SAAC Forum

The Cars => 1969-1970 Shelby GT350/500 => Topic started by: Dan353 on September 29, 2020, 06:19:41 AM

Title: Cooling problems
Post by: Dan353 on September 29, 2020, 06:19:41 AM
On my 69GT350 Iím having cooling problems at idle and low speeds the temperature at a light or in traffic heats up to the point of almost overheating. My car has a/c  and a three row radiator in it.  Does anyone know is a clutch fan set up from a 68 GT350 will work on a 69 Gt350?

   Thank Dan
Title: Re: Cooling problems
Post by: 69 GT350 Vert on September 29, 2020, 02:44:20 PM
Did you verify the radiator cap is not leaking and holding pressure? 
Title: Re: Cooling problems
Post by: Bob Gaines on September 29, 2020, 03:16:34 PM
On my 69GT350 Iím having cooling problems at idle and low speeds the temperature at a light or in traffic heats up to the point of almost overheating. My car has a/c  and a three row radiator in it.  Does anyone know is a clutch fan set up from a 68 GT350 will work on a 69 Gt350?

   Thank Dan
Dan ,I am assuming that you have a factory type 24 inch A/C radiator and fan shroud. The 68 gt350 fan and clutch will work but I don't think it will work any better then the assemblyline 69/70 GT350 flex fan.
Title: Re: Cooling problems
Post by: Dan353 on September 29, 2020, 05:06:31 PM
Thanks for the info everyone. Yes my radiator cap is good was thinking of trying a higher pressure cap.    If the 68 GT 350 clutch fan will give the same results as I have now the only choice is to try to put an auxiliary electric fan between the condenser and the radiator.  The auxiliary electric fans that will fit in that area are only rated at 1000 CFM not much air flow.  Anyone have a better solution was trying to keep it looking period correct and not have to use an electric fan.

Thanks Dan
Title: Re: Cooling problems
Post by: Shelbypat on September 29, 2020, 05:29:59 PM
Be sur condenser and rad are clean and free of air circulation.  You can jet them carefully with water garden hose and retest.

Patrick
Title: Re: Cooling problems
Post by: Bob Gaines on September 29, 2020, 05:54:17 PM
Be sur condenser and rad are clean and free of air circulation.  You can jet them carefully with water garden hose. Also shroud must be present.


Patrick
+1 . I would venture to say that your radiator is clogged up with debris . Even if it flushes out clear water it can still have debris interfering with the small passages inside. I  have seen many like that over the years and it is not evident unless the radiator top tank is taken off and the interior roded out or new core or replacement radiator.some of which where heavy compared to another unclogged one because of all of the debris inside . That size radiator should more than adequately cool that engine . I haven't done this but you might try  Rust911 | Performance Radiator & Block Cleaner. I have used the rust remover product with great success and have bought the radiator product but haven't used it yet.    https://www.rust911.com/ one of the  I would try this before putting one of those ugly pusher/puller fans on. Also replace your thermostat with a high flow version that has temperature of your choosing .https://www.summitracing.com/parts/mrg-4364/applications/year/1969/make/ford/model/mustang/engine-family/ford-small-block-windsor/engine-size/5-8l-351  . A 180 degree should be fine . I typically use a 160 but that is a debate for another thread. 
Title: Re: Cooling problems
Post by: Dan353 on September 29, 2020, 06:27:59 PM
Thank you for the advice. Iíve been chasing this problem for a while I already have a high volume water pump and  high flow thermostat (160 Deg) installed in the car the radiator is an aluminum 3 row 24 inch that I installed last year. This seem to be an air flow problem at idle and low speeds. The temp gauge only goes a 1/4 of the way when driving on the highway but you can watch it climb when at a long stop light or driving in traffic under 25 MPH.  I try the rust 911 maybe there is a restriction in the block.

Thanks Dan 
Title: Re: Cooling problems
Post by: Bill on September 29, 2020, 06:31:05 PM
I removed and stored my original clutch fan assembly and now use a straight driven fan assembly without a clutch. My GT500 runs much cooler, even at idle than when I had the fan clutch assembly installed.


