 from the factory use a fixed 4 blade fan non A/C and a flex type 5 blade fan for A/C cars. OP asks in his first post asking if the 68 GT350 clutch fan would work any better. I replied that I don't think that the clutch fan would any better than the stock flex fan.

[KR Convertible]

I'm a little surprised an a/c car has a fixed blade fan after 66.  It still sounds like not enough air going through the radiator.  Would be good to know which fan is on the car now.

[JohnHouston]

Because it only takes seconds and costs nothing, it might be worth checking timing.

John

[Bob Gaines]

I'm a little surprised an a/c car has a fixed blade fan after 66.  It still sounds like not enough air going through the radiator.  Would be good to know which fan is on the car now.

I don't know where you got that info because my reply #17 reads - " 69/70 GT350 from the factory use a fixed 4 blade fan non A/C and a flex type 5 blade fan for A/C cars. " .  Flex type fan for 69/70 GT350 with AC not fixed fan. They are two different types of fans.

[KR Convertible]

Maybe I should have said non-clutch.

[Dan353]

Thank you everyone for the information. I'm running the stock 5 blade flex fan.  I wonder if I have the wrong spacer for the fan.  I will also check the timing.  I've been given a lot of good suggestions I'll try them hope fully one will work thank you again

Dan

[JWH]

A good friend has a '67 big block and it was overheating this summer and driving him crazy. Turns out the radiator was a bit clogged up and a previous owner had sprayed the radiator with Header paint. Apparently, the type of paint is critical to the radiator cooling. After addressing these two issues, no more overheating and he could not be happier to drive the car anywhere.
Jeff

[shelbymann1970]

 This is a small block car. I own both and BBs always seem to get more heat under the hood. LIke I said I had the SAME problem and mine ended up being the radiator. If all else fails to fix with factory equipment might be time for a rad recore assuming it has been flushed and has the correct rad paint on it and correct timing. Gary

[Bob Gaines]

This is a small block car. I own both and BBs always seem to get more heat under the hood. LIke I said I had the SAME problem and mine ended up being the radiator. If all else fails to fix with factory equipment might be time for a rad recore assuming it has been flushed and has the correct rad paint on it and correct timing. Gary

OP said he has a aluminum radiator. Consequently that will complicate any recore or rod cleaning unlike a stock copper core tank. 

[shelbymann1970]

This is a small block car. I own both and BBs always seem to get more heat under the hood. LIke I said I had the SAME problem and mine ended up being the radiator. If all else fails to fix with factory equipment might be time for a rad recore assuming it has been flushed and has the correct rad paint on it and correct timing. Gary

OP said he has a aluminum radiator. Consequently that will complicate any recore or rod cleaning unlike a stock copper core tank.

Thanks Bob, went back and read ALL posts . Missed that post. Was going off the first  2 posts from Dan and wanting a STOCK look(no STOCK look with an AL radiator that I am aware of). So I am wondering are there AL rads out there that look stock? I'm looking to put a new rad in my SCJ Mach1 but all the AL ones I see are far from stock looking. Gary

[JohnHouston]

[quote Was going off the first  2 posts from Dan and wanting a STOCK look(no STOCK look with an AL radiator that I am aware of). So I am wondering are there AL rads out there that look stock? I'm looking to put a new rad in my SCJ Mach1 but all the AL ones I see are far from stock looking. Gary
[/quote]

No affiliation or knowledge of quality, etc., but cool craft (coolcraft.com) has some that look sort of kind of close to original in alyoooominium.  Probably the best bet if you want something that doesn't look like a box.

John Dillman

[shelbymann1970]

[quote Was going off the first  2 posts from Dan and wanting a STOCK look(no STOCK look with an AL radiator that I am aware of). So I am wondering are there AL rads out there that look stock? I'm looking to put a new rad in my SCJ Mach1 but all the AL ones I see are far from stock looking. Gary

No affiliation or knowledge of quality, etc., but cool craft (coolcraft.com) has some that look sort of kind of close to original in alyoooominium.  Probably the best bet if you want something that doesn't look like a box.

John Dillman
[/quote]Thank you John. I didn't know. I need to catch up with the times. Last time I looked AL rads didn't look like this. Searched NPD and found similar for about 80  less by another company. cool craft allows you a set of options. Both styles are similar to OEM tanks. I was looking at OEM repos and they were pushing 600 bucks so I was going to take mine to a local shop for pressure testing(been out of the car for 5 years now). Now I think before i'd recore(no #s on my rad) I'd got the AL route on my "day 2" SCJ Mach1. I wonder would there be any problem painting the Aluminum rad with Eastwood's radiator black paint?  Gary

[Pcunder]

All these are good suggestions but here's a couple.
If your car is "almost" overheating as you said, then maybe an overflow tank is needed to recover any lost fluid. Not factory perhaps, but problem solved.

If it's ONLY overheating during idle/slow operations, don't forget the correct pulleys.
Under-driving a WP pulley is fine at 8k RPM, but not at idle. Check both crank and WP pulleys. In this case, size is all that matters

Not to argue the thermostat point, but Ford usually specified a 180-190 deg F T-stat on SBFs.  Too low can sometimes lead to unintended consequences.

Correct fan placement should be about 1/2 way into the shroud.

I also agree about the thin, over-bored cylinder walls...most likely made worse when core-shift isn't eliminated in thin-wall castings like the SBF...

Lastly, you didn't say anything about the cam or heads but here goes:
-too much cam duration and the valves aren't closed long enough to transfer heat to the head. Not sure if hard seats make this better or worse.
-valve seats cut too thin (a la racing 3-5 angle valve job) sometimes make the above problem even worse and eventually lead to a burned valve.

I hope its something simple. I love the idea about the IR thermometer. I personally put a 68-GT350 fan/clutch on my 66 Mustang 351W (track-car) and never had overheating issues.


Good luck,

Phil