95BLKVette

It was around 67F today and in traffic with recirc a/c on the digital water temp gage read 239F and Analog water temp at head was pegged at 260F!

Funny thing was oil temp was only at 225F....

How the heck can head temp be hotter than oil temp when oil isn't even cooled!

So I pushed the vent only button and temperatures dropped to 185F digital and 210F analog.....after about 10 minutes driving.

I have a Dewitt's radiator and I know radiator isn't clogged as I have a screen system over my cooling air dam inlet under the nose.

Analog sensor?

antfarmer2

Your screen is blocking the air

WVZR-1

I don't believe the discrepancy is unusual but you could certainly confirm the calibration of the analog gauges by supplying the resistance values to the gauge and check the gauge.

Assuming this is a later LT1 car the ENG OIL TEMP values can be found in the DTC 52 chart or maybe DTC 62, ECT to PCM values in DTC 15. For the COOLANT TEMP I believe they mention a check at 1400 OHMS and then again at 55 OHMS, should be cold then hot. That's mentioned somewhere around 8A-82-11. In a '94 FSM it's Chart 9.

For a '95 or '96 you may need to see P0117/8 and P1114/5

Regardless of location all values are available in the FSM.

Checking should remove all doubt.

RollaMo-LT4

Was it really "pegged", or did it just look like it was?

Look closely at the gauge and you'll notice a small shaded area just before the needle stop at the high end of the gauge.

Unless the needle was actually resting at the stop limit, the gauge wasn't reading 260.

That gauge does not have a linear scale either, so it is very hard to tell what the temp reading really is using that gauge.

When the digital temp gauge reads in the 230°F - 235°F range, that analog gauge needle can be right up close to the shaded area.
But usually not quite into the shaded area.

That analog gauge is probably the worst gauge in automotive history.

don hall

Consider changing the analog (1 wire) sensor/sender...... $13 - $16 (RockAuto).

If you are buying from a local vendor, the
analog temp gage may be called a SENDER.

383vett

The oil temperature will lag the water temperature unless the motor is at 6000 rpm. Between every rounds at the strip, I like to wait until the oil temperature reaches at least 150 degrees before I race. The water temperature is at least 20 degrees higher when the motor is warming up

WW7

When my car is completely warmed up and I'm cruising without A/C , the oil temp is about 15-20 degrees hotter then the coolant temp...(Coolant 183 degrees) ....(Oil 200 degrees) average.... The C4 analog gauges have always been known to be off, and they have always said on here not to trust them..Using the A/C will raise the coolant temps alot , I have never been happy with the C4 coolant temps when the A/C is running........WW

Ozzstar

What's the secret to having your cars coolant temp at 183 degrees cruising? Using all stock parts the coolest my '93 will run is 200-202 at highway cruising speed (60-70mph), with air temperatures above 70.

WW7

I'm not running a stock setup, getting a Dewitts radiator will drop your running temp way down....I'm also running Dewitts high speed fan with the on/off temps set at 196 on/ 180 off, so my temps stay cool at lower speeds also......WW

95BLKVette

BTW, I have ceramic coated shorty headers and there is a brass 45 degree adaptor extension that extends the water temperature sensor at the head down away from the rear header tube, however, that puts the sensor head in some dead water as far as I'm concerned, I also have the sensor wrapped in insulating wrap to keep the header heat off of it.

Under hood temps can get really hot on this thing in traffic!

Yes, it was pegged all the way to 260F!

95BLKVette

Ok so my car overheated this past Friday night on the northbound Bronx river parkway. Turns out my electric water pump of 5 years finally flamed out. As far as the temps are concerned the analog gage was buried in no mans land way past 260 when the check gages light came on and I was shocked to see the reading. The digital gage showed the water pump temp at 230. Shut it down right away and pulled over....it gurgled for 5-10 minutes. Thank goodness I have all new hoses and radiator cap. Didn't boil over....had to have it flat bedded home. Checked it all out....blew the water pump which blew the water pump connector and relay before the 15 amp fuse blew. Changed out both. Waiting on a new Messiere's 50 gpm water pump....had a CSR.

So, the analog gage can read way past 260......car still runs fine and coolant looks fine also. Will be back on the road soon.

Herb

I need to change my water pump and always wondered how an electric pump would be on the street.

What's your opinion?
Thanks Herb

Silver96ce

As a precaution change the oil before driving again.
And Merry Christmas

aklim

If street purposes, what are you trying to achieve? I would definitely want a HUGE Noid Light to make sure it is getting power. Not sure if there is a way to make sure you get a light to inform you if it has stopped so maybe a temp warning light? Still, I'd be curious as to what the electric WP is there to do for you?

aklim

Read the link below and see if you really want to do it. Evaluate the effort and then the gain you are trying to achieve.

http://ls1tech.com/forums/lt1-lt4-mo...lp-please.html