[V8] Overheating - revisited

[Ingo Rautenberg]

I'm with Dave on this one.  I also have experience with this and  
replaced (needlessly) the fan clutch.  The radiator on mom's 2nd V8  
was clogged and my Heater core was breaking up (may have been the  
culprit) and little bits of plastic actually stopped the flow of  
coolant from the small hose from the radiator to the expansion tank.   
Nothing like no/low flow to encourage calcification of the radiator  
passages.  If you have one of those infrared pistol-grip  
thermometers, you can check for cool spots in the radiator.  If the  
radiator isn't getting hot, the viscous fan clutch won't get hot  
enough to work anyways.

Best of luck.

Ingo

On Jun 17, 2006, at 9:22 AM, Dave Head wrote:

> Having had a few V8s in the family over the nearly 10 years (4 - red,
> green, blue and white), the major reason here is a partially blocked
> radiator. Period. The problem is poor design coupled with poor
> maintenance. The poor design is the smaller electric fan beside the
> large clutch fan - this causes high and low temperature spots both
> vertically and horizontally across a crossflow. The poor  
> maintenance is
> due to not maintaning the proper coolant/coolant levels.
> I've seen them partially clog in as little as 4 years. It usually  
> takes 10.
> Yes, there is the rare problem with a viscous fan clutch, or a
> thermostat, or a fan speed issue. Once even excessive erosion of the
> water pump vanes.
>
> But relatively normal temps at highway speeds coupled with overheating
> in town are nearly always the radiator on a V8.
>
> Mike Del Tergo wrote:
>
>> UUmm,
>> all fans are not operating as they should or the airflow over the  
>> rad would
>> be suffucient to cool the car if it is OK on the hwy, when in stop  
>> and go.
>> If OK on the hwy then water pump/tstat/and rad are OK. What  
>> changes when
>> stopped?  Air flow, which the fan is supposed to compensate for and
>> apparently is not.  Could be clutch, as alsways with this car  
>> check replace
>> the 80 amp connection as well.
>>
>>
>>
>> Scott Baumann / PTS Power scott at ptspower.com
>>  All fans operate as they should (checked all of that out).  This  
>> is my
>> third summer I am facing with these issues.  I am seriously  
>> considering
>> parking this V8 for the summer and only using it for a cold  
>> weather car (85%
>> of days here in Wisconsin anyway).  Any ideas??
>>
>> Regards,
>>
>> Scott B in WI
>>
>>
>> _______________________________________________
>> Audifans V8 mailing list
>> Send posts to: mailto:V8 at audifans.com
>> Manage your list connection: http://www.audifans.com/mailman/ 
>> listinfo/v8
>> Have an Audi V8 question?  Check the Audifans Knowledgebase!
>> http://www.audifans.com/twiki/bin/view/Audi/V8
>> Have a V8 answer? ... Please help others by adding to the KB ...  
>> all contributions welcome!
>>
>>
>>
>>
>
> _______________________________________________
> Audifans V8 mailing list
> Send posts to: mailto:V8 at audifans.com
> Manage your list connection: http://www.audifans.com/mailman/ 
> listinfo/v8
> Have an Audi V8 question?  Check the Audifans Knowledgebase!
> http://www.audifans.com/twiki/bin/view/Audi/V8
> Have a V8 answer? ... Please help others by adding to the KB ...  
> all contributions welcome!