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

Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,360
This forum is for discussing any issue related to a car engine cooling system (NOT air conditioning!), including radiator, recommended coolant types, cooling fan, thermostat, overflow tank, air bleeding, belts and hoses, and even head gasket questions.

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  • Our 2005 Nissan Quest has had A/C problems from day 2 and Nissan has tried to remedy the situation. The first time we were told that the freon was improperly filled(air pressure not level...moisture in the line?) This was causing the A/C to constantly hiss and then it stopped cooling. Now we have the same problem. After the repairs it worked great for a week (38degree) air. Now, it is acting up again. I have contacted Nissan again and am awaiting their call. I was wondering if anyone out there is experiencing the same problems. I love my van and I hope this is a minor nuisance that can be fixed "permanently". I will post their remedy, if any, once they do something about it. The van is only 7 months old.

  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,360
    Oops! You're posting in the wrong forum. This is for Cooling Systems.

    You want this one:

    Climate Control Problems

    thank you


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  • Thanks "Host"...I appreciate it. I've reposted in that area.
  • briggsbriggs Posts: 1
    1996 Ford Contour, 2 Liter, 4 cyl, 5 speed, single cooling fan. Having problems with radiator cooling fan not coming on when engine gets hot. Fan will run on low speed when the A/C is on and will run on high speed when temp coolant sensor is disconnected, but if A/C is not selected or not in defrost mode, engine will overheat if not moving at a good rate of speed. Have replaced temp coolant sensor, temp switch and thermostat and have inspected wiring under the hood for problems. Flushed cooling system and refilled with fresh coolant, but all too no avail. My local Ford dealer's mechanic has not had a shot at it yet, but I have reason to lack confidence in his ability to troubleshoot electrical problems. My Haynes manual does not offer much help. Any suggestions? :confuse:
  • masterpaul1masterpaul1 Posts: 421
    This is a long shot, but try checking/replacing the cooling fan sensor/s. I'm having the exact same problem as you have described with our 98 Pontiac Sunfire over heating in temperature around 60 degrees. I have already drained the cooling system and replaced it with fresh coolant. I checked both cooling fan fuses and they seem to be okay. Next I will replace the temperature cooling sensor and pray that it will be the fix. I noticed that the cooling fan would come on at different times. The temp. needle never makes it out of the normal range, but will get very close to the high normal range. I don't believe that the thermostat is the problem since it only starts to run hot when in city driving. :)
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,360
    You may have two coolant sensors, one to turn the fan on and one to turn it off. You may be replacing the OFF sensor, which of course does you no good.

    You can test these sensors pretty easily but you may need a wiring diagram to figure out how your system works.

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  • sschmidsschmid Posts: 28
    Car is 92 Mazda 323.
    Replaced the radiator last summer (due to crack at the top) and left to drive to Fla. Noticed it running hot almost to redline on the way there. Had to drive with the heat on to keep it in satifactory range under highway driving. It was OK around town and fine highway as the weather cooled off. Now of course it is hot in Fla and I have same problem. I figured thermostat must not be opening all the way. Now I have to drive back north home from college. With no tools or a place to work on the car here in fla. I took it to Firestone and asked to have thermostat replaced. They are giving me a song and dance saying it is the water pump?
    I don't see how that is possible. AFAIK the water pump is either broke and you are overheating or leaking (not my case). I have never heard of one that works under certain conditions. They wanted over 400 to replace the pump and thermosat. or 153 to do just a themostat!!! Of course if I had them do the pump and themostat and it was just the thermostat problem would be fixed to the tune of over $400 to replace a $4 part. needless to say I left. Interesting thing was they had taken the thermostat out and where going to replace it even though I declined the work at $153. Then the realized they did not have the gasket which I had sitting in my car but they would not use. So they put it back together with the old thermostat and gasket. Took them about 20 Min to put back together. They charged me $16 for "looking at it". Now it seems to be running hotter.
    I am going to take it to another mechanic tomorrow who I hope will not be out to rip me off so any thoughts would be helpful.
  • cmcmilloncmcmillon Posts: 1
    if the oil isnt changed on the mazda, is it possible that the car can overheat??? and what should i do after the oil is changed? i noticed tonight that my gauge was going towards hot, and everytime i pushed down on the cluth and brake my mph gauges some what jumps from 2 to 3 what should i do???
  • masterpaul1masterpaul1 Posts: 421
    I'm not sure what kind of cooling fan you have, rather it's the electric or the pulley kind. If it's the electric cooling fan, you might want to try and check/replace the cooling fan fuses and the temperature sensor which is what turns the cooling fan on and off after the coolant reaches the number of degrees that the sensor is set for. For example, if the temperature sensor is set at 180 degrees, when your coolant reaches this temperature, the sensor sends a signal to the cooling fan to turn on. When the coolant reaches a temperature below 180 degrees, the sensor sends a signal to the cooling fan to turn it's self off. If you have the old kind of cooling fan that runs all the time from the engine pulley, first check to see if you have a clutch fan. If you do, it's probably time to replace it. (They should be replaced every five years). If you don't have a clutch fan, you might need to hose off the radiator cooling coils. Over the years dirt and stuff gets build up in these coils which insulation the heat. To check to see if the cooling fan is working, (electric cooling fan), lift the hood and let the car idle to regular temperature. Most thermostats are set for 160 to 180 degrees. Which means that the temperature gauge should not go past the halfway mark in the normal range. Look to see if the cooling fan comes on. If it doesn't, you need to change the cooling fan fuses and the temperature sensor. All of these parts should not cost over $50. Also, make sure that you have no leaks in the cooling system and that you have the right mixture of coolant 50/50 water and coolant. The coolant should be replaced at least every 5 yrs or so. Make sure the coolant level is at the "Max Cool" level when the car is cold. Hope this helps and good luck. ;)
  • dodgekbaddodgekbad Posts: 56
    Hi Mr Shift