Bill
Title: Re: Cooling problems
Post by: Bob Gaines on September 29, 2020, 06:32:09 PM
Thank you for the advice. Iíve been chasing this problem for a while I already have a high volume water pump and  high flow thermostat (160 Deg) installed in the car the radiator is an aluminum 3 row that I installed last year. This seem to be an air flow problem at idle and low speeds. The temp gauge only goes a 1/4 of the way when driving on the highway but you can watch it climb when at a long stop light or driving in traffic under 25 MPH.  I try the rust 911 maybe there is a restriction in the block.

Thanks Dan
Just curious if this problem is one that has happened all along since you owned the car or one that has recently manifested itself or when did it start?
Title: Re: Cooling problems
Post by: Dan353 on September 29, 2020, 08:18:12 PM
Bob itís been going on since I have owned the car  bought it in 97 the engine was rebuilt and bored over .040 around that time.  Iíve been driving it a lot more these past years to where itís becoming more of a problem.  Iím 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 wasnít sure if it would work. The measurements I took of the clutch assy would put the fan about 2/3ís in the shroud.  Just trying to save some money with all that has been going on lately
Title: Re: Cooling problems
Post by: Shelbypat on September 29, 2020, 09:38:44 PM
Does it overheat with a/c off ?
If the high side is over 250 psi, condensor will contribute to warm the rad insteed of cool it

Patrick
Title: Re: Cooling problems
Post by: Bob Gaines on September 29, 2020, 09:42:04 PM
Bob itís been going on since I have owned the car  bought it in 97 the engine was rebuilt and bored over .040 around that time.  Iíve been driving it a lot more these past years to where itís becoming more of a problem.  Iím 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 wasnít sure if it would work. The measurements I took of the clutch assy would put the fan about 2/3ís in the shroud.  Just trying to save some money with all that has been going on lately
Dan ,not what you want to hear but I hate to report that I hear of this same problem all too frequently . That is why I asked if it has always been this way or just started.  The most common denominator in almost every instance is the over bored engine . I got tired of the symptoms and I and others started sleeving all cylinders back to standard when rebuilding as a insurance policy against over heating. I have not experienced the over heating problem on a number of engines of my own that I did that insurance policy to. That is not counting the many dozens of engines others I know did the same thing on theirs. Not a inexpensive solution but one that has a high likely hood of success from my experience. You don't have much more to loose at this point so hopefully some of the suggestions along with the pusher puller fan will help . If they don't then you know what has worked for others to ultimately solve the problem for good.   
Title: Re: Cooling problems
Post by: Rickmustang on September 29, 2020, 09:43:31 PM
Try distilled water, a little coolant and water wetter. Something easy to try. Rick
Title: Re: Cooling problems
Post by: 427hunter on September 30, 2020, 02:18:34 AM
Before you do anything make sure it is overheating , my gt500 will show 3/4 up on the gauge when driving but it's only 170 at the thermostat housing. Get a infrared thermometer and check, they are dirt cheap now.
Title: Re: Cooling problems
Post by: Cobrask8 on September 30, 2020, 07:43:24 AM
Agreed with Bob on two counts

1 - Overbore. The engine cylinder walls are just now too thin, transfer much more heat, and the cooling system cannot disperse it with not big amount of air flow.

2 - Heat dissipation - If the cooling system is compromised - old/clogged radiator - it will also continue the upward spiral of heat. Do a quick A-B comparison, buy a cheap radiator from e-bay/RockAuto, and see if it makes a difference.

And, agreed on the gauge - Why not get a cheap mechanical gauge, just toss it in, and see the temps more accurately displayed?

