Thermostat

442olds · January 31, 2023

I have a 2018 Silverado with a 5.3.It has 104,000 miles and has been running well.I did have to put a transmission in it around 90,000.

Anyways,I don't think my temperature gauge is as high as it should be. I'm thinking about changing the thermostat. A quick search shows them being sold with the whole housing.Why are they selling them like that.Can't you just buy a thermostat?And I prefer GM parts.Anyone have a part number?

BO TIE 1 · January 31, 2023

Looks like that's how they come for our trucks. I checked gm parts direct

Water Pump Outlet Assembly with Thermostat - GM (12674639)

It's Tim · January 31, 2023

1 hour ago, 442olds said:

Why are they selling them like that.

$$$

15 Z71 · January 31, 2023

It's worth buying whole assembly. Takes about 15 minutes to change. I did mine over the summer. 3 10mm bolts and one clamp.

Grumpy Bear · January 31, 2023

I gutted the housing and installed this from IPSCO.ORG in the upper hose using a standard 54 mm SBC thermostat.

Allot of thermostat choices when done like this. I had them scallop it, but self-item is not so machined.

Currently running the Reische Racing 170F stat summer and winter.

Shown spliced into upper hose below.

16LT4 · February 6, 2023

On 1/31/2023 at 10:49 AM, 442olds said:

I have a 2018 Silverado with a 5.3.It has 104,000 miles and has been running well.I did have to put a transmission in it around 90,000.

Anyways,I don't think my temperature gauge is as high as it should be. I'm thinking about changing the thermostat. A quick search shows them being sold with the whole housing.Why are they selling them like that.Can't you just buy a thermostat?And I prefer GM parts.Anyone have a part number?

Does it matter? Replace the entire assembly, easy peasy. Mine was stuck open for who knows how long, and I just replaced it with Motorad 815194 from rock auto, the 194* T-stat in lieu of the stock 207* unit. $45, and easier to replace than a traditional thermostat (no RTV/gasket needed, the new houseing comes with an o-ring).

Before replacing that, however, I 1) replaced the temperature sending unit to ensure anything I'd see on the scantool was accurate and 2) looked at ECT on a scan tool. The dash gauge is hardly an accurate gauge.

442olds · February 6, 2023

I changed it this weekend.Very easy to do and now my gauge is right where it used to be.

There were no trouble codes.You just get used to where the gauge "used to be" and I think my thermostat was stuck open.Mileage seemed to be off a tad too,but it's all back to normal now.Thanks.

steelerdude15 · October 20, 2023

I need to replace my thermostat. Scan tool shows my ECT is at 189F on the highway and 194F in stop and go traffic. Should I stick with the GM thermostat or would I be okay to buy one from Advance/Autozone?

Grumpy Bear · October 20, 2023

1 hour ago, steelerdude15 said:

I need to replace my thermostat. Scan tool shows my ECT is at 189F on the highway and 194F in stop and go traffic. Should I stick with the GM thermostat or would I be okay to buy one from Advance/Autozone?

If you are going to stay with the factory thermostat setpoint of 207F then I'd stay with the OEM DIRECT FIT part number. Others may be the same set point, but they may not be the same body material and the matters in how quickly the thermostat responds to change. If you remember early radiators cracked near the inlet due to thermal cycling and the first fix was a piece of tape to block the air. But the later and more effective fix was a change in the thermostat itself to stop over cycling. The pill in some is stainless and is slow. Others brass and quick.

More than you asked for, but reasons matter to some.

Edited October 20, 2023 by Grumpy Bear
gramar and spelling

steelerdude15 · October 20, 2023

1 minute ago, Grumpy Bear said:

If you are going to stay with the factory thermostat setpoint of 207F then I'd stay with the OEM DIRECT FIT part number. Others may be the same set point, but they may not be the same body material and the matters in how quickly the thermostat responds to change. If you remember early radiators cracked near the inlet due to thermal cycling and the first fix was a piece of tape to block the air. But the later and more effective fix was a change in the thermostat itself to stop over cycling. The pill is in some is stainless and is slow. Others brass and quick.

More than you asked for, but reasons matter to some.

Thanks for the reply. Greatly appreciated.

Earl Cordova · October 20, 2023

On 1/31/2023 at 2:00 PM, Grumpy Bear said:

I gutted the housing and installed this from IPSCO.ORG in the upper hose using a standard 54 mm SBC thermostat.

Allot of thermostat choices when done like this. I had them scallop it, but self-item is not so machined.

Currently running the Reische Racing 170F stat summer and winter.

Shown spliced into upper hose below.

I really like your idea.

Does having the thermostat in the top hose change anything, like the way it heats up and cools down ?

Earl Cordova · October 20, 2023

I don't see the scallops as an option on their website.

Edited October 20, 2023 by Earl Cordova

Grumpy Bear · October 21, 2023

17 hours ago, Earl Cordova said:

I really like your idea.

Does having the thermostat in the top hose change anything, like the way it heats up and cools down ?

That first cycle is a bit slow, yes. But as I use a 170F thermostat it's 'late' is sooner that the factory 'normal'. So and issue that isn't. After the first it acts as normal. The Riesch Thermostat has a brass body and acts pretty quick to upsets. Someday I'll move that small bypass hose from the factory neck to the EPSCO holder and it will quicken.