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'72 mach1 noise and overheat issues. Please Help
I am looking for some suggestions and/or help with my '72 mach1 which has the Cleveland 351 in it. Mostly all original parts including radiator. The first issue is that I recently experienced is a whistling/vacuum like suction noise coming from the front center of the car, most likely engine area. It only makes the noise when accelerating and or when just starting to let off the gas. I assume it is a possible vacuum leak but not completely sure. I will have to check those but any suggestions as to which hose it could be and where it would be located based on the engine type of my car? Or other possibilities??? Thanks in advance.

The second issue, which after speaking with other mustang owners at car shows have said is fairly common, is my mach starting to get really hot while in an idol position. It is the 351 cleveland with a 4 barrel carb. I have the original radiator and although an electric fan may help, I have no intentions of changing. I am keeping the car as original as possible. The suggestions I have received are a product called Water Wetter to be used and also I believe what one had called like an inner cooler for that area... Any personal experienes or help would be great. I'm not a mechanic, though I have a good friend who is so please keep the terms basic so that I can relate it to him.
Thank You!

Most of my experience is with the 65-66 Mustangs and 289/302/5.0 SBF's. On the whistling noise, yes it prolly is a vaccum leak. One method for tracing down a vac leak is to spray WD-40 on hoses and manifold connections. When/if the idle RPM changes/goes up, a leak is indicated in that area.
Addressing the overheating issue. The early Mustang radiators are too small and are do not have a cross/diagional flow style radiators. By the time the 70 and later Mustangs had come out these two problems had been eliminated.
If your radiator is indeed the origional, it may be time to have it replaced, or at least rodded out(mechanically cleaned of deposits), or the thermostat may have gone bad. To check a thermostat, place it in a pan and boil the water. when you see the thermostat open, check water temp, thats the thermostats opening temp. The true best operating temp for V-8 gas engine is 185 to 195 degrees. So even if the origional temp range is lower use a 185-190 T-stat for more efficent operation and less internal wear on the engine. Just because your temp gage is reading hot, if the engine isnt loosing coolant or boiling over the system is just fine. Wierd as its may sound it's true.
Hope this is of some help.


Do yourself a favor and replace your radiator outright. I'd recommend a 3 core aluminum as a replacement. Many manufacturers sell radiators built to spec in size and shape with increased cooling capacity. Maintaining originality is a good thing, but busting head gaskets isn't. While cleaning it out and rodding it will help, that thing is most likely full of rust. You'll definitely want to flush out the engine as much as possible when you have the hoses off. You'd be surprised all the gunk that came out of mine. At a bare minimum I'd flush the whole system (including the water pump) with a hose at least twice.

If you feel comfortable with it, I'd also highly recommend changing out the water pump with a higher flow unit as well. I had no idea what I was doing and got it swapped out for $50 and 4 hours work. It's not that hard. Concur on replacing the thermo as well. I had overheating issues on my 70 w/302 but she runs a very cool 190-195 in the hottest weather.

While you are at it, I'd replace the temp sender unit as well. I replaced mine but it functioned the same as the old one.

I've heard Water Wetter may help, but it's not going to fix a gunked up system that's older than I am. I think it also needs distilled water only in the system but I may be wrong.

Oh yeah, that noise might also be a loose belt but it's probably a vac leak.


-Former 70 & 72 Mustang Owner.
-69 Torino GT, Formal Roof, 351W, Edelbrock 600 cfm, Edelbrock 351W Performer RPM intake, headers, AOD trans, dual flowmasters w/H pipe, Pertronix II Billet, 3.5 TRACLOC g/r, 15" Magnum 500s, 100A alt, aluminum radiator, electric fan, Pro-car seats, mini-starter...owned since Dec 13.
-70 Mach 1, 351W, Edelbrock E-Street EFI, VHX instrument cluster, Hooker headers, dual flowmasters, Pertronix II, 15" Magnum 500s, 150A alt, aluminum radiator, dual electric fans, Pro-car seats, mini-starter
Hi Tom. Did you have your car in this years Knott's show?
Do you have the proper thermostat? 351C DOES NOT EQUAL 351W.

