Overheating 347, any help appreciated

3

347 Pony

New Member

Jan 14, 2008

36

0

0

Sterling, VA

Jan 14, 2008

#1

• Jan 14, 2008

• #1

I have a 91 GT with a 347, aluminum GT40 heads, Trick Flow intake, 4 core Northern aluminum radiator, dual black magic fans, 180* thermostat, stock water pump. The car runs fine and stays right at 180* unless I romp on it a few times, then it starts to overheat. Someone told me the stock water pump might not be flowing enough for the big aluminum radiator, could this be the case. Someone also told me I have a blown head gasket, if that were true wouldn't it be overheating just sitting and idleing, or under normal driving conditions? Any help anyone can give me on this would be great thanks.

 

Grn92LX

Fidanza Man!

Founding Member

Jan 14, 2001

6,819

64

129

New York

Jan 14, 2008

#2

• Jan 14, 2008

• #2

It could possibly be your electric fan is too weak for the 347. I run a pep boys 3 core radiator, autozone stock replacement pump, 180* mr gasket thermostat and a sn95 electric fan and it cools my 11:1 347 just fine.

A blown head gasket won't make the car over heat necessarily.

 

3

347 Pony

New Member

Jan 14, 2008

36

0

0

Sterling, VA

Jan 14, 2008

#3

• Jan 14, 2008

• #3

Thanks, I am thinking about going with the single 18 inch black magic instead of the duals.

 

Juiced88Coupe

Founding Member

Aug 1, 2001

367

0

0

Austin, Texas

Jan 14, 2008

#4

• Jan 14, 2008

• #4

347 Pony said:

Thanks, I am thinking about going with the single 18 inch black magic instead of the duals.

Click to expand...

Why dont you use a OEM fan, and get rid of that black magic junk?

 

3

347 Pony

New Member

Jan 14, 2008

36

0

0

Sterling, VA

Jan 14, 2008

#5

• Jan 14, 2008

• #5

Speed shop recomended the black magic, dosn't rob any power from the engine via clutch

 

3

347 Pony

New Member

Jan 14, 2008

36

0

0

Sterling, VA

Jan 14, 2008

#6

• Jan 14, 2008

• #6

It wouldn't be the fans if I am thinking correctly because the car doesn't run hot at idle or while under normal driving conditions.

 

5spd GT

"the 5.0 owns all"

Founding Member

Aug 7, 2002

9,516

6

99

Arkansas

Jan 14, 2008

#7

• Jan 14, 2008

• #7

OEM fan set-up hurts horsepower, if that is what you are after.

A Black Magic fan does not take up enough radiator area in my opinion to effectively draw heat out of it.

As for the overheating, sounds like a lack of flow or capacity is the issue.

I used to have a very similar issue, but mine was solved when I added a h/c/i package.

New radiator and new headgaskets were a part of that.

 

Juiced88Coupe

Founding Member

Aug 1, 2001

367

0

0

Austin, Texas

Jan 14, 2008

#8

• Jan 14, 2008

• #8

5spd GT said:

OEM fan set-up hurts horsepower, if that is what you are after.

A Black Magic fan does not take up enough radiator area in my opinion to effectively draw heat out of it.

As for the overheating, sounds like a lack of flow or capacity is the issue.

I used to have a very similar issue, but mine was solved when I added a h/c/i package.

New radiator and new headgaskets were a part of that.

Click to expand...

I should have been more clear I guess, use a OEM electric fan, Taurus, MK VIII, ect.

 

U

UnderdogGN

New Member

May 7, 2006

74

0

0

Jan 14, 2008

#9

• Jan 14, 2008

• #9

I had a black magic fan on my car for a while. If you beat on it or it got heat soaked, it would run very hot. I switched to a taurus fan, now it never gets even close to where it used to be. Just a thought. Good luck.

