Engine temperature is this ok?

[sriat]

Yesterday I was out driving my 84 and when I put it in the garage I could hear it boiling. I looked under the hood and found that it was boiling coolant into the overflow. But not so much to dump coolant onto the floor.

I checked the gauge and found it running about 230F. I turned the key to on and ran the fans and it cooled off enough in a min to stop the boiling.

A few facts.
1. Checked coolant and found it to be good mix and was flushed earlier this year.
2. I have the Z51 package and have 2 fans (1 push 1 pull) both are running
3. I recently had the AC upgraded and was running the AC
4. I am in KS and temp has been around 100 for the first time this year. Today will be above 100. I am sure this has an effect.
5. I was driving the unit in town then to my house on interstate for only a couple of min.
6. I drove the car later in the day and watched the temp. In town it was getting hotter (not above 230) and when I get it on interstate it cooled down over 20 degrees.

Thoughts? Is this normal (the warnings are not coming on)

 

[C4Tom]

First, I would crawl under the front of the car and carefully stick your hand up into the air intake to check for debris in front of the radiator.

 

[sriat]

I looked at the radiator. Nothing on it. Thanks for the help.

 

[85vette]

The radiator has another unit in front of it for the AC unit and it can easily get plugged with debris in there. Pull off the top plastic cap which covers them both and clean it out and that may solve your problem.

 

[geekinavette]

With a good coolant mix (at least 50/50), you're not boiling at 230 deg. The "gurgling" you hear isn't boiling, it's the radiator cap releasing pressure from the cooling system into the overflow tank. 230 of course is "uncomfortably" warm for most of us, but realistically that temperature should not cause anything abnormal, and is not uncommon at all with a C4 in 100 deg temps. Much above that though would start to be cause for concern (don't ever let it get above 250). Now there are a couple of things that can cause the pressure release you're seeing at 230 deg...the most simple being a defective radiator cap. The cap is not supposed to release pressure into the overflow unless the cooling system is above about 16psi (if memory serves). If the cap is good then that means there is excess pressure in the cooling system from somewhere else. I hate to even mention it...but 84 heads are VERY prone to cracking around the coolant passages in the head. This is a problem I had with my 84...there was a crack in a head that didn't open up until right at 210 deg, allowing combustion pressure into the cooling system. Anything below that temp and it was fine, above that temp and it would start "gurgling" into the overflow tank.

To try and keep the temps down, of course check for debris between the radiator and AC condensor...that area is a garbage magnet. You can also install a lower temp fan switch available from Mid America. I have recently installed a Robert Shaw thermostat and found that made quite a difference, but I also have a Dewitts radiator (HUGE difference from a stock radiator), so I have no idea of the RS thermostat makes much of a difference by itself.

Bill