Overheating - Not the regular pattern

[GrolarBear]

In my 2012 Taurus SHO, noting special, mostly stock except for straight pipes, about 105,000miles.

Yesterday I was in traffic and blipped the throttle to get around someone. Suddenly I got a chime on the dash, a warning light shaped like a temp symbol on display and the needle shot up past H on the gauge. I don't know if it was sitting in its normal place just below half before that or if it was high and I didn't notice it.

Within a few seconds, it started dropping and I put the heat full on and it went down to maybe 2/3 up the gauge, the heat out of the vents was MUCH warmer than I ever remember getting. It was about 40*F outside.

With a bit of playing around I and stressing because I was stuck in stop-and-go traffic, usually a disaster when you're overheating, I noticed that it followed the opposite pattern of an overheating car- when I was stopped the gauge started dropping, it almost seemed speed related, the faster I went the higher the temp gauge went. If it wasn't for the fact that the heat was much warmer and you could hear (ticking from parts expanding under the hood) and smell that it was warmer than normal and the fan was running on high the whole ride back I would have initially guessed that it was a problem with the gauge.

I tried reproducing it today and I couldn't. I drove it for about 10 miles, the gauge climbed to its normal, just under 1/2, and sat there. I tried blipping the throttle and nothing, I tried flooring it and besides a 4 wheel slide (it was raining), nothing.

Any idea what is going on?

 

[GrolarBear]

Another data point- I've been chasing what I believe was an air bubble in the cooling system. I've had tepid heat at idle, but as soon as I give it a little throttle (even about 1200rpm/very gentle cruise speed) I get warm heat. I initially thought it was something with the climate controls/heater doors because sometimes I didn't seem to have heat with it set to auto and I did when I changed it to the manual, but it got worse when I replaced the cam position sensor and had to disconnect the 2 heater hoses behind it and lost a little coolant, this was last spring, it's been driven a bunch of high 90*F days since then so I don't expect it to be related to my current overheating problem.

Chasing that I tried revving it up to 3500rpm a few times, holding it for about 30 seconds, then letting it down to idle and shutting it off after a minute trying to pump the air bubble out. That had strange results, it seemed to fix the problem for the rest of the day but it would come back the next day.

I also don't believe that it is related to the current overheating problem since this did not seem to affect the temperature on the gauge at all or the running temperature of the engine

 

[Bluezone]

Sounds a bit like you might have a loose clamp somewhere.

 

[yaycandy]

Remove the coolant cap and let it run with heater at max. Just keep an eye on it if it starts to overheat. It shouldnt if it has coolant in the bucket. Make sure its in the hot range (the coolant) after its at temp and still running. Bubbles displace coolant so it should drop a bit as bubbles come out. Ive had my intake manifold off a few times and did the coolant on the car at least 5 times. Best thing is just the old school way. These new ways dont work well on the car.

Running it with the cap off changes it from a pressurized system to a non pressurized system temporarily. It will also tell you if the head gasket is shot if oil mixes into the coolant.

 

[GrolarBear]

I ran it with the cap off tonight, it heated up to its normal spot and sat there for a little bit, then all of a sudden (well it probably took 20-30seconds) shot up to full hot and the chime went off on the dash. The heat was set to manual and 90* (max) with the fan blowing, and the air temp out of the ducts was barely above ambient.

No bubbles, oil, or change in coolant level in the tank.

 

[GrolarBear]

Sounds a bit like you might have a loose clamp somewhere.

?

What makes you say that?

 

[Bluezone]

?

What makes you say that?

Sounds exactly like the problem I was having when the weather got cold. Hoses are old and don't conform as well around the aluminum fittings and spouts. The coolant contracted when it got colder out and pulled air into the system. Tightening the clamps got rid of the problem. I wasn't losing coolant.

 

[GrolarBear]

Huh, I've never seen that happen, typically old hoses end up sticking to the ******* and hold even without a clamp (you'd have to peal them off). I don't believe I've seen any worm drive clamps on any coolant hoses on my car, they all appear to have the spring clamps.

Man, that would be a nightmare on these cars, they seem to have coolant hoses everywhere.

 

[GrolarBear]

LOL, hosenipples (2 words) are a real thing on a car, nice that it's censored.

