Cooling Systems -- Problems & Solutions (Radiator, Fan, etc)

dave8697

thanks for the help. I have had two other problems with the car. The evap purge code set first in Aug '05. It was code P0441. It says that the evap system failed a vacuum leakdown test. I couldn't even find the charcoal cannister on the car. It ran good and the fans were still normal. Then 2-3 months later, the fans started running. Since the CEL was already always on and I had it read at autozone as P0441. I had it checked again and was still only P0441 all thru that winter. Then in summer of '06 I had the P0121 for MAF circuit low read by autozone when the idle acted up. The P0441 was still there but still just these 2 codes. It took a while to solve the idle problem by replacing the throttle body gasket, some vac fittings, and cleaning the MAF and throttle body. Since I fixed the idle just a few weeks ago, I will go to autozone and re-read the codes this week. Hopefully the P0441 will be the only one. I haven't ever disconnected the negative bat term because it's under the rear seat and I havn't learned how to open that up yet.

As far as relays go, I swapped L&R relays in the engine compartment fuse block and then swapped back a long time ago when it first happened. I noticed with either relay out one fan ran at hi speed and one at low, depending on which relay was out. Then recently, I got two used relays from a Riv. I have them in the car now and they didn't help. That's when I took one of them out so that one fan can run hi all the time and one fan always runs slow. Just to aid fan motor life. So I don't think all 5 relays can be failed.

Now that I understand the schematic, I will check the a/c schematic. In looking thru the serv manuals yesterday, I noticed there is a sensor on the radiator that I checked by just uplugging and re plugging today. There is also a sensor for the coolant overflow tank. I saw it sticking up through the coolant to almost the surface. I then added some water to raise the coolant to between the hot and cold fill levels. I will know tomorrow morning if either of those things help.

kiawah

Yep, the output of the PCM is signalling the relays to drive the fans high speed. So you have to go back further upstream, to understand the feeds INTO the PCM, and see if you can find (or deduce) which sensors or feeds into the PCM might be causing the problem. At this point, don't know whether one of the inputs to the PCM is bad, or the PCM itself. If you have service manuals giving details on the PCM, you might be able to figure this out.

sgruber1

I have a 2000 Intrepid R/T

When the weather is warm and I drive with the Air ON.
The car runs hotter than normal. The fan runs (could be because the air is on). After I park the car and let it sit for a while it is very hard to start! Cranks and sputters.
If I press the accelerator while cranking it slowly begins to fire and run. Once started it smooths out and runs fine.
I have no Idea what would cause this. HELP!

usscout5

I have a 83 Cj7 with a chevy 350 from Hk with 60 miles on it. Radiator is new 3 core 18 inch electric fan pulling lots of air nothing in the way or obstructing air flow. new hoses 180 deg thermestast new gage and sending unit and new water pump. It is over heating when you hit the gas anything over 2500rpm you let off the gas and it stays at the temp you went back to an idle does not lower. I have no idea what is going on there is 3 things left for me to check 1)make sure no gasket or selent is blocking on water pump or intake. 2)belts are not slipping which should not be no squel or anything else and 3)to rap headers in header tape. but other than that i need ideas cause i am running the same set up as others and they are running 160 170 and i am sky rocketing but never had it over 230 cause i do not want to void the warrenty. What could i be missing???? :confuse: :confuse: :confuse:

usscout5

look at your fuel lines and if there is a way to check the temp on any of them check it sounds like the fuel is getting hot and evap before getting in to engine

Mr_Shiftright

I wonder if they built that engine way too tight for you?

One thing I'd also do is test the coolant for combustion gases, to make sure once and for all that it's not a rebuilding error and/or cracked head.

since the engine overheats on acceleration I'm kind of suspicious.

stec1979

My wifes car overheats. We've had the system check by Midas and they told me that there is no power getting to the fans. They dont do electrical work so they cant fix it. I'm not trying to spend alot of money on this car. I just need it to work for less than another year. Could a bad relay be the reason that there is no power to the fans?

kiawah

I don't have a neon, and you'd have to get a set of electrical schematics to really trouble shoot this. However, there are typically a couple things involved in this circuit.

