93 sedan overheating

[black93]

Hello all - new member here...

I just purchased a 93 sedan with 98k miles in otherwise great shape. It's 100-105 in the afternoons here in Kansas City & the car has been running right at the temp redline when idling or in slow traffic. No temp light comes on and the car is otherwise acting fine. I had the coolant flushed & replaced, and the thermostat was replaced yesterday. System pressure test was ok. Today the car is acting the same, if not a little hotter, and when I shut the car down this afternoon, there was a rather loud boiling sound coming from under the hood, which ended in less than a minute. There is no discernable fluid loss or odor. The boiling noise is new - was not heard before the flush/fill/thermostat.

From reading a couple threads here, might this simply be air in the lines? I believe the fan is working (has belt-driven fan). Called the shop that did the work & was basically told that it's crazy hot outside & old cars will get hot. Was not impressed with that answer.

Any thought

 

[scoffman]

the boiling sound would be caused by air in the system. when you hear it look at your resevor and see if air bubbles are coming out. It should eventually stop doing this when it works all the air out of the system. If you are confident all the air is out of the system and it's still overheating, it's probably the radiator is going bad and needs replacement. I would take a VOM and check the temp sensors to make sure they are not giving you a higher than normal reading (bad reading). There is also a way to check that information that is sent to the ECM via the climate control readout. Search the site and you should find it. Although I'm not sure if 93's are able to do this?

 

[scoffman]

Oh and I call BS on the old cars run hot when it's craxy hot outside. If it's running hot there is something wrong.

 

[ARCStig]

Mine runs normal even with the radiator half empty. 😀 (need to fix leaky intake gasket)

 

[black93]

Thanks for the advice, the shop agreed it was air in the system and undertook this rather odd looking procedure where they jacked the front end up in the air to bleed the air off. They then suggested I drop $400 on replacing the fan clutch & water pump since they thought it was still running a little warm (around 210-220 idling in 80 degree weather). That seems excessive, but I see that those items are right up front under the hood - could someone with limited mechanical aptitude but some experience (I've swapped a water pump on a '96 Buick with 3.1L V6 before) have a reasonable chance of doing this operation himself?

 

[paart]

Since you have done a water pump before, it shouldn't be much of a job. Keep track of where everything goes, and note the length of the various bolts that secure the pump, being sure to put everything back in the correct position. Some of the pump mounting bolts will go into water jackets, so be certain to put sealer, such as "Permatex #2" on the threads. Clean the mounting surface very well with a razor blade or fine sandpaper, before installing the gasket.
When you refill the system, fill it with coolant, run the engine until the hose from the thermostat to the radiator starts to feel warm. Shut it off, and check the coolant level; it should be down after the thermostat opens. Recheck it again later. Getting "air" out of the system shouldn't be an issue.
Be certain that the fan clutch is bad before replacing it. Check for leaks around the seal on the shaft. Rotate it by hand, and see if it moves smoothly, and with some resistance against the internal fluid. Look for obvious damage to the unit and coil spring on the front. If it seems ok, it probably is, hot weather overheating is rarely caused by a bad fan clutch.
Your issue may be due to some radiator clogging.
At 100 to 105 F ambient temperature, it is not unusual to have some "boiling" into the overflow bottle after stopping the engine. That coolant will be pulled back into the engine, when it's restarted. As long as you don't loose coolant, you should be okay. You might consider replacing the radiator cap, if you haven't done so. Be certain to obtain the correct cap.

 

[black93]

Thanks for the tips. I think the fan clutch is probably ok - fellow at the shop suggested replacement "because the fan seemed slow" and because the labor would be discounted since replacing the water pump requires removing the fan assembly. Being upwards of a $200 part I think I will pass unless replacing the water pump doesn't fix the problem.