Engine 95 Gt Fine At Idle Overheats At Speed

Shaker1995

New Member
Mar 7, 2016
2
0
1
24
Hey guys,

Relevant upgrades: TFS aluminum heads and stage 1 cam, recent downsize from my 3rd 3 core aluminum fluidyne radiator to a 1 core O'Reilly (Lifetime Warranty), also a 160* thermostat(down from the initial 180* recommended by the guy I purchased the car from, but having chronic heat issues and a recent head gasket replacement i wanted to play it even safer.)

What all is new (>100 miles): 160* Thermostat, radiator, water pump, coolant hoses, coolant temp sensor, heater tube and heater tube hoses.

I only recently finished an almost full rebuild on my 95 mustang GT with the WC T-5. This was my first rebuild and unfortunately i attempted things in the wrong order, hence almost. I resurfaced the cylinder heads and installed them before taking a look at the crank and I ended up having to have it machined.

So I went through all the work without pulling the pistons having the block machined/checked/fluxed and the cam bearings replaced ( I was told it had around 10k miles on the block when I bought it ~5k ago).

Since the rebuild she has been running well but she has been getting quite hot, the M in normal which my IR thermometer reads as 233*. Yesterday she idled for a solid 10~15 minutes at a significantly lower temp around the R. But as i went to drive home (1-2 miles) she started heating up which was when i was able to get the 233* reading.

What I get from all this is that everything is working fine at idle but under load the cooling system is incapable of getting the job done.

Any and all help greatly appreciated and Happy Fourth of July!
 
  • Sponsors(?)


90sickfox

I didn't really have an issue with the stink...
SN Certified Technician
Mar 2, 2015
5,384
4,413
203
42
Aluminum heads transfer heat to the coolant faster than stock heads. The radiator may be too small. Is all the air out of the system ? Is the fan functioning properly ?
 

a91what

SendMeUrDataLog
Mod Dude
Apr 6, 2011
10,202
6,107
204
31
Hillsborough county
In any efi system the ecu is expecting to see warm engine temps. 160* the Stat is not enough. Period. The fans on your car (assuming the ecu controls them) won't even turn on until 205-210* then they typically shut off around 185*...... your thoughts t-stat doesn't even get a chance to close.
My recommendation is to put a stock thermostat back in the car (it's not carburated.... "most" efi dont even achieve closed loop control until 180*.)
Check and see if the air dam (plastic piece under the radiator core support) is in place it should bend forward slightly, if it's damaged or nonexistent that's a problem as well.
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
33,054
9,313
224
Massachusetts
I agree. Lowest tstat I'd run is 180, and to be honest I'd stick to the stock 192 degree tstat. All a colder thermostat does is cover up a problem, and sometimes it makes things worse. The thermostat could be always open and coolant could potentially flow through the radiator too quickly and not be cooled properly. Modern EFI engines need to run in the 190-200 degree range.

I also agree that a 1 core is probably two small. I'd also check to see if the plastic deflector is mounted to the underside of the radiator support along with the other various plastic deflectors inside the engine bay.
 
