My girlfriend took the 89 Vette out today. She called to tell me that the coolant temperature was reading 220*F while in traffic. Its 20*F outside. What does a 89 TPI L98 Engine safely run at (or generally run at?)?

Also, the coolant light on the dash intermittently goes on and off from time to time (only stays on a few seconds then goes right back off) The car is full of coolant, so is the overflow, and I checked the oil dipstick to make sure there wasn't any coolant mixed in. Car runs fine, everythings cool. What could be causing this?

DG

 

should be fine. in fact in my 89, the fan doesn't even turn on until about 229 degrees or so. it will then reach maybe 234 before dropping back down to 218 or so....

 

Assuming it wasn't on Defrost or Bi-Level, ECM grounds the Main Fan Relay when the Coolant Temp Sensor indicates 226 Degrees. The Aux Fan Relay, if equipped, is grounded by it's switch at 228 Degrees. Should the Controls be on Defrost or Bi-Level, then the ECM would ground the main Relay when the a/c fan switch (on the high pressure line) reached 220 psi which is about 120 degrees at the Condensor. With an Outside Air Temp of 20 degrees, it would probably never reach that pressure.

 

The 220* coolant temp is just fine. What does it run when you drive it? What is the dash light? Low coolant level? The radiator probably isn't as full as you think it is.

 

Thanks for the info guys,

I don't mean to with this topic. I just did a seach and found a couple of others in the same situation, but I guess i might as well ask the question while your all looking at the topic.

I am going to change the coolant with the green stuff and distilled water this weekend. I also want to change the thermostat to a 180*F.

Now I have the regular electric fan and the aux fan.
What do I have to do to turn them on at 180. One of them has a sensor that has to be replaced (the one that screws into the left head)... I know that, but does that also correspond with the ECU? As for the other fan, how do I turn that one on at 180 also. I dont have a tuner. Is that something the Chevy dealer may have?

(where do I buy a new sensor for the fans, will advance or autozone have it?)

DG

 

If you change coolant types, you must flush every bit of the old coolant out before you fill with ethylene glycol or you will make brown thick sludge. At stoplights, a 180 thermostat will not lower your coolant temps, nor is it required. You do not have abnormal coolant temps and 220 can be seen under 35 mph or stopped. The main fan is operated by the ECM and comes on at 228 F and the auxilliary fan is operated by a thermostatic switch between cylinders 1 and 3 and it comes on at 238 F. GM says to shut off the engine at 260 F and let it cool down. You would need to replace the mem-cal chip to change the on temp of your fan, but it really isn't necessary. None of these temperatures is harmful to your engine. With a 180 stat and fans programmed to come on at 180, you will likely have your fans on all the time. Take a deep breath and stop worrying about your coolant temp UNTIL it reaches 260 F, and I doubt it ever will.
Your low coolant light comes on because you have low coolant. On C4's it is necessary to fill the cooling system while the thermostat is open and race the engine slightly which will drop the coolant level in the radiator. Air gets trapped in the cooling system because the engine is lower than the top of the radiator. Loosen the rad cap and let the engine idle to the opening temp and remove the rad cap, race the engine slightly and fill the radiator and then replace the radiator cap and last, let the engine back down to normal idle. NEVER open the radiator cap (from closed) on a hot engine! Also, C4's pick up all kinds of road debris which sticks in the front of the radiator and my lazy way of cleaning the radiator is to blast water from a garden hose backwards through the radiator. A badly clogged radiator needs to be removed and cleaned. Also look into the front of the car and see if the a/c condenser is clogged with anything as air passes first through it before going through the radiator.

 

also, debris that gets in between the AC condenser and the radiator will fall down in traffic, only to be picked back up and sucked against the radiator by the fan when it starts up again, limiting airflow through the radiator.

 

The temperature isnt alarming, but you may need to burp your cooling system, the radiator may not be as full as you think. There's a procedure on my website.

Could need a new rad. cap as well.

 

OEM specs for the '89 fans were 226 Main and 228 Aux. The Aux should rarely if ever come on (plenty of Vettes were made without it). Running both on hot days can tax the (overtaxed) alternator and when the fans slow down, temps will creep up. Green was the factory fill. There is no reason to be low on Coolant unless it's leaking.

 

Corvette coolant class 101 please.
thanks

 

What we have here is a "Dead Horse Rising"......

 

If you install a 180deg T-stat you should have the calpac chip reprogrammed to bring on the fan around that temp for best operation.

Or you can install a 180deg aux fan switch and jumper the Dk Grn wire to the Dk Grn wire of the main fan relay so as to control both fans.

 

Except on mine I used a 200* aux fan switch/sensor with a 180* stat. That way the fan doesn't come on just as the stat opens. The fan switch goes off at 185*. Otherwise your aux fan could run all the time. Not a great idea IMO. I got my switch/sensor at Mid America for $15. It goes in the head between plugs 1 and 3 on the drivers side.