Alternative Thermostat Options for S54 Engines

[ZiMMie]

Alternative Thermostat Options for S54 Engines

In another thread, I previously suggested a thermostat that turned out to be more appropriate for S65/S85 engines, due to its significantly larger diameter. Apologies for the confusion.

If you've already purchased that thermostat based on my earlier recommendation, you may want to offer it to someone with an S65 or S85, where it would be a better fit.

Correct Thermostat for S54 Engines:
A better fit for the S54 is the MotoRad 4046 series, available in various opening temperatures. Below is a list of MotoRad part numbers and their equivalents from other reputable manufacturers:

| Opening Temp | MotoRad | ACDelco  | Gates   | Duralast |
|--------------|---------|----------|---------|----------|
| 160°F / 71°C | 4046-60 | 12TH7D   | 33577   | 4046-60  |
| 170°F / 77°C | 4046-70 | 12TH7C   | 33578   | 4046-70  |
| 180°F / 82°C | 4046-80 | 12TH7B   | 33579   | 4046-80  |
| 190°F / 88°C | 4046-90 | 12TH7A   | 33580   | 4046-90  |

You can verify or find more equivalents by visiting the MotoRad site:

https://motorad.com/part/4046-70/

Click on the "Interchange" tab to find compatible part numbers.

These thermostats are generally available online or at local auto parts stores, with prices typically ranging from $20 to $50.

Fitment Note:
The 4046 thermostat has an outer flange diameter that matches the S54 OEM thermostat, so it should be a direct fit.
However, I have not tested it myself—if you do, please share your results with the community.

Cheers!

[0-60motorsports]

Alternative Thermostat Options for S54 Engines

In another thread, I previously suggested a thermostat that turned out to be more appropriate for S65/S85 engines, due to its significantly larger diameter. Apologies for the confusion.

If you've already purchased that thermostat based on my earlier recommendation, you may want to offer it to someone with an S65 or S85, where it would be a better fit.

Correct Thermostat for S54 Engines:
A better fit for the S54 is the MotoRad 4046 series, available in various opening temperatures. Below is a list of MotoRad part numbers and their equivalents from other reputable manufacturers:

| Opening Temp | MotoRad | ACDelco | Gates | Duralast |
|--------------|---------|----------|---------|----------|
| 160°F / 71°C | 4046-60 | 12TH7D | 33577 | 4046-60 |
| 170°F / 77°C | 4046-70 | 12TH7C | 33578 | 4046-70 |
| 180°F / 82°C | 4046-80 | 12TH7B | 33579 | 4046-80 |
| 190°F / 88°C | 4046-90 | 12TH7A | 33580 | 4046-90 |

You can verify or find more equivalents by visiting the MotoRad site:

https://motorad.com/part/4046-70/

Click on the "Interchange" tab to find compatible part numbers.

These thermostats are generally available online or at local auto parts stores, with prices typically ranging from $20 to $50.

Fitment Note:
The 4046 thermostat has an outer flange diameter that matches the S54 OEM thermostat, so it should be a direct fit.
However, I have not tested it myself—if you do, please share your results with the community.

Cheers!

Yup I have the wrong one but thats not an issue, i'll just give to someone who has the S65/85 for cheap when they come round to the shop with a Tstat issue.

My only question would be how reliable is the Motorad brand? Shall we look at others like the ACDELCO?

Also,if you can, why dont you go ahead and test the fit and function/performance 4046-60 for the rest of us.

Would be greatly appreciated..........especially if someone can do it over the next three months in Texas or and Arizona.

[m3_sancho]

I got the Motorad brand since there is no alternative available.

What I noticed. The Motorad is longer than OEM, both the spring part and cup part. Diameter is correct but flange thickness is less than OEM so it doesn't sit flush with the housing. Also the cup sits deeper in the housing. Maybe somebody can elaborate if that's going to be a problem technically?
See pictures attached. I labeled the Motorad as 71 degree in the pictures.

\

[jayjaya29]

The motorad unit will essentially act an always open thermostat. This will not work.

[oceansize]

I'm glad I simply bought Anri's when it was available.