Just a Question about Engine Temps Does the early 80's 4.9L I6 Usally Run hotter than all the other Engines that they used. And is it better to use an OE Thermostat or a Diffrent Degree One I see there is the choice of 165 and 195

 

I do not believe the 4.9L engine runs hotter than "all the other engines". Use the original temperature thermostat for best overall performance. [normally 195F]

If yours seems to be running hot and you are basing this on the factory gauge, understand that these gauges are not the most accurate. You might consider an aftermarket gauge [for testing purposes] or find someone who has an IR thermometer and check the temperature.

 

Thanks for the Info appricate it all. Orderd a New Rad and Getting a new thermostat for it tommrow. Hopefully will take care of any issues that am having with it seems to Be Going though Coolant. but there were a few leaks hope that i took care of the problem now

 

I always figured if the coolant was staying in, you don't have a heating problem.
In my 72 I ran a 205 year round and picked up a 1 1/2 mpg in city winter driving.

 

All the hoses are hot. Heater up and lower but it just seems hotter than normal but the rad i believe is the orginal soo not as free flowing as it should be. for 32 years old i think its due.

 

I don't know about where you live, but I could say the same for here [100+ yesterday and predicted for the next 5-6 days].

Perhaps your ambient temperature is higher than normal?

 

Interesting input. Not meaning to hijack, but I monitor and record every tank for gas mileage and know that my mileage decreases by approximately 1 1/2 mpg in the winter.

 

Cold starts and short trips take their toll on mpg.

What wb3 said X2. Cooler is not usually better.

 

82 inline six, heater gauge shows 3/4 when driving about a 1/2 hour down the highway! no leaks under the hood, replaced all crack vacum lines, and the problem started. have 61,000 on the motor, this motors indestructable as ford says, beginning to wonder sometime, Help!any Ideas. thought the hot weather might be a factor?

 

I also kept a log book of every fill back then and that was a true long term average, not just one or two tanks that most people make their claims on. I also ran the 205 year round, even though the hottest days were maybe low 90s. I only overheated to the point of loosing coolant once and that was towing my friends heavy 1969 vintage American jet boat with a 455 Olds on a 90 degree day. Even then it only percolated over after I shut it off on a hot soak.

 

Duh! Ill figure it on my own dont care about mpg. running at 200 degrees.

 

I read your previous post as well as this one and I am not sure how to answer, but...

I'll take a stab and say that it sounds as though you might have a cooling problem IF your factory gauge is correct registering ~3/4 of range after driving for a half hour. The big "IF" is because our gauges are known to not be accurate, especially if the IVR [Instrument Voltage Regulator] is acting up or the sending unit is defective. At best, if original, these items are 26+ years old. When the temperature gauge indicates higher than normal, have you also noticed that the oil pressure and fuel gauges read higher as well?

Is it possible that your radiator is partially plugged or obstructed? There might be enough cooling capacity for light duty work, short trips or when driven in cooler weather, but insufficient cooling capacity when worked harder [i.e. highway use] or when driven in hot weather. When the gauge reads high, try turning your heater on [max heat and full fan] and see if the temperature drops.

Is the bottom radiator hose really soft so that it collapses as the water pump draws the coolant through it?

Perhaps you can get someone who has an infrared thermometer [hand held] and simply point it at the radiator or thermostat housing and measure the actual temperature as soon as the truck can be stopped and the hood opened [safety first!].

Just some thoughts. Maybe this can get the ball rolling...

P.S. Welcome to the forum!

 

The stock gauges are accurate for pass/fail just like an idiot light. But to get definitive readings requires an aftermarket gauge...one that actually displays the temperature.

 

The hottest I ever got my engine was 235 or so, and that was with a trailer that was loaded heavier then my truck is honestly capable of pulling safely while pulling a steep grade at about 75 mph with the outside temp at 108.