HG's, overheating, fan clutches etc.

Discussion in '80-Series Tech' started by Dansan, Aug 7, 2005.

  1. Dansan

    Dansan

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    I've followed the various threads on this topic for some time and gone back into various archives via the search function. What a remarkable body of information on this topic!

    One comment that sticks out for me is from Idaho Doug and that is to the effect that these trucks, aside from wrecks, can only really get hurt from overheating.

    The tales about HG failure and the problems that can create are scary, but replacing the HG as a pm item is scary as well, unless of course you have the time and skill to do it yourself.

    My read on the topic though is that frequent radiator maintenance, preferably with Toy coolant and close attention to belt condition, fan clutch condition and the integrity of the radiator itself can largely forestall an HG issue. My impression is that even a temporary spike in operating temps can start the HG on the road to failure.

    For my own part, the coolant, belts and rad issues all seem to be under control. The only thing that jumped out at me was the fan clutch and I ordered a new one from CDan last week, strictly as a pm item.

    Before it arrived, we went on a 3 day trip from LA to Zion NP in Utah. The coolant and the thermostat in the truck were new, as were the belts and most of the major hoses, including the PHH. The truck , 1995, has 119K soft miles and I'm the original owner.

    For anyone familiar with the route on I-15, temps varied from 98 - 107 the entire trip. Baker was 105 on the big thermometer as we drove out of the valley up to Halloran summit (4,000ft). No issues with AC on #3, OEM temp gauge didn't move. Return trip, similar temps, 100F on climb from Primm up hill into California. AC blasting and cold all the way, no changes in temp gauge.

    When the truck had 80K miles, I travelled from Chicago to LA, pulling a 4,000# trailer in high temps for the entire trip, without any cooling issues. The moral, at least for me, is if all or most of the components are functioning right, overheating is not any sort of issue for these trucks.

    When I got home and saw the package from CDan with the fan clutch, my thought was to wait for some real indication of failure in the current one, before replacing it. I felt good about having it on my shelf.

    When I opened it up though and checked the resistance (to turning) that it had, it seemed very different from the one on my truck. I frequently check the one on my truck and while it does have resistance, my unscientific assessment is that the new one is at least 3 times as diffucult to rotate.

    How long might a marginal fan clutch slowly damage the overall system to the point where when its noticed, significant damage is already done?

    I now feel a lot more inclined to change my fan clutch tomorrow, rather than be smug about having a "spare" on the shelf.
     
  2. CruiserLegolas

    CruiserLegolas

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    "How long might a marginal fan clutch slowly damage the overall system to the point where when its noticed, significant damage is already done?"

    That's a good question and I hope someone has some insight. I just replaced the thermostat and the radiator, but not the fan clutch. The fan clutch test that people have mentioned seems to uncover a bad fan clutch, but not necessarily one that marginally works.

    The dealer told me that my fan clutch was working, but I would hate to damage my new radiator due to the fan clutch...I guess I should be ordering one soon just to be safe.
     
  3. Elijah

    Elijah

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    i'm also gonna be ordering the fan clutch, pm only. after much reading it seems the cooling system is the one thing you can't really overkill. better safe than sorry.
     
  4. Dusty

    Dusty

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    Dansan
    you suggest that overheating is not an issue if the cooling system is in top shape. how fast did you attempt to run the halloran summit at 105 degrees?
     
  5. Dansan

    Dansan

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    Dusty,

    I went up the hill at between 65 and 75mph, with the OD off at some points. Lots of people were passing me.

    Being as I had the original fan clutch, rad etc. I was watching the temp gauge and feeling the AC to see if it stayed cold, which it did.

    Others have pointed out that the OEM temp gauge is not really reflective of operating temps until it goes into the danger zone, but that AC cutoff indicated you had passed a certain point.

    My thought is that a rig with all of its cooling system in top shape should be able to go up that hill at 70MPH on a 100+ day, AC running and no issues.

    As mentioned, I towed 4,000# through that area under similar conditions and had no issues except for the low speed.
     
  6. Dusty

    Dusty

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    Dansan
    "I went up the hill at between 65 and 75mph, with the OD off at some points. Lots of people were passing me."

    I wish i could say the same for myself. The last week in may I ran the same pass with similar speed and conditions with a heavy rig and had the ac cut out near the top. my elctric guage read 220 when the ac cut and got as high as 228 by the top. (i shared this in a prior post) since that time i have installed a new oe fan clutch. thanks for the post
     
  7. IdahoDoug

    IdahoDoug

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    Interesting. Another data point supporting that an as-new cooling system is up to the task. He's owned it since new and the coolant has not been neglected (fastest way to damage a HG), etc. I've posted my own extreme heat experiences towing overweight with no A/C cutout, etc.

    This weekend, we towed with the 97 and on a 96 degree day I had my foot to the floor for 1.5 mins with no issues despite a 23-25mph speed due to a 6000lb boat trailer. It's the climb up to Boundary Dam in NE Washington state for anyone in the area. Mucho steep. A/C blasting all the way.

