1995 mustang overheating BAD!!

Tw807b

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Feb 17, 2020
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Deltona FL
Ok I’m new here and I’ve never really worked on my own car before I’ve always paid someone to do it. The past couple years I’ve started doing things myself and learning what to do on my car. So here is what i have and the issue I’m running into. 1995 mustang gt original 5.0 engine was replaced with a 1985 mustang gt motor that was rebuilt into a 347 stroker motor. Simple swap I thought I had a mechanic do it that I trusted which has now flaked on me. So for the engine it has 19lb injectors I know small side till I can afford to replace them. The cam I’m running is comp cams 35-324-8. I’ve replaced the thermostat with stock replacement 195 degrees. Replaced maf sensor with stock replacement. 1.7:1 rockers. Also I found out my cats have been removed and are empty. My intake is stock that was on my 1995 mustang gt. No coolant in the oil no gas bubbles in the radiator that I can tell. No black smoke or rotten egg smell from the car. I’ve sprayed carb cleaner on every hose I can find and it doesn’t cause the engine to rev so no vacuum leak I could find. But within about 8 minutes my engine temp goes all the way to H and my headers are glowing red and slight amount of smoke is coming off my passenger side header area. Guys I’m at a lost own what the issue is much less how to fix it and I’m afraid to turn the car on because I feel I might destroy the motor. Please help if you can
 
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VibrantRedGT

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Putting stock stuff on a stroker motor is not good. It's trying to breathe but can't. I bet it's running lean, really lean. Do you have an adjustable fuel regulator on the car or stock? If not get a fuel pressure gauge with a schrader valve. On the fuel rail up front there is a schrader valve (like filling up your tires) where you can add a aftermarket manual gauge. Should be at 34-38psi stock. Stock fuel pump?

This motor is generating a lot of heat being a large motor with stock intake, stock injectors, etc. Tell me you're not running the stock radiator? My stock radiator couldn't keep up with just heads, cam, exhaust on the stock 302. Once I switched to a 3 core aluminum the temps never went over 190 and I live in South Florida where it's 90 degrees every day. The stock thermostat is more like 198, always run a 180 stat and make sure it has a hole in the housing. If not drill a tiny one to reduce air pockets. I bought a Stant 180 stat recently and it had the hold in it already.

Passenger header is glowing red at idle? What color smoke is it? That it really hot, probably burning the coating off the header.

Lot's of variables here, could be anything. It's going to need a radiator anyway so I'd start there. Find a Mishimoto, Fluidyne, C&R 3-core aluminum to replace the this stock garbo and ditch the stock thermostat. Don't know where you live but here in Florida it doesn't get cold so I don't run much coolant, about 80/20 mix (80% distilled water, not from a hose). I also run 2 bottles of Water Wetter.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
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Along with the above advice I would go back and verify everything, do this while you are waiting for the funds to update the cooling system and calibrated maf for 24lb injectors.
Check timing, make sure the distributor is at #1 plug tower on cap at 0* tdc. You can set the timing after you upgrade the maf/injectors.
Make sure the spark plugs are the right ones for engine.
 

Tw807b

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I live in Central FL, and yes the fuel pump is stock fuel rails are stock, radiator is also stock yes. i just bought the 195 stat so can i drill a hole in it and that be ok ? also for both headers are glowing pass and driver, pass side is only one that smokes, i guess color wise is grey/clear like nothing white or black. as for coolant its 100% anti-freeze no water or 50/50. timing is set at 12. spark plugs are stock for standard 302 do i need new ones ?, also forgot to mention it is an automatic trans. ( dont hate me), would this be the radiator i need to get ? https://www.americanmuscle.com/mishimoto-radiator-stabilizer-9495auto.html
 
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VibrantRedGT

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100% coolant? Why? We don't live up North in the freezing cold. Drain all of the radiator and fill with distilled water. Just use coolant in the overflow resevoir. The motor will still have coolant and mix with what is in radiator. Go buy two bottles of Water wetter and throw that in. Don't add Water Wetter to 100% coolant you're throwing money away. The hole in the stat just prevents air bubbles. Maybe that will get you under 210. It will need the 180 stat eventually though, for like $8 with gasket I'd still install it right away.

Do you have a code scanner? I bet you get lean codes. This scanner would also test if the radiator cooling fan is coming on at HIGH. It will test low and high speed. Could be that it's only seeing the low speed. You would get a code for that.