    You might remember me from the tranny forum with a k car that had a bad tranny. I junked it, and found a '98 Explorer for cost! through my brother's friend in the car biz.

    Anyway, the coolant in the reserve tank was brown and foamy. I assumed the rest of it was as well, so I flushed it in front of my parent's house (and left a decent sized stain in the street in the process - when my bucket didn't catch all of it). Much to my surprise - the coolant in the radiator was green. It was consuming a lot of coolant too, and I could smell coolant while driving. My temp is slightly cooler than the middle of the gauge, and both my heat and A/C are working. I added some stopleak in the radiator to alleviate the smell assuming there was a pinhole leak somewhere. It seemed to stop the coolant smell and maybe the use of so much coolant, but I am not sure yet. It could be too early to tell.

    I have new coolant in there now after the drain and fill last night. Although, I never drained the brown stuff out of the reserve, and it used it since I only poured 1 gallon mix in the radiator after the flush, and it takes 1 3/4.

    I refilled the reserve, and drove to work this morning (16mi ride). I looked in the reserve and spots of brown again. The oil dipstick looks OK - a little high - but looks like oil nevertheless. The tranny dipstick looks good, and appears to just have tranny oil on it. There's no white smoke...should I just ignore it?
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,360
    Well I think you should take that reserve tank off and really flush it out for one thing.

    As for possible oil in the radiator, you could have a leak in that part of the radiator that helps cool your transmission fluid.

    You could also have your cooling system pressure tested for leaks. This can often spot not only leaks but head gasket issues perhaps.

    But yeah, just keep an eye on things. Can you see inside the radiator. Does it look plugged up or are the outside fins corroded and breaking off?

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  • dodgekbaddodgekbad Posts: 56
    One other thing I should mentioned is that the engine sounds sort of like a tea kettle that's boiling. It used to sound worse before the drain and fill though.

    It's too late for flushing that reserve. I didn't put enough coolant in the radiator after draining it, so it just took the brown stuff from the reserve. I had to refill it.

    Even with the new stuff, it looks like little, oil deposits, are in the coolant. It could be the stop leak I put in however. That was brown in color also.

    I looked in the radiator with the cap off, before I flushed it. It was pretty dark in there, so I could not really see if anything was plugged up. Although what is strange when I first flushed it - cold coolant started coming out of it, but then it paused. A little while later, a new wave a very hot coolant just started pouring out of the thing, leading me to believe something could have been clogged up in there.

    It looks like draining the coolant was NOT wasteful at all, like my family said. I feel relieved to get that first step out of the way. I am tempted to just ignore it however. The smell is gone, and the reserve coolant is relatively clean now. Plus I don't have temp problems. The tranny fluid is red as ever on the stick, so if it were mixing, wouldn't be red/greenish on the stick? I am starting to think it was the stop leak that didn't circulate.
    As for the fins on the rad, they look relatively good compared to most I've seen. Thanks
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,360
    Have you ever checked your thermostat?