Typically there is a call for cooling either: a temperature sensor which indicates the engine temperature is high, and/or the air conditioner on.

There is usually 1 or 2 fuses, to power the circuit.

There is usually 1 or more relays, to convert the 'on' signal coming from the temp sensor, a/c, or engine computer...to a higher current set of relay points that will handle the current draw of the fans. There could be multiple relays, for instance one for each fan (if there are multiple fans). Sometimes they'll run the fans in a high/low speed, and they can do that with relays flipping the fans to parrallel or series mode.

Then the fans themselves.

The one thing you can easily do is check the fuses, to see if they are blown. If they are ok, then I would see what the relay situation is. You may or may not be able to swap relays, depending if they use a common relay for different circuits. You may end up having to buy a relay if you aren't sure. If the problem is neither the fuse or the relay, then you're going to need to get a copy of the vehicle electrical schematics....or you will have to take it somewhere to have them work on the circuit.

stec1979

Thanks for your help. I found the relay when I was looking at the car earlier. Its in kind of an awkward spot. I think I'm going to try replacing that. If that doesnt work maybe I'll blow up the car and post the video on break.com and try to get $400 for the video. Thanks again.

coldknight300

I just received the radiator fan assembly for my 300m. I wanted to know if anyone has recently or at some point has had to change their's out. If anyone has any sugestions on how to make this job easier, I would happily appreciate the advice. Thanks A Lot!

mpac1365

My '96 Explorer just had an oil change and a top off of freon (with dye--in case there's a leak).

The AC was not getting cold. It gets ice cold now -- but, I also notice the vehicle temp gauge heading towards red -- I only noticed this driving through town - not high speed.

I've scanned this thread and it seems it could be anything from a bad sensor to a bad fan setting or a bad head gasket, or?? Okay, I am NOT a mechanic and probably messed the terms up...

If I keep the AC on Normal, the vehicle temp is normal --- as soon as I max the AC -- the vehicle temp rises -- not overheating, just heading towards red...

Any thoughts, tips, suggestions?

Thanks...

Lost Musician...

kiawah

Are your radiator cooling fans running? And is your radiator topped off w/coolant?

mpac1365

I will have to check on both of those.

mpac1365

Coolant is/was topped off. Any fan I saw - was running.

I idled for a bit with max AC on - no issue.
I drove for about 15 minutes - vehicle temp got up to halfway and that was it - no further. I did notice the temp gauge dip slightly when I turned the ac off.

Other than that - I may have to drive the vehicle for a little while longer.....and, it was about 88 degrees this afternoon when I was driving -- now, it's about 15 degrees cooler with an impending storm - does that make much, if any of a difference?

Other than that - maybe it was just all of the fluids settling from the oil change? (okay, I'm reaching -- but, reaching is cheaper)....

Mr_Shiftright

I'm thinking that the cooling fan is not switching on as it is supposed to when the AC is turned to MAX. The AC switch on MAX should activate the cooling fan. I'm not sure if you have two fans or what, but make sure the fan or both fans are running when you are on MAX AC. If not, this is probably a relay that is supposed to activate the fan when you switch on AC to that setting.

aero_smith

Hello,

This problem has me stumped. The car overheated sometime ago and I replaced the radiator and hoses. After driving for a few days, the coolant level dropped again, which I topped off again. I tried to look for bubbles in the radiator by idling the car for 10 mins. After reaching temperature, I saw the coolant level rise rapidly in the radiator, but no bubbles.

I did a similar test in my Honda CRV and after reaching temperature, the coolant level remained the same. ANy idea whats wrong with my lancer??

kiawah

After you replaced the radiator and hoses, it is common that you would have air in the system which gets trapped. When you filled the radiator up, the air is still trapped in the engine (for instance, heater core). After you warmed the engine up, thermostat opened, and you had enough coolant flow to flush out the air and it is then collected in the radiator. Once you fill it back up and have enough heat up cycles, you should be fine.

aero_smith

Thanks for your reply, but I am doing this test a month after replacing the radiator. Do I have an issue with the head gasket?

I see a lot of antifreeze in the overflow tank. It should be pulled into the radiator without having me top it off...

