overheating help 1995 gt 5.0

Hi,
Sorry to hear your having issues, it sounds like a failed head gasket, allowing combustion gases to enter the Coolant, overpressurizing, causing the coolant to escape. small bubbles rising, But may be other reasons. Some insight, testing a few things so it can be isolated, will help us to
be certain:

#1) Does overflow occur with a cold motor, do you see the bubbles rising with the cap removed when the engine is started cold?
2) How long does it take to start actually evacuating the coolant.? Instantly after starting, or take some time & just keeps getting hotter, uncontrollably, how much time?
3) Pull the Plugs, do they all appear the same. tan color, any that stand out as different from the rest, whitish or very clean looking in electrode color?
4) Does the motor otherwise run fairly well?
5) Any coolant in your Oil?
5) IF the Coolant erupts within seconds or minutes, pull a plug wire, start the motor, are ther still bubbles in the Coolant? Repeat until you see significantly less or no small bubbles rising..
- John

Hi, I’ll give a proper response once I get Home, about 40min’s. Did anyone recently replace the Heads, if so, sounds like a gasket installed backwards. Have you tried a coolant system flush yet, get any sediment out of there. Can’t hurt to try, either way it’ll help. Post back in a bit-k?
-John

Hi,
Pretty Nasty! The mystery sludge in your coolant passages is inorganic salt, separated and solidified from & within coolant, & possibly “hard” H20. Occurs in non-coolant changed Motors. Coolant containing inorganic salts, nitrites, phosphates and silicates.
Excess minerals accelerate the process. “Hard” water, an example.
High Silicate #’s cost less than running Ethylene Glycol, it lowers boiling points similar, & low temperature protection similar to Ethylene Glycol based Coolant. Cheaper.
Inorganic salts deplete within a couple years. Once depleted, they become slimy, pasty, cause restrictions, blockages.
Like feeding yourself a giant 3lb Triple bacon cheeseburger if you have Heart problems.
Did you try bypassing the heater core? Still together, garden hose,.
The CPU CTS will give false readings if any crud or air cavities exist, same W/Gauge.
Isolate the Cylinder that runs hottest in the Head. Yank each Cyl’s wire, 1, try, replace, 2,try,replace, etc. Bubbles in Coolant concern, should be less, none at all if a leaking Cylinder’s Combustion stops.

No PCV. Blocked off, or in place, disconnected? Plug connected to a bypass?
A chunk of debris may have broken loose & travelled when the Coolant line burst, flow altered, blocking a coolant passage..
The head closer in location to the engine’s thermostat housing is less effectively cooled than the other. Passenger side on 5.0’s.
Any possibility the Cat is clogged on that Cyl bank? Verify two plug wires, or injector wires are not inverted..
The salts breakdown, slime to chunky masses, a pasty-like buildup shown in your Pic’s, that’s what’s inside your motor, now, narrow coolant passages most vulnerable.
Smell Coolant at tailpipes? Sweet smell.
Seen this before, only similars that mimic it are adding large amounts of coolant system “stop leak”, barrier at a leak, & wherever else it travels, any coolant lines..
You may be dealing with both..
Since the motor had run very hot, change the Oil/Filter, high temp properties break oil down. Just an FYI, keep in mind...
So, I’d first try these, pull the plugs:
1) Verify whether Head gasket(s) has a Cylinder to Coolant passage leak by performing:
A) Cylinder Compression Check & leakdown tests OK, look in radiator for slow bubbling..
B) A Coolant System Pressure test. Spark Plugs removed from Block. 15psi is fine. Can rent, or borrow.
2) Drain all Coolant from the Block, drop the Radiator hose & dump into a clean bucket. & Measure amount, check Spec’s Exact capacity. Fill the Block with H20, see if the coolant system takes the exact amount
Acquire a Hydrocarbons reader & Check Coolant for Combustion Gases.
Of no findings, or any- post them.
I’ll help you, as will others.
If bubbles in coolant persist, next is Intake, Head gaskets.
A few good coolant flushes.
Pull the Intake off & view the condition of the passages (Borrow/Buy a small tipped Borescopes for best views).

Just Heads up, next.
-If the Intake came from the same motor as the one pictured, Remove the buildup and spray out the passages with compressed air, pull the steam plugs out of the Block & flush it through (Plastic in the valley with rags laid atop, flat). Keep Other clean rags close.. Don’t want any getting into the valley, Oil.