 

[yaycandy]

I ran it with the cap off tonight, it heated up to its normal spot and sat there for a little bit, then all of a sudden (well it probably took 20-30seconds) shot up to full hot and the chime went off on the dash. The heat was set to manual and 90* (max) with the fan blowing, and the air temp out of the ducts was barely above ambient.

No bubbles, oil, or change in coolant level in the tank.

Nice. As I suspected. Change thermostat. Make sure you put the jiggle in the right spot. Cant remember if its up or down. Gut says up. But look at it before pulling it

Factory Hose clamps on the coolant system are made to expand and contract with the hose. Thats why they are a bitc h to get off and have alot of tension

 

[Bluezone]

Huh, I've never seen that happen, typically old hoses end up sticking to the ******* and hold even without a clamp (you'd have to peal them off). I don't believe I've seen any worm drive clamps on any coolant hoses on my car, they all appear to have the spring clamps.

Man, that would be a nightmare on these cars, they seem to have coolant hoses everywhere.

Yes I generally see the hose stick as well. Actually this is the only car I found that I've had this particular problem. Mind you, it's also the only car that I've taken to the track multiple times during the year. Wonder if that has anything to do with it.
Also you have to avoid using nippleclamps too. LOL

 

[Zpak]

LOL, hosenipples (2 words) are a real thing on a car, nice that it's censored.

So is a, t r a n s, good luck typing it though.

 

[luigisho]

LOL, hosenipples (2 words) are a real thing on a car, nice that it's censored.

Stick around, there are lots of car terminology that software engineers deem problematic

 

[SeanDev]

Did injectors a few days alao, also dumfounded how many lines run just through intake. For a stuck hose I found using a channel lock with tape over groves, grasp hose and give a few twists, make it easier to slide off.

 

[SHOdded]

check both engine fan operation as well as coolant level/presence of air bubbles.

fans are not needed above 40-45 mph, but can definitely be triggered by stopngo traffic.

the cooling system is easy to get air trapped in. you can raise the passenger side of the vehicle to make the coolant tank the high point, normally it is the thermostat that is the high point of the system. then run engine and cabin heat on max for 30 min to get the air out. or use a spillfree funnel to help you do so.

coolant should always be filled to the top of the cold fill range. make sure you service coolant regularly. at that mileage, it should have already have had at least 2 changes by now.

 

[GrolarBear]

I bought a vacuum coolant dealeo, pulled it down to roughly -26inhg (-.9bar) according to the gauge. I let it sit for about 15min and the guage dropped about .5inhg (almost nothing, the rubber stopper didn't fit the tank well because the tank has a step inside it, honestly I was suprised it held that well). I eneded up pulling it down 2x and it sucked up roughly a gallon of coolant.


I tried 2 more times and the vacuum oraface sucked up a little coolant and wouldn't pull down below about -16inhg and it didn't suck up any more coolant.

I drove it around the 'hood for half an hour, and for the first 15-20min it looked good, then the gauged started climbing. By 30min I was at full hot again:

 

[GrolarBear]

So at this point, I'm reasonably confident that I don't have any leaks (it didn't leak down significantly with a strong vacuum on it), I haven't seen any evidence of combustion gases in the coolant (not one bubble while running, but I'm wondering if I have to get a combustion gas tester and test that), and I have pretty good confidence that it actually is getting that hot (the way it sounds and feels).

What's next?

 

[luigisho]

Change t stat? Check radiator for clogging? h2o pump issue...stuff that can make coolant not circulate properly--collapsing hose?
Fan cycles properly?
Other than that--if not leaking coolant then maybe gasses getting in. Cracked block, leaking head gasket. combustion gasses hot spots? I dunno. THere is a handful of stuff to look at. A pro with a full service shop might be able to track this down quicker. If time isn't an issue then press on good sir.

 

[Bluezone]

I agree. I'd be looking at the thermostat at this point.

 

[GrolarBear]

Is there a quick/easy way to drain some coolant out of the top end so I can remove the thermostat housing without losing too much coolant (radiator cap hidden somewhere under the core support that is reasonably easy to get to, hose that I can disconnect and use the water pump to pump some of the coolant into a bucket...)? Something to prevent from making too much of a mess (I'm doing this in the driveway and today and the next few days the weather is supposed to stay <low 40's).

Also, probably not my problem but is this cap supposed to click: