strotter13

First off I apologize if I posted this in the wrong thread.

Issue: 1992 Base Model Vet (LT1 Engine) Overheating when at idle or slow city driving.

I read all of the threads, I cleaned the radiator off, I flushed the fluid, then I realized my fans weren't coming on, even when the car was up to 215 degrees.

I pulled the plug for the fans at the relay, jumped them and they work.

I read that the fans come on when signaled to because of temperature and when you turn the AC on.

When I turn the AC on the fans come one, but not when the car gets hot.

So I let the car temp creep up to 210, while idling, then turn the ac on, and it cools back down to the 190's.

Is my solution to just turn the AC on when the car gets hot?

Suggestions? Thanks for any help!

auggy

Yes, as crazy as it sounds turn on the a/c. I also believe the fans come on closer to 230-235 not 215. Their is probably nothing wrong with your car. Sidebar here and beware --when you open up the system you take a chance of causing an air pocket(s) which will cause overheating. Some years have bleeder valves to remedy this. From what your saying it sounds like you do not have this problem.

strotter13

What would you say the max temp I should let the car get up to is?

Mine is equipped with a bleeder valve in the thermostat housing, and I used that to clear the air when I flushed the radiator.

Thanks for all the help!

Frizlefrak

C4's are designed to run hot. 225-230 in traffic isn't uncommon and won't hurt anything.

First thing you need to do on ANY C4 when you buy it is remove the radiator and clean the front of it. C4's are bottom feeders AKA road vacuums....you'll be amazed at what's on the front of it. 50% + blockage is common if it hasn't been cleaned in a while.

To answer your next question, yes, you MUST remove the radiator.....No, you cannot clean it in the car. It's not a big deal, just do it. Takes about 15 minutes to pull it out.

So pull it out, sit down with a bucket of soapy water and a nylon brush, straighten any bent fins, and clean off all the debris. Flush it off good, put it back in the car, and be amazed as it now runs 20 + degrees cooler.

Here's what it could look like...

desertmike1

Max temp for pretty much any car is 260/265°f because this is were 50/50 mix boils over..

under normal conditions, you should not see temps above 235°f even idling around town on a hot day with the top off you probably won't see temps above 230° Kick on the A/C and those temps will drop to 190-215°

If your cooling system is "Tight" it will self bleed any trapped air out.

strotter13

Thanks for the help.

Frizzle I did clean the radiator, however I didn't pull it out. I was able to get a good look at it through the passenger side of the shroud, and it was a bit dirty, but I blew it out with some compressed air, and it looked good. 15 minutes for you to pull it out, but for a newbie like me, try an hour (at least).

Ok, so I was freaking out at 230 (because the temp gauge pings up close to the warning area), but it sounds like 230 is a normal operating temperature and I shouldn't be concerned unless it gets up there in the 250's.

Thanks all.

RIPJWB

You sound EXACTLY like me, when I first got my car. I have the L98 motor and found it quite alarming that the fan would not kick in till it got to the 220's .
Even if the whole front of the radiator was caked with dirt, I can't see why that would have any effect on the fans kicking on. I could be wrong, but that would only effect the fan's ability to actual cool the radiator.

auggy

It's a personal decision but I hit the a/c at 220 ---I do not like the engine getting hot and don't want to wait until 235 to find out I have a problem. I am in an area with a lot of heavy traffic. Their are ways to get the fans to come on sooner but I don't want spliced wires and don't have a way to reprogram the ECM so I just go low tech and hit the a/c.

Aaron71771

The LT1 is designed to run hotter, I think the fans kick on at 230F without the air on. It shouldn't run much hotter then that sitting in traffic on a hot summer day.

If the radiator is clean and the system is staying at or below 230, you are fine. If you start messing with the programming or adjusting the cooling system to make it run cooler - you end up hurting performance and emissions.

Benny42

That's not "hot", it is factory design operating temperature. Just drive it.

lt4obsesses

Agreed. Not sure about the '92 design, but in my '96 the primary doesn't come on until it hits 228. The temp at idle will continue until 230 when the secondary comes on, then it starts cooling down.

Ben J

If 230 is normal operating temp why is gauge almost pegged out, just wondering.

Frizlefrak

Because the gauge isn't linear. It's also not accurate. Go by the digital, not the analog gauge.

Frizlefrak

Now the debris isn't on the radiator anymore....it's on the back side of the A/C condenser.... and it's still blocking airflow.

Trust me, even if you're a novice, 30 minutes tops to get it out and give it a proper cleaning. Both my 84 and my 95 ran in heavy traffic at about 210 in 105 degree ambient temps and seldom got any hotter. They ran at 190 on the highway. I gave the radiator a cleaning that would make a drill sergeant proud....

PLRX

C4 nOOb's Cooling Guidance

Frizlefrak

Yep.

Thanks Pete.

RollaMo-LT4

Look at your gauge closely, and you'll see a shaded area at the high end of the gauge.
Unless the needle is actually into the "shaded" area, the car isn't overheating.

That analog gauge has caused more issues with new owners than any other part of the car.