Excessive Engine Heat

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  #1  
Old 07-03-02, 03:07 PM
rckowal1
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Excessive Engine Heat

Issue is with 1999 Dodge Caravan, V6 3.3L engine, automatic transmisssion, 60,000 miles.

With the onset of hot weather (90 to 96 degrees), my Caravan started running VERY hot. To see if the air temperature was a major factor, I checked engine temps during the morning when it's cooler & during the peak heat of the day - engine runs a wee bit cooler when outside air temp is about 80 degrees. Although it hasn't boiled over, the engine temp needle gets up to just under the red mark. Also, when the engine temp gets up that high, the A/C starts to blow air that's much warmer than room temperature. When the engine temp is a bit lower - when car is first started & driven for a short time - the A/C blows really cold air like it should.

As expected, if I run the heater inside the car, it significantly reduces the engine temperature to more normal temp - while greatly increasing my discomfort. When driven at freeway or highway speeds, the engine temp climbs up to near red line in about 5 minutes. With continued driving, the temp pretty much stays at that level.

I've already done a lot of home work on this problem; including checking to be sure the engine thermostat is opening - it is. Watching, & topping off coolant in radiator & overflow bottle. The engine cooling system is tight - no leaks or loss of coolant. Both the A/C fan & the radiator fan appear to be running normally. I cleaned the outside of the radiator & A/C condenser - to get rid of bugs, lint, etc. - using a high pressure car washer. I burped the cooling system to check for air pockets - none seen. A/C system was professionally checked for normal operating pressures & topped off with freon - abt. 3/4 lb. was added. The A/C pressures were normal. I've checked the oil for signs of water contamination & it's clean. No white smoke or moisture seen in the exhaust. None of these efforts has decreased the engine temperature in the least.

Resorting to professional help, I've been to six licensed auto mechanics &/or Engine Cooling-A/C shops' No instrumented diagnostics done but outlined here are their "shooting from the hip" opinions.

#1 Mechanic: Bad thermostat.
#2 May have bad thermostat but it looks normal for this weather. Visual check done.
#3 Looks normal for this weather. Visual check done.
#4 A/C radiator shop: Probably needs a flush
#5 A/C radiator shop: Could be a number of things but suspects bad engine head gasket ($1200)
#6 Didn't see anything wrong during visual hands on check.

Can anyone help? I want to fix it whatever it takes, but I'm out of good ideas. At the same time, I don't want to give the pros an open check book when they seem to be quessing. I've stayed away from Chrysler dealer shops since they don't seem to be any sharper than the smaller shops, but they can sure run up huge repair bills & take a long time to get the job done.

Your help & advice will be very much appreciated.

Best regards, Dick
 
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  #2  
Old 07-03-02, 03:17 PM
Joe_F
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Whoa Nelley.....

Do the electric fans ever come on? If they don't we've got trouble Houston. Common failure is the relay behind the LH headlight. Bring direct power from the battery to the fan to see if it spins.

Let the vehicle idle and observe if the fan goes on after some time (may take up to 30 minutes or so). Also turn on the A/C and see if the fan goes on. I believe this vehicle has two fans, one for A/C, one for cooling.

Most if not all of these "opinions" can be checked scientifically, but if you ask any mechanic off the top of their head, they will give you typical occurences. The thermostat and coolant flush should be done without reservation...bar none, every year on the dot.

Bouncing around from garage to garage will only frustrate you and net you a different answer each time.
 
  #3  
Old 07-03-02, 03:27 PM
rckowal1
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Excessive Engine Heat

Thanks for the reply Joe, it's very much appreciated.

After posting, I realized that I had failed to mention that both the A/C and radiator fans appear to working normally. I've since edited my post but apparently your reply was moving faster than my edit in cyberspace. Is your thinking affected any by my updated information?

Since a thermostat and flush job shouldn't cost that much, I'll give that a try after the Holiday.
Any other ideas?

Best regards, Dick
 
  #4  
Old 07-03-02, 04:49 PM
Joe_F
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I'd have to go with the stuck thermostat and flush for now. Use an OEM (Chrysler) thermostat and clean out the cooling system.

Have the shop check the whole thing stem to stern. See what that nets you.

Alldata.com shows no technical bulletins on cooling issues for this model.
 
  #5  
Old 07-03-02, 07:09 PM
tstokka
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is it really getting that hot? I've seen people get upset cause their guage is telling them its hot and it turns out that its not above 220. temp sensor was the problem. At least they are looking at their guages, some people don't. I would to the flush and thermostat change and have them check the temp of the coolant and compare it to the guage.
 
