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Nyhm 05-17-2012 03:41 PM

Coolant Overflow 05 V6
Hello guys/gals, brand new to this forum and hoping to find an answer to my problem because it is seriously starting to irritate me a lot. Occasionally when I take drives that last about an hour or so my coolant in the tank will literally overflow out of the cap which is tightened securely causing a pool of antifreeze to form under my car. I replaced the thermostat about a month ago thinking that might be the problem but it happened to me again yesterday afternoon. Some people have told me I have a blown head gasket but there is no sign of that and the engine runs fine and never overheats. I'm trying to solve this as soon as I can mainly because of the pets in my neighborhood, I don't want any of them to drink this under my car and die. Any advice?

JimC 05-17-2012 10:45 PM

A blown head gasket will cause exactly what you describe. It was the only sign I had of the problem. The car never overheated according to the gauge, but would blow coolant out of the cap.

It was under warranty (so a long time ago) - and since Ford was paying for the replacement I'm sure that is what the problem was. Never came back after they replaced the head gasket and I now have 202,500 on the car.

Nyhm 05-17-2012 11:13 PM

I thought you could hear something extremely coming from the engine plus it doesn't do it every time. If that is the case do you have a rough cost and getting it replaced?

JimC 05-18-2012 08:50 AM

When mine went there was no sound or anything. Just the coolant blowing out of the reservoir.

Can't help you on a price. Mine went while the car was under warranty so I never really saw the bill.

If you can get a look from underneath though you might see some coolant leaking down one of the heads. When it happened on a friends car we had his on a lift, looked up and noticed the coolant at the back of the head on the passenger side. That was the first clue he had an issue. He fixed it himself though so again, can't help you with a cost.

Nyhm 05-18-2012 09:28 AM

So I guess my next question what would've caused it? I don't run it super hard or anything. I was also told that if the head gasket was blown your oil would be contaminated with antifreeze or vise versa

bigblue95z 05-18-2012 10:21 AM

Most of the time you will see oil in coolant or coolant in the oil, but that's not every time.

You should start with a cold start and let the engine get fully up to temp. Then check both sides (before and after the water pump) to be sure it is pushing coolant around. Could be a bad water pump. You can use an infered temp gun to find out. If it drops more than about 10*, you prob have a bad water pump. That way you can rule it out.

Nyhm 05-18-2012 10:32 AM


Originally Posted by bigblue95z (Post 7944113)
Could be a bad water pump.

Have you seen a bad water pump cause this problem before? I just find it weird because it doesn't happen every time and the temperature gauge is never goes above the normal (middle) and it boils out of the cap, nowhere else.

Art161 05-18-2012 12:49 PM

I don't think the stock water temperature gauge is particularly accurate. Mine works its way from full cold to the center of the scale and doesn't go any higher--cold weather on the highway or hot weather in the city makes no difference in the position of the needle. Somehow, I don't think the temperature is really staying the same; it's just that the gauge doesn't show the temperature increase. It makes most drivers happy to see the needle point straight up all the time while driving. The gauge acts pretty much as an "idiot light" from the center on up. By the time the needle would move up, you'd be boiling over big time, not just a little.

bigblue95z 05-18-2012 01:04 PM


Originally Posted by Nyhm (Post 7944123)
Have you seen a bad water pump cause this problem before? I just find it weird because it doesn't happen every time and the temperature gauge is never goes above the normal (middle) and it boils out of the cap, nowhere else.

Yes. You have to think about where the temp sensor is compared to the coolant flow. (and not all cars use the same sensor for the gauge and ECM) It can be boiling in the block pushing coolant/air back to the resevoir, but since the coolant isn't flowing, there is an unequal distribution of coolant temp. Your hot water never feels hot as soon as you turn it on, right? Even though at the other end, it is scalding hot. And I wouldn't put much stock in the OEM temp gauge. Your oil pressure fluctuates all the time with throttle, but do you ever see the gauge move? Get your car up to temp and when it starts to happen, kill it and check the temps throughout the coolant paths you can get to with a temp gun. They shouldn't change more than about 10 degrees. If they do, you have a coolant flow problem. Whether it's a clogged radiator, bad water pump, etc.

Nyhm 05-18-2012 03:00 PM

Maybe I should go get the radiator flushed to see if that will fix my problem for cheaper huh? I'm a college kid so im fairly broke haha, here's a picture of my car too, gotta get the stripes re-done though

tx_zstang 05-19-2012 11:48 AM

Nice looking car!
When you put the t-stat in, did you put it in upside down? Just a thought.

baddog671 05-19-2012 04:03 PM

This may sound too simple but...


Originally Posted by Nyhm (Post 7943361)
literally overflow out of the cap

How about a new cap?

Nyhm 05-20-2012 06:30 PM


Originally Posted by tx_zstang (Post 7945116)
When you put the t-stat in, did you put it in upside down? Just a thought.

I don't think so, I pretty much did a mirror installation also my dad was helping me.


Originally Posted by baddog671 (Post 7945271)
How about a new cap?

Already tried that also

Whatleys 10-03-2012 08:03 PM

What was the fix? Mine is doing the same thing!

drakefamily2 10-04-2012 01:31 PM

I would pull the radiator and have it cleaned at a radiator shop. This is a lot cheaper than paying for a new head gasket. My neighbor had to get head gasket replaced on a pontiac and I think it cost him about $1500.

Shadowtech 10-04-2012 05:26 PM

On my 2006 that i don't have anymore it was the Fan Resistor. Fan wasn't coming on (fan motor was fine but the resistor (big) was broken)

Whatleys 10-05-2012 05:40 AM

Fan seems to come on just fine. Took it to a shop and did a pressure check, not a blown head gasket. The mech couldn't figure it out either.

Hernandezsalvador52 06-12-2014 07:01 PM

I am having the same problem with mine right now I changed the radiator and thermast and still keeps on doing that have you got yours fixed if so what was wrong?

Whatley79 06-13-2014 10:19 AM

Been there
Ok stop with the head gasket. Not saying its 100% not that but it wasn't for me. And lots of others, plus you can do a simple pressure check on the overflow. First go get a cap from ford. I hate going to the dealer but trust me. If that is not the prob. I know this makes no sence but it is what fix the same problem I had, and others. Change the overflow! Not sure if it's the neck that gets warped or the threads but for a $100 bucks or so I never had a problem again. Also run your engine with the cap off until it overflows. This will get any air out that also causes that to happen.

Hernandezsalvador52 06-19-2014 10:07 PM

So I have to buy the new overflow and the cap then I run the car with no cap till the water comes out then when do I add more water????

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