[17txcamaross]

Originally Posted by BMWM.D.

I took the car out for a drive today, and grabbed a few logs like I promised. We’re having a freak October heat wave, so it was 90-91 degrees outside the entire trip. I started the car cold, let it idle for about 10 minutes, and did another 5 minutes of stop and go driving before getting on the freeway. The freeway drive was about 15 minutes.

When I exited the freeway, the My Link was showing 91 degrees. My IAT1 was at 93 degrees, and IAT2 was at 100 degrees.

I did probably another 10 minutes of city driving before parking the car to run into Best Buy, then to grab some lunch. This gave it a good chance to heat soak. IAT1 had crept up to 104, and IAT2 had reached 111 by the time I shut it off. This was after sitting at a few stop lights and moving through slow moving traffic in 90+ degree temps.

After letting the car sit parked for 20 minutes or so, it was warm. When I started it up, IAT1 was at 129, and IAT2 was 133. Not too shocking considering it was 91 degrees and parked with a fully warmed up engine.

I headed back to the freeway, and temps had dropped to 95 degrees (IAT1) and 122 (IAT2) by the time I hit the on-ramp. This was only about 3 minutes of driving at 50 mph or so.

After 8 minutes on the freeway (including a quick WOT pull to speeds I won’t mention), temps had dropped to 91 degrees on IAT1 (exactly what the My Link display was showing), and IAT2 was at 102.

I hope that helps as to the delta between ambient temp and IAT2 on a ZL1 with stock heat exchangers during normal driving. As you can see, my IAT2s are typically no more than 10 degrees over ambient as long as the engine hasn’t been shut off and allowed to heat soak, or sit idling in traffic. And even after letting it sit and hit over 130 degrees, it quickly recovered.

Thanks for the update. My ride is at the performance shop so they can vacuum fill the system and figure out what is wrong. On my 15 miles drive to the shop all freeway temps had gotten to 142 and this was all freeway at between 55 and 75 mph. At a stop light it would climb higher and then back to 140 or so. Will be picking the car up tonight and look forward to seeing good temps with now worries.

[BMWM.D.]

Yeah, that’s really hot.

Personally, I probably would have just bought a reservoir like the one ADM sells. I have it on my car, and it makes potential air issues a thing of the past. I was originally looking at buying the GM fitting and trying to adapt it to the BMW vacuum filler tool I have. But I feel the reservoir was a better solution, and close to the same price after buying all the fittings I would have needed.