7 replies to this topic

[Jeff Wasilko]

I had my first test days after installing the SD radiator at NJMP with the ambient temps in the mid-high 80s. Water temps exiting the head (at the stock gauge location) were pretty much locked at 180F.

 

I've got a pressure sensor in the heater core bypass hose, and was often only seeing 2PSI, which was setting off the alarm on my dash...

 

Is it common to have very little pressure in the system with the water temp running so cool?

Thanks!

 

-jeff

[Jim Drago]

Jeff

You likely have a small leak or loose hose somewhere. That is not normal,

Jim

[James York]

Or a bad cap....

[Duncan]

I had a similar issue with my cooling system.  I had installed a low pressure warning switch and was not building pressure.  There were no coolant leaks that I could see.  I bought a Stant pressure tester and found a small leak on one of the heater hoses.  One hose clamp later and the system built pressure properly.

In summary, you can have a leak that's so tiny you can't see it, but it's still enough to affect the system building pressure.

 

Duncan

[Jeff Wasilko]

Hmm. I pressure tested the system when it was empty (and used a vacuum fill) and it seemed ok. It held 18PSI for 10 minutes or so.

 

My data does show that the pressure is typically 4-5 PSI, but dips occasionally.

 

I'll re-test it now that it's got water in and see if that shows any obvious leaks.

 

I'll try swapping the cap, since that hasn't been tested.

Thanks for the tips.

[Jeff Wasilko]

The pressure test with the sytem filled at 18psi was fine, but when I cranked it up to 25psi I started to get weeping around the lower hose that goes into the mixing manifold. I reseated that hose and it held 25psi for 30 minutes.

 

I also swapped in a brand new cap. Thanks for the tips! I'll be back at the track next weekend...

[Jeff Wasilko]

Looks like either the cap or hose fixed it. I need to pull the data to see for sure, but I wasn't seeing alarms after making both changes.

[Jeff Wasilko]

This problem cropped back up later last year, and I re-pressure tested the system and tried to find a leak, but didn't find anything.

 

I looked thru a good collection of data and noticed a correlation between temperature and the pressure drop that was the same across many runs.

 

I decided to try swapping the pressure sensor, suspecting that it was not working correctly. Yesterday was the first test day of the season and it looks like the new sensor has resolved the issue. Hopefully that's the end of the issue for now.