Thread starter Similar threads Forum Replies Date
1992 5.Slow GT B303 cam swap on my 92 GT now running rich and falls on its face, idles fine tho. Fox 5.0 Mustang Tech 6
1995COBRA 95 Cobra starts right up and idles fine at first, but then after about 2 minutes, I try and restart and it does not hold an idle. 1994 - 1995 Specific Tech 12
96nickSn95 Runs Fine But Idles Low When In Drive SN95 4.6L Mustang Tech 7
Johhny J Car Idles Fine Then Dies Fox 5.0 Mustang Tech 1
f8tlfiveo Was Idling Fine..... Fox 5.0 Mustang Tech 3
V8_Kind_Of_Guy Car Idles Fine, Give It Gas And Wants To Die Fox 5.0 Mustang Tech 11
M Idle Drops Immediately After Start, Then Fine 1994 - 1995 Specific Tech 6
B 98 Gt Starts Fine Then Shuts Off While Driving/idling SN95 4.6L Mustang Tech 20
B Engine Engine Starts, Idles Fine But When I Push The Peddle It Dies. SN95 4.6L Mustang Tech 4
PlatinumDevil Car wouldn't idle, clunk, running fine... SN95 4.6L Mustang Tech 0
Crs Car starts, idles fine, dies when put in gear. Classic Mustang Specific Tech 3
D 351 idles fine dies when in gear Classic Mustang Specific Tech 4
Methodical Car idles fine until..... see pics inside...help 1994 - 1995 Specific Tech 20
6 5.0 missing at idle, but runs fine otherwise Fox 5.0 Mustang Tech 1
Pokageek Car idles fine but cuts out half the time at a stop. Ideas? 1994 - 1995 Specific Tech 18
mustanggt94 TWEECER NEWBIE HERE! Need help fine tuning: Idle & Bucking problem 1994 - 1995 Specific Tech 11
L HELP: drives fine for 15 min, then wont rev up or idle nicely SN95 4.6L Mustang Tech 3
trlps_ low compression in bank 2, bank 1 is perfectly fine 1996 - 2004 SN95 Mustang -General/Talk- 5
Driver460sz Engine Ran fine, cleaned throttle body, blows sweet white smoke now. Fox 5.0 Mustang Tech 8
G 98GT, runs fine when cold, dies after warm 1996 - 2004 SN95 Mustang -General/Talk- 1
D Electrical foxbody won't start without starter fluid, starts and runs fine for a few days Fox 5.0 Mustang Tech 2
Andresquintana.mma Hard to start runs fine when it turns on Fox 5.0 Mustang Tech 17
W 1989 CFD special edition random stall? Fox 5.0 Mustang Tech 10
J Will 3.73 be fine with Procharger? 2005 - 2014 S-197 Mustang -General/Talk- 0
A 1999 3.8L Head Gasket symptoms but Gasket looks fine SN95 V6 Mustang Tech 1
X 05 mustang 4.0l v6 a/t has no reverse. All other gewrs work fine. 2005 - 2014 S-197 Mustang -General/Talk- 0
hoopty5.0 Update! Lifters are fine, the mechanic is the problem. 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 16
N RMP goes to 2 in Drive, turn car off and back on and it drives fine??? 2010 - 2014 Specific Tech 0
revcor Electrical Horn/cruise Control Don't Work, But Fuse Is Fine? Fox 5.0 Mustang Tech 13
Dirt bike kid Drivetrain Yes I Have A 94 Gt With Manual Trans It Drive Fine And :poo: Into 2 And It Don't Seem Pull No More? Fox 5.0 Mustang Tech 0
C Car Cranks But Wont Start After Maf Sensor Cleaning - Please Help. 1996 - 2004 SN95 Mustang -General/Talk- 0
N No Power At Wot, Revs Fine In Neutral Fox 5.0 Mustang Tech 14
robertdeuce Running Fine, Now Won't Start Fox 5.0 Mustang Tech 3
T What A Fine Mess I've Gotten Myself Into... 1996 - 2004 SN95 Mustang -General/Talk- 1
jonestyler22 1967 Electrical - Turn Signals Don't Flash, Work Fine With Emergency Flashers Classic Mustang Specific Tech 4
1stanger1 Ford Taurus With No Heat And Everything Works Fine.... Other Auto Tech 1
zac101191 Reading Low Fuel Pressure But Car Runs Fine 1996 - 2004 SN95 Mustang -General/Talk- 0
all1knew problems with interior door handle, exterior works fine 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 2
9 1988 GT with MAF Mod (Was Fine). Fox 5.0 Mustang Tech 1
S Fuel 99 Cobra Svt Cranks Fine But Wont Start SN95 4.6L Mustang Tech 7
The_Dude Running Fine One Minute And Wouldn't Start The Next Fox 5.0 Mustang Tech 7
tca7291 90 Gt Starts Fine Then Backfires And Stalls Fox 5.0 Mustang Tech 8
B Car Makes Noise When Turning Key. Starts Fine 2005 - 2014 Specific V6 Tech 7
jcgafford Ran Fine. And Now.... Fox 5.0 Mustang Tech 4
K In gear car revs to 1300rpm fine then after a few seconds start to sputter SN95 V6 Mustang Tech 9
R Can the crank still be fine after wearing through babbitt layer? Fox 5.0 Mustang Tech 15
B Driver side window won't operate but window motor is fine Fox 5.0 Mustang Tech 8
B Driver side window won't operate but window motor is fine 1994 - 1995 Specific Tech 2
S 18x9.5 03 cobra style wheels. cant fine them. anyone ever had rims re plated? 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 5
mustanglover32 Both windows non-op, fuse is fine. Ideas? SN95 V6 Mustang Tech 2
Similar threads