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  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech

Intake heater hose fitting size

  • Thread starter Thread starter C0V3R
  • Start date Start date May 21, 2009
C

C0V3R

Member
Feb 14, 2003
524
0
16
Australia
May 21, 2009
#1
  • May 21, 2009
  • #1
I'm looking at making up some braided heater hoses for themustang - does anyone know what thread size the intake manifold heater host fitting is?

Thanks!
 

dbfarr

Member
Sep 17, 2005
191
0
17
Boise ID
May 22, 2009
#2
  • May 22, 2009
  • #2
Heater elbow

11/16 for the elbow deal, but my performer rpm intake required a bushing as well.

Water in elbow, 64 - 73 289 Water In Elbow Silve Mustang

The bushing is probably 13/16 or 7/8, not sure, let me know how to measure and I'll confirm.

My question is, can I ditch the elbow? Don't wanna buy another, would rather just plumb directly to the intake.
 

Tim65GT

Active Member
Feb 24, 2004
1,149
2
39
West Texas
May 22, 2009
#3
  • May 22, 2009
  • #3
I'm pretty sure it's 1/2" NPT

You would probably want something like one of these adapters.

View attachment 257001


View attachment 257002
 

CraigMBA

New Member
Mar 24, 2007
783
1
0
Orange, CA
May 22, 2009
#4
  • May 22, 2009
  • #4
You cannot just ditch the stock elbow. It has a restrictor inside of it and will nuke a heater core with a single pass over 3000 RPMs.

Somebody ask me how I know this.
 
D

D.Hearne

New Member
Sep 29, 2000
11,730
6
0
south louisiana
May 22, 2009
#5
  • May 22, 2009
  • #5
The heater hose bung on all intakes are either 1/2"NPT or 3/8"NPT.
 
C

C0V3R

Member
Feb 14, 2003
524
0
16
Australia
May 22, 2009
#6
  • May 22, 2009
  • #6
Thanks guys. Craig, When I took mine off aaaaaaaaaages ago (since binned hence asking the question) it seemed to be just a rightangled pipe with thread.

Do you know how big the restrictor is? If its not too big I might just run -8 instead of -10 line
 
C

C0V3R

Member
Feb 14, 2003
524
0
16
Australia
May 22, 2009
#7
  • May 22, 2009
  • #7
dbfarr said:
11/16 for the elbow deal, but my performer rpm intake required a bushing as well.

Water in elbow, 64 - 73 289 Water In Elbow Silve Mustang

The bushing is probably 13/16 or 7/8, not sure, let me know how to measure and I'll confirm.

My question is, can I ditch the elbow? Don't wanna buy another, would rather just plumb directly to the intake.
Click to expand...

FYI I currently have 2 temp sensors in my intake - 1 in the correct space and one in the heater hole. The other water pump line is just blocked off.

I have been running this setup for 2+ years with no problems at all.
 

dbfarr

Member
Sep 17, 2005
191
0
17
Boise ID
May 24, 2009
#8
  • May 24, 2009
  • #8
CraigMBA said:
You cannot just ditch the stock elbow. It has a restrictor inside of it and will nuke a heater core with a single pass over 3000 RPMs.

Somebody ask me how I know this.
Click to expand...

What about the later model 5.0 metal tube setups? I've got one of these, just don't wanna chance the o-ring inside of it.

Anyway, they don't seem to have any sort of restriction.
 

BarnStang

Founding Member
Mar 2, 2001
1,260
3
39
Hagerstown, MD
May 24, 2009
#9
  • May 24, 2009
  • #9
THe restriction is the extended tube sticking down in the water stream. I found the thread from the 5.0 forum. Read past the 5.0 tech on the heater core down to the part about the flow restrictor. THere are pictures father down
Mustang

THis will allow you to use a regular AN elbow without bursting the heater core.
Note: this applies to a 5.0 heater core, the early heater core may be diferent. You would need to check the sizes/fitment etc. so you don't send an aluminum slug flying into the heater core!
 
2

2+2GT

10 Year Member
Apr 25, 2009
3,333
10
79
Southeastern Pennsylvania
May 24, 2009
#10
  • May 24, 2009
  • #10
BarnStang said:
THe restriction is the extended tube sticking down in the water stream.
Click to expand...

No, it's not. That tube is a reverse standpipe, its function is to prevent air bubbles entering the heater.

See below for the restriction.

C0V3R said:
Thanks guys. Craig, When I took mine off aaaaaaaaaages ago (since binned hence asking the question) it seemed to be just a rightangled pipe with thread.

Do you know how big the restrictor is? If its not too big I might just run -8 instead of -10 line
Click to expand...

You have to look inside the hose nipple. The steel head that provides the 90° bend on OEM units is only drilled about 3/16" inside the bend, constricting much smaller than the 3/8 tube standpipe and the 5/8 hose connection. I can't say if repro connectors are made properly in this regard. The thermostat water neck with the bypass hose nipple also originally had a steel insert controlling it down to about 1/4". Replacement and repro units commonly have a larger ID, permitting too much coolant to bypass the radiator.

It would be a simple matter to insert a small steel tube to create this restriction.
 
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