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  • dodgekbaddodgekbad Posts: 56
    Negative on that thermo check. How do you do it?

    Oh, and reserve bottle coolant is brown again. I had the A/C on today too and still, it runs just below the middle on the temp gauge. Thanks
  • lildoerslildoers Posts: 1
    My fiance just did a radiator flush (coolant) and now the coolant light is on. Is there something to reset? His car is a 1998 Pontiac Grand Am, 2.4 ltr auto
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,360
    There's a little plunger (like in your toilet) in the reserve tank where you fill it, and this is either stuck or broken or the level in the reserve tank isn't high enough.

    RE: THERMOSTAT -- you pretty much have to take it out to check it, and if it isn't expensive, it's a GREAT idea to just replace it, since you have all that goop in there.

    Stopleak is kind of a desperate measure, so you shouldn't overdo it.

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  • dodgekbaddodgekbad Posts: 56
    Why the thermostat? I would do it I think, but from what I understand, I'd have to drain the coolant again that I already did last week. Besides I don't have heat or A/C problems. Everything seems to work fine except the Reserve coolant is brown.

    I think that Stop Leak did the trick (despite being brown in color) because it doesn't seem to use any coolant now. Also it doesn't smell either. And judging from when I drained it last - I am willing to bet the coolant is green in the radiator - just the reserve bottle coolant is brown.

    I've used a compression tester on a 2 stroke dirt bike before. Is it as EZ for an SUV as unscrewing a spark plug; putting in the gauge; and starting the engine 6 times for each plug? That'll tell me if the rings are good, No? But where can I get the specs?

    Or maybe pressure testing that coolant systems sounds like a good idea? Maybe it's that water pump not pumping the stuff around. But how much is that? I just upgraded from an '88 k to a '98 Explorer (albeit for cost) but it broke the bank in a way. Plus I am a tightwad who has some junior mechanic skills, and hates mechanics. Thanks Mr Shift.

  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,360
    Well you have to realize you haven't fixed anything. If the stopleak has stopped your problem, it's going to come back.

    I suggested the thermostat because you said coolant was pushing out the reservoir or radiator. If the thermostat got partially stuck, there would be poor water circulation and you'd get a fast overheat and coolant blowing out. And besides, thermostats don't like stop leak very much. It is after all, clogging all small openings, as it is supposed to do. Stop leak isn't smart, it doesn't know which openings are good and which aren't good.

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  • dodgekbaddodgekbad Posts: 56
    When did I say coolant was pushing out the radiator? I am not sure what this means. I know you're trying to help and I don't want to argue, but could it just have been a pinhole leak somewhere that I couldn't spot?

    So what should I do? It doesn't use coolant any more, or smell, so the stop leak appears to be working. Either that or the do-it-yourself drain and fill, did the trick. I drained it after put the Stop Leak in, so I probably drained whatever Stop Leak was there anyway. I am not sure about draining again to get to that thermostat with my new coolant and all.

    But why Brown in the Reserve? Could it just some Stop Leak in the bottle. It's been like 90 degrees here and the needle is just running a little on the cooler side, by about 1/6 on an inch, on the gauge.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,360
    Well if the problem is solved for the moment, that's good. I'd have to see this brown stuff before I could say what I think it is.

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  • rzombierzombie Posts: 2
    HI, I am having problems with my 1998 Ford Contour.
    When I drive on the highway my car works like it should all the readings are right for temp and only when i start up my car does the coolant light come on. But when I drive for about 20 mins on the highway my coolant light comes on and then when I pull over to check it the all the coolant dumps on the ground through the pressure release hose. I am completely stumped and so is every person I have brought my car too (INCUDING THE FORD DEALERSHIP)

    Now I was stupid and spent tons of money changing just about everything the cooling system.

    I have changed the water pump, hoses, radiator cap, thermostat, temp sender, temp sensor, I have had the head gasket checked 4 times (all came up negative)

    so I am completely out of ideas

  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,360
    How was the head gasket checked? Did someone test the coolant chemically for carbon monoxide residue? You could have a tiny crack in the cylinder head and while it will not leak water into your oil it could heat up your coolant---long shot, but worth a try.

    Otherwise, I'm wondering if your car requires a certain way to refill the coolant--that is, maybe you have air in your cooling system because it wasn't bled off properly during coolant filling.

