Was out cruising in the Bonneville today and was just wondering how hot is too hot for the thing? I had the AC on max the whole and was in town most of the time. Outside temperature was 95+. The temp gauge would max out right on the red line and would cool no more than the mark just to the left of the max mark. Is this normal for stop and go traffic? Out on the highway the temp gauge usually hoovers around the middle. BTW what are the temperature readings for each mark on the gauge? Also at one point the car starting missing and acting like it was hot and funny and I took it out on the highway at speeds of 65 or so and it started running fine. Could this be a problem with the high temps? I don't think anything is seriously wrong, but I just wanted to confirm with all other bonny owners. I have a 180 stat installed and the factory tranny cooler and everything else seems just fine Any opinions?

Mine stays below the middle mark in stop and go, but I never turn the A/C on. On the highway at 70+ it'* about 2/3 of the way to the first mark.

You're running like 260... I'd look into that.

mine doesnt even come close to the middle mark even if im sitting parked with the AC on....i was parked for like 10-15 minutes and it never made it to the middle mark...like right between 200 and i guess the middle mark is 240?

On my 92 the 12 o clock position is 200 degrees. Mine usually runs at 200 or maybe 1/8 inch above that mark on the gauge. And I am running a 195 thermostat.

It'* impossible to run at 260 like was suggested. All the coolant would just boil away.

These instrument clusters are finnicky, and it'* possible for them to give the wrong readings if there is a problem.

If my car was getting into the red the check gauges light on the DIC would flash so I don't think i'm getting hot enough to hurt anything. I think it'* just more of a concious thing on my part just not wanting to blow the car up when really it'* probably not anymore than anything normal due to the extreme heat and stop and go traffic with the AC on.

Not entirely true. Remember, the coolant system is not at atmospheric pressure when the engine is hot. The coolant system is pressed up to some degree with a hot engine. But 260 is too hot if that is an accurate indication, it should be down around 200 nominal.

Yes ok I should have been more specific. It is true that the increased pressure does raise the boiling point, and so does the addition of antifreeze. It actually raises it more than I would have thought. Prestone claims a boiling point of 265 F with a 50/50 mix and a 15 pound cap.

It may be an iron block/heads, but they can't take 260* for long. Things will wear very quickly. Don't drive it except to maybe a repair shop.

Check to see if the thermostat is sticking.

Ok first of all It isn't getting up to 260 degrees. I just seen it get up to the red and as soon as I started driving it went back down to 220. Most of the time it hovers around 190-210. The fans are working properly and the T-stat checks out fine. I think it was just me being paranoid. Maybe I should shut the AC down in town when the temp is 95+. The check gauges light never flashed and I never had steam so I don't think I have a problem except my driving habits.