351C over heating

['70MACH1 10]

I have a heating problem with the new motor. It came stock with a 22inch 2 core radiator, which I replaced with a 4 core 24 inch. I have a flowcooler high volume water pump and a new pusher fan with 1400 cfm's. Without the pusher fan it runs with needle pegged. When I turn on the fan it runs about 85% hot. I've had this car 35 years and has always run hot but not this hot. Last night I took it out about 10pm when it was cool outside and still the same thing. The upper hose was really hot and the lower one was just hot. I had taken the the thermostat out and it still hot. I did the pan of boiling water to check and it was fine. It is the one came with the water pump. Should I be looking at a cross flow radiator? As always any help would be greatly appreciated!

[Rsanter 152]

Be sure you are using the correct thermostat as it is different from other engines. Also be sire the brass restrict or disc kiss in the block below the thermostat

 

Bob

[RogerC 136]

http://www.network54.com/Forum/119419/thread/1357483464/351m-400+thermostat+questions--

 

Post about half way down shows the correct one.

[Brian Conway 264]

Over heating is a problem we all have had experience with. You say your gauge reads at the high end. Before adding anymore ' stuff ' to help the cooling I would check the real temperature at the radiator and measure the resistance at the temp. sending unit. You will need a voltmeter and a thermometer. My 428 car at 180 degrees reads about 30 ohm's of resistance. For me this test is a good place to start and others will have a different approach. Brian

Edited July 30, 2014 by Brian Conway

['70MACH1 10]

Great help an advice as usual. I measured the flowcooler stat and the copper part on the bottom was 11/16. I will track down the robert shaw 333 series. Thanks for the tips and the links!

Edited July 30, 2014 by '70MACH1

[stangnet33 88]

Brian made a good one, also do you have access to a temp gun ? I seen one at Costco for $22. Would be easy to confirm if it's really that hot.

[Unkleen 11]

If a new engine rebuild, have you confirmed the head gaskets are not backwards on 1 or both heads? That will cut off cooling flow through the heads.

[Midlife 814]

It's always wise to check to see if it is truly overheating instead of going just by the gauge. Have you used an infrared sensor ((~$45-$70) to determine the true water temperature? It could be as simple as your sending unit is for a idiot light instead of a gauge.

 

Just trying to make sure you take care of the obvious first...

['70MACH1 10]

I do have a friend with a temp gun and will try that tonight. My machinist put the motor together, so not worried about the gaskets.

[Rsanter 152]

The problem with the cooling on the 351c is that where the temp sensor is if you have the wrong thermostat you will be bypassing cooling through the front of the engine all the time so the temp guard will read cool or normal and be working fine and the rest of the engine can be too hot

 

Check the gauges as specified.

Check that you have the right thermostat and the disc is still in the block.

And then look for other signs that the engine is overheating like boil over and such then use all of that to help determine the problem

 

Bob

[Wycked69 20]

All very good and valid information. Often people have installed the incorrect thermostat and have this over heating issue in the 351C.

 

Best advise (as previously indicated) is to check with an temp gun to see if in fact you have higher temps than normal. Overheating (and assumed over heating) can be caused by a number of things. Lets not forget these temp gauges are not the most accurate either.

 

Being a 351C fanatic for a number of years, I struggled with learning what was the correct thermostat and found the attached information regarding Thermostats.

 

I would advise whether you have an over heating problem or not to make sure you in fact have the correct thermostat if you do not know.

 

>The first photo below is the incorrect thermostat and is one typically found in a 351W

>The second photo is the correct thermostat

>The third photo is a comparison of the two

>The fourth photo is of the restrictor plate in the engine block

Edited August 1, 2014 by Wycked69

[Wycked69 20]

I forgot to mention that although there was a period of time you could not get the "Flowcooler" thermostat, I have been getting them lately from Mustangs Unlimited.

 

http://www.mustangsunlimited.com/itemdy00.asp?T1=FK333+01

 

You can also find them at Summit Racing.

[Chris'69Mach 23]

I do not believe you have the correct cfm volume fan. I think that the 1400 cfm range is for the straight six. I just added a 3000 cfm puller fan to my 20" radiator and it cooled it down, but not enough for my liking. I have the stant 180* stat too on my 351C. I did notice that I have some oil seepage at the head gaskets. So I have on order a new set of amx bolts and gaskets for the intake, exhaust and heads. That should cool it down to where I would prefer it to be. I have either blown head gaskets or the tool that owned it before me did not replace the bolts with new.

['70MACH1 10]

I have the correct thermostat and it works. I think the problem is the 11.5-1 compression. My old book says that it came with 11.495-1 according to De Tomaso Internet community forum it really only had 10-1. I just wanted the stock compression and I was going to run octane booster. The car runs fine on the freeway but not at all around town.. Any thoughts?

