no coolant circulation, new water pump

[profbooty]

hey all I just finished my timing belt and water pump change.

engine runs fine, but the coolant doesnt seem to be circulating. there are no leaks, the belt appears to be tensioned properly on the water pump. I put in a new thermostat as well. i can squeeze all the pluming going into the radiator, and hear the resulting suction sound in the coolant tank. the coolant level doesnt change at all while the engine is on.

any suggestions

[Devil Inc]

Have you tried bleeding off the air in the cooling system? If it is air locked it won't circulate at idle but it might at speed. Is it a possibility the thermostat is in backwards, causing it to close when it gets warm?

[jlevie]

Having the thermostat in backwards won't keep it from working, but the engine will probably overheat before the stat opens.

My suspicion is that you haven't properly bled the system. Try the procedure below, while always works:

1) Using ramps or a jack get the front of the car 1' or more higher than
the rear. That will make the radiator and bleed screw the highest point
on the engine and facilitate removal of air.

2) With the bleed screw open, add coolant until no more air comes out of
the bleed.

3) Leave the filler cap off, or at least loose, and set the heat for max
temp and fan speed. Leaving the cap loose will prevent air that's still
in the system from causing a "coolant fountain" once the engine heats
up. Start the engine and allow it to warm up to operating temp. As it
warms up occasionally crack the bleed screw to release any air and top
up the coolant as necessary.

4) Once the engine is at temp bring it up to 2000-2500 for a few seconds
several times. Then crack the bleed until no more air is released. At
this point the heater should be throwing lots of hot air, which
indicates that the heater core is filled with coolant. You may have to
repeat this a few times to get all the air out.

5) Drive the car a bit, allow it to cool back down, and recheck the
bleed for air. Over the next few days you may get very small amounts (a
few bubbles) of air out of the bleed screw.

[kenika65]

+1000

Damn dude thats how you take the time to help someone out the right way. Props

To the OP this is the way to do it^^^ and after you do it a couple times you will realize that its not quick and easy to get the air out of your colling system, it takes time and patience.

[Ral]

Hmm... this helps me out a lpt too. thanks man.

[jlevie]

A trick that works on my 87 325is that will speed up the initial fill is to remove the radiator end of the overflow line that runs from the radiator to the expansion tank. With the expansion tank full, the cap on, and bleed valve open. Blow into the expansion tube to apply pressure to the expansion tank. That forces coolant into the system and pushes out air. Close the bleed when coolant is flowing from it and reconnect the overflow when coolant is coming from the nipple in the radiator.

For this work well, the nose of the car has to be up in the air, per the above.

[elsabor67]

That is the way to do it. Props J. on the writeup. I made the mistake of not bleeding the cooling system properly and hosed my radiator on the Autobahn. After replacing the radiator with a better one, I took my time and bled it like that and it took a while but now it's perfect.

[mops]

what i always do in my cars.. old hot-rodder trick....
drill small hole in the thermostat, some say 1mm some say 3mm, i do 1mm (even puncture it with small nail), in the collar, close to the outside edge. Install thermostat with the hole up top. it's not possible to install it backwards, it wont fit. now, 1mm hole is small, so it will not pass enough coolant to make any noticable difference, but it will pass any gasses through the thermostat (remember hole as up top as possible). that includes any air trapped in the engine as well as steam that flashes of the hot spots.

since i made that hole (my is 2.5mm, which is kinda too big - engine takes longer to warm up. try 1.5mm or 1mm) system is properly bleed after first warmup/cooldown cycle. I can feel that all hoses are full of coolant... even when cold. which wasnt the case before 'the hole'.

google the internet, there's alot of info about that trick.

[kenika65]

there are thermostats that come with the hole.

[golde30]

Dont Forget To Spray Paint Your New Water Pump!

[badvibrations]

Dont Forget To Spray Paint Your New Water Pump!

bwah??
lately i cant tell jokes from seriousness here...

[NC325iC]

lol, he will forever be ripped on for that