Temperature Problems

[Speed Demon]

Took my 66 Mustang out today in 19C degree weather. I'm surprised how much the temp fluctuates in this car. The car has an alloy radiator installed which according to the previous owner is not very old. The radiator also has a 14 inch thermo fan attached to it which operates with a manual switch which I hate.

The car today ran at about 1/4 on the temp gauge on the highway cruising, but with only 10 minutes of cruising in town the temp increased to maximum on the gauge. I have ordered a new 160deg thermostat and will be replacing that hopefully later in the week.

I just replaced all the water in the radiator with coolant mixed at 33% coolant and 67% water. I have also replaced the dash in the car in the last week as it used to have an autometer temp gauge in it and I have put an original 66 Mustang dash in it, all gauges seem to be working normally.

Here's a couple of pics of the temp gauge today. I'm hoping its the thermostat that's causing all the problems and probably the thermofan is a bit on the small side.

[GLENN 70]

Gauge is high too high but did the water boil and pour out the over flow . If it was that hot you would know if it was that hot that's for sure . Go buy a themo gun from super cheap and double check ,they are a handy thing to own .

[cap70]

Do you still have the normal fan ? or does it just have the thermo fan?
if you only have a thermo fan you will need to make sure you turn it on if your speed is below about 80k's
Its to late if your waiting for temp to go high and it means your not concentrating on driving if you have to watch the gauge.
I would get a thermo switch for it asap. the 1's that go in top radiator hose work well ( look a bit ugly tho) and use the manual switch
as a back up.

[boofhead]

If your driving along the highway and the temp is stable (and reasonable position on the gauge) then the radiator is fine. Meaning it is able to cool the engine when sufficient air is passing over the fins. It also shows the thermostat is working fine. Meaning it is opening and allowing water to pass the radiator. The likely issue is the electric fan. So;
1) When running is the fan turning the correct way?  I have seen many fans wired in reverse so check it.
2) Are you running a shroud?  It does make a big difference to the level of effectiveness of the Fan (either electric or mechanical). I suggest you install a full should for your electric fan.
3) The fan does not pull enough CFM. You need a lot of air to be moved so I would upgrade to a better quality fan - check out SPAL as an example of quality fans.

[Speed Demon]

Thanks guys.

Firstly to answer all questions, yes the radiator at cold has about 1/2 an inch clearance. Yes I may have a faulty sender unit. I will check that against the temp of the block maybe tomorrow when I have time. I'm getting a new thermostat in the next few days so i'll change that as soon as it comes in.

Not sure whether the water boiled as I was too concerned getting back on the road so the cool air would cool it down. I've got a thermo gun so where should I point the infra red, at the block?


No I dont have the normal fan just the 14 inch thermo. The thermo fan runs constantly as I always just turn it on when I start the car up. The thermo was actually on when the temp reading was this high. I would like to get a thermo switch for sure as I have one on my Torana, I just dont know if a 14 inch is big enough?

What size thermo do all you guys have? My engine is not really worked as far as I know, it only runs a 2 barrel carby so I shouldn't be seeing temps as high as this.

[shaunp]

Thanks guys.

Firstly to answer all questions, yes the radiator at cold has about 1/2 an inch clearance. Yes I may have a faulty sender unit. I will check that against the temp of the block maybe tomorrow when I have time. I'm getting a new thermostat in the next few days so i'll change that as soon as it comes in.

Not sure whether the water boiled as I was too concerned getting back on the road so the cool air would cool it down. I've got a thermo gun so where should I point the infra red, at the block?


No I dont have the normal fan just the 14 inch thermo. The thermo fan runs constantly as I always just turn it on when I start the car up. The thermo was actually on when the temp reading was this high. I would like to get a thermo switch for sure as I have one on my Torana, I just dont know if a 14 inch is big enough?

What size thermo do all you guys have? My engine is not really worked as far as I know, it only runs a 2 barrel carby so I shouldn't be seeing temps as high as this.

They don't need a thermo they need  shroud and 5 or6 blade factory fan. Make sure the Dash reg is ok.

[boofhead]

I do not know if you read my post above --- any way run a fan that covers the most surface area as possible (16" may fit) and preferable use (or make) a shroud which its 1 inch from the surface of the radiator fins.

[shaunp]

Id make sure it is actually getting hot before I panicked too much, the Gauges are super unreliable. 