    Makes me wonder if those with everything else in top shape (coolant, thermo, belts, fan clutch, cleaned rad fins) should look at a professional radiator cleaning (requires removal) or a new OEM radiator to index their cooling system.

    I may be heading to LA in the next month and I'll be doing some of those hot passes. If I purposely go up at WOT and have no issues that should be a data point worth considering.

    DougM
     
  8. locrwln1

    locrwln1

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    Had a radiator shop tell me once that "most" fan clutches lose approximately 100 rpms per year. So his take (did not make any money off of me) was that fan clutches should be changed out every five years or so under normal yearly mileage. So just a thought if you have any doubt about the condition. On the other hand, my 4runner had, as far as I know, the original fan clutch from 1988 and 116k miles. Never had any cooling problems.
     
  9. chukarhiker

    chukarhiker

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    Did the Prestone flush and installed the new 3-core radiator and fan clutch from CDAN 2 weeks ago. Towed the Tent Trailer up Ebbetts Pass last week with the AC on high and foot in it with no heating issues at all and the AC blowing cold the whole time. Two weeks ago I would have been losing the AC with nothing in tow. I can now hear the fan spinning where I did not before. Seems that the AC blows cooler than it ever did also.
     
  10. Dansan

    Dansan

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    I happen to own a 1995 Acura Legend sedan, which I bought with 104K on the clock. If you read the Acura forum for this model, its very well populated with comments about overheating and failed head gaskets.

    When I bought my particular car, it came from the original owner and he had every receipt for what he had spent, including a new radiator, shortly before I purchased it. Interestingly, he had tallied $7,100 in maintenance for the car in the period he owned it, versus the $4,600 I had spent on the LC in the same period.

    That particular Acura has the same rad failure issues as the LC, and people constantly talk about their cars overheating. I had the opportunity to drive mine on the same route I just drove my LC and it performed flawlessly, with the LC at full blast.

    Many of the second owners of the Acuras might be guys in their 20's who buy them with a view to adding performance mods. If they happened to pick up a car with lax maintenance, their, shall we say, hearty use, will provoke premature failure in several areas. This is a car though, much like the LC, that will give excellent service if properly maintained.

    Having said that, it may not be fair to characterize the LC or Acura cooling systems as weak areas. The right description may be that anything less than anal attention to the cooling systems will provoke big problems.

    The LC's are indeed so reliable that many people who own them through 80K or so, then sell them, may have very spotty maintenance records. The cumulative effect of that type of situation might well be early failure in the cooling system.

    If someone is buying a used 80, without maintenance records, they should factor in the costs of a radiator, fan clutch, belts, at a minimum and perform some test to assure the integrity of the HG. This would be in addition to the condition of the various other components.

    I like to see people buy these used and get a good deal, but I also cringe at some of the expenses people face after they buy them.
     
  11. willywaxer

    willywaxer

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    I have a '96 with 120K miles (bought used in '98 with 30K miles) and have maintained it regularly since the purchase included a 100k bumper-to-bumper warranty and lifetime oil service. However, on a recent hot day with the AC blasting, my engine started to overheat (into red) and the battery light went on. Pulled over and noticed 2 of the 3 belts had disintegrated. These belts were previously replaced by the Toyota dealer as part of the regular 80K service. Dealer said they were properly adjusted, just wore out. Hence, I'm beginning to question the quality of fan belts used in these models. Either that, or they are under a lot of stress. Definately worth having spares on hand. I replaced all 3 and had the 120K service done. Seems to be cooling just fine, didn't look like any damage was done.

    Interestingly, the unrelated pinging problem that I and many others have been experiencing (thought to be poor fuel) went away after the 120K service. They did a lot of things so I have no idea which was the culprit.
     
  12. santiagol

    santiagol

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    You consider your belts to be of poor quality because they only lasted from 80k to 120k? How long should belts last?
     
  13. powderpig

    powderpig SILVER Star

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    Willy. The belts are good quality, but you are right. They do not last forever. Inspections need to happen more often than every 40k or more. The responsiablity lies with the owner as well as the place that maintains it. Do not blame the belt for the lack of inspections. When do you look under the hood? If never then you need to learn what to look at and when. Maybe a quick look under the hood when the fuel is going in to the tank. later robbie
     
  14. willywaxer

    willywaxer

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    Don't be naive, I look under the hood frequently. This is not my first car. I've owned at least 40 of them, starting in 1969, including 8 Toyota trucks (currently have a Tundra, an LX470, a CLK55, and the LC). I know what worn belts look like. I've always made at least 50-80K on belts, though I typically change them out before 50K. For belts to completely blowup after only 35K miles (had the 80K service a little late) is too soon in my experience, particularly with my style of driving. Also, I live in the Pacific NW, a moist environment...belts last longer here then they did when I lived in hot and smoggy L.A.

    How many miles has it been since you changed YOUR belts?
     
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