Do you have the 351C Bypass in the motor?

If you are unfamiliar, please search for these 351C bypass and you should find a good starting point with photos and such.

Until you know where you stand on this issue, you are wasting your time.

A properly tuned 351C 4V will not overheat at idle...not even a Boss. However, once you play with the cam, carb, timing, etc., you are on your own.

Regarding sucking sound, do you have vacuum operated hood flaps?

Take pictures, start labeling, disconnecting, plugging. Don't forget labeling.

Also, check air cleaner to carb seal.

[Image: 11jmcuc.png]
351C Bold Manners, Brash Attitude
Favorite Teams: Michigan Wolverines and Whoever Is Playing Ohio State.

When I drive past a herd of cows, the cows MOO at me
Thanks Tubo, Rutkak, Mach71351c, and Wolverine for the replies. I greatly appreciate the help. I will take note on the vacuum leak suggestions and look into that in the coming week. As far as the overheating goes, I will take into consideration the new radiator route and look into those options. As far as the other suggestions as far as cleaning, and flushing out everything, I personally like that option and will look into that first and see how it goes. Along with the new parts that were suggested...Fortunately for me I have a couple of things going for me; 1.) I live right next to an NPD warehouse, so anytime I need parts, they are open for me and NO SHIPPING needed. Smile 2.) One of the sponsors I was able to get for my car, is Gates Corporation, so most of the hoses and pieces I need will be free Smile 3.) The Mach itself has always been a CA car and the shape of everything, including the engine, is in really great shape for original. (I'm still going to follow everything you guys suggested but just saying, thank God it's overall shape is way above par)

*Mach71351c - I was indeed at the Knott's show this year, and so was the car (in the show). Were you there? It was a great first experience and I was able to meet and take a picture with Henry Ford the III, so that was awesome. I'll post some more car pic's in a few.

Recently added louvers to the back. (These are from NPD) turned out pretty good. We used a vinyl piece for the bottom part of window because of the fact you can't have a louver due to trunk being able to open.

A picture from my most recent car show (Woodland Hills, CA. hosted my the LA PD) ...I had to find a way to compete with some of these other cars who have owners with great financial means. So I was able to get several big name sponsors to cover parts I was in need of. In exchange, I came up with designing a magnetic sign, with the number "72" (year of my car) and I placed the advertising decals on it. This way it isn't permanent and I can take it right off if I am not doing a show. It's a win, win.

Engine Pic...If you look closely at the lower right part of the picture, you will see part of a silver, long, canister. That is one of the few changes I've made which turned out awesome, especially seeing it through the grill with the hood down. It's my coolant reservoir tank!

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...And as far as the hood flaps, no I do not have them on the car yet, that's something I am still working on getting. So it's just the cowl hood with the open slots. The pic above will kinda show that.
when you changed to the radiator reserve did you switch the original rad cap to a vented cap. It won't mean much as far as overheating, but lots of people forget to change the cap.

if you want to stay original you can have the rad boiled and recored or you can get a repop rad with a 3 row core the will look original.

your cooling system might just be clogged up a little and you could try a back flush to try and get sediments out.
72H i was noticing the chrome overflow also...if you change out the 13 psi rad cap wouldnt it increase the water temp? Also it looks like the original riveted fan. my car had the original riveted fan which i believe was a 4 blade and had a history of not staying riveted! Don at OMS might know something about this? i swapped it out for a 6 blade flat black steel fan that is readily available and fits in the shroud like a glove. looks completely original and i believe it went a long way to resolving overheating problems i had when i first got my car.
Water Wetter = snake oil.

It may mask an underlying problem, but it will not fix it.

Pete - MotoArts Decals and Signs
'71 Sportsroof 351C-4V/4-speed - FINALLY under construction - no, wait, on hold again...
'90 Mustang 7-Up 5.0 ragtop, rolling beater
'66 Sunbeam Tiger Mk.IA, survivor
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