  #6  
Old 07-04-02, 06:13 AM
rckowal1
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Thanks for the reply. I don't have any way to check the actual coolant temperature but I can tell you that the engine, hoses & radiator really feel very hot. But regardless of what the gauge says, or doesn't, its very clear that I can't use my air conditioner now but I could up until several days ago - no matter how long I drove & how hot the outside air temperature was. Also, I regularly pay attention to my gauges & the engine temp gauge is way higher than ever before. It was never, ever, up to the edge of the red line before. Also, my neighbor has the exact same car & its operating just fine - the A/C works & temp gauge goes up only 3/4 of the way. To me at least, this strongly suggests some kind of a cooling system problem. I think your advice to flush & change the thermostat is probably the best route to try right now. I'm also going to have the shop check the gauge, actual coolant temp, etc. Since they're also experts in A/C, I'm sure they'll sort it out. Have a great 4th of July.
 
  #7  
Old 07-04-02, 10:48 AM
rckowal1
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Update On Excessive Engine Heat

I test drove the problem child again this morning in cooler weather. Between 81 and 85 degrees F, I drove about 15 miles in half (30-40 MPH) city traffic & half highway (40-50 MPH) speeds before the A/C started blowing warm (75 deg. or more) air and the temp needle got up next to the red line. This is definitely abnormal.

In fact, this A/C has always cooled the cars interior very well for sustained (1 hour) periods at freeway (55-70 MPH) speeds. In fact, it rarely had to be set any higher than low fan speed to keep it cooler than 70 degrees, regardless of the outside temperature. At max fan speed it got so cold that it would give your skin goose bumps.

What I can't seem to get through my thick skull is whether this is an A/C or an engine cooling problem. Or a combination of both! I'd really appreciate some comments from the experts on this.

Additionally, I would like to know wether this warming & loss of A/C cooling in the car is due to the A/C system shutting down/malfunctioning - (???like a high temp safety shutdown?? or something??). Or is it just that the A/C's refrigerating action is some how being defeated by an over heated engine cooling system?

Joe, what do you think?
 
  #8  
Old 07-04-02, 11:53 AM
Join Date: Jun 2002
Location: Long Island, NY
Posts: 1,531
Many times I've seen the most basic things overlooked. With cooling system diagnois first thing is to check is the coolant level. At that time cap is thrown in tool cart or on the bench. System is throughlly checked over, but pressure cap often forgotten about.

Has anyone tested the pressure cap?

Larry
 
  #9  
Old 07-04-02, 12:46 PM
rckowal1
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Hi Larry, Thanks for the reply.

No, the cap has not been pressure tested. I don't
however understand how it could contribute to this problem when there is never any loss of coolant. Can you educate me on how a defective cap could cause overheating if no coolant is lost??

Best regards, Dick
 
  #10  
Old 07-04-02, 01:51 PM
tstokka
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will the temp go that high without running the a/c? If it does then I would concentrate on the cooling system, if it doesn't then i would look at the A/C system.
 
  #11  
Old 07-04-02, 02:37 PM
JackMaster
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Mysterious Caravan

Dick,

It sounds like you have really checked things pretty thoroughly. A couple things come to mind that I have not seen posted as of yet.

1) Belt condition & tension - since you are having "hot" cooling system problems and inadequate a/c function at the same time, I would check the belt as it drives both the water pump and the a/c compressor.

2) Water pump - is it adequately circulating the coolant?

3) System Restricion - I think Joe's recommendation of flushing is vital here. It may be possible you have some foriegn material lodged somewhere (heater core?) in the cooling system.
 
  #12  
Old 07-04-02, 02:55 PM
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I agree with JackMaster, if your heating up on the highway it's not a fan problem. A bad cap would have you losing coolant. Sounds more like circulation is not happening. Check your belt(s) and your water pump. A good flush never hurt any thing!
 
  #13  
Old 07-04-02, 05:19 PM
rckowal1
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Thanks guys for all the input. It helps me to better understand what's probably going on here.
Answer to your questions are:

A couple of mechanics & I have all looked at the belt and water pump. Externally there's no sign of any kind of problem there.

The excessive heating occurs when the A/C is on, or off. When A/C is on, it seems like it's just getting hot quicker.

By the way, I also checked the transmission fluid & it's clear & clean.

As several of you have suggested - the indications seem to point to a lack of adequate coolant circulation; thermostat malfunctioning or even the dreaded head gasket failure. Another web site discussed gasket failure symptoms at great length. One of the scenarios it that it can allow hot combustion gases to enter the engine cooling system causing it to overheat.

I'll post the diagnosis of the AC/engine cooling system shop tomorrow.

Best regards, Dick
 
  #14  
Old 07-05-02, 05:43 AM
Joe_F
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Dick,

It could be anything, but as others have told you, the basics need to be checked. Any competent shop could check it.

1) If the radiator cap is bad, cooling system boiling points are effectively reduced. You can change the cap (5 dollar item) to rule it out as a possibility.