[mert]

+1 on using a laser temp sensor or apply a mech gauge to see what is really happening.  "Hot" and "cold" are random marks on a factory gauge and after market sender are notorious for being crap!  I test temp with a point-and-read at the water neck, top of rad, bottom of rad, and at a few spots on the intake (near the heater hose outlet/inlet are good places) and water pump case to get a view of the whole system, not just one spot.

Dump the thermo fan.  The cheap ones most use to "upgrade" and save $ at the same time (interesting how you can do both!)are garbage.   Replace with a stock setup as Shaun notes. 

The PO replaced a stock 15-18" fan (you do not note engine size) with a smaller unit.  It will most likely not move as much air (as free cfm ratings most manufacturers use do not take into account the losses thru the core).   Most independent tests show stock setups work as well, or better than, most thermos. New cars use them as they are cheaper to make and install (china cost plastic and electrics, less installation time on the line!)

Do not use a 160 tstat, go stock 180/190, this will make absolutely no difference to final operating temp. And assuming a "standard" build your engine will prefer it warming up faster (less wear, longer life).

[barnett468]

yes, you definitely have a cooling problem . . run it by a radiator shop or auto repair shop and have them check the temp with the infra red gun that was mentioned right behind the thermostat housing if you donlt have one.

as mentioned, do not run a 160 thermostat, it's too cold if it works, plus it can cause a marginal cooling system to run hot . . run a 180 or 185.

your fan is likely chinees and doesn't flow enough air as was mentioned . . i would not buy a spall unless you are rich . . if you need a fan, buy a used ford taurus one and cut the shroud down to size if you have the narrow 66 type radiator . . if your radiator is wider you can use a contour dual fan or lincoln fan.

i would buy a dcc brand controller for it or at least a soft start box.

you may need a higher amp alternater with one of these but lots of people get by with the stock one.

i would also set the ignition timing to the optimal level but this takes a bit of dloing . . an inaccurate ignition timing can definitely cause an engine to run extremely hot.


 . . . . . . . . . . . . . . . . . . . . . . heres the taurus fan

 . . . . . . . . . . . . . . . .


here's kind of what one will look like cut down . . you can make strap type brackets for it to mount to


.

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[evan]

I'm with Shaun on this one. Mine runs cool in city traffic on 45+ degree days. Running a normal copper 3 core radiator (Natrad?), 3.5" shroud & 6 blade flex fan.

If you do however want to stick with a thermo, I've had a Davies Craig thermo switch kit sitting in a cupboard for years. I bought a thermo but ditched the idea when I realised my alternator wasn't big enough. Davies Craig Part no. 0404

http://www.daviescraig.com.au/Controller___Switches-MECHANICAL_THERMAL_SWITCH_WITH_RELAY__12V___PART_No__0404-details.aspx

Make me an offer if you're interested.

Evan.

[GLENN 70]

I am with barnett468 on this one ,a 180 themostat and a Taurus fan ,they are the best and are two speed . Bench test one and go from low to high speed and its hard to hold that's for sure .  Will be hard to get a used one ,but summit racing sell them or are a copy ,got a few mates that use them and they seem ok . Still check what the real temp is 1st .

[barnett468]

.
yes, the taurus and lincoln fans will suck small pets right off if the sidwalk as you drive by. 

you can get used fans here but shipping will be pricey . . i would not use an aftermarket taurus reproduction fan like the ones summit sells unless someone here has actually tried one and can attest to to it because it might not flow as much . . the low price suggests this to me . . the same flow spal is around $180.00 us but i would also see if you can get a new one from the ford dealer in australia . . a new contour fan was only around $160.00 in the us from a dealer.

http://www.monsterautoparts.com/FORD/taurus/ford_taurus_cooling_fans.htm

[Speed Demon]

Yes I will check what the real temp is first and replace the thermostat. Can I get a thermostat from the local autobarn or supercheap for one of these cars, if so can someone give me a part number?

One of those Taurus fans sounds expensive especially if new. Can someone put a link up for one of these also?

If the thermostat was stuck shut would I be seeing any circulation of water/coolant in the radiator? When I changed from water to coolant/water last week I was seeing flow in the radiator, could this be because there is a bypass of the thermostat?

