Community Forums

wolfe10 · 08-23-2015, 09:13 AM

Need the specs on the radiator cap for 2003 Alpine 38FDDS with Cummins ISL.

The only information on the OE cap is the brand logo "S" (Stant) and D2. No part number.

Thanks.

Brett

Old Scout · 08-23-2015, 09:51 AM

Search tool on this forum is your friend--believe 16lbs, vented cap is the agreed on specs for the rad cap. Besure to check coolant level only when engine is at ops temp. Many owners have added an overflow tank to the expansion tank when it is likely they are checking the level cold and adding too much coolant. Assumming the OEM expansion tank is a closed system--not sure why you would needed a "vented" cap but letting air back into the expansion tank as engine/coolant cools is probably OK. I am sure other owners will argue about the need for an "extra" overflow tank--but 13 years and 156k miles later and never needed the extra tank--go figure?????

GMDavidson · 08-23-2015, 11:18 AM

My 2001 had a 12lbs cap. When I wanted to replace it while traveling through Page, AZ, the closest I could get was a 14lbs, with I've been running for years now.

I'm interested in an overflow tank. Unpredictably my systems overflows and doesn't seem to have anything to do with overfilling. May have to add 2 gals or more of coolant. What are folks using for an overflow tank?

Rich and Cork · 08-23-2015, 06:31 PM

Quote:

Originally Posted by GMDavidson

My 2001 had a 12lbs cap. When I wanted to replace it while traveling through Page, AZ, the closest I could get was a 14lbs, with I've been running for years now.

I'm interested in an overflow tank. Unpredictably my systems overflows and doesn't seem to have anything to do with overfilling. May have to add 2 gals or more of coolant. What are folks using for an overflow tank?

You should only be filling to the sight window of the reservoir. Sounds like you are overfilling. Don't think you should need an additional tank. There is a lot of room for fluid expansion.

Renipladlo · 08-24-2015, 10:43 AM

Hmmm, thought it was 17 lbs for the cap. Guess it is time to replace mine. Cummins would know I think. EM knows as well, hey Mike, please chime in here for the correct answer.

Koop · 08-24-2015, 12:12 PM

The only spec I found from Cummins stated minimum cooling system pressure of 7 psi. That's really low. I believe my original cap was 14 psi, when I replaced it I found a 13 psi cap at the local auto parts. I posted about it here.

wolfe10 · 08-24-2015, 02:39 PM

Just got off the phone with a parts guru at Stant.

Correct PN for 10 PSI cap is Stant 10237
Correct PN for 13 PSI cap is Stant 10229

According to Cummins, for the ISL, you need a minimum of a 7 PSI cap.

I bought the 10 PSI.

Either should be under $7.

Brett
2003 Alpine 38FDDS

dennis45 · 08-24-2015, 06:42 PM

Quote:

Originally Posted by GMDavidson

My 2001 had a 12lbs cap. When I wanted to replace it while traveling through Page, AZ, the closest I could get was a 14lbs, with I've been running for years now.

I'm interested in an overflow tank. Unpredictably my systems overflows and doesn't seem to have anything to do with overfilling. May have to add 2 gals or more of coolant. What are folks using for an overflow tank?

Per the attached photo, my Overflow Tank (white plastic tank) was a standard OEM item supplied by Spartan Chassis.
The over flow tank provides a reservoir to contain fluid off the pressure cap at normal operating range. In addition, since the hose off the pressure cap goes into the bottom of the tank, it prevents air from being drawn back into the cooling system during the cool down period when the engine is shut down.
Removing entrained air in the cooling system is critical to reduce the effects of Cavitation Corrosion to cylinder liners, water pump etc.

Mule Skinner · 08-24-2015, 07:46 PM

Mine came with a 8 lb. cap. Took a few years to figure out, but that was why I was loosing coolant. I would see small wet spots on the ground after parking for a few minutes.
I changed it to a 16 lb. No more coolant loss.

dennis45 · 08-25-2015, 10:29 AM

Quote:

Originally Posted by Mule Skinner

Mine came with a 8 lb. cap. Took a few years to figure out, but that was why I was loosing coolant. I would see small wet spots on the ground after parking for a few minutes.
I changed it to a 16 lb. No more coolant loss.

Yes, and I can tell you that all New Caps do not necessarily live up to their rating out of the box. I went through three before I found a good one. Maybe it's a Made in China thing....