2) If the coolant hasn't been flushed yet, start there with a new thermostat. That's the first step.

Let's start there and see what we have. Again, bouncing around from shop to shop to ask their .02 gets you very little as you will get varied opinions, as you are also getting here.

Who knows, the third guy you asked may have been just sitting down to eat his turkey sandwich when you called. He probably gave you a typical answer to your problem based on his experience. With that being said, he may have just answered you this way to get you off his back . Who knows?

Take it to a trusted shop, explain the problem and tell them to call you with what they find and post back what you are told.
 
  #15  
Old 07-05-02, 12:40 PM
rckowal1
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Excessive Heat Update

Thanks for the advice Joe. It's much appreciated & making more & more sense.

I had a radiator/AC shop diagnose my problem. He gave me the bad news that it's a head gasket & he wants $1200 to replace it.

Because I had a gut feel that this shop may be less than trust worthy, I called a neighbors friend who is a service manager at a large auto service center. He doubts this diagnosis since it's extremely unusual for this model car to have a bad head gasket at 60,000 miles - unless it's been carelessly abused. Anticipating the question, "why didn't you go to him in the first place" it's because they're closed until Monday.

In the meantime, I've taken the car to another radiator/AC shop. This one was recommended by friends who also don't trust the shop that did the above diagnosis. Although shop #2 charges $35, I think I may get a more objective opinion from them. Isn't it interesting how we all become experts on auto service centers after the fact?

I've also talked to a different service shop to check the going cost of replacing the head gasket. They quoted me $550. This just further raises my doubts about the ethics of the shop that did the first diagnosis. I know they need to make a living too, but at twice the going rate?

I'll post the results of the second opinion when the jury returns it's verdict.

Best regards, Dick
 
  #16  
Old 07-05-02, 01:09 PM
Joe_F
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Dick,

I question why you brought it to the first shop. Monday is right around the corner and with a holiday weekend upon us, many businesses closed up early and are gone until Monday.

With that in mind, go to the second shop and get a 2nd opinion. The shop should be able to spot the head gasket pretty easily. A gas analyzer can detect the presence of hydrocarbons in the cooling system. That is a key off to a bad head gasket. So, ask them to do that....they will check other ways too.

Then, get a roundabout quote from the Chrysler dealer and make your repair choice. If it turns out to be the head gasket, I would call up Chrysler and ask for a goodwill extension of your warranty, perhaps they will pick up some of the tab on the repair.

A vehicle with 60,000 miles shouldn't blow a head gasket. That will be your argument with them to pay for part of the repair.

But, let's not go there until we know what we are up against.
 
  #17  
Old 07-05-02, 02:10 PM
JackMaster
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Dick,

Without seeing the vehicle myself, I would question a blown head gasket based upon the information you have provided.... in your original post you stated there is no moisture or white smoke being emitted from the exhaust and the cooling system is not leaking (coolant level remains full) in addition, you do not make any mention of decreased or poor performance..... Are you absolutely certain the cooling fan is working properly? With the a/c warming and engine temp climbing at the same time, it sounds like the fan may not be opearating properly and pulling air through the evaporator and radiator as needed, preventing adequate dispersment of heat from both ...hmmmm it HAS to be this or things I mentioned in my first reply......BUT then again, it may just be coincidence that there are actually 2 separate conditions occurring here.....
 
  #18  
Old 07-05-02, 02:15 PM
JackMaster
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Talking

O.K., I just have to ask this one.....

What are your winters like there? As in Alaska, do you happen to place cardboard or other material between the radiator and evaporator that you may have forgotten to remove?????!!!!!!

 
  #19  
Old 07-05-02, 03:05 PM
Join Date: Jun 2002
Location: Long Island, NY
Posts: 1,531
I doubt the headgasket also, you said no loss of coolant. If head gasket is leaking combustion into coolant you have to have bubbles rising up into the top tank of rad. Topup coolant to the very top of the neck and watch for bubbles no matter how small.

I have never seen a headgasket leak at a water jacket that didn't consume some coolant(maybe a small amount)

From your observations sounds like a heat transfer problem. It's ok in cooler weather, but when it warms up or you use the a/c (just adds more heat in front of rad to deal with) it can't handle it.

If you can seen into the rad I would drain down the coolant to below the core. Look for any scale or corrosion in the tubes. If you find any I would reccomend sending to rad shop to be boiled and rodded.

Also check the fins for being rotted. Run a screw driver along the fins lightly. They should dent, if they flake the rad ng

Larry
 
  #20  
Old 07-05-02, 04:05 PM
rckowal1
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Thanks to Joe F, JackMaster & Toyotaman for all your help, it's appreciated.

