i just re-installed my cored radiator with new hoses. followed instructions on anti-freeze container filling the radiator with 50/50 mixture of distilled water and antifreeze. all hoses are tight with clamps. ran engine idle for 15 minutes with heater turned on high but the temperature gauge indicated she was running hot. is this normal? is there an acclimation period? i'll check this morning to see if more fluid is needed. any suggestions?

If you installed a good thermostat it can hold air in the block until it opens.

I've also seen where the instrument cluster voltage regulator has gone bad which makes the temperature and fuel gauges read high. Temp gauge will show hot or over heat, fuel gauge will show above empty but you run out of fuel.

Trapped air can certainly mess things up, but aaaaactually, If you install a good thermostat, it's got a jiggle pin and bleed hole to prevent air being trapped behind the stat. What's more, if there were significant enough air trapped behind the stat, the temp sensor would be surrounded by air rather than water, and would never rise above the normal range.

Jimmy, you mention having "filled the radiator" with 50/50 water and antifreeze. What about the rest of the system? Did you clean/flush it out? What about the thermostat? Is it new? If so, what brand and temperature rating did you use? Did you install it properly? (there are a couple ways of doing it wrong that prevent it from opening or from opening fully). How 'bout the radiator cap; what kind and rating have you got, and do you know it's good?

There is no break-in or acclimatising period with a new radiator. Craig's suggestion of a fault in the temperature indicating system (false overheat indication) is a good one to check. The sender can go off calibration, the instrument cluster voltage limiter can go off calibration, or the gauge unit itself can distort—all of these are much more likely if the engine has actually, really overheated.

Get a suitable thermometer. Warm up the engine with the radiator cap removed, and take a direct reading of the temperature in the radiator's top tank. That way you'll know if it's actually running hot, or the gauge is crying wolf.

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Too many people who were born on third base actually believe they've hit a triple.

After flushing/filling, replacing anything in the cooling system, I usually run the vehicle to hot the first time without pressurizing (Radiator Cap loose or not on at all) to let air escape, then I pressurize and check again.

Thanks everybody. Today before starting the engine i checked the radiator and sure enough, it needed some more fluid so I filled it up, started the engine and it seems fine now. Today was a good indicator as well as temperatures and humidity were stifling and high. I would like to get a new thermostat though and I was wondering what to lood for--i.e.--who makes the best and which auto parts store carries it??? Also, what are the tips on installing one. I'm not sure the specs on the cap but the guy at the radiator shop put a new one on because he said my last one wasn't up to par. I'll check on specks tomorrow.

Stant 160 deg thermostat.Car will run cooler than ever.
It sounds like you are in a warm climate like me.

Soon someone will be on to tell you to use a 180deg stat which is stock.They will also tell you you will get better milage with the 180.

Personally I never worried about gas milage as my slant is not my daily driver,and haven't seen any difference anyways.It is up to you,but your car will run cooler with a 160.

To install:Drain the cooling system to below the thermostat.

Remove upper rad hose.
Remove the housing bolts and the thermostat and housing.
To install use a new gasket.
Make sure the vent hole is facing up.
From this point reverse the removal procedure.

Good luck
JZ

Stant SuperStat, p/n 45358. Correct temp rating is 180°. Pretty soon someone will be along to advocate using a 160° thermostat. You can do that if you have an arbitrarily low idea of where the temp gauge needle should point and are looking for reduced gas mileage and increased oil contamination.

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Too many people who were born on third base actually believe they've hit a triple.

Ouch!

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

Hook Line & Sinker

You expected any less from me?

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Too many people who were born on third base actually believe they've hit a triple.

In all fairness Dan you live in a totally different climate than I do here in Southern Cal.Today was 106 with no end in site.

What works for you in Canada doesn't necessarily mean it will work for me in California.

In the hot climate areas I wouldn't hesitate to put in a 160 stat.One of the best things I have ever done to my cooling system.

Needle points to cool,right where I want it.
Gas milage is fine.
Oil looks perfect.

JZ

I've lived in lots of different climates, from very hot to very cold.

180° is the correct thermostat rating whether you're in Tucson or Toronto. If you are relying on a colder-rated thermostat to keep your car cool, you've got other/bigger problems.
Sorry, no. You may be happy with it for reasons of your own, but it's not a good thing you've done.
What you want in terms of where the needle points isn't the same as what's best for your engine.
Better with a 180° stat.
Oil analysis is not done with the eyes.

You'll please excuse my tone here. This is one of those deals where there is science and fact on one hand, and guesses and opinions on the other hand, and in the balance hangs the answer to a technical question asked by someone who genuinely doesn't know. Some people consider the notion of "right answer" vs "wrong answer" to be politically incorrect. I am not among them.

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Too many people who were born on third base actually believe they've hit a triple.

.>>>>

So where should the temp needle rest at? MIne moves off of cold and stays on the cool side. Think I might have the incorrect thermostat.

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

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Above is a representation of the lines on your temp gauge. Under normal conditions with the engine warmed up, the needle should be right around the center of what is presented here as the green zone, between the 2nd and 3rd lines on the temp gauge.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.