Cadillac Repair: 95 cad. sls 4.6 northstar, temp guage, southern cali

Question
I have an issue with this car starting to run hot. I recently had the heater core replaced by an pretty well respected chain here in southern cali. the issue is since then the car has been running really hot. on the interstate up to 230 degrees... I had changed the waterpump, thermostat and belt changet in oct 09. no issues, stays normally between 188 to 203..... but since the heater core change, they put regular green anitfreeze in it on accident, it has been going from 188 to 232 degrees. this car has NEVER ran this hot, not in the mountains nor in florida. the gm of the place that serviced it apologized and flushed the system completely refilled, but that hasn't helped. what is the normal operating temp for these cars? and he said the fans don't even come on till it hits 220 degrees.. I have NEVER noticed this car go that high before. any help will be appreciated. Dale

Answer
Hello,

I just addressed this issue today in which someone was running a Caddy engine hot and the warning that went along with it. If the engine is running above 200-210, not good. If the temp guage goes between half and 3/4, time to get it handled now!

You have been to 230 and you most likely have already caused engine damage. This is not like the old cast iron chevys where you could run them hot and do no damage. You have an alluminum block and alluminum heads that cannot take the heat.

As for the difference in the pink and green coolant, I know they are not supposed to be mixed, but I do not know the end results.

You can check the cooling fan by having the engine off-key on. A/c on high cool or defrost. The blower should come on within a minute or so, or something is wrong with the motor or relay.

These engines are notorious for overheating issues and there are just too many possibilities that can be wrong.

I have owned Cadillacs for over 20 years and know the weak point is their engines over the last 27 years. Great car as long as they run but can be a money pit. In fact, just got rid of my last Allante a couple of months ago and went back to a Chevy truck.

I wish you luck, but I think you are going to take it to a competent service center for diagnoses. You may find that apology may have cost you hundreds of dollars.

Rob