 

http://pantera.infopop.cc/eve/forums/a/tpc/f/5650045562/m/319104265

[Rsanter 152]

If a car runs cool when moving faster but heats up moving slower or not moving them the problem generally is the lack or good flow through the radiator.

Do you have a fan shroud?

It could also mean your radiator is too small or partly plugged

 

Bob

['70MACH1 10]

Yes Bob it has a fan shroud and a fresh radiator.

['70MACH1 10]

Is any one else running that much compression on a 351C? If so how are you cooling it?

[Wycked69 20]

Is any one else running that much compression on a 351C? If so how are you cooling it?

 

I have a 351C in my 68 Fastback. It has a 10.8:1 Compression ratio. I have a standard factory big block radiator, stock fan and fan shroud, stock water pump and I have no overheating issue at all.

 

I may be wrong but I highly doubt your motor has a 11.5:1 Compression ratio. Your pushing the upper limit of being able to run pump gas with that kind of C/R. Octane boost will do nothing for your octane rating. That stuff is B/S and they should be ashamed of leading people to believe it "boosts" their octane rating.

 

It could be that you initial timing is set high or the location of your fan in the fan shroud. To much clearance between the fan blade and shroud and the shroud serves almost no purpose.

 

Post some photos of you fan blade and shroud set up.

 

Did you use the temp gun to find the hot spots when the temp rises ?

[moneypit1 10]

Have a 351C with closed chamber head engine always ran hot no matter what I did changed out thermostat several times, screwed around with temp gun and then spent a ton of time on the internet researching.

Year later bent a valve so pulled engine out repaired valve and installed water pump without the by pass, Summit Racing part # WND-8209 pretty pricey $155.95. Problem solved I live in southern Nevada day temps around 112 in summer and it does not overheat at all runs right in the middle of gauge hottest day. From my research on the internet I also found that with out the by pass you can run the thermostate without the skirts or the 351m/400.

[LoneWolf2U 136]

Is any one else running that much compression on a 351C? If so how are you cooling it?

 

Yes, my old school build is right at 11.35-1 and running a 24 inch stock rad,clutch fan and shroud. I did add a few plates to direct the air flow to and thru the rad and it helped to lower the temps and control flow.

as said timing is everything, check yours as it is a free fix, then look for other problem areas.

[69cat&stang 10]

sorry to hijack the original post but i have to disagree with Wycked69. I found that the Lucas octane boost does work. we have to use it in my sons cougar which has a 351 Windsor we add it to a good premium gas, which here is the Shell v-power ( 91 octane with no ethanol in it here in Canada) to keep it from spark knocking. if we don't use the boost it runs on after turning it off and it seems to run hotter along with the spark knock. the car has been professional tuned so i know that 's not causing the spark knock, it went away after we started using it. to each his own, i feel it does work, some don't but the Lucas does make a difference.

 

Lots of good info here to help you out. good luck with your 351C. i've got one in my stang and i'm running a 160* thermo ,stock pump and a four row rad/shroud with a flex fan with no issues. i did add a pusher to the front just in case but hardly ever turn it on

['70MACH1 10]

Wycked 69 it does have 11.5-1 compression and only has 100 miles on the motor. As far as the octane booster goes only one works NOS. It has a flow kooler high volume water pump. Mach 1 Rider do you have any pic's of the plates you put on?

[jandj1970 13]

70MACH1 are they pictures of your cooling setup ? If so shouldn't the fan sit closer to the radiator as well as sitting in shrould more ? Someone mentioned timmimg check that ( also check your not a tooth out when the dizzy was set back in ) , how are the plugs its not leaning out is it.

Or maybe go to a clutch fan setup, my dad ran one on his 289 solid cam motor. the fan came off may Cleveland and it kept his engine cooler.

http://www.summitracing.com/int/parts/flx-5237/overview/make/ford

 

Also is it a stock bore size, or is it 30 thou over ?

['70MACH1 10]

The bore is 4.044 over. The fan is about 2 inches from the radiator and it's seems to be a short shroud. The clutch fan and 6 blade fan from summit might be a better choice, than the stock 5 blade fan. The plugs pic isn't very clear but their pretty red in color. I'm assuming because of the octane booster.

[jandj1970 13]

70MACH1 , I have just had a look at my dads fastback, he runs factory shroud and 5 blade fixed fan. And his fan is halfway into shroud mate.

Also heres a link from mustang monthly theres a picture with fixed fan.

http://www.mustangandfords.com/how-to/engine/mump-1109-how-to-troubleshoot-engine-overheating/?cx_navSource=related-bottom