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I have a 2005 Dodge Durango that has about 85,000 miles on it. The temperature gauge on the dashboard should always be in the middle, however when I drive for about 10 minutes or so it will start to go up higher and higher until it reaches the H (hot) at the top of the gauge after about 15 to 20 minutes or so. Normally I have been pulling over and letting it cool a long time before it gets to the H (hot) so that it doesn’t get too hot. But one time (just to see what would happen) I let it go ALMOST to the H at the top, then pulled over, popped the hood and looked to see what I could see. Yep, definitely overheating (not just a crazy temp. gauge). It was very HOT.
So now I’m off to try and figure out what it is. I checked for debris, plastic bags, etc. and found none. I don’t see any coolant leaking anywhere, I bled the system by opening the bleeder valve and letting all the air out, water pump is good, fan clutch is good and thermostat was good. There is no water or milky stuff in my oil. There is no water or white smoke coming from my tailpipe.I don’t know what else to do. Could it be a fuse or relay? If you think that it could be then is there a simple test I can do to check them without having to have an Ohm meter or DVOM???
Any other ideas?? I am baffled!! Thanks to all in advance!
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How old is the t-stat,sounds like it is not opening-sometimes new doesnt mean good had a few out of the box that were crap.also look for coolant flow,we had a impeller break off pump pulley turned but no flow.
if i may add, is your AC on? if your condenser is clogged and full of debris, if you turn your AC on, your engine temperature can spike, also… if your radiator is full of junk air cant circulate through it, and if the inside is corroded out, it will not decipate heat as it should and the car will overheat even if the radiator looks good. is anything obstructing air flow too the radiator?
I assume you’ve checked to ensure you’re not losing coolant? When you pulled over and popped the hood, how do you know it was overheated but not just normal operating temp?
So, if you’re not losing coolant, and you’ve checked for any codes, I’d check the temperature sending unit, usually located somewhere close to the thermostat housing with a wire on it. You can do that with a VOM meter. Check the sensor for large resistace swings with one lead to a solid ground and see what you get while the engine is running and at what you believe to be operating temp. Sensors are pretty cheap on domestics.
M.Hey nallarano, the new t-stat that I bought is only 4 days old. I tested it in boiling water with a thermometer to make sure it was opening and closing at the right temperature (195F). Coolant flow seemed to be okay. Impeller? Hmmm…not sure what that is and so I guess I haven’t checked it yet. Thanks for the advice.
Yes, the AC was on but is was also off many times when it would overheat. So it overheats with the AC both on and off. I haven’t checked the condenser yet. Is there an easy way to do that without special tools? The radiator is being serviced today just to make sure but it looked good from the outside. Though it will be serviced today on the inside. Have you ever heard of someone taking the radiator off and then blowing through it on one end and saying, “It doesn’t seem like air is flowing through the radiator like it is supposed to be” as he asks me to put my hand on the other end and feel the air that he is blowing though there. Yes, I could feel his air but he said it should be stronger. Does that make sense?
Yes, I checked visually to make sure I wasn’t losing coolant but I have not checked it by putting the system under pressure (15 psi) and then looking for leaks. Do I need to do that too even though I have checked visually? I knew it was hot because I SLOWLY turned the bleeder valve and it began to spew out steam and coolant. Plus the radiator cap was very hot and also there was gentle boiling of water/coolant.
What do you mean check for codes? I haven’t checked the temp sending unit yet. I guess I’ll need to get a VOM meter. Or maybe I should just replace the sensor all together — it might could use a new one anyway because of it’s age right? Thanks for the advice.
I’m leaning towards a bad sensor due to the erratic readings you’re getting on your temp. gauge. I’m not certain you’re actually having overheating. One thing you can try, if you had the tools, is measuring the temp of the cooling system with an infrared thermometer/temp sensor, at the top of the radiator and the bottom while tne engine is running. ECTG did a video on that recently.
A pressure test is a good way to determine the integrity of the cooling system. Test the cap too. Even if you don’t actually see any leaks, it could be losing coolant and it might be evaporating on a hot engine. Back flushing the cooling system (I prefer a back-flush while ECTG doesn’t) is a good way to clean out accumulated gunk in a cooling system including the radiator. For less than 10 bucks you can buy a Prestone flush kit at a parts store and for a couple of bucks score a can of cooling system flush. DIY. All you need is a garden hose, water supply and the flush kit.
Sounds like a radiator guy has his hand on the bucket and is headed towards the well to sell you a new radiator even though there’s no concrete proof that it’s got a problem and your varying temperatures are not likely related to a plugged radiator. It either allows coolant to flow or it doesn’t and if it’s plugged either partially or completely,
I’ve never seen one that plugs intermittently enough to cause your overheat and then unplugs itself to cool down then plugs up again to overheat again. See if your radiator guy has a good explanation for that one. Besides, when I’m troubleshooting and I hear hoof beats, I like to think horses first, not zebras.Any time you open a cooling system that’s under pressure and the engine is warmed up, it’s pretty likely you’re going to get some boil-over (due to reduced atmospheric pressure on the system lowering the boiling point of the coolant) and some steam. So neither one of those tests are definitive to show anything other than coolant on board, a system under pressure (both of which are good signs) and the engine is warmed up.
