LottaBallsCamaro and I have recently bought a 87 IROC . The coolant temp gauge wasn't working, so we bought one from a junkyard today. At first, it appeared to be running okay, but it never showed a temp above 150*. That seems too low. I was expecting around 220* like my 305 runs at. What is a normal temp (or range) that an L98 runs at?

 

my 87 L98 iroc w/160 t-stat and hypertech fan switch ran around 150*

 

If it is bone stock then it should be around 220 deg, I would let it idle and check at what temp. the fans are coming on at or if they are running all the time. It may have an aftermarket switch telling the fans to come on earlier than stockand the thermostat may be stuck open. Hope this helps

nick

 

Thanks for the advice. I'll check the fans tomorrow. My RS had a problem with the thermostat being stuck open, so I hope it's not that. Is there any way to distinguish between a problem with the thermostat and a problem with the gauge without having to do very much (I guess I sound really lazy, but I'm pretty much through with working on cars this weekend )

 

The fans are fine. I kind of wonder how accurate the gauge is, since I don't know how long it was in the junkyard sitting. The gauge works, but is there any way to tell if it is accurate (i.e. if my engine really is running at 150*, or if the gauge is just saying that)?

 

pull your thermostat and put it in some boiling water, see what temp it take to open it and see if it sticks open or closed at time. on the highway my L98 runs 180 because I have the thermostat, and about 200 in town, because Ihave the jet fan switch. without those you'd should be at 195(highway) and about 215-220 in town.

 

A simple way to determine accuracy of temp guage is to take off the radiator cap(ENGINE COLD) and get a thermometer. You can usually find one a a parts store fairly cheap. Start engine and let it run for about 10 min. . Compare temp a guage with thermometer. This will tell you how far off the guage is. I have a stock 89 rock and I will tell you even if you REMOVE the thermostat at idle it will run up to temp and the fans will turn on. Also, to check if the guage has full swing look at it when you crank engine. It should swing to the top(max temp) during cranking. Common problem with guages is they tend to bind. Took one apart and they are pretty poorly made. Also temp sender could be defective. Good Luck, Danno. 89 IROC, L98

 

MLBC (Somehow that doesn't seem quite right?),

All GM temperature sensors operate over the same resistance range. You can connect a fixed resistor of a known value and allow the dash instrument to stabilize. The indication should correspond to the temperature in the chart:



Get a ¼ watt resistor from Radio Shack or your favorite local electronics supplier and connect it to the B+ voltage in place of the sensor. A 150 ohm (or thereabouts) would be good since it should be nearest the midrange of the instrument's gradualtions. If it's close, you'll know pretty quickly. If it's way off, head back to the bone yard for a different one.

 

Vader never ceases to amaze me. That would be one heck of a way for ANYONE, to calibrate their gauge readings...spend a buck or two for a 8 or 10 resistors.

Great advice.

Vader,

You're taking all the fun out of me hanging on to my Fluke digital temp meter...only leaves me with checking header tubes now...

 

Mike,

I'm not sure which Fluke you might have, but if you have an older one with the type K thermocouple (like an 8066B), they are really handy for checking cat converter temperatures. I'm not sure if the newer autranging 70 and 80 series with the type J T/C will take the temperature. (Does that tell you how old I am?)

Not only that, it's gotta be really handy for quick reference checks on a lot of items, like condenser temperature vs. pressure to determine blockage, radiator temperature vs. coolant temperature to determine scaling and corrosion levels, A/C efficiencies, oil and trans fluid temperatures, and the occasional ill relative if you can catch them in the right position.

The Fluke is a lot faster than jamming a resitor in the wiring harness, but the reaiator is a lot more stable since it "fakes" a constant temperature. If you're really **** you'll want to have the resistor to set up the gauge on a bench, so you can take it apart and caibrate the d'Arsonval movement spring. When you're all finished, you'll have a really accurate P.O.S. dash gauge, at least accurate at one temperature.

 

:hail: Vader :hail:

When I grow up, I want to be just like you!

 

Vader, why not make it easy on the poor woman? How about a twenty turn potentiometer in place of the resistors. Then you could check linearity of guage movement. Just a JOKE. When you ask for it here you get a wealth of info. Danno