Car Analogy

No need to do full radiator flush just to get air out. Just follow the billman radiator bleed procedure.

You loosen the bleeder valve, a 10mm bolt with an bleeder nipple, located between throttle body and valve cover, while you squeeze the upper radiator hose, then retighten. You do this with engine warm, but not running. You do it over and over until no more air, and heat runs hot all the time.

Start engine, run for a min, shut off, bleed, restart, etc. Bleeder only opened while engine is off.

It would suck if it turns out you do need a radiator, afyer you did a full flush with all new fluid. Just bleed it first.

GetS2pd

I did this just last week. I rented AutoZone's Loan-A-Tool cooling system tester for a $250 deposit (refunded if you don't break anything). The test kit had adapters for different makes/models radiator fill necks and thermostats. I suggest that you pressure test your system. Just keep in mind that, with AutoZone, if you pay by credit, it'll take a few days for your bank to receive the deposit refund. That's why I paid with cash (or use the debit option) - I got refunded instantly. Good luck!

Not to thread steal, but I'm still troubleshooting my cooling system. Current symptom is that the temp fluctuates rapidly from normal op temp (180) to 200 during slow speeds. I have a Bluetooth OBDII interface with Torque Pro on my phone. My car has always ran around 180 degrees and would slowly creep up during stop and go traffic. Now, it it goes from 183 to 208 within a minute of sitting then the radiator fan comes on. Using the cooling system test kit, the system held 16.5psi for 20 minutes with no drop in pressure, and the radiator cap held the same pressure for 5 minutes. No visible leaks, no coolant from the water pump weep hole, and the water pump spins freely. No oil in the coolant, and no coolant in the oil. I've replaced the thermostat and used Billman's bleeding procedure. The only thing I can think of is a blocked radiator (replaced about 7 years ago from a cracked plastic end tank) or maybe a failing water pump (it does have 140k+ miles on the original pump), so I'll be taking the pump off sometime in the near future to see if I spot anything wrong. I've been driving my truck as the S sits in the garage until I get it squared away. Any suggestions would be welcomed!

Car Analogy

I highly doubt its the water pump. That is not their failure mode. Its a simple vane pump. If it spins, it pumps, unless the vanes are broken. If that happened, there would be hella noise.

That sudden a temp change screams air in the system, or a failing thermostat. If you feel the need to disassemble things for diagnosis, I would start with removing the thermostat, and running statless for a while, to rule out the thermostat.

But first, when the temp makes a sudden spike, how is the heater output? Next time it gappens, turn it on full blast. If its not virtually burning your fingers if held up close to vent, you still have air.

I changed my coolant recently, and used the Lisle funnel. I found it made making sure the system was fully bleed that much easier, and less messy. I would recommend doing the coolant bleed over with aid of this device before you start disassembling cooling system components.

GetS2pd

Thanks for the input. I forgot to mention that I tried to look over the thermostat - watched the temp get to 200deg and felt the lower radiator hose. It was slightly warm but didn't seem like the thermostat was open (OEM is supposed to be fully open around 194 IIRC?). So I replaced the thermostat with a brand new OEM then did Billman's bleeding.Lower hose had the same result, so I swapped thermostats again with the cheap Failsafe one. At least now the lower hose gets hot around 190deg.

I'll look around for the Lisle funnel and try monitoring the heater vents when it spikes as I take it for a test drive this weekend. Thanks again!

GetS2pd

So I bought the Lisle funnel (don't know how I did without it) this weekend to bleed the system. Before doing so, I drove around monitoring the coolant temp. When it hit to 200deg, I turned on the a/c and watched the temp drop to 179 from the condenser fan. That made me decide not to troubleshoot the water pump. Got home and used the funnel to bleed a little bit of air after I let the engine cool down from the drive.
Thanks for the advice! Seems like everything is just about back to normal. I'm gonna try to bleed it one more time today.

Car Analogy

The Lisle Funnel is one of those things thats so simple, so effective, you wonder why didn't I think of that!

When I used it for the first time I was sold. So much less mess. So much easier. Plus its not expensive.

Slowcrash_101

I stumbled on it by accident, I was doing a coolant change and noticed the heater would get hotter whenever I squeezed the upper rad hose, and I saw bubbles coming out of my funnel. I never bought a spill free funnel, just have a regular slim neck funnel that fits the radiator fill neck. When I want to move the excess to the overflow tank, I just use a cheapo hand pump. I have one for gear oil, brake fluid, and coolant.

GetS2pd

Sorry to thread jack again, but wanted to add to the post just in case someone else ends up with my problem.

Haven't been driving the S until I got everything squared away, so I've been bleeding the system with the Lisle funnel every chance I got. There was always air bubbling up the 3 different days I tried to bleed the system.

Last weekend, I noticed a small amount of dried coolant right underneath the recovery tank cap. That made perfect sense as to why there was always air in the system even after performing the pressure test (held 16.5 psi for 20min with NO drop), That test had the adapter seal inside of the radiator fill neck, bypassing the recovery outlet/tube to the recovery tank.

I ordered everything for the recovery system from the dealer except the tank itself and only paid $16. Replaced the parts this week and everything is back to normal. The system stays at 183 degrees with steady driving, gradually increases with stop and go traffic, and no more air in the system.

I searched this forum for "coolant" and found several threads mention the recovery tank cap gasket failing. Thanks for the advice on the funnel!