Cooling problems

[Dan353]

On my 69GT350 I'm 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

[69 GT350 Vert]

Did you verify the radiator cap is not leaking and holding pressure? 

[Bob Gaines]

On my 69GT350 I'm 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.

[Dan353]

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

[Shelbypat]

Be sur condenser and rad are clean and free of air circulation.  You can jet them carefully with water garden hose and retest.

Patrick

[Bob Gaines]

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. 

[Dan353]

Thank you for the advice. I've 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 

[Bill]

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

[Bob Gaines]

Thank you for the advice. I've 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?

[Dan353]

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

[Shelbypat]

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

[Bob Gaines]

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

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.   

[Rickmustang]

Try distilled water, a little coolant and water wetter. Something easy to try. Rick

[427hunter]

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.

[Cobrask8]

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.