A parts store, like O’reilly or one of the other chains, (or even local ones) will likely have an OBDII scanner to communicate with your Durango’s computer and would check it for codes. They usually don’t charge for that service and if it shows any trouble codes, they’ll tell you what they are.
A VOM is a cheap investment and worthwhile having around for lots of things like checking sensors, electrical outlets, battery volts, ad infinitim. You don’t need something really fancy. Even a small pocket-sized version will do you fine. I don’t like to throw parts at something for the sake of either the part’s age or isolating a problem. I’d rather diagnose it and then replace the defective part or solve the problem.
You’re quite welcome. Glad to help when I can. ;>)
MarkI’m surprised no one has mentioned this one yet. But the fans, have you checked to make sure then are coming on? You might want to check the fuse while you at it.Go to orileys, Autozone, or whatever you chose just go and rent a pressure tester to check for leaks. I have see clogged radiators due to people using that fix a head gasket stuff with doesn’t work and will make a big mess of things. I think getting a new wont be a bad idea. But remember if thats not leaking then it might no solve your problem.
Hey to all (exceptionalchris; Sparks4184; johnbkobb; 13aceofspades13; nallarano)…
I think I found the problem with the overheating condition. I took my radiator to get serviced (flushed, cleaned, etc.) and then had it put back in. After that I took it on a drive with the AC off and no overheating problems. Then I took it on a drive with the AC full blast and still no overheating problems. Great! Hopefully that fixed it. Time will tell I guess.
As a side note: I know this had nothing to do with the overheating problem but I wanted to mention it anyway. I also had replaced something to do with the tension pulley bearings or something like that. When he took them off (2 of them – two of the round things that the big tension cooling belt goes around) and spun them I could hear the bearings rolling around in them. He said they were ok for now but would need to be replaced soon so I told him to go ahead and replace them now. When he came back from the store with the new ones and spun them I could hear nothing but silence this time. I did not hear them rolling around. Anyways I know this had nothing to do with the overheating problem but I just wanted to mention this as a side note. Thanks again to all!
While the radiator cooling fins may have been partially clogged, intermittent overheat? I’m still a bit skeptical on that one. A broken tensioner pulley? I can see that causing overheat problems if it’s intermittently causing the belt to not turn the water pump. Good catch on your guy’s part. It might have had more to do with the problem cause than you’d think. And you sure can’t argue with success. Congrats.
MHey Sparks4184,
Thanks for the added points!! Much appreciated. I see what you mean about the tensioner pulley. I like this forum so maybe I’ll be talking to you some more in the future … and I like to get greasy too (even though I’m a girl)! ha, haYes I would see if the fans are working (let it idle, raise the hood and wait for them to kick on). An overheat of a vehicle that young is not normal, as I’m sure you agree. First though was bad thermostat but if you changed that it rules that out. Radiator COULD be blocked or bad but on that young a vehicle I doubt it (although it is a possibility). Personally, having a tech blow through one side of my radiator and having me feel to the other side would be sort of comical to me. Maybe that does mean something but I doubt it since the route through the radiator is not a straight direct line but it goes all throughout the radiator in order to cool the water/coolant. I would suspect the water pump might be bad and would try to rule that out first. I’m not sure on the troubleshooting for that but when the vehicle is running (operating temp) feel all the hoses to and from radiator, coolant tank, engine, etc. Do they feel hot? I have had a water pump fail before and when it did, it was a catastrophic failure, meaning it broke the serpentine (drive) belt and I had a large gush of coolant flood out of the part. In that case, of course I was “dead in the water” and the car broke down where it was. But I’m sure a pump could be going bad and cause issues as well. Keep us posted!
The Fans in my Daewoo dont work at all. I tried to bleed my cooling system after i replaced my Thermostat and idled the car at 2000RPM like Eric said and the fans never came on. I was overheating when the old housing blew and the fans never came on. Car operates at normal temp (usually 1/8 below the middle mark) just fine with no working fans. Maybe turning on the A/C (even though the A/C dont work) will kick on the Condenser fan?
Hi. Actually I know some women who are great mechanics/technicians. Welcome to the Forum !
Also, I did some more thinking on your radiator issue after I got some sleep. As I put the symptoms together with what the radiator tech found, I can clearly see your engine temp fluctuating quite a lot. Since the radiator had gunk in it, the engine would heat up under load because the radiator wouldn’t cool it fast enough and cool down when it wasn’t. DUH !!!
Sorry I seemed to be casting “asparagus” on the guy. I guess sometimes being in the radiator repair biz can be a “Tankless task”. (Oooooooooooooooooooo noooooooooooo) LOL !
Mark
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