Sorry if I didnt reply to your post boofhead. I was typing my reply while you replied. I think a 16 inch fan will fit just. The current fan definitely has no shroud so that too could make a big difference.

To Evan hows $50 plus postage for the controller sound mate?

[evan]

To Evan hows $50 plus postage for the controller sound mate?

Make it $40 & you've got a deal! 
Where are you in Melbourne?

Send me a PM & we'll tee something up.

Evan.

[Speed Demon]

Yeah mate in Melbourne, no prob sending you one now.

[SXTY8]

Just a thought...have you checked the 7 volt regulator? An intermittent fault will give that reading at times.
In my experience if the gauge was that far into the hot setting, it would be carrying on like Puffing Billy.
My 390 ran hot in heavy traffic with the stock radiator and fan until I fitted an el cheapo thermo fan.
Since then, no probs.

[Speed Demon]

Hi,

Where exactly is the 7 volt regulator, is that the little box on the back of the dash and how to I check it?

[GLENN 70]

A few mates have got the aftermarket tauras/Lincoln  fan and they have been ok so far . About 6 years ago I went into a Ford dealer USA and they wanted hundreds of dollars for them . The themostat is easy to buy ,just a ford one XR to XC .

[Speed Demon]

Too easy. Should be able to get one from Supercheap then.

Presuming I need to get a thermostat for a windsor and not a cleveland? This part number sound correct? TT2000-192

Any answers to these questions.

One of those Taurus fans sounds expensive especially if new. Just done a postage estimate for a fan from Summit and it was $117 for postage for an $85 thermofan lol.

If the thermostat was stuck shut would I be seeing any circulation of water/coolant in the radiator? When I changed from water to coolant/water last week I was seeing flow in the radiator, could this be because there is a bypass of the thermostat?

[boofhead]

The gauge cluster uses a 5 volt regulator. Most of the gauges would be affected if the regulator was the issue.
I generally change them out for a solid state device but this is a side issue.

If you thermostat was stuck closed then you will get no heat in the radiator (as the water can not pass through without the thermostat allowing it to.  If the thermostat was stuck open (or you did not have one) then water flow would be to high so it would heat up relatively slowly though it would not stabilise and then overheat. The water would cavitate and be unable to cool in the radiator.

[Speed Demon]

The gauge cluster uses a 5 volt regulator. Most of the gauges would be affected if the regulator was the issue.
I generally change them out for a solid state device but this is a side issue.

If you thermostat was stuck closed then you will get no heat in the radiator (as the water can not pass through without the thermostat allowing it to.  If the thermostat was stuck open (or you did not have one) then water flow would be to high so it would heat up relatively slowly though it would not stabilise and then overheat. The water would cavitate and be unable to cool in the radiator.

Hmmm so it sounds like it might not be the thermostat. Never mind I will change it anyway.

I'd imagine a sender unit would be pretty cheap for these, it might be worth changing that too I guess.

[barnett468]

Hmmm so it sounds like it might not be the thermostat. Never mind I will change it anyway.

I'd imagine a sender unit would be pretty cheap for these, it might be worth changing that too I guess.

don't waste your money on a new one, they read inaccurately . . you need a good used one . . the fact that yours starts below the middle and sweeps to hot when idling suggest to me that you have an original sender or one of the older repo correct ones and that it is working properly . . the infra red will help determine this.

what ids the pressure rating on your cap?
.

.

[StephenSLR]

first is never have the water level in your radiator to the top always leave 1/2 " gap for expansion

Better still, get an overflow reservoir and top up fluid via the reservoir not the radiator.

When your radiator pressure gets high it releases fluid into the reservoir and when it cools down it draws back fluid from the reservoir, instead of drawing back air.

When you heat up and keep losing fluid you'll end up with less fluid in the radiator over time.

Corrosion in your radiator occurs at the line where fluid and air meet, when you have an overflow reservoir you will never have air in your radiator; provided you don't let the reservoir run dry.

You may also want to check you have the right radiator cap and that it functions when the pressure gets high enough.

As for thermos, a Davies Craig 16" fan has a larger motor and shroud incorporated into the design; it pulls more cfm than 2x14" Davies Craig fans.

s

[Irish]

Often the best thing to do is look at what is not original. I run a standard radiator, and a standard 4 blade mechanical fan with no shroud. It see's track work, and idles in traffic in Brisbane's summer. Never gets close to hot.