Bleeding cooling system question (How to?)

I replaced the radiator in my 02 Venture.... I followed what I thought was the correct procedure for bleeding the cooling system but the car still overheats when I sit too long so that tells me that I haven't gotten it all out. Does anyone have any good tips to get the air out?

thanks in advance,
Larry

When I do something where I need to bleed the system, I usually fill the system as full as I can with both bleeder screws open. Replace the cap, close the bleeder near the water pump, and make sure there is plenty of coolant in the overflow tank. Run the engine until coolant starts to dribble out of the bleeder screw near the thermostat housing. Close that screw. Let the engine cool completely, then run it through another cycle of heating up then cooling, making sure the overflow tank doesn't run low. It may take a few cycles to completely purge the system of air bubbles, but after two it should be done for the most part.

If you still have problems, it could be a sign of other problems.

Thanks for the quick reply.... I assume it isn't another problem because it didn't heat up like it does now. There was a small issue with overheating at idle but that was because the radiator was all plugged up. Now, I can't even leave it idling for more than a minute and the temp climbs right up. One thing I didn't consider but should be a non-issue is the radiator cap itself. It has one of those manual pressure reflief valves on it but that should not play in the equation. If the bleeding doesn't work, I'll address that issue next.

Thanks again for the advice, I'm on my way out the door to give it a try.

LB

CDRU nailed it when he said sometimes it takes a few cycles of heating up and cooling off (as in overnight) to purge all the air. Once you get it running cool, don't take the cap off unless you have a darn good reason. If it needs coolant add it to the overflow tank.

New radiator cap? Good info on how caps and overflow (reservior) tanks work. http://autorepair.about.com/cs/coolingsystem/a/aa081801a.htm
If there's a groove worn in the caps big rubber washer you need a new one.
I'm in the deep South, use a 7 lb cap and it got hot here and so far so good.
I think the book calls for a 15 lb cap so go with that.

WARNING-CAUTION: DON'T REMOVE THE RADIATOR CAP ON A HOT OR OVERHEATED ENGINE BECAUSE YOU COULD BE SERIOUSLY BURNED. If you think about it, there isn't much you can *SAFELY* do with a hot engine, so let it cool down before doing maintenance or tinkering.

Don't put cold water in a hot engine because you could warp or crack a head. Put the hood up and let it cool an hour then SLOWLY replace the coolant. If you have access to hot or warm water use it. Since I got ours purged and the reservior at the proper level the coolant hasn't moved 1/32". Idling in slow moving city traffic when it's 90F degrees ambient, temp gage goes up maybe a 1/4 to 1/2 inch.

Question please: Wht did you replace the 02 radiator? Was it plugged with a jelly like substance? The PINK Death DexCool strikes again. If that's the case some of the jelly in the engine or heater core could have broken loose and plugged the new radiator. Find a radiator shop and they can take the top and bottom hose loose and blow out the radiator with a water and air pressure gun, and/or remove the t'stat and blow out the engine cooling system.

For what it's worth, I flushed ours ten times then replaced the DexCool with good ole green Prestone universal coolant, and it works fine. ;-)

Well, I figured out the problem....and yes the pink death struck again.... how long did you change to green stuff? I still don't see the point of the dexcool because if it is changed every year, the radiator should hold up fine..... anyway, the fans don't come on until the temp gauge climbs almost to overheating but then it comes right down now that it is bled properly. I'm guessing the next step would be to replace the sensor that controls the fans....it must be no good because the temp gauge moves from just under 1/2 to almost 3/4 before the fans come on..... Does anyone know where that sensor is located?

thanks again,

LB

Speed, as long as it doesn't go over to the red hot mark I wouldn't worry about fixing somethin' that ain't broke. Not being a smart a** here, but until it gets to the red mark it is not overheated.

I never was able to figure out those fans because sometimes I sit in traffic and they never come on and then sometimes when I start the engine and it is hot they come on. The temp gage is normal and they will come on and run for maybe a minute then shut off and cycle on and off, so I'll be dad burned if I know how them fellers work. Maybe my sensor is not working right but no idea where the sensor is located. Go ask Mr Goodwrench or maybe CDRU or another member knows.

