need instruction on changing radiator fluid...

[Terry S]

Don:
1. Draining cold is fine. Besides, draining hot is a pain. I know of no advantage to draining coolant when hot unless you want to burn yourself.

2. The problem with flushing at home is, unless you could get the block drain plugs out (there is a brass colored one on the drivers front of the block but I have not seen one for the passenger side as it may be under the motor mount or something else) you will leave an unknown amount of water in the system. This makes it a guessing game on how much dexcool & how much water to put in to get a correct 50-50 mixture. I think flushing is not really necessary unless you have a dirty cooling system.

You can get much of the coolant out by draining the radiator and pulling the thermostat. Having the back of the car higher than the front will help get more coolant out. If the old coolant tests 50-50 just refill with 50% dexcool and 50% distilled water. If it tests more or less than 50-50 add more or less than a 50-50 mix of new coolant & water to try to get to 50-50.

Make darn sure you get the air purged from the system or you can overheat the engine. Pulling the top coolant hose away from the nipple at the throttle body and keep the hose higher than the nipple will let the air out while you slowly refill the coolant tank. Have the heater on and on hot before and after drain & refill. will allow Keep a very close eye on the temp guage. If it starts getting hot shut it off and let it cool. Then pull the hose slightly away from the nipple while the engine is running and see if you cannot get the air to purge. Refill the coolant tank as necessary.

Antifreeze is poision and can kill animals who drink a small amount, so don't let them get near it. Dispose of the old coolant properly. Some sewer districts will allow you to put it down your house sewer line.

[don527]

thanks for all the responses.

it didn't turn out as smoothly as i hoped and hope i can get some suggestions...

i ended up following the instructions posted here by others which is basically taken verbatim from the shop manuals.

once i got the right allen wrench, draining (cold) was easy. again, i used the basic instructions so didnt look for drain plugs on the block even though it sounds more thorough.

the car doesnt really have that many miles so the the coolant looked as good as the stuff i was putting in.

i used prestones premixed dexcool fluid... has 50% distilled water premixed in so that i wouldnt have to be concerned about ratio.

I filled the reservoir with coolant as instructed up to the "base of the neck." I emptied a whole jug and had to start on a second jug of coolant to get to the base... and went a tad over the base.

i figured no big deal... start the engine, idle for a minute then cap it and cycled my revs until 99 degrees C (210 F).

now the interesting part... i take the tank cap off again and the instructions say to let it idle for one minute and then to fill the tank to 1/2 inch above cold full.

I restart (coolant temp showing 91 degrees celcius) but after the minute, it's still filled up to the base of the neck. From the instructions, I'm expecting it the fluid level to be dropping/lower while idling and in need of more coolant and am confused

Without having to add, i thought I'd leave it uncapped and let it idle another minute or two... maybe it's got to circulate more and rid air bubbles?

anyways, i thought that was the case cause i thought i saw a few bubbles during the next minute but all of a sudden coolant is overflowing out of the reservoir and onto my garage floor!

i shut off the engine. the coolant level is about 3/4 inch above the cold full mark near the top of the reservoir. I cap the reservoir and start up the car again and run it at idle until it reaches about 102 degrees celcius and shutdown (actually I was also prepping for the hurricane by backing up the car into the driveway and then back into the garage making space for the other car never going past idle-1000 rpms).

After I shut down, the coolant level is about 1/4 inch above cold full and I haven't been back to the car since cause I had to deal with prepping for the hurricane.

After all that... I have questions....

Should I be concerned with air trapped in the coolant passages because things didn't go according to plan?

If the reservoir is overfilled... do I need to be concerned about causing damage or is there a overflow tube that any extra coolant can escape thru?

should i try to redrain/refill again?

I forget... what coolant temp range should i look for to make sure that it's running correctly?

Thanks,
Don

[Subdriver]

Don,
I read this whole thread today and didn't realize it was three years old until near the end. How funny.

I wouldn't worry. I have changed my radiator fluid numerous times now due to various problems and had similar experiences as you with no problems.

First time I followed the shop manual procedure and had the exact same experience as you. Essentially no extra fluid was needed. I believe the system vents itself very well as it fills. Now I just pour fluid in, run it a minute or so and top it off, then watch level from that point on. I have not yet had to add coolant after the initial fill, so no extra bubbles are coming out and my car is running under 210 hot on the track in 100 ambient temps in a 40 minute SCCA race (but with Ron Davis aluminum radiator and AMSOIL oil and external oil cooler). But, as a note, I check my radiator coolant level prior to every track session, which is obvious very often as I have it on my pre-track session checklist.

I also believe the level rose because of expansion of the fluid as it got hot. The excess fluid will come out of the reservoir fill cap (that is the pressure relief point). I'd keep an eye on reservoir level for awhile.

As for temps, keep an eye on them to for awhile. Thermostat opens around 190F and slow speed fans come on around 230F or so, so normal temp should stay within those bounds. If you had bubble trapped in the block, which I highly doubt you do, oil temp might rise to abnormal levels, so I'd watch that as well. Before my T1 prep, my oil temps were normally around 200-245 on the street, cooler on the freeway, hotter in stop and go traffic.

Good luck with the hurricane. Looks like it is weakening. Hopefully it won't regain much strength before it hits FL.


P.S. I use Redline water wetter in my car with no apparent ill effects. However, I haven't noted much improvement with it either.