Van overheating

Tiny
LILB72714
  • 1998 DODGE CARAVAN
  • 6 CYL
  • AUTOMATIC
  • 164,000 MILES

I have a 1998 dodge caravan that keeps overheating no other symptoms flushed radiator and changed thermostat already any ideas? Also can van drive with no thermostat

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Saturday, July 16th, 2011 AT 1:13 AM

36 Replies

Tiny
CARADIODOC
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  • 28,841 POSTS

Have you heard the fan turning on? Lots of other problems can result from not having the thermostat installed. The engine CAN over heat because the hot coolant won't stay in the radiator long enough to give off its heat. More commonly the engine won't get hot enough to switch to "closed loop". That will result in a loss of fuel economy.

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Saturday, July 16th, 2011 AT 1:27 AM
Tiny
LILB72714
  • MEMBER

Yes the fan is working, it seems like the coolant isnt getting through to the engine. Thats why I tryed a radiator flush but that did not work

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Saturday, July 16th, 2011 AT 2:00 AM
Tiny
CARADIODOC
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If the upper radiator hose is hot, coolant is circulating. There's two fans for the radiator. Be sure both are turning on. Look at the cooling fins between the tubes in the radiator. If they crumble when you scratch them, they are corroded away and the radiator isn't able to give up its heat to the air. That will cause more overheating at highway speed.

If it does not overheat on the highway, insufficient air flow is the problem at lower speeds. Look for a bug collection in front of the AC condenser or anything else that is blocking air flow through the radiator or allowing air to bypass it.

If the upper radiator hose is not too hot to hold onto for very long, suspect a leaking head gasket. Combustion gas can form a pocket under the thermostat which will let it close. Thermostats open in response to hot liquid, not hot air. Your mechanic can perform a test that draws air from the radiator through a glass cylinder with two chambers partially filled with a dark blue liquid. If that liquid turns bright yellow, combustion gases are leaking in.

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Saturday, July 16th, 2011 AT 10:06 AM
Tiny
JIMISCAT
  • MEMBER

I had the EXACT same problem, with my 2000 Caravan. Had radiator hoses replaced, thermostat replaced TWICE, system flushed forward and backward several times, coolant sensor (?) Replaced, block tests run and block sealer used. Cost me almost $300. STILL overheated.I could only drive about 7 miles til water in reservoir would boil, temp gauge would go to H and overheating Indicator light on dash came on. Mechanics told me they checked everything mechanical, it had to be some kind of sensor, even said the needle in my gauge might be faulty! They told me to bring it back AGAIN! Then I had a friend check the codes. NO CODES! So that meant it was mechanical and not electrical. Anyway got a guy who fixes cars on the side to check it. Said it was water pump though the other "Mechanics" said that wasnt it. Anyway it's fixed now! The guy who fixed it took out the thermostat too and left it out, he said its not needed in the summer.I was worried about that at first but I dont need the heater now and my temp gauge works fine without it and. My van runs cooler than ever.

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Sunday, July 24th, 2011 AT 12:06 PM
Tiny
CARADIODOC
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So you have an idiot for a mechanic is what you're saying? You have not solved the problem, just covered it up. Engine parts expand and fit properly when the coolant temperature reaches 195 degrees. 99 percent of engine wear takes place in the few minutes before that temperature is reached. You're running it constantly in a state of excessive wear.

The pistons are oval-shaped when cold. As they reach normal temperature, they expand more one way. The engine designers know that and account for that. They fit properly at normal operating temperature. The piston rings don't seal as well below the proper temperature so there's more blowby which condenses in the oil to form sludge. Instead of burning off and being drawn out by the PCV system, the hydrocarbons build up and reduce the oil's ability to isolate moving parts from each other and to carry dirt and contaminants to the filter.

Once a pre-determined temperature is reached, the coolant temperature sensor signals the Engine Computer to go into "closed loop" at which point is begins fine tuning fuel metering based on readings from the oxygen sensors. When the temperature is too low, it stays in open loop and fuel delivery is a rough guess. The computer will set the fault code "engine running cold too long" in memory. That will not trigger the Check Engine light, however, many self-tests are not performed until normal operating temperature is reached. There can be sensor problems or other running problems that may be detected but not recorded so that valuable information will not be available.

How do you know the water pump "fixed" the problem? If it did, why did your "mechanic" have to remove the thermostat? What does he know that the engine designers don't? Why did you use block sealer? If the test was positive for a leaking head gasket, you should understand thermostats don't open in the presence of hot air that pools under it from that leaking gasket. They only open in the presence of hot liquid. By removing the thermostat, no air can collect there. It will find its way to the overflow reservoir.

I'd hardly call that "fixed" and I certainly wouldn't be so proud as to want to share this solution. Everything you've replaced was to address the symptoms, not the cause of the problem. Why do all other engines run fine WITH a thermostat?

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Sunday, July 24th, 2011 AT 3:48 PM
Tiny
BOYDPRO
  • 1998 DODGE CARAVAN

Air Conditioning problem
1998 Dodge Caravan 6 cyl Front Wheel Drive Automatic 131000 miles

I got a service engine light which was quickly followed by the engine over heating and the AC not working. I then traced the problem to the Radiator fan relay. I have now replaced the relay 3 times in as many months. Each time everything worked fine until the srvice light reappeared. This last time I did not get the service engine light or any info from the van other than the same symptoms as before. So now I have a brand new relay, but the fans still will not run. Some one told me that old fans could be drawing too many amps, so I have replaced the fan module as well before this last relay. When I jump the wires in the harness at the relay, the fans do run. And the relay checks out ok. Any idea where to go from here? ECM maybe? I hate to make that investment if it's not for sure the problem. Thanks for any help.
-Jason

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
RASMATAZ
  • MEMBER

Could be a problem with the coolant temperature sensor or the engine temperature gauge sending unit giving the computer improper input signals therefore not energizing the fan relay or computer itself.

