My old radiator decided to look like a hose after my dog got done with it (leaking everywhere). So, I replaced it, the hoses, and put in a 180 Tstat. Temps still climb to 220ish, and go as high as 240ish with the AC on. Turn AC off, temps slowly creep back down to 220ish. I say "ish" because I don;t know the real accuracy of the gauge. It was stable, even with AC on before I changed the radiator.

Anyway, my air dam is intact, and both fans run all the time (PO slice and dice on the wires to keep them on). There is no loss of coolant anywhere and I dont see the lower hose collapsing.

Is it bad that the fans run all the time? What could be causing my high temps with a 180 stat?


Thanx in advance.

 

Not good for the fan motors. They wear out quicker this way. The fan is supposed to cycle on and off and it turns off completely after 35 mph.

 

Did u verify that you got a good thermostat? I have seen them bad right out of the box before.

 

I just dropped it in. Will probably change it out again this weekend, along with a new cap.

I did do the mod to the tstat (where u drill a couple holes in it) and if the tstat is bad coolant would still circulate, but not as much..makes sense i guess.

 

These cars were built to run 220-235* from the factory so you're running in the normal operating temp range. Unless your boiling over, you're fine.

First fan is supposed to turn on 225* by the ECM, second fan should turn on 235* by the switch in the head. Since your fans are turning on and running all the time, your hurting yourself on the highway as your fan's are actually obstructing the airflow.

 

Is your water pump old? I've seen engines overheat at idle because the water pump fins were worn out and couldn't pump enough water at idle. The temp would go down after revving the engine up.

 

Try and restore your wiring to work like it should and you wont have any problems.
These cars are designed to run hot while sitting for emissions. Normally, the temp will bounce off the thermostat on the highway.

 

Before you go and do more work on the car you really should have the engine temperature checked with an inferred temperature gun so you can test it against the gage. Until you do that your just "guessing". Call around and ask if they will do it for you. It takes less than a minute of their time and rarely charge for it. Second, you should always replace the radiator cap when you’re having a problem.

With what you have now (180 stat, fans on) you should not be running that hot .My fans kick on at (primary 190*) secondary (200*) with 180* stat. Even on a hot day in traffic it will barely touch 220*.


I understand that when we tell members that these cars were designed to run at those IMO insane temperatures its telling them it’s OK and normal. And I’m wondering if the members telling them that are running their cars at those temperatures ?



Just because GM designed them that way does not mean its best for the car or performance. ALLOT of members here strive to run on average between the 180*to 200* mark including me. I even installed large trans and engine oil coolers to help. There are negative aspects of either running to cool or too hot. So I strive for a middle ground.
The only reason I say this is because if you’re going to spend time and money working on the cooling system you might conceder setting it up to run at a cooler temperature than stock.

I’m not a mechanic or engineer so I rely heavily on what I have read and done using this site for the last 7years.
My car was a $ 500.00 wreck when I bought it so I’ve had plenty to work on.

 

I changed the radiator cap when I did the radiator. My water pump looks old (kinda rusty looking), but I am not sure exactly how old. Might change it out when I get some more funds. Not sure if it is the problem, once the temps go up they stay up, moving or not.

However, now that it is cooling down, it is starting to run a little cooler. Still runs hot during the day, but at night it runs nice and cool.

Also just changed out the O2 sensor if that is a consolation.

 

Do what Ron say's,get yourself a infrared temp.gun,and verify that the temp is as high as your gauge is posting.I got one from Harbor Freight,very inexpensive,cheaper than chasing a problem that probably doesn't exist.

 

I am not running anywhere near that temp. I agree that it is an absured number. What I meant by my above post is that's the way GM designed it to run, and it does work. HOT HOT (apparently not too hot) when sitting for excellent emissions ratings. When the car moves, its designed to cool off to around 195* (thermostat rating) at anything more than about 40 mph, with or without the A/C on.

I agree with Ron in saying that if you are going to work on your cooling system, you should make it more performance oriented instead of leaving it emission oriented, but not everyone feels this way.

 

I can't disagree. My cooling system is basically stock, except for a BeCool radiator and aftermarket fan switch which turn the fan on at 215* instead of 225*. It just seems to be easier to dial in the carb for tuning. I used to run a Jet Fan switch that turned on at 200*, off at 185* until it melted due to header heat. I may yet go back to that temp. The main thing is it turns the fan on sooner thus keeping the car cooler. I also run a 180-stat which really only makes a difference on the highway so far as I can tell.

 

Taking into consideration the way your fans run constant and you have a 180* thermostat I would pray that the gauge is reading high because if its right on you have a problem. The temp gun is going to decide it for you.

If you decide to skip the return to stock settings and install something that will come on a little earlier than as far as the fans are concerned you may just want to bypass the PO hack job and wire in your own fan circuit/circuits depending on what type of controller/switch you use.
Are you familiar with how a relay works ?
Have you ever ran 12v wiring using a relay ?