1992 5.0 100% bone stock

-according to factory gauge (which is not user friendly I know) engine temp runs around 250 in traffic on 95+ degree days here in south louisiana.
-pulled 196 thermo and replaced with 180 and completely flushed the system.
-burped and as best as i can tell got all the air out.
-radiator does have some calcium(?) buildup.
-after all this gauge still shows 250 when not moving down the interstate and about 225 on the highway.
-i checked the temp of the coolant/water mixture at the fill neck on the radiator with my wifes digital food thermometer(don't tell) and it reads a consistent 205-216 while in the driveway at idle.

Should I be concerned? What's the next step?

Thanks!

 

Next step IMO is to either replace that factor gauge with another or get an aftermarket temp gauge. I gets over 100 here in central Texas and even with the AC on my temp never gets above 190. I also have a 180 thermostat, new coolant, new cap. Try another gauge first and then go from there.

 

I went through hell on this one... Just got mine squared away (and the A/C decided to die to repay me...). Anyway...

Fan clutch. It would be my first guess. Temps dropping with speed helps. Someone mentioned to me to get a laser thermometer and shoot the thermostat housing and I just went ahead and smacked myself to save others the trouble... I even own one.

When I had my gauge reading "250-270" the laser revealed an actual of around 205-220 tops. So what you saw (and we will never tell her) jibes with what I saw.

I assume you have an even 50-50% mix water to coolant. No Under Drive Pulleys (created by Satan himself, I just KNOW it), and the radiator is in fair shape, right? Is this "little bit of Calcium" inside where you can see it? It is worse where you can't see, I assure you.

Get in there and check for oil on the fan clutch. I thought mine was fine, it was a little dirty. When I removed it I saw literally a half pound of dirt and oil stuck to the inside of the fan. Mine was toast. That and my UDP being ditched and stockers going in makes mine run cold as can be.

Also, checking the cap couldn't hurt. Sounds silly, but high school physics reminds us on this one. Then the sending unit (cheap at AutoZone and a 5 minute fix) would be cheap insurance. Intake manifold, up front, drivers side next to distributor, one red wire with an elbow connector.

Now for me the darn A/C... Sheesh...

Keep us posted!

 

How bizarre! When I finished the project MY A/C went out...kinda. At some point all the hood slamming broke the vac line that controls the door and the air would only come out of the defrost vents. It's a conspiracy...damned computer controlled vehicles. Not only that but I managed to run the battery so low listening to the radio that it wouldn't take a charge after. A $30 flush and thermostat turned into a nightmare.

Anyway, I will check into the laser thermometer and see what kind of reading I get. The more I think about it, I believe the water temp at the fill neck is AFTER it's been cooled by the radiator, right?

How do I check the cap? Can an auto parts store do this?

Yes the mix is 50/50 and I'm leaning towards a new radiator regardless of the temp as it just looks really bad in there. Water seems to flow fine out of the visible cooling tubes(?) however. No under drive pullys.

Fan clutch may be an issue as I never hear the fan really kick in anymore. Never really thought about it.

Thanks for the info.

 

I thank God for this one, the Compressor Clutch Cycle Switch was my problem (so far it seems to have done the trick anyway!) Cold A/C for me now.

Back to you. The neck of the radiator is not really where you wanna be aiming at. This is an awfully cool area and not accurate. Shoot for the thermostat housing my friend.

If your car has a stock fan clutch (not electric) you are not likely to hear it kick on. It should be relatively seamless to the casual observer... Look to see if you have lots of oil, dirt, etc in the general area. My bets are still here, no air movement doesn't a cool car make.

And when you actually SEE calcification and other growths I would feel fairly comfortable saying a replacement wouldn't HURT the situation. New radiator for sure.

Checking the cap: I wanted to ensure I had no leaking head gasket, cracked head / block, etc, so I went to Auto Zone (and after my last experience I will NEVER return) and borrowed their pressure tester.

You remove the cap and place this "cap-like" apparatus on the radiator and pump it up to the caps rating. Let it sit and if the pressure holds for a couple minutes it rules some items out. (And thankfully mine held fast)

On the other hand, it has an adapter to check the cap as well. Similar process. Put the adapter on, pump and see if it goes to the rating on the cap (mine was rated 16psi and crapped out @ 7psi). Then get a new cap. Simple is fine. Despite what my Honda friend says, the good cap is not worth 27HP at the wheels (kidding of course).

Do NOT pump the system above the caps rating. The system is designed to hold at THAT psi, not above. Let's not get carried away here...

Keep us posted. I just went through hell with this so I would love to be able to help out someone else...

 

Get a better gauge.
Upgrade to a full aluminum radiator first, if still over heats then you need to get an electric fan to move away from engine driven mechanical.

 

I had the change the waterpump on my 93. I also had to change the smog pump, which locked up on me. I chose to bypass and remove it.