-Run a high-quality coolant using organic-acid technology; “OATs”. This coolant type eliminates inorganic Salt issues due to their composition, eliminating corrosion, formulations May be used in many different app’s, and adding dissimilar coolant types if low(Use after doing tests, pulling Intake & viewing inside crossovers.
Work on that after this-k?
Good luck!
-John

Hi,

-Any new Codes when since you reset the last ones?
Well, using the same motor may have the same deposits, you flushed it, hopefully ran good Glycol Coolant, will eat away at what’s still in the Block. Is the Heater core clear- (garden hose), or temporarily bypass it with a lazy loop.
What cylinder(s) was the IR Thermometer aimed at when the IR thermometer showed the very high temp when aimed at the Exh.manifold/Header?
1) A Passage of active Combustion traveling directly to a Coolant passage, not just temp., but pressure, pushing the coolant out of the Cap?.Most Likely a head Gasket, less likely-a warped Head or crack..
2) A blocked passage, vital to engine coolant flow, a passage restricted so intently that restrictions allowing small amounts of coolant to get past become steam- evacuating coolant out by pressure.

3) A very lean condition, clogged fuel injector, etc. so out of time with Valve & spark, have a Fuel Pressure gauge on the fuel rail?

I don’t see a link between the Lower hose popping, aside from the spring which keeps the hose from collapsing getting pushed up into the Pump, stopping the impeller, was the Spring present? it may contribute to issue, pumps may spin outside, impeller may not, some rebuilt ones may fail, OE is the best, & well worth it.
Another more remote possibility is the Pump’s designed to rotate the opposite direction, they are made for relocating, or motors designed for them. I’d bought one once & realized this, wrong number on the Box.
You used a UV dye, similar to an A/C test. Tests, they work well, but each for its own troubleshooting purpose.
Bubbles rising in coolant as you checked suggests the combustion leak, & to rule it out being the Comp test & the leakdown test, and the typical Coolant System Pressure test.
The reason why I’d recommended removing a plug wire, firing it up for several seconds & viewing if bubbles cease, occur less, replacing wire & moving to the next wire, you’ll know when you locate it, quick.

Verified the Thermostat (travels in the correct direction.
Pick the Car up in the front, bringing the Radiator to the highest point in the Coolant system, fire the motor, turn on the Heat to max, max fan., that’ll purge any trapped air, if it exists.
Verify all your wires are correct to the Cam’s firing order, If Cam’s stock, it’s the 86’-95’ 302/351W OE firing order. Rarely, Cam’s may change the firing order, I.e;. non H.O to H.O Cams.
Just some FYI:
Very Important that (1) (Indicating Cylinder #1) on the Distributor Cap faces the rear Distributor center of the block (aftermarket Caps may not have the (1).on the Cap).
If not lined up, the rotor will be out of phase, as the PIP signal from within the Distributor uses the #1 cyl’s ID pulse to keep fuel Injectors timed during the intake stroke, and fires the rest based on the firing order sequence. If incorrect, it can be a loss of power, to downright low performance, Mileage & other issues, just in case you were unaware..Many are not.

Any chance crud ended up in an injector, when the lover Intake was installed, it can clog an injector causing a lean condition.
Lucas fuel additives can remedy this.
Any comments or questions, please feel free to ask!
If you’re having trouble posting the video you mentioned, make it on YouTube & transfer it from there, or there’s a few App’s that convert it to the appropriate file type.
Best of luck!
-John

Hi, No problem!
Usually, it’s the lower Radiator spigot, I’d use a large Dishpan (Plastic tub used in a Sink for washing Dishes). Or, an Auto parts store has low profile drainage Tubs.
Stick a jack under the rear of the Car, lift it slightly when it stops pouring out, careful not to hit the container with the Car.
Container below, Cap off, loosen the clamp enough to rotate, get a nutdriver on it & pop the front lower radiator hose off above it, and let the coolant flow out into the tub.
Keep a few rags around., just in case.
Use a Wet/Dry Vac with the hose precleaned with a Garden Hose & a little dish soap, run the Vacuum until dry & clean the tip, suck coolant out of the Cylinders, where the Cylinders meet the Pistons.
I’d consider pulling both Heads, getting them checked at a reputable shop & cleaning up that side, too.
Remember, the large Coolant slots on the Head Gaskets are supposed to be in the back of the Block, many say “Back”, some do not.
If installed backwards, it could have sparked your issue, or if the head wasn’t flat, I’d just do both, then you know they’re right.
That’s up to you.
Wash the cylinder wall and piston (about 1” up & across, away from the piston to wall direction- no media near the Rings) with solvent on a rag, add a tiny bit of oil around the Pistons, apply a large bead of Petroleum Grease around the piston to wall around the
perimeter, get it in between, taper it out on the piston edge & cylinder, add some light oil to the walls & stuff a rag inside each, you pull it out later & keeps pieces from falling in.
Roll the motor once you vacuum coolant out so no Pistons are at TDC
Then you can clean the pieces off the Block, carefully & using the Vacuum.
Any questions, don’t hesitate!
Good luck!
John