 

5spd GT

"the 5.0 owns all"

Founding Member

Aug 7, 2002

9,516

6

99

Arkansas

Jan 14, 2008

#10

• Jan 14, 2008

• #10

Juiced88Coupe said:

I should have been more clear I guess, use a OEM electric fan, Taurus, MK VIII, ect.

Click to expand...

I agree

http://www.dccontrol.com/

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

33

129

Jan 14, 2008

#11

• Jan 14, 2008

• #11

By overheat, you mean it's boiling over? What temps do you actually see?

 

PUNISHER RACING

Active Member

Aug 27, 2007

1,124

0

36

FORD CITY, PA.

Jan 15, 2008

#12

• Jan 15, 2008

• #12

I know this might sound stupid but is the water pump turning the right way, CCW I only say this because I have seen it happen!

 

3

347 Pony

New Member

Jan 14, 2008

36

0

0

Sterling, VA

Jan 15, 2008

#13

• Jan 15, 2008

• #13

I have seen it happen too, it is spinning the right way, normal operation it runs right at 180 - 190, if I jump on it it gets up close to 225 - 230

 

PUNISHER RACING

Active Member

Aug 27, 2007

1,124

0

36

FORD CITY, PA.

Jan 15, 2008

#14

• Jan 15, 2008

• #14

Sounds like you are pushing water through the rad too fast, maybe try a smaller crank pulley. Did you ever have a LM1 on the car before you might be real lean also. Its not the old flipped head gasket issue is it?

 

8

86bluecobra

Advanced Member

Dec 20, 2004

4,265

12

69

B.C. Canada

Jan 15, 2008

#15

• Jan 15, 2008

• #15

Another thing it could be is not pushing enough coolant through the rad. Do you have new rad hoses? Is it possible one is collapsing on you and restriting the flow?

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

33

129

Jan 15, 2008

#16

• Jan 15, 2008

• #16

You cant push water through the coil too quickly - it's a closed system with impediments that restrict flow naturally.

As David mentioned, you very well might not have enough heat rejection ability. The radiator does ok at idle and cruise but when you get on it, it cannot reject the additional heat-per-time that's created.

The last quick variable is to ensure that the air dam is present (if you doubt your fan, to have a valid test, you have to romp on it and then keep cruising at 50 mph to see if temps come back down. There needs to be air flow through the coil and the air dam is very important in this regard).

 

D

DonMaximo

Member

Sep 25, 2003

217

5

19

Lewisville, Texas

Jan 15, 2008

#17

• Jan 15, 2008

• #17

This was my thought. Cheap/Used hoses collapsing under higher RPMs will restrict the flow...once you left off throttle, hose will return to normal dimension as will your temperature.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

33

129

Jan 15, 2008

#18

• Jan 15, 2008

• #18

Do you guys not have a spring in your lower radiator hose (it's the one that can collapse, though it's not real common on 5.0's)? Since springs are OEM I thought that was a given..............

 

8

86bluecobra

Advanced Member

Dec 20, 2004

4,265

12

69

B.C. Canada

Jan 15, 2008

#19

• Jan 15, 2008

• #19

HISSIN50 said:

Do you guys not have a spring in your lower radiator hose (it's the one that can collapse, though it's not real common on 5.0's)? Since springs are OEM I thought that was a given..............

Click to expand...

True Hisson but like any part if it is old perhaps it has broken somehow. i know its not common but its always those things that seem to bite me in the butt.

 

3

347 Pony

New Member

Jan 14, 2008

36

0

0

Sterling, VA

Jan 16, 2008

#20

• Jan 16, 2008

• #20

The upper hose was real firm when the thermostat should of been open, I was at a red light light last night and it shot up to 240*, I pulled over let it cool down, took it to a buddies shop. We pulled out the thermostat and now its running fine, very cool with no thermostat but it was also 25* here last night. I think I will slap a Mr gasket 160* thermostat in it and let it ride. Maybe the old 180* was just stuck? No signs of oil in the coolant or vice versa though so I guess thats a good sign.