Thanks...

kiawah

That's true, if this is a lingering problem there is something else wrong. Do a cylinder pressure test, to see what you are dealing with.

rcorbell

Hello All and TIA,
1995 Pontiac Grand Am 4cyl.
I replaced the radiator due to a crack in the top. In trying to find the thermostat, I disconnected the water outlet and subsequently broke it ( it is made of hard plastic ). The water outlet connected the radiator hose to the engine and feeds to the heater core. After replacing it ( 12$ part ) the car runs fine for a few days and then it exploded. I have since bypassed the heater core thinking it may be clogged. Replaced the water outlet and same thing. Car shows 1/3 heat on the Temp gage and floats there during street driving. On the highway it stays 1/3 heat. When I get off the highway it runs up to 3/4 heat and then pops... I've replace 3 water outlet parts in 10 days. Any ideas?.. ( new water pump is only 26 $ )... Thanks -=R

ray80

Thats an interesting one. Are you perhaps overtightening connections on that plastic? Radiater cap, did you replace that also with a proper one? (just ideas I really don't know the answer)

rcorbell

Nope... they are tight enough with a "one handed wrench" but not too tight. I thought there might be a blockage in the line, so I bypassed the heater core ( being in Fla we don't need the heat and the AC is already dead ). Something is creating pressure enough to burst the connector, but not the hoses. Seems to be happening right after highway driving. Funny but the car ran 10 days after the first pop, then only 24 hours till the next one then 3 days till the last one. -=R :confuse:

kiawah

Do a cylinder pressure test, to make sure you don't have a blown headgasket.

0patience

The thermostat is at the flange that bolts to the bottom of the water pump.

It is almost easier to pull the water pump to get to it.
And if you plan on keeping the vehicle, you may want to replace the waterpump and thermostat together. I realize it is an added expense, but in my experience you may get the new thermostat in there, only to find a leak in the water pump a short time later.

I do agree with Kia though, you should check to make sure you don't have a headgasket leak.

newb1

Hey guys, I have a problem. I noticed this morning on my way to school that there was a bad odor being emitted from my heating fans. By the time I get to school and park the car, I notice steam being emitted from my Engine area. Now, I've never had this happen before and I'm a novice with cars, so naturally I'm concerned. I just had my oil pan replaced a few weeks ago, if that makes any difference. I checked the coolant level and it seems to be ok. I'm trying to figure out what the cause is before I take this to the a car dealer (I am not under warranty btw, so this would cost me lots, but I'll do it if I have to). My temperature gauge says the car is running at normal temp. After 8 hours of the car being parked, I take it to go home..and again the same thing happens, 20-30 minutes into the trip, I smell the odor again, and by now it's dark so I couldn't see if there was still steam emitting, but I have a hunch it was. Please Help!!!

Mr_Shiftright

Sounds like you might have a leaking heater core.

thomcos

I am looking at a 2001 buick regal has 112000 miles clean in and out but I had my dad look under the hood, he found water under the oil cap this car has been sitting for about 3 months so the dealership head mech. has put a dye in oil, I m driving car around to get oil warm to see if a leak is there. is this a good test I dont want to put money out could be a gasket problem or leak intake manifold into oil.

Also transmission in the year a problem?

thomcos

no steam

thomcos

can u help with my question

kiawah

Water on the bottom of the oil cap is not good. If the water is from a cracked head or blown head gasket (allowing coolant to seep into the oil), that is very bad.

The only other thing I guess that it might be is condensation, but I can't imagine how you would get that much liquid into a closed engine. I would think if it was flooded, you'd have other noticeable symptoms.

But sitting for 3 months with water in the engine would give me a clue to run, not walk, away from this one.

Mr_Shiftright

doesn't have to show steam to be a heater core leak, in fact they don't show any visual signs. It's the stink of the coolant that tips you off.