"how long did you change to green stuff?" 'Prolly 'bout a month since I went to Prestone and no ramifications thus far. I know a few cars buffs like me who have switched DeathCool to Prestone and no problems for any of them.

Had the intake manifold gasket replaced and they put DexCool in it. I ran it about a week to make sure it wasn't going to leak then I flushed it ten times. Here's how I flush: Take 1/4" ID tubing and with the engine cool stick the tube down to the bottom of the radiator and siphon the DexCool out in a 5 gal bucket. Don't let it go on the ground :nono: because anti-freeze is toxic stuff and should be taken to your recycling center for proper disposal. By the way, did you know if you dump one quart of oil on the ground it has the potential to contaminate ONE MILLION GALS OF GROUND WATER?

Fill the radiator up, crank the engine and fill it plum full, let it run until the t'stat opens and the heater blows hot air, shut down and siphon the DeathCool out again. Let the engine cool ten minutes or so and repeat the start up - warm up and siphoning process BUT DON'T SUCK HOT COOLANT WITH YOUR MOUTH! :nono: Use a siphon pump or shop syringe to get it started. I do that a few times then fill it and drive it five miles or so. Let the engine cool sufficently and siphon it again, drain-siphon-refill ten times and I feel pretty certain 90% or better of the DexCool is gone Bye-Bye.

If every trace of the DeathCool is not gone, no big deal, BECAUSE, the 'Universal' Prestone label claims to be compatible with ANY anti-freeze on the market including DeathCool. I dumped in a gal of Prestone, finished filling with our pure well water, did the air purge drill and that's it. Scroll down on the home page and click: Prestone® Helps Eliminate Antifreeze/Coolant Confusion for Consumers With Launch of All Makes All Models Antifreeze (http://javascript<b></b>;: getPressRelease('2004','5');). http://www.prestone.com/company/news.php
Three cheers, a big HIP-HIP-HOORAY and a tip of the Hatlo for PRESTONE! You da' man Prestone, you da' man!

Have a good friend in the hospital and will be sitting with them better part of the day, so if you have a question I will get back with you late this afternoon. Keep the faith, hang in there and we'll all help you get it squared away. :iceslolan

thanks for all the good info.. I may end up going to the green stuff also... I've always been told if you change the coolant once a year, you will never have problems... Anyway, I understand the not broke, don't fix it idea but this is my wife's car and I don't want to take any chances. I will probably try changing that sensor this weekend because I didn't have that particular issue before. I may even put an actual temperature gauge to it to see how hot it actually gets..

Again, thank you for the help and I'll let you know if I make any progress....

LB

http://www.are.com.au/feat/techt/thermostat.htm Easy to see how using the wrong stat can cause problems.

"I may even put an actual temperature gauge to it to see how hot it actually gets." http://www.aa1car.com/library/overheat.htm Venture takes a 195 degree stat but that is the "start to open temp" and when full open you'll 'prolly see 200 to 210 degrees. Read the link. Don't use a 180 degree stat because the engine is designed and calibrated to run on a 195 and your gas mileage will be less.

"I will probably try changing that sensor this weekend because I didn't have that particular issue before." Trying to recall excatly what the thread was about and where I read it in this forum, but it got down to removing a coling system sensor and cleaning the end because the DexCool jelly had gummed it up causing incorrect readings. Maybe yours needs cleaning?

I've been busy because my business is summer time & hot weather based and I forgot to stop by Goodwrench and find out where the sensor is located. When you find out please post it. Be careful working with a hot engine and the coolant and have a nice week end.

Just had a head scratcher. I wonder what temp is indicatited by the temp gage hash marks? Mine usually runs lower than half way so that must be around 220 to 225. So what temp is the half way mark, the 3.4 mark and the last mark before the red mark? If you look on the lower right of the engine you'll see a temp sensor and I guess it goes to the temp gage.

Just wanted to follow up. I reset the computer last night and the issues seem to be resolved. The low speed fan was not coming on before and it is for now anyway. We'll see what the future holds.....

thanks for all the help!!

LB