220*F too hot for an '80s era 305?
 

Since my ’87 T/A spends most of its time in a garage because it’s only a weekend driver in the warmer months, I take the time once every two to three weeks to fire it up and let it run it for a bit even if I do not drive it. My Typical routine is to let it run 25 min to a half hour. During that time I mostly let it idle. I run it through the gears (auto) and allow it to roll out, then back into the garage a few times (large garage stall), pump the brakes, exercise the steering w/ full right and left turns, run the A/C, and move HVAC controls through all the positions, etc. For about 10 minutes of that time I rev it up to maybe 2,100RPM and hold it between 1,800 to 2,100RPM to simulate what it would run at on a highway. While I understand nothing is better than actually driving it to give it exercise, I believe my little garage warm up is better than doing nothing at all when not being used for extended peroids.

That said, in the five months I’ve owned the car it seems to reach a consistent operating temp and remain there. Whether on the open road, stuck in stop & go traffic in July, or my above garage routine, the needle reaches a certain point below the center/220 hash mark and stops there every time. My guess is it’s around 200*F give or take, but I’m not really sure. The car is bone stock, so it must be where the factory set it. Last night while I was again running it in the garage it crept up to 220*F (needle to the center of the gauge) for the first time while I was holding the engine at around 2,000RPM for several minutes. I don’t know whether it had leveled off there or if it was still climbing when I noticed it, but I immediately dropped it to idle and turned the heat on full and the needled dropped back down to where I normally see it. A friend who is a tech and an old Chevy/Pontiac enthusiast said my ‘80s era 305 (LB9 TPI) was not designed to run at those temps, and although unlikely, there is a remote possibility damage could have occurred. This surprised me considering I know more modern GM V8s run around 230 or so due to emissions. I assumed mine would be no different. I would not have thought much of this brief hotter than usual operation until my buddy told me that. Now I’m a little concerned I stressed the engine. I figured his would be a good place to ask.

Thoughts?

Re: 220*F too hot for an '80s era 305?
 

220, while a bit high for that combo, probably would not have done any damage to the engine. Just to be on the safe side, do a full service on the cooling system, (drain/flush/new 'stat/new coolant/new hoses/blah,blah,blah). See how it is after that. Also, double check the accuracy of your gauge.

Re: 220*F too hot for an '80s era 305?
 

Pretty normal actually; well within the factory's intended operating parameters.

If it has an electric fan, the fan DOESN'T EVEN COME ON until the temp reaches about 235°. IOW, in the opinion of the factory design engineers, (not that I'm accusing them of knowing anything about how cars are supposed to work or anything radical like that, just using them as a point of reference) don't think the engine EVEN BEGINS TO NEED ANY COOLING AT ALL until it reaches 235°.

So I'd say 220° is perfectly acceptable, completely normal, and not only no cause for concern, but even cause for feelings of relief.

Re: 220*F too hot for an '80s era 305?
 

:crazy: My thoughts are along the lines of disregarding pretty much anything else this "friend" has to say about your car ......

Re: 220*F too hot for an '80s era 305?
 

The factory had these cars running that high to help reduce emissions and increase the life expectancy of the catalytic converters. If you pull the cats and do not live in an area that requires emission checks you would do better to get a lower thermostat, provided you had a member burn you a chip that reflected the changes you would be doing by lowering the coolant temp.

Re: 220*F too hot for an '80s era 305?
 

Nothing to worry about. The stock configuration has a 195° thermostat. So you're not going to see it run colder than that no matter what. Add on to that that the fans don't turn on until 223° (driver fan) and 235° (passenger fan) and you're well within operating levels.

All that temperature level is doing is allowing the moisture inside to boil off and make sure that the oil gets to the proper warmed up temperature.

You're good.

Re: 220*F too hot for an '80s era 305?
 

Hitting 235 while idling is ok.
Hitting 235 while going down the road is not normal.

Re: 220*F too hot for an '80s era 305?
 

Thanks for the replies! :thumbsup:

Thanks guys! That pretty much lifts my concerns. Didn't make sense to me that potential damage could occur when the needle is only at the mid point of the gauge (assuming it's somewhat close to accurate).


It's never come close to that on the road so far, so if I see a higher than normal temp the next time I drive it on the open highway I will know something is potentially wrong with the cooling system.


The cooling system was inspected and serviced at a Buick (former Pontiac) dealer last May, but the car is 26 so you never know. The next time I pass a Harbor Freight I'll pick up a cheap infrared thermometer and start measuring.


Unfortunately I live in an emission enforcement area.


He's a good guy. Perhaps I took what he had to say a bit to the extreme.

Re: 220*F too hot for an '80s era 305?
 

So I've put a couple hundred miles on the car this weekend and no issues with running hotter than usual. Guessing all is OK with the cooling system and that one time rise to 220*F was due to lack of airflow in the garage.

Attached is a pic of where the needle on my gauge tends to sit at operating temp 99.5% of the time, give or take a hair. Any idea of what temp that is suppose to represent?

Re: 220*F too hot for an '80s era 305?
 

Looks like about 180 deg to me. DEFINITELY not too hot.

Re: 220*F too hot for an '80s era 305?
 

My cars sweet spot is 180*to 190* but will climb to 220* in traffic..
Your gage (if its correct) puts you IMO in that same spot and is absolutely perfect.

Re: 220*F too hot for an '80s era 305?
 

Yep, let it idle to 227, that's where fans supposed to kick on, boil point of AF is 235. As long as fans kicking on your good.

Re: 220*F too hot for an '80s era 305?
 

Agree with everything above

Re: 220*F too hot for an '80s era 305?
 

Reid has really done a fantastic job on this thread and it is widely overlooked.
If your system is completely stock, have a read and you will see that you have nothing to worry about.

https://www.thirdgen.org/forums/cool...ans-arent.html

Re: 220*F too hot for an '80s era 305?
 

So which is it 227 or 235 ?

My Drivers side fan kicks on w/ temp, passenger with AC .... so what is correct ?

Re: 220*F too hot for an '80s era 305?
 

..........

Re: 220*F too hot for an '80s era 305?
 

Thanks again everyone for the answers. I believe my cooling system is currently performing as designed.