The only other foul smell I can think of coming through vents is mold from the AC moisture which isn't vacated. That might require a special spray in the vents or some disassembly.

jarci

would like to know what is the reason why my cooling water/coolant suddendly overflow (flow back to the coolant reserve tank) every time i stop my engine from a long travel. here's the condition before that thing happened : i always ensure that the coolant reserve tank is properly fill-up before i start the engine, then after that, i start the engine, proceed to my destination approx. 1 hr travel time, at that stage (when the engine is on for about 1hr) i dont see any indication that the engine temp. reached the over heating stage, normally my indicator reach middle level only. then when i stop, the coolant from the engine overflow (everything flow back) to the coolant reserve tank. worse case, after the engine cools down i see that the coolant reserve tank is already empty of coolant. thus, if i will not replenished it, i will encountered engine trouble (over heating) during my return trip.
Now, I already replaced my water pump, radiator cap, and ensure that the radiator was free from clogged and leakage, but still the problem was there.
May I know what is my problem and how to correct it. My car is Toyota Corolla model 95.

dgrasser

Try looking at your thermastat. This is the most likely cause.

Mr_Shiftright

that's a good place to start. Also it would be good to know the REAL temperature of your coolant as opposed to what the gauge says. If the thermo doesn't cure it, see if a scanner can read your coolant temperature on your car.

thomcos

Thank you all for the information, on the 2001 buick regal the dye test showed no leak, but you our gut to us walk away for this buy. The car gauges showed no overheating, but there was this order that smelt like coolant. After reading a few replys I feel better and greatful to walk away.

Thanks to All

diy_1

Hi my 92' camry radiator fan always stayed on?? it started 4 weeks back for 2 days then its stop, now it started again for couple of days now, the temp' here is on the minus side, i don't think the rad' fan should be on at all?? when i turn my key to on (not starting engine) the rad fan start ?? and it keep running when i turn on my engine too?? any help / advise will be greatly appreciated.

Thanks
DIY-1 :confuse:

paisan

Do you have your defroster on? If your A/C clutch is engaged, then the fan generally will also be running.

-mike

michaelp37

it is 10 degrees out right now the fan runs all the time full speed,,car does not over heat but does run in the middle,funny because at 10 degrees and the fan running all the time, you would think it would be running on the cold side?

car also stalls for no reason but only when idling fine when you are driving.

michaelp37

having the same problem with my 97' cavalier,,all cars are alike in so many ways,,I think my problem is the same,, my a/c is not on, and the defrost is not on or engaged but runs full speed,if I figure this out I will contact you.

globenk02

I have a 2001 Honda Civic, 50,000 miles. Oil light came on and it was stalling at red lights. Filled the coolant and it ran smoothly for a few weeks, then overheated again with white smoke coming out from under the hood.

Turns out the radiator has a hole melted in it. Auto shop thought it was the radiator cap because it was broken and a plastic piece probably fell in. Then tested some more on the freeway and turns out thermometer is broken and head gasket has crack (minor? as it wasn't detected the first time of testing). $300 for radiator and $700 for gasket.

Sorry I'm not too familiar with cars... Is this a reasonable price, and is there any way to fix a gasket rather than replace?

And why would the thermometer break - is this unusual for a Honda Civic that has been running smoothly so far?

bolivar

Did the OIL light or OVERHEAT light come on?

If the oil light, and you continued to drive the car, I would think you would have significantly damaged the motor.

If the car overheated, and it has a bad head gasket, you better hope a head gasket replacement is all that is needed. If a bad head gasket leaked coolant into the oil, and you continued to drive the car while this was happening, you could have also damaged the motor significantly.

$300 for a radiator and $700 for head gasket replacement is pretty decent prices. The cost of a thermostat will be minor ($20 ??) compared to the other prices.

Why did this happen? Who knows? Have you serviced this car according to the maintance schedule? In its 7 years of age (even with the low milage), you should have replaced the coolant 2 times - at 3 year intervals. This might have contributed to the problems if not done.

Also, with head gasket replacement, I would change the oil and filter at the same time.

foreignauto

I have a 97 Jetta and the Temp gage reads between 1/4 and 1/2 (both normal)depending on driving conditions. 1/4, when I am driving along and flowing with traffic. 1/2 when the car has been driven for a while and is sitting idle after the drive. However, the temperature indicator is flashing all the time. I was thinking it was the Thermostat, but the heater and HVAC works fine at all temps. However, I noticed that the radiator fan was not on when I check under the hood yesterday. Could the problem a bad fan or a bad fan fuse?

blondiemom

Does anyone have the Coolant refill proceedure from the owners manual for a 95 Buick Regal?

