93 mustang possible bad head gasket?

[Bdubbs]

Hey guys,

My new to me car is a bone stock 93 5.0 with 27,500 miles on it.

A little background. The previous owner said he overfilled the overflow tank and some was pouring out of it once the car got up to operating temperature. The following day I decided to open the radiator cap to check the fluid. The engine was completely cold and I had pressure at the cap. Fluid was pouring out. I removed some fluid from both the radiator and overflow tank. I also replaced the radiator cap. This one looks bad.

The car does have a bad original water pump that needs replacement.

Fast forward to today. I normally do my own work, but having a local repair shop next door to my shop check some things over on it for a second opinion. The previous owner definitely used the red coolant for some reason. The whole system is getting a flush with green coolant going back in. Also the repair shop couldn't get the operating temp over 170*. Probably replacing the thermostat as well, maybe it has a 160*?. Also they said the upper radiator hose was hot, but felt like air pockets inside of it. That's when they said, hopefully it's not a head gasket. But I'm wondering if the system has air pockets and possibly a bad t stat.

The plan is to test the coolant and do a compression test. It still might have the original spark plugs as well they look rusty orange just like the cylinder heads.

I haven't driven the car much at all. Starts up fine, and idles perfect.

So how common are bad head gaskets on these cars?

Not sure why my picture quality is bad with my new phone.



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[BlksvtCobra01]

My question is when everything is flushed out, water pump changed. Are you doing hoses as well? Make sure all the air gets out. When I got mine my Fox back in 2003 it overheated. Coolant hadn’t been flushed since 97 and the radiator was gunked with chunky coolant but no oil looking coolant. I changed the radiator, hoses, water pump, and thermostat to a 180. Let it run and it wanted to overheat again. I was pissed. Ended up it had a huge air pocket in it. A good friend of mine shoved a garden hose in the radiator and we got the air pocket out.

Is your oil clean? Any coolant in it?


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[Bdubbs]

My question is when everything is flushed out, water pump changed. Are you doing hoses as well? Make sure all the air gets out. When I got mine my Fox back in 2003 it overheated. Coolant hadn’t been flushed since 97 and the radiator was gunked with chunky coolant but no oil looking coolant. I changed the radiator, hoses, water pump, and thermostat to a 180. Let it run and it wanted to overheat again. I was pissed. Ended up it had a huge air pocket in it. A good friend of mine shoved a garden hose in the radiator and we got the air pocket out.

Is your oil clean? Any coolant in it?


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Yes I already have new motorcraft upper and lower hoses that will be going on along with a stock motorcraft t stat. I bought oil and filter and planned on doing that as well. But since the shop is already working on it, they will be changing it. It looked dirty, but I wasn't really looking for anything else when I checked it.

Now I wish I would have looked things over more before I dropped it off next door.

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[OX1]

I own 2 heavily modified Fox's (my 86 Capri 5.0 since new). I've never blown a head gasket with my Capri, had bolt-ons, then 150 NOS, then turbo kit for 20 odd years, beating the crap out of it the entire time).

Not going to say I've never had an air pocket, but I don't recall these cars being a general PIA about it. I've changed antifreeze for one reason or another at least 30 times since the 80's (on my foxes and many others foxes, as I grew up in that era, was 22 in 86 when it pretty much all started).

 

[BlksvtCobra01]

Yes I already have new motorcraft upper and lower hoses that will be going on along with a stock motorcraft t stat. I bought oil and filter and planned on doing that as well. But since the shop is already working on it, they will be changing it. It looked dirty, but I wasn't really looking for anything else when I checked it.

Now I wish I would have looked things over more before I dropped it off next door.

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Good luck. Keep us posted.


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[Bdubbs]

Good luck. Keep us posted.


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I definitely will.

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[Detroit Iron]

I was one of the unlucky ones to have a head gasket blow on a stock engine. I think it is pretty rare on these cars. I had a 91 coupe back in the day with a bone stock engine and about 60K miles and I had a seeping head gasket leak that was intermittent. One of the most frustrating problems I've had owning a car. I was on the highway one day and the temp gauge went from normal to red in 10 seconds. I pulled over and had coolant bubbling out of the overflow. I let the car cool and it drove fine after that. I changed the thermostat and radiator cap after that it was fine for months until it happened again and then it blew completely. I had milk shake or tell tale signs. The engine was seeping hot gases into the coolant passage thru the bad head gasket.

I doubt you have blown head gasket from what you described. Having pressure in the system after the engine cools off sounds like a bad radiator cap. You're going down the right road with changing the radiator cap, water pump, thermostat and hoses and get all the red coolant out. Stick with the motorcraft stock 192 thermostat, stock engines like these and they don't fail like the parts store brands. You also may want to look at the radiator. Even low mile cars will eventually leak due to corrosion (totally normal for 30 years.). I had my stock radiator recored at a shop after it started leaking. I would rather keep it stock and support a local guy than buy some shiny aluminum Chinese POS.

Keep us posted and don't get frustrated. All these old cars have quirks that need to be worked out.