Heat has to be dispersed somehow.
Title: Re: Cooling problems
Post by: shelbymann1970 on September 30, 2020, 07:54:15 AM
Bob itís been going on since I have owned the car  bought it in 97 the engine was rebuilt and bored over .040 around that time.  Iíve been driving it a lot more these past years to where itís becoming more of a problem.  Iím 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 wasnít sure if it would work. The measurements I took of the clutch assy would put the fan about 2/3ís 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
Title: Re: Cooling problems
Post by: KR Convertible on September 30, 2020, 10:13:03 AM
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.
Title: Re: Cooling problems
Post by: Bob Gaines on September 30, 2020, 10:37:04 AM
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.
Title: Re: Cooling problems
Post by: KR Convertible on September 30, 2020, 12:53:24 PM
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.
Title: Re: Cooling problems
Post by: JohnHouston on September 30, 2020, 01:18:29 PM
Because it only takes seconds and costs nothing, it might be worth checking timing.

John
Title: Re: Cooling problems
Post by: Bob Gaines on September 30, 2020, 01:20:41 PM
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.
Title: Re: Cooling problems
Post by: KR Convertible on September 30, 2020, 01:32:54 PM
Maybe I should have said non-clutch.
Title: Re: Cooling problems
Post by: Dan353 on September 30, 2020, 05:02:04 PM
Thank you everyone for the information. Iím running the stock 5 blade flex fan.  I wonder if I have the wrong spacer for the fan.  I will also check the timing.  Iíve been given a lot of good suggestions Iíll try them hope fully one will work thank you again

Dan
Title: Re: Cooling problems
Post by: JWH on September 30, 2020, 07:20:27 PM
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
Title: Re: Cooling problems
Post by: shelbymann1970 on October 01, 2020, 06:46:56 AM
 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
Title: Re: Cooling problems
Post by: Bob Gaines on October 01, 2020, 01:24:04 PM
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. 
Title: Re: Cooling problems
Post by: shelbymann1970 on October 02, 2020, 08:01:11 AM
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
Title: Re: Cooling problems
Post by: JohnHouston on October 02, 2020, 10:19:41 AM
[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
Title: Re: Cooling problems
Post by: shelbymann1970 on October 02, 2020, 12:22:17 PM
[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
Title: Re: Cooling problems
Post by: Pcunder on October 02, 2020, 01:37:40 PM
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
Title: Re: Cooling problems
Post by: Dan353 on October 02, 2020, 05:42:53 PM
The only deviation from stock on my car is a Edelbrock performer cam, Aluminium radiator,  K&N air filter. The engine was bored .040 over it has stock heads, pulleys and fan  its a close ratio 4speed also Iím running a Gear Vendor over drive and a 325 rear gear the cooling problem is at idle and low speeds.

   The stock looking radiators  I have a ACP radiator I know Griffin has one that looks almost exactly like the ACP Iím not sure who else makes them.

I have received a lot of good information here and I really appreciate it.  now itís time tip put it to use.   Thank you everyone
Title: Re: Cooling problems
Post by: shelbymann1970 on October 03, 2020, 06:21:02 AM
The only deviation from stock on my car is a Edelbrock performer cam, Aluminium radiator,  K&N air filter. The engine was bored .040 over it has stock heads, pulleys and fan  its a close ratio 4speed also Iím running a Gear Vendor over drive and a 325 rear gear the cooling problem is at idle and low speeds.

   The stock looking radiators  I have a ACP radiator I know Griffin has one that looks almost exactly like the ACP Iím not sure who else makes them.

