Coolant change/bleeding

I replaced my coolant tank and cap, and also replaced the water pump and thermostat with a low temp version (did this myself). I drained coolant at the rear, and at the front. Refilled the system, ran the heat on high, and kept adding coolant as needed. Left the cap off until there was some coolant coming out, then drove the car. Added more coolant, repeated. Engine temp seems correct - most of the time the gauge is at 180, occasionally goes a bit higher, but nowhere near the danger zone. I took a long 2 hr round trip in the car when I was ready, then later took a short trip to dinner with my wife. On the way home, coolant light came on. I was surprised to find coolant was low (tank almost empty) so I refilled it. Yesterday I drove by my mechanic's to show him the car, and we both noticed smell of coolant. But no obvious leaks. I thought perhaps I had overfilled it, and there had been some overflow. So I'm still monitoring, but my mechanic said often he has a hard time getting all the air out of the system and was wondering how I had done it. Any thoughts on whether I did something wrong? I'm not ruling out a leak somewhere, but I don't see anything getting wet.

U didnt fo anything wrong. It may take 6 or so trips for the coolant level to even out if u dont use s vacuum tool to fill. It will just burp air for a while.

Leave the bail up on the coolant tank for awhile and keep checking the level.

I agree with the others, you didn't do anything wrong. Leave the bail up for 5-6 complete heating/cooling cycles. Check coolant level frequently during this period. Make sure the coolant tank cap is on TIGHT. Your cap is blue and ends with part number 04...right?

Thanks. Tank and cap are new genuine, latest part numbers, yes. I was not familiar with the "bail". So I did a search and found this thread . Sounds like excess air would bleed out of the cap anyway? But I'll try the bail method. My next question was going to be about the low temp thermostat - I installed a 71c/160f Wahler and the gauge usually sits about 180 or a bit to the right. I hadn't driven the car enough before the work to know if that's any different than stock, but another search suggests the dash gauge is wildly inaccurate. If that's true, how do I know when I'm overheating? Clearly pegged to the right is bad, but where should it normally sit? Further reading suggests every car is different. Hmm, I just got a Durametric, guess I'll see if coolant temps show up in there.

I have heard, but have no personal experience, that the Wahler thermostats are notoriously inaccurate. They apparently do not open fully and in some cases get stuck. A much better alternative is the LN Engineering low temp thermostat. Certified to work correctly. I remember one thread where there was a contrast (with pictures) of the two different thermostats. They guy just put in a Wahler thermostat and was having similar problems as you are now experiencing. A search through the threads might be worth the time.

Mine sits just south of center on the "0" of 180* I've done just as you twice now without issue...Bail up through a few drive cycles.

I don't mean to hijack this thread but I have the black cap on my coolant reservoir...do I need to change to blue and if so, why? Thanks.

The original coolant caps had a P/N ending in 01. The caps failed. There were replaced with three upgraded iterations, and the current blue cap ends in P/N 04. Parts fail and get analyzed, then a new cap is designed. Just the way it goes.

I was one of those guys that recently swaped a new walher to a ln t-stat. I didnt like the temps it was giving me. Remember just because it opens sooner doesnt mean your car will run cooler. I just means it will take a little longer to heat soak the system. The car will get to the fan turn on temp eventually depending on driving conditions and ambiant temp. If your low speed is working on your fans and the rads are clean the motor should stay under 210 or so and thats more then good.

This kit works well. Otherwise it will take several trips in your car to bleed the air out. You Tube

Sorry to reopen this guys I�m new here. But I�m having an issue where I drive hard and the coolant level goes low and the light comes on. There will be coolant spritzed out the cap and around expansion tank. When I open the cap and release the pressure all the coolant returns to the tank. I have no visible leaks and have vacuumed the system multiple times. I�m changing radiators now and have already done the cap, thermostat and waterpump. Any ideas? Thanks!

U should use an Airlift to bleed after doing the rads and wp. If u dont it will take about 10 drive cycles to get the air out. U have to let it cool completely before u pull the cap or the fluid rushes back jnto the resi.

Did you put the thermostat in correctly, facing the right way? You could have installed it backwards.

Hi Everyone My first post on the forum... I recently did the coolant service on my 2001 C4 Cab. I took the advice I found elsewhere, and invested in a purge tool like this one: https://www.harborfreight.com/coolin...kit-64985.html I can't remember which adapter I used. But I had to go one size small and put two (I think) turns of electrical tape on the adapter. That gave me a good seal. I also left the rear of the car elevated, and put the front down on the tires. No issues having used this approach. Robert