Engine temperature

Stephen Newell · Nov 8, 2018

I have a 1993 G20 Chevrolet van with a 350 V-8 engine. I've had the van for about nine years and the temperature if the gauge is correct had been running around 120 degrees, summer or winter. I just put a new engine in it and replaced the thermostat and the temperature sensor and now it's showing about 140 degrees. What I've read about the engine is it should run around 200 degrees so I was wondering what everybody else thinks.

Ozlander · Nov 8, 2018

I think you need to install a 195* thermostat.

Steve@Advance · Nov 8, 2018

If it has a 195 thermostat, I suspect the gauge is wrong.

Did you replace the sending unit after it was overheated? The heat may have damaged it.

Stephen Newell · Nov 8, 2018

That's what I have.

DoubleO7 · Nov 8, 2018

It is the o.e.m. gauge and/or the sending unit.
I put a real bulb type no sending unit aftermarket gauge in my 1999 Tahoe.
Basically the same chassis and driveline as your G20.

My o.e.m. gauge reads 155, the real gauge reads 195.

Get you a thermostat housing like this for the gauge bulb.

https://www.summitracing.com/parts/...MIlIfWi4fG3gIVEAFpCh0wMQDaEAQYAyABEgKdKPD_BwE

504 · Nov 8, 2018

It may be a bad new thermostat.

Stephen Newell · Nov 8, 2018

The sending units are different on mine. The one for the computer is in the intake manifold and the one for the dash gauge is in the left head between two of the spark plugs.

flying belgian · Nov 8, 2018

Put the thermostat in a pan of water on the stove with a cooking thermometer and see what you got.

Stephen Newell · Nov 8, 2018

Yes, I replaced both the temperature sensors, the one for the computer and the one for the temperature gauge.

The squirrels that made the instruments made it more like a computer. It has everything all wound together in one unit so if the gauge is bad it's probably not replaceable. I know the entire cluster isn't available anymore. The back of the think looks similar to this.

jd man wis · Nov 8, 2018

How many core radiator in it. A new motor will always run hotter then an old one because of the drag of the new rings and pistons. We use to build the 350 in the stock car on the track with good rings and pistons that were loose so we had good power but with a 4 core radiator in it would run cool as the other guys were over heating. On your van do you have rear heat if so that more water to try and heat up 140 is cool I would not worry about it not unless you need hear from the heater core.

Bob · Nov 8, 2018

Checking with a scan tool, what temperature is being reported to the 'puter by the other temp sensor?

It's a lot more critical that the .puter gets an accurate temperature vs.the dash gauges.

You said you replaced the sender, did you use OEM?

Temp senders (IMHO)see definitely on my "buy OEM" when possible list.

David G · Nov 8, 2018

I agree with Bob, but do not know if the 93 had ODB2

Stephen Newell · Nov 8, 2018

It's on OBD1 and currently isn't throwing any codes.

Stephen Newell · Nov 8, 2018

That information isn't available with a scan tool, it's OBD1. Both the temperature sensors were OEM.

JF in MI · Nov 8, 2018

In a case like that I usually start checking everything and anything with a non-contact thermometer. They are pretty cheap and accurate these days.

Stephen Newell · Nov 9, 2018

Do you think I could get an accurate reading off the intake manifold? It's about all that can be reached. This thermometer sounds like a good idea. I had been thinking along the lines of putting in a second gauge but there isn't really a place in the cab to do that.

Hobo,NC · Nov 9, 2018

You need to do as Bob suggested PERIOD!!!! confirm the actual temperature to prove the gauge readings are right are wrong then move on...

Texasmark1 · Nov 9, 2018

Over the years engines were designed to run hotter. +1 on the 195F thermostat. My 2011 sits rock solid on 210, new from the factory that way but it has a pair of thermostatically controlled sequential electric fans, not belt driven fan like yesteryear, that cycle 0,1 or 2 as the temp requires.

HF sells a non contact infrared thermometer for about 30 bucks and half that sometimes on special sales. Get one. You'd be surprised how many times and places you will use it.

Get the engine running and up to temp. Shoot the intake manifold near the engine coolant outlet (where the tstat is located) and get your temp. Ought to be real close to the design temp of your tstat. While you are at it, shoot the upper and lower tanks of you radiator and see how well it's working.

Oliver 500 Wa · Nov 9, 2018

That information isn't available with a scan tool, it's OBD1.

It may be that you need a different "scan tool". I have one for my OBD1 93 Mitsubishi. It really is just software that runs on a PALM 3 (remember those?) and an interface cable. Reads just as much data as any early OBDII (1995-2004). Maybe something similar is available for your vehicle

Stephen Newell · Nov 9, 2018

Mine just causes the check engine light to blink and you read it almost like Morris Code.

Oliver 500 Wa · Nov 9, 2018

Mine does the same thing if there is a code, but there is a data port too that you connect the reader cable to.

Hobo,NC · Nov 9, 2018

(quoted from post at 06:03:07 11/10/18) Mine just causes the check engine light to blink and you read it almost like Morris Code.

It just jumps the A & B terminal at the ALDL... Dats all folks..

All you needed to do is read the engine coolant temp sensor (ECT)
I prefer to read the voltage that way you can just tap into one side and never break the connection.. I really prefer a real scan tool that will give you a menu.

http://ricksfreeautorepairadvice.com/test-engine-coolant-temperature-sensor-ect/

Stephen Newell · Nov 9, 2018

Interesting article if you could read it through this.

Engine temperature

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