I have received a lot of good information here and I really appreciate it.  now itís time tip put it to use.   Thank you everyone
I didn't know there was one let alone at least 4 companies that make rads that look like OEM or close. But then again I have not looked for a rad in decades. I might replace my rad in my SCJ Mach1 with an AL one. Did you paint your ACP rad Dan? Gary
Title: Re: Cooling problems
Post by: Dan353 on October 03, 2020, 11:18:04 AM
I used Eastwoodís radiator paint on the cooling fins where they can be seen.  And used a a semigloss in the upper tank
Title: Re: Cooling problems
Post by: Bob Gaines on October 03, 2020, 01:53:13 PM
I used Eastwoodís radiator paint on the cooling fins where they can be seen.  And used a a semigloss in the upper tank
FYI the Eastwood radiator paint regardless of gloss black or semi gloss will dull down from fresh applied sheen once it goes through a few heat cycles.
Title: Re: Cooling problems
Post by: Bigblock on October 06, 2020, 01:39:57 PM
Do you have a auto parts store temp sender in the intake manifold? They can/usually read high.
Title: Re: Cooling problems
Post by: shelbymann1970 on October 06, 2020, 03:30:47 PM
I used Eastwoodís radiator paint on the cooling fins where they can be seen.  And used a a semigloss in the upper tank
FYI the Eastwood radiator paint regardless of gloss black or semi gloss will dull down from fresh applied sheen once it goes through a few heat cycles.
so what do you recommend Bob? I got a few cans of the Eastwood for my SCJ but it isn't a concours but a day 2 car. I'll be freshening up a 20 plus year old resto on my vert once I get all of my "original" parts ready to put on to replace service parts. Gary
Title: Re: Cooling problems
Post by: Bob Gaines on October 06, 2020, 06:59:33 PM
I used Eastwoodís radiator paint on the cooling fins where they can be seen.  And used a a semigloss in the upper tank
FYI the Eastwood radiator paint regardless of gloss black or semi gloss will dull down from fresh applied sheen once it goes through a few heat cycles.
so what do you recommend Bob? I got a few cans of the Eastwood for my SCJ but it isn't a concours but a day 2 car. I'll be freshening up a 20 plus year old resto on my vert once I get all of my "original" parts ready to put on to replace service parts. Gary
If you use the gloss black you will have to live with the the extra gloss until it dulls down. The semigloss will look normal assemblyline right after application but will dull down further after a number of heat cycles. I suppose it depends on your expectations . For instance if it were going on a show car the gloss paint may not have time to dull down and you may lose points in judging. If you use the semigloss so that you do not have to worry about too glossy while judging then you will have to contend with it later on dulling down farther then semigloss after a number of heat cycles.
Title: Re: Cooling problems
Post by: Dan353 on October 25, 2020, 10:35:52 AM
I just want to make sure I have the right fan on my car.   Does anyone know the correct fan part number for a 69 GT 350 with Air Conditioning?  Iím not sure but this might be part of my cooling issue.

Thanks Dan
Title: Re: Cooling problems
Post by: 5s386 on October 28, 2020, 04:31:56 PM
My 69 GT350 was overheating, and loosing radiator water. Turned out to be an intake water leak (hidden) in the rear, by the cowl. New intake manifold fixed it. And the intake bolts I replaced, too.
Title: Re: Cooling problems
Post by: Bob Gaines on October 28, 2020, 06:12:32 PM
I just want to make sure I have the right fan on my car.   Does anyone know the correct fan part number for a 69 GT 350 with Air Conditioning?  Iím not sure but this might be part of my cooling issue.

Thanks Dan
In reply 22 you state that you have a 5 blade flex fan. Regardless of if it is the correct factory application fan or not, one 5 blade flex fan will not significantly effect cooling + or - over the other .  You probably don't want to read it again but the info what was in reply #11 and #14 are most likely the cause and the cure . 40 over is a lot on a block. Since this is a condition that has manifested itself since you owned the car the over heating because of overbore is very plausible. It might be time to try the auxiliary electric fan to see if that band aids the problem.
Title: Re: Cooling problems
Post by: 69mach351w on October 29, 2020, 01:15:36 PM
Agreed with Bob on two counts

1 - Overbore. The engine cylinder walls are just now too thin, transfer much more heat, and the cooling system cannot disperse it with not big amount of air flow.

2 - Heat dissipation - If the cooling system is compromised - old/clogged radiator - it will also continue the upward spiral of heat. Do a quick A-B comparison, buy a cheap radiator from e-bay/RockAuto, and see if it makes a difference.

And, agreed on the gauge - Why not get a cheap mechanical gauge, just toss it in, and see the temps more accurately displayed?

Heat has to be dispersed somehow.
+1, you can even secure it under the hood for a quick installation, get up to operating temperature, pull of the road and quickly check temp under hood.