 

[Bdubbs]

I was one of the unlucky ones to have a head gasket blow on a stock engine. I think it is pretty rare on these cars. I had a 91 coupe back in the day with a bone stock engine and about 60K miles and I had a seeping head gasket leak that was intermittent. One of the most frustrating problems I've had owning a car. I was on the highway one day and the temp gauge went from normal to red in 10 seconds. I pulled over and had coolant bubbling out of the overflow. I let the car cool and it drove fine after that. I changed the thermostat and radiator cap after that it was fine for months until it happened again and then it blew completely. I had milk shake or tell tale signs. The engine was seeping hot gases into the coolant passage thru the bad head gasket.

I doubt you have blown head gasket from what you described. Having pressure in the system after the engine cools off sounds like a bad radiator cap. You're going down the right road with changing the radiator cap, water pump, thermostat and hoses and get all the red coolant out. Stick with the motorcraft stock 192 thermostat, stock engines like these and they don't fail like the parts store brands. You also may want to look at the radiator. Even low mile cars will eventually leak due to corrosion (totally normal for 30 years.). I had my stock radiator recored at a shop after it started leaking. I would rather keep it stock and support a local guy than buy some shiny aluminum Chinese POS.

Keep us posted and don't get frustrated. All these old cars have quirks that need to be worked out.

Thanks for sharing your experiences. I don't seem to have any of the symptoms that you had. I would think with a bad head gasket my engine would be running hot. Can't base it off factory temp gauge. But I believe the shop was using a temp gun or something else.

I'll keep the radiator in mind. Hopefully it's good, I don't want a aftermarket one.

I will definitely keep you all informed. It's driving me crazy waiting for answers.

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[mat50ho]

Typically you can start up the car cold / no pressure on the cooling system with the radiator cap off if a headgasket is bad bubbles will be seen in the coolant. For really small leaks you can use a combustion gas tester for the coolant.

Based on the above it sounds like you have a air bubble in the cooling system do to a leaking water pump.

 

[Bdubbs]

Typically you can start up the car cold / no pressure on the cooling system with the radiator cap off if a headgasket is bad bubbles will be seen in the coolant. For really small leaks you can use a combustion gas tester for the coolant.

Based on the above it sounds like you have a air bubble in the cooling system do to a leaking water pump.

Thanks for the help!

The other day when I was replacing the radiator cap, I left it off with the car running. I didn't notice any major bubbles that would indicate a bad head gasket. I'm assuming bubbles in the radiator indicating a bad head gasket, would look much different than just bubbles indicating air in the system?

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[Bdubbs]

Update:

Good news! No blown head gaskets!

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[mat50ho]

Thanks for the help!

The other day when I was replacing the radiator cap, I left it off with the car running. I didn't notice any major bubbles that would indicate a bad head gasket. I'm assuming bubbles in the radiator indicating a bad head gasket, would look much different than just bubbles indicating air in the system?

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Yes steady bubbles with a bad headgasket. Burps is the best way to say air pockets in the system.

 

[365 Saleen]

Having pressure in the cooling system after the engine cools off is no big deal. I see it all the time on cars at the Dealership I work at. A lot of things can affect this phenomenon. Barometric pressure, humidity, temperature all play a role in how pressure can be built and maintained in a cooling system.

 

[Detroit Iron]

That's good news there is no blown head gasket. Now just do all the other normal things when buying a used car, change all the fluids and filters. And don't forget about the breather under the PCV valve. I had one that was completely gunked up, this will keep the crankcase pressurized and cause leaks. Enjoy the car.

 

[Bdubbs]

That's good news there is no blown head gasket. Now just do all the other normal things when buying a used car, change all the fluids and filters. And don't forget about the breather under the PCV valve. I had one that was completely gunked up, this will keep the crankcase pressurized and cause leaks. Enjoy the car.

Definitely.

I ordered up new plugs, wires and fuel filter. I forgot about the pcv valve and the mesh screen. I'll have to order that up.

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[gimmie11s]

Update:

Good news! No blown head gaskets!

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That is great news, but how do you know? Did they do a leak down and provide results?

Anytime im looking at a car with coolant overflow bottle "issues", or a car that has had all or many of the cooling items replaced (tstat, radiator, water pump, etc etc) i mentally prepare for head gasket/s and begin to go hard from a negotiating perspective.

People lie so much about overheating.

 

[Bdubbs]

That is great news, but how do you know? Did they do a leak down and provide results?

Anytime im looking at a car with coolant overflow bottle "issues", or a car that has had all or many of the cooling items replaced (tstat, radiator, water pump, etc etc) i mentally prepare for head gasket/s and begin to go hard from a negotiating perspective.

People lie so much about overheating.

I already own the car. They did the combustion leak test. Which test the coolant for combustion gases.

There were no symptoms of a blown head gasket. The shop just mentioned those dreaded words.

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[gimmie11s]

Nice...

 

[BlksvtCobra01]

Are you keeping this stock? Or modding it?


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[DoneItDeliberate]

I would do a leak down test on every cylinder and takes notes on leakage for each cylinder. A leak down test will nearly always tell you if you have a problem with a cylinder (blown head gasket, damaged/bent valves, dropped valve seat, piston/ring damage, cracked block). I prefer a leak down test over compression testing, IMO it is a more reliable way to test a cylinder's ability to hold cylinder pressure.

Way back when, I worked for Teague Custom Marine, a top name in the performance marine industry. One of my responsibilities was to test/inspect damaged engines before tearing them down. I was instructed to leak down every engine before I started to tear it down for repair.