Help on normal operating temps on daily driver OEM 5.0

MrPerfect2

5 Year Member

Jul 23, 2019

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Jul 23, 2019

#1

• Jul 23, 2019

• #1

91 GT vert - auto - 327 gears , clean engine with stock fan shroud and stock lower radiator air deflector, new heavy duty fan clutch , new 192 thermostat ( not drilled ) new rad cap , 50/50 blend coolant , stock overflow tank , newer stock size radiator , older water pump - using a mechanical water temp gauge hooked into temp sender intake manifold port . During Ambient air temps around 97 degrees w/ 50% humidity . Car runs about 200-210 in stop and go traffic . Runs 220-225 on highway cruising . Held 185 degrees for 30 minutes today thru traffic - today’s temps are 75 degrees - should be 80 degrees this evening on highway trip home ( will know later how those car temps are ) I heard the cars computer prefers minimum 195 to run best ? Question I have is it unusual and unsafe to be at 225 when outside air is mid 90s with higher humidity ? How come highway cruise is higher temps then city ? Thanks for input

 

Mustang5L5

That is…until I whipped out my Bissell

Mod Dude

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Jul 23, 2019

#2

• Jul 23, 2019

• #2

Modern EFi engines run around 200 degree. Running around 210 is still somewhat normal but I would start keeping an eye on the guage. At 220F, I would be trying to do something about keeping the temps lower.

What's the condition of the radiator? Is it new? Old? Gunk in the fins internally? Bent fins on the radiator itself?

 

MrPerfect2

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Jul 23, 2019

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Jul 23, 2019

#3

• Jul 23, 2019

• #3

Radiator “looks” about 5 years old - fins are not bent - flow is strong when cap off before it got hot - I am going to spray some degreaser on radiator and wash any dirt out of fins this week and try the burping air out parking on incline then .

 

MrPerfect2

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Jul 23, 2019

#4

• Jul 23, 2019

• #4

 

MrPerfect2

5 Year Member

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Jul 24, 2019

#5

• Jul 24, 2019

• #5

It Holds 185 in city and 195-200 on highway in 70 degree weather for 45 min drive - I suppose the 97 degree high humidity drove up the water temps the other day

 

Mustang5L5

That is…until I whipped out my Bissell

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Jul 24, 2019

#6

• Jul 24, 2019

• #6

Could probably improve that a bit though.

My car holds 188* in all conditions.

 

MrPerfect2

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Jul 24, 2019

#7

• Jul 24, 2019

• #7

I am a bit confused on the whole “closed loop” principle - I heard the ECU runs open loop until certain temperature - how does this work ?

 

Mustang5L5

That is…until I whipped out my Bissell

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Jul 24, 2019

#8

• Jul 24, 2019

• #8

MrPerfect2 said:

I am a bit confused on the whole “closed loop” principle - I heard the ECU runs open loop until certain temperature - how does this work ?

Click to expand...

Open loop refers to vehicle warmup where sensors get ignored and the car runs on ECU programming during startup. It tends to run a little richer, which is why the exhaust note tends to seem a bit "fuller" and more appealing.

Close loop occurs at different parameters depending on the vehicle. For the Mustang, around 140-150F or so it will switch over and now rely on sensor inputs to control fuel trims. Some claim it happens at 180F, but I've seen someone break down the coding in the A9x family and it's actually pretty low.

 

MrPerfect2

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Jul 24, 2019

#9

• Jul 24, 2019

• #9

Yeah I heard higher temps close loop - why do people say 180 ? Is it like an on an off switch or a gradual closing of loop ?

 

MrPerfect2

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Jul 26, 2019

#10

• Jul 26, 2019

• #10

I did the burp procedure and added some foam weather stripping to close a gap around edge of fan shroud where it contacts the radiator - there was a 1/2 “ open because my fan shroud mounting - I figure this will force the fan to draw more air through radiator instead of through gap around it

 

Real time recon

Mustang Master

Aug 21, 2016

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Jul 26, 2019

#11

• Jul 26, 2019

• #11

1990 Mustang GT 302/345 holds this temp year round with 30* to 95* outside air temp.Stop & go, red-light, or open road,doesn't matter

 

MrPerfect2

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Jul 26, 2019

#12

• Jul 26, 2019

• #12

Beautiful engine ! It’s like a work of art ! But ,That’s a totally different car though now ..I am guessing you have very few OEM parts . Mine is simply a OEM GT ...

 

Real time recon

Mustang Master

Aug 21, 2016

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Jul 26, 2019

#13

• Jul 26, 2019

• #13

MrPerfect2 said:

Beautiful engine ! It’s like a work of art ! But ,That’s a totally different car though now ..I am guessing you have very few OEM parts . Mine is simply a OEM GT ...

Click to expand...

Thanks.Yeah lots of Ford GT-40 stuff on & in.
Hey ,have you flushed out the colling system ? Also I'm running a 180 degree stat .

 

MrPerfect2

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Jul 26, 2019

#14

• Jul 26, 2019

• #14

I have changed coolant , but not force flushed - when I burped it last night and level dropped when thermostat opened , the flow appeared strong . Cruised in to work steady 182-188 degrees , 30 min drive in traffic . Ambient 70 degrees - keep in mind , I got stock iron heads and 192 thermostat .

 

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Real time recon

Mustang Master

Aug 21, 2016

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Jul 26, 2019

#15

• Jul 26, 2019

• #15

MrPerfect2 said:

I have changed coolant , but not force flushed - when I burped it last night and level dropped when thermostat opened , the flow appeared strong . Cruised in to work steady 182-188 degrees , 30 min drive in traffic . Ambient 70 degrees - keep in mind , I got stock iron heads and 192 thermostat .

Click to expand...

Sounds good 2 me Sometimes these 302s are hard to get ALL the air out after flushing.

 

Last edited: Jul 26, 2019

Mustang5L5

That is…until I whipped out my Bissell

Mod Dude

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Jul 26, 2019

#16

• Jul 26, 2019

• #16

Cruising in the 180s looks good to me. Keep an eye on it

 

Decipha

Active Member

Aug 22, 2007

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Jul 26, 2019

#17

• Jul 26, 2019

• #17

in a perfect world coolant temp should be 212 degrees f for gasoline, slightly hotter for e85

on a stock foxbody ----
if engine coolant temp (ECT) is below 56 deg then it wont go in to closed loop til coolant temp gets up to 136 degrees

if ECT is above 56 and less than 170 at startup then it goes in to closed loop after 100 seconds

if ECT is greater than 170 at startup then it goes in to closed loop after 60 seconds

 

Reactions: FastDriver

MrPerfect2

5 Year Member

Jul 23, 2019

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Jul 27, 2019

#18

• Jul 27, 2019

• #18

I think I just added an extra cooling core , lol - ran heat on low - outside air 90 degrees ( top down convertible so heat all feels same to me ) dropped water temps to 204 cruising in and out of city for 30 min straight

 

Potomus Pete

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Jul 27, 2019

#19

• Jul 27, 2019

• #19

Mine runs the exact same as the stock gauge shown. I always wondered what others had with no #s.

 

Rt jam

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Oct 17, 2015

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Jul 28, 2019

#20

• Jul 28, 2019

• #20

The ECU, closed loop, open loop, has NO control of the cooling system. The thermostat regulates to 192. If it can not, this the problem you are looking for.

MrPerfect2, if you only have high temperatures on the highway. I'd start with a radiator. As they age and have build up on the inside of the cores, they lose their effectiveness to cool the water.