GMC Savana or Chevy Express Operating Temperature

[mctwister15]

I would greatly appreciate it if anyone with a GMC Savana or Chevy Express would be willing to share what their engine's operating temperature usually sits at.  Looking to compare temps to my 2001 5.7L V8 GMC Savana 2500.  Not quite sure if I'm running a little cold or if everything is fine. Thanks!

 

[highdesertranger]

You can go by the thermostat. What is the temp of the factory thermostat? with todays engines most manufacturers want the temp between 200° and 210° so the thermostat is usually about 195°.

Highdesertranger

I see this is your first post go over to the "Newcomers Corner" and give us an intro.

 

[MrNoodly]

I just got back from running to town. The temperature gauge on my '07 Express, 4.8L engine, 300k+ miles, not towing anything, read a tick mark and a half below the 210° line while cruising at highway speed and while driving in town. That's normal for my van. The only time it gets higher than that is on slow, steep, uphill grades in the summer. Then it'll go a tick above 210°.

 

[mctwister15]

Thanks for the input! I'm currently running around 180-185 and am currently in cold weather in New England. Whenever I turn the van off, the gauge will then move up to the 210 tick, but then will drop down back to the bottom of the gauge when I start cold again. Haven't really had any issues, but had a mechanic mention I might be running a little cold while I was in to have some other work done, but the thermostat seemed to be mechanically functioning fine. He thought everything was fine, but I've been in my head about it

 

[highdesertranger]

What year is your van? 180-185° is much to cold for a newer van. Somebody has done something, Like install a colder thermostat(Bad idea) or worse removed the thermostat.

BTW how are you checking the temp?

Highdesertranger

 

[user 423]

In many vehicles the temp gauges aren't marked in degrees but just show a scale from Cold to Hot with a red zone at the upper end.

My Ford van is like that and runs about 1/4 up the scale when at operating temp.

Since I'd like to know what the actual temp is, I check it with an infrared thermometer.

It has a 195 T-stat and the thermometer shows around 200 or so when at operating temp.

An IR thermometer is useful for checking for other things like uneven braking, hot bearings,etc.

You might ask the mechanic how he knew it was running a little low. Maybe a scan gauge that can read temps?

 

[highdesertranger]

An IR thermometer does not show actual temp. is is usually 10° cooler than the actual temp, depending on where the measurement is taken. With an IR thermometer you are reading the temp of the metal on the outside of the engine not the actual coolant temp. even if you shoot the radiator fins it is still off by about 10°.

Don't get me wrong an IR thermometer is an excellent diagnostic tool and will get you in the ballpark.

Highdesertranger

 

[user 423]

How about right on the T-stat housing. Wouldn't that be pretty close to actual coolant temp?

So if a shop was checking the temp, how would they get a good reading?

Do OBD2 vehicles have temp reading capabilities?

 

[highdesertranger]

Depends what the thermostat housing is made out of, 4 most common materials are cast aluminum, cast iron, stamped steel, and plastic. Think of it this way when you put a pot of water on the stove and turn it on the temp of the pot or the water is not the same as the flame. Even with no water in the pot the temp is not the same as the flame.

If a shop wants a correct reading they install a known good mechanical gauge into the engine coolant where the sensor is located. That's what we did when I had my shop. We also put a mechanical thermometer into the coolant through the radiator cap. However we only did this when there was an issue and we needed a precise reading.

Like I said an IR thermometer also works just add 10°.

Yes OBDII has a temp reading. But you are reading through an electronic gauge which are known not to be real precise. So when we had issues with the OBDII reading not being in range we would check it against a known good mechanical gauge like I pointed out. We would never check it against a IR reading because those are not accurate enough.

Still an IR thermometer is a great tool. the most common use we used them for was locating a dead cylinder.

Highdesertranger

 

[user 423]

OK,thanks. I'll remember that it's running a little warmer than what the IR shows.

 

[mctwister15]

Problem solved! There was a hole drilled in my thermostat. Put in a new thermostat and we are running warmer now!

 

[user 423]

How big was the hole?

 

[highdesertranger]

Some thermostat are supose to have a hole. It's an air bleed/bypass hole. some have a little poppet in the hole. I hope you installed an AC-Delco Thermostat. Highdesertranger

 

[vanstu]

I have a buddy (mechanic) that took a ford 4X4 truck and turned into a stealth tow truck for repo jobs. It was not designed to do what he made it for. Besides beefing up the rear end suspension he wanted better instrumentation than the original gauges would give him. He ended up mounting thermistors to the oil/tranny/coolant systems to a separate set of gauges to give him a better idea of what was happening--

He had to really hammer the drivetrain as repo is "grab and snatch" and get the hell out of there-- I wouldn't ride with him as he got shot at multiple times!

 

[snicrep]

I just got back from running to town. The temperature gauge on my '07 Express, 4.8L engine, 300k+ miles, not towing anything, read a tick mark and a half below the 210° line while cruising at highway speed and while driving in town. That's normal for my van. The only time it gets higher than that is on slow, steep, uphill grades in the summer. Then it'll go a tick above 210°.

I have a 98 express 7.4 ltr gas. I noticed it runs on the cold side. It hardley comes up in cold weather, and runs prob 180f when its hot.

 

[abnorm]

^ Change (or install) the thermostat