Overheating and Spewing Coolant

[teal5oh]

So guys, could really use some assistance on figuring out what exactly is wrong with my car. Last Monday the car overheated randomly and coolant started spewing from the overflow tank right after I shut the car off. I've already replaced the thermostat, water pump, and overflow tank cap. This was all done on Saturday, and the car ran great, until today. So now, I have no clue what else there is to replace besides the radiator itself. It started acting up again today after I had left home to travel about 15 miles away. The car drove fine all the way there, and then as soon as I shut the car off, I heard the same spewing noise and saw smoke coming from the hood. So I raised it and saw the coolant spewing out of the overflow tank reservoir again. I waited about 2 hours for it to cool down, and I filled the tank with 5 32 oz sized cups of water so I could get home. On the way home, I tried to keep the engine as cool as possible so I avoided any acceleration above 2000 rpms. The car didn't overheat on the way home, and then when I arrived I opened up the hood to hear the same spewing noise, but only minor coolant leaking occurred. Now, the radiator hose is really tense, like it has a lot of back pressure. Wouldn't this mean that the coolant isn't flowing through the system properly? Please feel free to ask any questions if I made something unclear. Thanks in advance guys!

 

[davidglanza]

Sounds like head gasket is gone..

 

[teal5oh]

Sounds like head gasket is gone..

well crap.

 

[98snakehorse]

Possible head gasket or your overflow cap isn't sealing correctly

 

[ReplicaR]

You can test for blow head gaskets with a special tool. I'd recommend getting the tool. Look into something called Block Tester.

 

[ReplicaR]

Possible head gasket or your overflow cap isn't sealing correctly

The overflow is not supposed to seal anything at all. In the cooling system like the pushrod mustang, the pressure is generated by the radiator cap. Overflow tank is actually vented on top of being loosely capped off.

 

[g36 monkey]

you aren't noticing leaks anywhere else??

 

[teal5oh]

you aren't noticing leaks anywhere else??

Nope

 

[teal5oh]

There's no coolant and oil mixing at all like there would be with a head gasket. Also no white smoke out of the exhaust. The overflow tank starts overflowing first, and then the radiator cap starts to overflow as well. The radiator coils also start to steam or smoke. This same problem happened 6 months ago and we replaced the water pump and the problem was solved until now.

 

[1Fine99]

I've already replaced the thermostat, water pump, and overflow tank cap. This was all done on Saturday, and the car ran great, until today.

What kind of thermostat did you install? Is there any crud/debris in the bottom of the overflow tank? I don't think it would hurt to pull the radiator and flush it out (if you didn't already when you installed the new water pump). Refill the system and burp out as much air as possible.

 

[teal5oh]

What kind of thermostat did you install? Is there any crud/debris in the bottom of the overflow tank? I don't think it would hurt to pull the radiator and flush it out (if you didn't already when you installed the new water pump). Refill the system and burp out as much air as possible.

Just an autozone thermostat. Same one that we had in there before and it worked for quite some time. The car is now at a shop and it's going to be checked to see if a head gasket is the problem. Thanks for your help guys, I'll be sure to keep you updated.

 

[1Fine99]

Just an autozone thermostat. Same one that we had in there before and it worked for quite some time. The car is now at a shop and it's going to be checked to see if a head gasket is the problem. Thanks for your help guys, I'll be sure to keep you updated.

Since you said there was no oil in the coolant hopefully it turns out not to be a head gasket issue. If the head gaskets are OK it couldn't hurt to flush out the rad and overflow bottle and toss in a new Motorcraft thermostat and rad. cap. Good luck!

 

[AzzLyp]

Auto zone t-stats are junk compared to the oem t-stats. They're much smaller in the middle. That's most likely not the issue though. One thing to check, probably too late now though since the shop has it, is hot/cold spots on the radiator. I had a problem with my engine overheating and it turned out to be a bad cap and air in the system. I put the car on jack stands in the front, bled the system and replaced the cap, no more problems.

 

[98snakehorse]

The overflow is not supposed to seal anything at all. In the cooling system like the pushrod mustang, the pressure is generated by the radiator cap. Overflow tank is actually vented on top of being loosely capped off.

Good point:waytogo: Hopefully the op get her figured out.

 

[teal5oh]

Got news back today and.... it's not the head gasket! So that's good news. The entire cooling system is going to get completely flushed tomorrow and refilled, so hopefully it'll all work out then!

 

[RichV]

Head gasket issues are sometimes hard to diagnose because it could be a fine crack or split. If the HG fails in the right spot, it will just over pressure the cooling system, cause the coolant to puke out the overflow, then overheats because you are low on coolant. Does your gauge show normal temp when the coolant is puking out the overflow? Then you have a pressure problem. If the gauge reads high, then it pukes, it's a temperature problem. I assume your fan works as they should?

Also, cheesy as it seems, smell the radiator cap from the spring side. If it smells like exhaust, could be the HG. They also have a test kit that measures exhaust gasses in the cooling system to help diagnose.

 

[hotmustang95]

I'm guessing your fan is malfunctioning because the electrical plug to it is making false contact. Next time it overheats stop and check the fan. Carefully touch the plug wire and see what the fan does. If it starts and stops that's your issue. Happens often with our cars. Lots of amps going through that plug creating heat plus the heat of the engine bay starts to melt and soften the plug allowing the metal pins inside to move around.

 

[brelon]

I had the same problem, and it turned out to be a burned ground pin in the cooling fan plug. I replaced the radiator, thermostat, water pump, ccrm, and temp sensor. Every time I popped the hood the fan was running, but it would randomly overheat. No coolant in oil or oil in coolant. It sucked to say the least...


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[teal5oh]

It ended up being a wiring problem. The wires that were supposed to tell the fan to kick on were all burned together so the fan wasn't kicking on properly. It's all fixed now though, thank you all for your help!

 

[Witzy0070]

I love it when a thread comes together.