I posted about a week ago that i'm going to do a coolant flush and
radiator removal for a cleaning. Got alot of nice replies. Thanks to all.
Now i'm going a little further with the project and need some more
suggestions. Where i live there are a few bridges and if they open to
let a ship pass you sit and wait. All the waiting and the temps go way
up.
I'd like to put in a 180* thermostat and a temperature switch that will
turn my fans on sooner. This C4 is a 1988. I've seen switches in
magazines, but don't have a clue as what to use. Thanks

 

What temp do you think is high?

 

you don't have a problem unless your temp is higher then 255*. so don't over think this

 

Iirc the cooling fans do not turn on until the car gets to about 235.

Gary

 

You could address this a couple different ways, you can get a fan temp switch that will turn the fans on sooner. To do this you remove the fan temp sensor on the driver's side head and replace it with the new one that turns the fans on sooner. These lower temp fan switches are available in a few fan temperature options. The second option would be to have a prom burned/programmed to turn the fans on sooner (temp of your choosing). To switch the prom go under the passenger's side dash remove the ECM and then take the prom out and put the new one in.

The lower temp fan switches are avaliable from Eklers (and other places).

If you choose to go the PROM option, Scott Hansen of tuned port induction programing service has done a good job for me in the past.

Hope that helps!

 

Thanks, i think i'll try the lower fan switch.

 

Doesn't 255* seem high? What temp does oil start to break down?

 

C4 coolant temps were designed to be high in order to reduce emissions. Temps in the 190-225 range are normal. The ECM will turn the secondary fan on at 238 degrees and then turn off when coolant temps reach a lower value.

Unless there is something wrong in the cooling system, there is no real need to go to a lower temp thermostat or some sort of override for the fan operation. The C4 was tested in all sorts of climate conditions from sub zero temps to the high 110's and more.

Are the lower air dams in place and in good condition? The C4 is called a "bottom breather" in that air for cooling comes up from under the car and the air dams direct that air into the A/C condenser and radiator. Cleaning both components is important for good airflow.

When you pull the radiator, it would be a good idea to replace both the radiator hoses. You didn't say how mny miles are on the car, but if it has high mileage and it looks like the water pump is original, it might be worth it to replace the water pump.

Also, the fans are automatically turned on when the A/C is operating. So if you see temps climbing when idling and the car is not moving, turn the A/C on!! Once the car starts to go fast enough to provide sufficient airflow, the fans really don't do a lot; in fact, they will turn off at some point.

 

Thanks for the advice. Something else to think about.

 

All i would have to replace is just the switch that is in the head? Ecklers
has a switch that comes with a bunch of wiring and stuff, so does CC.
I like the idea of just replacing a switch to turn fans on a little sooner.

 

You replace the switch and it comes with a small amount of wiring, but it is really simple to do and it comes with instructions, so nothing to worry about.

Then again replacing the PROM is really easy too... If you are fairly handy neither option should be to daunting.

Best of Luck with it!

 

Where is a good dealer to get a prom to turn fans on at a cooler temp?

 

How do i get hold of Scott Hansen?

 

Did you ever say what temp you are running at that you think is too hot?

 

If your fan is kicking on at ~225 or so and then pulling the temp down to ~200-205, there is no need to worry. That is how they work. Worry when the fans are on and the temp doesn't drop.

Cleaning out the area around the radiator is a good idea. I try and do mine every 3-4 years just as a maintenance item.

 

I don't want this car to run over 200*. I live in a state where we don't worry about emission checks. High temps cut down on horsepower. I plan on removing the radiator and cleaning the area underneath, but if GM
created this car to run at 238* just to pass emission testing then maybe
something wasn't engineered right?

 

IIRC, Hyperjunk does that. Find someone who bought it for a performance gain and found out otherwise. He might be more motivated to sell cheap.

 

I would get it all working efficiently before working on keeping it at 200 or below. The occasional spike isn't the issue. It is whether it keeps at that level or not on normal driving. So yes, my car sees over 200 under certain conditions. So lets say, stop and go traffic with the AC on full. Well, say I keep it at 150 degrees, what am I going to do with that extra power in traffic? Rev it when I get tired of making "vroom! Vroom!" noises?

In normal operation, what are you getting? And I don't mean find out by reading the gauge. I mean "What does the ECM see?".

 

I guess i'll keep it as is, except for the thermostat. Will put in a 180* one.
Thanks for all the help.

 

I'd scan it first and see if you have cold spots in the radiator. If so you need to replace it.