Responding to all of your comments is a bit like trying to wash an elephent - you're not sure where to start.

JackMaster, our winters can be cold but not to the point where anybody puts cardboard in front of the radiator. Also, I cleaned the exterior of the radiator with a pressure washer so other than a few bugs that are stuck in the fins, it's clean as a whistle. I am absolutely positive that both fans are running. The AC fan starts when the AC is turned on & the engine fan when the thermostat kicks it in. I can both see & hear them run. Also, there is no white smoke/steam or moisture coming from the exhaust at any time. And there is no loss of performance or any symptoms other than the ones posted.

Toyotaman, the radiator fins are in very good condition. No signs of damage, corrosion, rotting, etc. And I am certain there is no loss of coolant. The coolant reservoir is filled to the normal line & falls when hot, then rises when it cools. I've even checked the coolant level in the radiator several times now and none is being lost. When I looked at the radiator coolant level with engine running & cap off, I didn't know what to look for but I don't recall seeing any bubbles. I remember seeing the coolant level rising until a small amount over flowed out of the neck. I assumed this was due to the pressure increase/expansion caused by the engine heat. Once the thermostat opened, the coolant level dropped abruptly. I had to add about a half quart to replace what flowed out.

Joe, I'm following your advice. the car is at shop #2 waiting to be checked out tomorrow. Also, I know the service manager at a Chrysler dealer who will give me the straight stuff on a head gasket job. Don't know about Chrysler cooperating on a good will warranty action though. When I had a transmission problem just after the warranty ended they all but told me tough S__t. But it's always worth a try.

Enjoy the rest of the holiday guys, Dick
 
  #21  
Old 07-06-02, 11:23 AM
rckowal1
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Success At Last

Thanks to the help that all of you so gratiously provided, and the work of a good trust worthy service shop, my Carvans running fine again.

Even by remote control (internet) you called it correctly on the first try. And it wasn't a head gasket - only a faulty thermostat that wasn't opening all the way. Total cost out the door - after full credit for the diagnostic charge, topping off the coolant & tax - was $55.17. A far cry from the first diagnosis of a bad head gasket at $1200. Although it took some time & some inconvenience to get to this point, it was worth it.

Most of you also recommended a flush (as well as a thermostat) but the shop said they didn't believe it was essential right now. In addition to testing for combustion gases in the coolant, they also checked the cap, the temperature gauge reading of the coolant temperature & said they're fine. Frankly, I think they were getting ready to take off to continue their holiday. So they preferred to get me out the door rather than making a few extra bucks. Regardless, I plan to have this done soon since the the old coolant is due to be replaced anyway.

One more question guys, the shop said my water pump was beginning to show early signs of emminent failure. It's not leaking yet but there is some staining at the weep hole. What should I expect in terms of mileage before it's likely to go bad? Would it be a better idea to do a package thing soon including the pump, power flush & new coolant at the same time? I've gotten a quote of $185 to do it all at once. Sounds fair to me but you're the experts - what do you think? Maybe it will be less expensive as a package than piece meal/one at a time.

Once again thanks a bunch guys, I really appreciate your hospitality and help.

Best regards, Dick
 
  #22  
Old 07-06-02, 01:18 PM
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Posts: 247
I would suggest the pump,etc. It sounds reasonable and by far less headache than breaking down. I would though have the shop show you exactly what their seeing, if you can see it as they described then you might go ahead and have the work performed.
As far as the air conditioner not cooling when you were having the problem,that's the design of just about any system out there.
The computer reads the higher engine temperature and cuts out the voltage to the compressor.I thought i'd mention it just in case the shop hadn't.
 
  #23  
Old 07-06-02, 01:31 PM
Joe_F
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Thumbs up

I agree with Fordtech. Pitch the pump. If it breaks when you're on the road, you're going to get soaked for a repair and not be a happy camper.

Always head off trouble. It's cheaper in the long run.
 
  #24  
Old 07-06-02, 05:55 PM
rckowal1
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Thanks Fordtech & Joe,

I intend to replace the pump when I get a bit better idea of cost & time to get it done. I only have one car so it takes some planning & effort to line up a ride, schedule the car into a garage, etc.

In the meantime, I was hoping some one would tell me just how urgent this condition is and if $185 is a reasonable price. The shop that did the thermostat didn't go into any detail.

Best regards, Dick
 
  #25  
Old 07-06-02, 06:24 PM
Joe_F
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Sure, it sounds reasonable. The pump is probably 50 bucks right off the bat. Say at least an hour's labor at 75 bucks, that puts you to 120 or so. Add another 20 bucks for supplies, fluids, etc and you're up to 140/150.

I'm guessing on the labor of the pump, you can always goto the autolibrary link in my signature file yourself and see how involved it might be. That will give you an idea for yourself.
 
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