    The reason I say this is that your coolant light is related to coolant level---your coolant seems to be surging, which it will do if there is air trapped in the system.

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  • rzombierzombie Posts: 2
    We have done the Chemical and 3 different types of pressure checks. We also thought about there being air in the system so we drained it all and we filled it back up and let the car run to have all the air be pushed out.

    I was wondering I have heard that there is a flapper on the top radiator hose could this be the problem?

    Thx for replying :)
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,360
    Man, this is a tough one.

    Usually when I face a problem that seems to defy logic, what has happened is that I assumed a new part or repaired part was now functioning when in fact it was not. Given that perhaps 3% (in some cases) of new parts and 10% (so I've read) of rebuilt parts, depending on who rebuilds them, can be defective, it is possible that this is happening to you.

    Question is, on which I'm not clear yet---is your car in fact overheating or just burping out fluid?

    My understand of what you are saying is:

    1. coolant light goes on immediately after cold start. (if true, then you have low coolant right off the bat).

    2. Coolant light goes out, but comes back after highway driving.

    3. Coolant then gushes out.

    If #2 is as you stated, then either coolant has expanded to shut off the light, and then there is an overheat (in other words, the coolant light can light for more than one reason.)

    If #2 is as you stated, perhaps the coolant overheated because initiallly there wasn't enough of it. In other words, the air problem gives the coolant level light a false reading when cold--then the water pump kicks in, and the coolant temp rises, expanding the coolant, shutting off the light. As you drive, the trapped air interrupts the coolant flow, heating it up, putting the light on again, and eventually the coolant boils over.

    Just speculating here---this is the rzombie Theory #1---. :)

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  • daniels1daniels1 Posts: 2
    Can some 1 tell me if the 2 types of compressors for this car are interchangeable ?Mine is the nonswitching type and I have only found one in a months search of bone yards and the crazy thing leaks around the shaft.The other type is a dime a dozen in my area.
  • Hi Guys,

    Just wanted to know, the cooling fan has not been turning on when the engine gets really hot. I changed the rad fluid and just recently changed the sensor in back of the thermostat thinking that was the problem because when I unplug the wire harness on the sensor the fan goes on an as soon as I plug it back in it shuts of and never comes back on.
    I do not have air conditioning and it is an automatic if that can help.
  • osirisosiris Posts: 1
    Ok, I have a 1999 Mercury sable 3.0 v-8 my mechanic told me that I needed to flush my radiator and while I was at it to replace the thermostat. So I bought a new one and a new gasket. When I took the little housing for the thermostat off the thermostat fell so I wasn't quite sure which way the spring was supposed to go. But I put it in with the spring pointing toward the center of the engine after I flushed everything and reconnected all the hoses and stuff. Then I put in the half coolant half water. Then I drove it around all day today and it is leaking green coolant all over after I drive. I checked where the thermostat is and the other hose under the car that I had previously disconnected but it wasn't leaking there. The coolant reservoir was steaming and making a whine and was leaking from somewhere underneath it. What did I do, did I put the thermostat in went houseing, thermostat, gasket, engine...

  • davids1davids1 Posts: 411
    My 1999 Chevy Tahoe w/5.7 liter engine has a small coolant leak. How small??? When the vehicle sits overnight there may be a puddle of coolant approximately 4 inches in diameter directly below the bottom pulley. A small amount of coolant can be seen on the sway bar (i think).

    I have changed the water pump, the upper and lower radiator hose, the thermostat and the two smaller hoses that feed coolant to the heater core (i think, again). I am confident the leak is not coming from one of these components as the leak is the same now as before.

    Does anybody know what the potential source of this leak could be? There is some coolant on one of the hose couplings on the hose that connects to the transmission, but I am not convinced this is the source.

    Thank you
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,360
    On hard to find leaks you can always pressure test the system. Do you have a freeze plug in that location?

    Also, one must never presume that just because a part is replaced, that this eliminates that part as a culprit.

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  • davids1davids1 Posts: 411
    I don't know if there is a freeze plug down there or not. I was hoping to find somebody that had experience with the 5.7 liter chevy power plant and the location of potential leakage sources as there are certainly enough of them around.

    As far a the repalcement parts go, I replaced them myself so I'm confident in the quality of the install. I have also verified that the leak is not coming from the new thermostat, the new hoses and the new water pump. The leak is coming from somewhere low on front of the engine.

    Thanks again for any input.
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