My Low Coolant light is lighting on my dashboard and last week I put a 50/50 mix of coolant into the reserve tank. The light didn't go off the first time I used the car, but it has gone off and on since then. I notice that there is still the same amount of coolant in the reserve tank as when I refilled it.

I know I have a small leak in the intake manifold gasket (have had it for the 4 years I've owned the car.) I have never had a problem with this fluid level before now and thought I would "top off" the radiator myself. I have found that I cannot get any coolant mixture to go into the tank (by funnel after taking off the radiator cap.) I just noticed that there is a sticker on the frame next to the radiator that warns of a "special proceedure" necessary to fill the radiator and that it's in the manual. Any help I can get on this would be greatly appreciated since I have to do this myself.

Thanks!

ray80

I don't have the procedure but you could get registered at www.mygmlink.com with the regal and see an online manual there (might be usefule for other things also)

Mr_Shiftright

Sure could be a bad fan or fan relay or sensor or fuse. Your symptoms suggest an AIR circulation problem, not a COOLANT circulation problem. So I don't think the thermostat is the cause. Reason? As you drive faster the temp goes down. This would not happen with a bad thermostat.

Also you might need to determine what the temperature actually is in the coolant. I think on your car a computer scan can tell you that. Your temperature light should not be going on ---- or is this a coolant LEVEL light? I'm not sure on your car.

Certainly your fan should be going on if the car idles for a long time, unless maybe if it's really freezing where you are right now. But even so, it should come on eventually.

sbladen

I have a 1991 Mercury Topaz and I am looking for an online owners manual or a detail of the fuse box or boxes in the car

kiawah

You might want to try www.helminc.com.

If they have your manuals online, you can get a 2 or 3 day subscriptions really cheap, and then view or print whatever sections you are interested in.

tennis56

I have a 1997 Ford Mustang that when the engine is turned off, the radiator fan continues to run to the point of killing the battery. I pulled the fuse for the fan and that obviously cut it off. However, that was a quick fix last night so I could go to bed.
What do I need to check and how to do it?

kiawah

You'll really need to get your hands on a set of electrical schematics for your vehicle, or someone that has a set for your car jump in.

Generically speaking in an electrical cooling circuit, there are two or three things which should turn the fans 'on' (think of these as inputs), they are:
- a temperature sensor that has sensed a coolant temperature higher than a given level,
- the air conditioner or defroster being turned on
- some Engine Control Modules sensing specific vehicle/engine operating conditions.

On the 'output' side, are typically one or two fans, that will run at either a slow speed or full speed. These are DC motors, so if given the full 13V they will run at full speed. I've seen different circuitry that uses relays to put the two fans in series, effectively giving each fan 6.5 volts so they run slower. I've seen circuitry which used diodes to drop the voltage.

In the 'middle', are usually a set of relays which translate and switch the voltages for the fans. These relays, depending upon how they are turned on and the circuit is wired, would provide either no voltage (fans off), full voltage (fans on full speed), or lower voltage (fans running slower). I would suspect that one of your relays is bad, as this is fairly typical. Usually what happens is that the set of output points on the relay become fused together, so the voltage is continually given to the fan.

Depending on the car, you can go hit or miss with swapping out the relays. A digital ohmeter/voltmeter would be helpful with the schematics, to definitively prove what is bad before you start throwing parts at it (perhaps unnecessarily).

roger821

Hi there...

I have a 1997 Honda CR-V with 143K miles on it. Today when I was driving home from work, my dash temp was showing the regular 1/2 setting, which is where it has stayed after I replaced my radiator 6 months ago. Tonight, it suddenly dropped and almost went back to the cold setting - it dropped to about 1/8 while I was driving on the freeway at speed. It stayed there even when I slowed down off the freeway for about 5 minutes, and then it returned to the normal setting. I didn't notice any smells, steam/smoke, or noises in my engine. The air temp is now 42 degrees in Houston, which is way colder than normal, but my car's never done this before. Does anyone have any ideas as to what happened? Thanks...