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Discussion Starter #1
hey guys this is my first post here and i hope someone can help me with a problem, i have an 03 ford focus se engine code P and im having a problem. I just replace the thermostat water pump and hoses. but now im getting an overheating problem, the car starts venting coolant out of the overflow tank cap. also when i drive to work in the morning the car will try to overheat, the odd part is it happens on almost the same spot on the road evertime. the needle never goes into the red and i can hear my cooling fans come on but after the temp returns to normal it never does it for the rest of the day. this is driving me nuts and my mechanic cant find any problems neither one of us can get it to overheat. it only happens on my way to work, when i go home its fine? any suggestions please????

Thanks in advance
ian
 

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Is the engine legitimately hot when this happens? If so - you may have a problem with one of the rad hoses collapsing if it doesn't have the spring in it.

Have you checked to see if it cracked the head?
 

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stand there with the car idling and make sure that the fans are actually turning on. This might take a while as the temps outside are getting cooler so give it at least 5-10 min idling to see...I had an identical problem where the guage wasnt showing hot temps but when I pushed it REALLY hard i got a code that read cylinder head temp high....I replaced the resistor w/ adapter which was melted and then replaced the relays and that fixed it. The resister/w adapter that Im talking about is right in between the two fans.
 

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Discussion Starter #4
The hoses are all good i just replaced them all, and as far as i can tell the head is fine, the oil isint milky and theres no coolant coming out of the tail pipe. and the fan are good when it did the overheat thing on me this morning the fan kicked on fine and cooled everything down after that the temps were good the rest of the trip. like i said nothing is making sense on this car.
 

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Discussion Starter #5
although last night when i had the car idling for almost an hour the fans never once kicked on...but the car temps were nice and cool.
 

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Discussion Starter #6
lets say this is my trip to work
|-------------------------------------------------------------------|

the car tries to overheat here

|---------------OOO------------------------------------------------|

thats whats weird its the same part of my trip everytime.
 

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Depending on the actual time in minutes that it takes, I'd say the thermostat is likely stuck closed. You can simply remove it, but if the problem is something else- like a clogged radiator or bad water pump, then you'll still overheat.
 

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Discussion Starter #8
yeah me and my mechanic thought the new thermostat we installed may have been bad so we replaced it again.....didnt fix anything and like i said the water pump is brand new. how long should it take for the fans to kick in on an idling focus, like i said i had it idling for almost an hour they never kicked on.
 

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Throwing parts at a car without testing anything can get expensive. Sometimes that's all you can do, but there are ways to test this one that are easily available. Does your engine say "Split Port Injection" on the valve cover?

You can monitor the engine temp through the electronic odometer test mode while driving- follow this procedure: 1) engine off, key off- press and hold odo reset button. 2) Turn key to on, continue holding odo reset button 3) Gauges will jump and flutter and the odometer will read [test]- release odo reset button. 4) Now each time you press and release the odo reset button you'll scroll through one of the test functions, there are about 30. Look for the readout to change to [15 C] or whatever is a logical temperature in C for your engine at the time. Overnight or after sitting at work, it should be a few degrees off ambient temp. Yes you will have to learn what temps in C to look for, but it's really not all that hard. 5) Start the engine without turning the key to OFF and the odometer will stay in test mode. You should be able to see the temperature cycling as the thermostat opens and closes. We have had a few problems with faux overheating due to bad temp sensors. In that case you'll see temps go suddenly from say 95C to 150C which would be like 302F and your hoses would melt so that's illogical. If you have an infrared thermometer or you want to duct tape a cooking thermometer to the upper radiator hose that will give you an idea of what the actual engine temp is. I wouldn't expect the two readings to be perfect but within 10-20 degrees F or so I'd consider normal due to heat buildup under the hood and mechanical differences.

FYI: cooling fans only perform a function when the car is moving slowly or sitting still. If you're driving on the highway, your overheating is due to something else- clogged radiator, bad head gasket, broken spark plug insulator, clogged catalytic converter, bad coolant reservoir cap.

Clogged radiator: first figure out if the evil AR summer bug assault has clogged up the outside of your radiator, and be prepared to remove it to really clean between the condenser and radiator. For internal clogging, check to see if you can feel water flowing through either the lower radiator hose or the upper hose with the thermostat removed or with the engine heated up sufficiently for the thermostat to open.

Bad head gasket: You'll be losing coolant and eventually you'll see some in the oil most of the time. A few times you won't see coolant in the oil, but you will be losing it and you should smell it in the exhaust.

Broken spark plug insulator: that's the ceramic insulator around the center conductor- you'll have to remove the plug to inspect it- this is a fairly rare issue, but when it does happen, the car overheats quickly because uninhibited heat from the combustion chamber is being transferred to the coolant passage around the spark plug hole. It only takes one plug failure like this to overheat.

Clogged cat: usually causes other noticeable issues like extreme loss of power, low exhaust output. You can diagnose this by removing the upstream O2 sensor from the manifold and seeing if the engine runs better without it in there.

Bad reservoir cap: This one is really tricky to figure out. Sometimes it will just overheat, and other times you'll lose coolant and overheat. The cooling system must retain some pressure in order to function and prevent the coolant from boiling. When pressure overcomes this in normal operation, the cap allows coolant/pressure to escape through the overflow. Sometimes a bad cap that won't retain pressure forces coolant through the overflow before it should, and sometimes a bad cap will simply cause the heat sink operation of the coolant to fail- and the coolant boils.

That's about all I can think of for now- as far as freaky cooling problems. The fans might be part of the problem if the problem occurs at low speeds and idle, but not while driving. I get the sense it's happening while driving. To check the cooling fans, turn on the AC. One cooling fan should work on high speed with the AC on. If your AC has no charge, let me know and I can tell you how to bypass the controls so the fan will come on. The cooling fan resistor and the cooling fan plug should be checked and are known to be damaged over time by the exhaust heat.
 

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wait a sec... there are 2 relays...one that goes on for low fan speed and the other for high. is it possible that your low one isnt turning on, you overheat slightly then the high one finally kicks in? relays are fairly cheap...try to replace those.
 

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Discussion Starter #13
hey guys sorry for the long wait for a response but between work and the holidays you know how it goes...anyway heres where im at now. on sunday i replaced the coolant temp sensor and that seemed to fix the problem. from sunday to wensday the coolant temp would get to about 104c and the fans would then kick and on drop the temp back down. seemed like all was fixed, then yesterday on my way to turkey day dinner it did it to me again exactly as before. the difference now being coolant is no longer venting from the cap. also when i idle the temp will get to about 104c and the fans will kick on. before replacing that sensor the fans never kicked on while idling. im going to try and replace the low speed fan relay and see what that does also im going to replace the coolant sensor because i may have got a defective one, not likley but you never know. but anyone who has any other ideas would be helpfull lol.. also can anyone tell me what there normal idling and driving temps are so i have something to compare to.

thanks again
 

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Discussion Starter #14
ok quick update, went out and checked the relay it has a big burned hole in the side of it. repalced it, perkes of working at a parts store lol, and we will see what happens
 

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Posted via FF MobileBlueoval - you ought to start a thread with YOUR issue, so folks can help.... The gent you asked a question of last posted in November, he MAY not be checking in often.... Checking dates on posts sometimes helps see what is "current". Luck!
 
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