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
NOTNIMBAAB
  • 1998 DODGE CARAVAN

Engine Cooling problem
1998 Dodge Caravan 4 cyl Front Wheel Drive Automatic 134000 miles

I am the original & only owner of the vehicle. 6 weeks ago my car was leaking anti-freeze and overheating. I had the radiator replaced by a mechanic (not dealership). A slow leak continued, so I returned it to mechanic who "tighented" it.

All seemed fine.

I just took an extended trip - 7 hours each way. Temp gauge was fine until I hit bumper to bumper traffic. The the car suddenly started to overheat. During the trip I put in 4 gallons of anti freeze. The temp gauge only went up in bumper-to-bumper traffic -- not at red lights, etc.

What could the problem be & what is the estimated repair costs for various scenarios?

I'm trying to get an idea as to when to purchase a new car or to keep repairing this one/

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
RACEFAN966
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  • 5,127 POSTS

You said you replaced the radiator but how about the thermostat? Now is the engine fan coming on? You put in antifreeze so I take it is still leaking? Has the water pump been checked and all the hoses? I would take it to a shop unless you can do this and have a pressure check done on the cooling system and find the leak. If you do this keep in mind to never pressure the system more then you radiator cap say's on it. If you cap say's 16 lbs then keep the pressure with that. If you have no external leak it could be an intake gasket or something like that too.

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
NOTNIMBAAB
  • MEMBER

The mechanic has it now. He did not replace the thermostat with the raditor.

He did a pressure check and there is no leak.

He recommended changing the thermostat - which I told him to go ahead & do it.

I worry that there may be a blockage. I know the labor involved in that is time consuming but not sure how costly.

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
RACEFAN966
  • EXPERT
  • 5,127 POSTS

If you are using coolant there is a leak it may be internal like an intake gasket but coolant don't just diapear. So it is either using it or it is leaking or it was overheating and boiling it out. You didn't say if the coolant fan was working. Let me know what happens.

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
NOTNIMBAAB
  • MEMBER

The mechanic said the coolent was boiling out.

The thermometer was replaced as well as a relay switch and fuse. I'm a novice, so my terms aren't correct, but the car was fine when moving. When standing still in the traffic the relay switch didn't kick the fan on.

Your opinion -- is mechanic correct and this should solve my problem?

I had it fixed, but need peace of mind and not go crazy & buy a new car.

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
RACEFAN966
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Yes I think the mechanic is on the right track with the information given. With a new thermostat and fan relay you should be back in business. Let me know how it goes and thanks for your support and have a great weekend.

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
LEGITIMATE007
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Hey guys, if I may interject, If you havent done it already, check the engine coolant temperature sensor too;thats what is gonna tell the computer to kick the fans on. And since you've replaced the harness that might do the trick

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
MACARINA
  • 1998 DODGE CARAVAN

Engine Cooling problem
1998 Dodge Caravan 6 cyl Front Wheel Drive 216000 miles

My 98 dodge Grand Caravan 3.3 engine has developed an odd problem. The engine is overheating at random times mostly when the AC is on but without also. The problem seems to appear in stop and go traffic. Some days it will run without problems. I live in AZ and it is over 100F every day here The car run well in any temperatures until recently.
I have owned this car since new and have replaced many parts and in the past two years also the radiator, fan assembly, just replaced for the fourth time the Fan relay and harness, water pump is one year old. Thermostat is also new. When overheating the Fans are running at full blast regardless of that if the AC is on the temperature starts climbing rapidly. Coolant is clean and fresh there is no debris in it. I have done a pressure test on the cooling system No leaks. There is no oil in the coolant or white smoke from the exhaust. I already did a leak down test on the engine everything checks out OK. Any ideas?

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
RASMATAZ
  • MEMBER

Do a block test to make sure combustion gases are not making it into the cooling sysytem and also retest the Stat. Make sure there's no airlock in the system.

If the block and pressure test passes check the following: Thermostat, Pressure test the Rad. Cap, Clogged radiator, Fan clutch, Radiator electrical fan, collaspe hoses, water pump.

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
NOTNIMBAAB
  • MEMBER

I did have the sensor replaced.

All is working fine for now.

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
LEGITIMATE007
  • EXPERT
  • 5,210 POSTS

Awesome, come back whenever you need to, we'll be here for ya

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
RETIREZZZ
  • 1998 DODGE CARAVAN

Engine Cooling problem
1998 Dodge Caravan 6 cyl Two Wheel Drive Automatic 43000 miles

overheats. Had dealer check. They replaced themastate, temp. Control, checked fans, radiador, replaced pump, checked hoses, and still overheats. Put rebiult engine in with 33400 miles on it and still overheats. New transmission twice now in last 21 months. Beleive due to overheating? Not one dealer can find problem causing this. I run the heater & fan to keep cool. It does it at diferrent times. Mostly hot day very bad and going up hills. I heard that maybe the catlytic converter might be the problem. They never check that. Also heard that the "tsb"'s are bad on these. What is that? I really need help on this one. I can't keep putting a transmission in every year or so. First time at this.
Martha

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Friday, May 26th, 2017 AT 6:55 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
  • 68,227 POSTS

Hi:
It sounds like you replaced everything there is to the cooling system. Your idea of checking the cat conv is a good one. The only other thing I can think of will deal with ignition timing or a vac leak. Check to make sure that it is within specs.

Also, TSB stands for Technical Service Bulletin.

Let me know whatyou finds.

Joe

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Friday, May 26th, 2017 AT 6:55 PM (Merged)

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