That radiator link you posted is for an Automatic Transmission, if you have an auto that would work. If not the 5-speed is a different part number and always like $10 cheaper (no A/T lines).
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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You're gonna need to invest some time and money learning auto mechanics, here is a place to start so you know how check timing, adjust valves and other stuff.
 

96pushrod

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i used to live where it got cold and just always done that for the coolant, and yes i have code scanner it only pulls code 159 which is MAF it doesn't pull any other codes, and yes auto trans, this is the scanner i have https://www.summitracing.com/parts/...MIpZPwmvPb5wIVi56fCh2rxQ_xEAQYBSABEgInVfD_BwE
Unless you live in the artic circle, you never need to run anywhere close to 100% coolant.

A 347 with a stock intake? I’d honestly call bs on it even Being that.

I can say I’ve never seen a header that glows red hot at idle, maybe your timing is completely fubar’d.

You’ve got a good bit of reading up to do. Checking timing is very easy, so is setting it. There are several guides on how to do so.

As far as the overheating goes - is the electric fan even cutting on? The factory radiator wouldn’t really worry me much with Your power level, assuming it’s not clogged and functioning properly.

I’d check that fan and timing and then report back to us.
 
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Tw807b

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Unless you live in the artic circle, you never need to run anywhere close to 100% coolant.

A 347 with a stock intake? I’d honestly call bs on it even Being that.

I can say I’ve never seen a header that glows red hot at idle, maybe your timing is completely fubar’d.

You’ve got a good bit of reading up to do. Checking timing is very easy, so is setting it. There are several guides on how to do so.

As far as the overheating goes - is the electric fan even cutting on? The factory radiator wouldn’t really worry me much with Your power level, assuming it’s not clogged and functioning properly.

I’d check that fan and timing and then report back to us.
yes its 100% 347 stroker, yes its the stock intake 95 mustang gt came with, the radiator and fan work fine ive flushed the radiator twice an everything flows smooth. when i picked up the car once the engine was installed and drove it home everything was fine no heating issues nothing drove for a few weeks no issues and suddenly one day when i was driving it i noticed it got way hot then it been that way ever since for a couple of months now. this link will take you to the pistons i have https://www.summitracing.com/parts/slp-h273cp30/make/ford
 

Tw807b

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here are some pics below i dont know if it will help at all
 

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Tw807b

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Deltona FL
and a few more the one with just a part of the header is where it smokes, the other is the glowing one driver side but it does on the pass side as well.
 

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VibrantRedGT

"STANGNET'S PENGUIN SMACKER"
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No wonder it's running hot, that header is hotter than sun.

It has no cats so not possible for a clogged cat? It's like the heat is trapped right there.

Normally you see glowing headers under full throttle for a while but this may be the first I've seen glowing at idle.

Why is heat trapped right there is the question? Is there even exhaust coming out of the driver tailpipe? It's almost like the collector is closed and heating is stuck in the header.
 

Tw807b

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No wonder it's running hot, that header is hotter than sun.

It has no cats so not possible for a clogged cat? It's like the heat is trapped right there.

Normally you see glowing headers under full throttle for a while but this may be the first I've seen glowing at idle.

Why is heat trapped right there is the question? Is there even exhaust coming out of the driver tailpipe? It's almost like the collector is closed and heating is stuck in the header.
both sides glow like this, yea no cats they where removed long time ago by my step-dad, exhaust does come out of both tail pipes.
 

96pushrod

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Those headers look like they just got done running the Texas mile.

You must buy a timing light and see where your timing is at. Also, do you have a wideband?
 

96pushrod

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Does it idle at a very high rpm as well? Would indicate a large vacuum leak which could lead to a very lean condition. If your headers are glowing like that in sure those exhaust valves are close to history.
 
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Tw807b

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No idea what a wide band is. And it idle between 1000 and 1500, I’ve only let it get that hot twice haven’t turned it on since, scared of messing something up
 
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96pushrod

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If you google “wideband” it’ll tell you pretty much everything you need to know. Gives you real time afr.

The idle fluctuates between 1000-1500 when warm?

We’re really just shooting in the dark unless we know where timing and fuel are at.
 

KRUISR

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Apr 16, 2015
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A couple other thoughts... could the thermostat be installed backwards?

Have you tried turning the heater on full heat and full fan. Does it blow hot (it should) and does the temp come down at all?

When the car gets hot while running, does the electric fan come on (at all)? Possibly the sensor used to turn on the fan was not connected or has failed.

Just some thoughts.