Delica Canada | Mitsubishi Van Club

I finally got around to changing my coolant and everything went well but afterwards while driving around I noticed I could hear fluid moving around periodically.

My guess is that there are air pockets in the cooling system. What is the best way to rid the cooling system of air pockets? I've heard from some other threads you can start the van with the rad cap off and wait for air bubbles to stop.

Can somebody let me know if I'm on the right track and perhaps elaborate on the bleeding process? Much appreciated as always.

- Jason

I checked the radiator this morning and it looks like it can use a top up. I'm guessing the hoses and engine block must have taken some coolant when thermostat opened up.

I will top up and bleed out air bubbles tonight.

Is it recommended to bleed the system multiple times to do a through purge of air?

sigurross wrote:Is it recommended to bleed the system multiple times to do a through purge of air?

Yes. Start bleeding it with a cold engine. Remove the cap, start it up and let it run/warm up. As it's warming up, you'll see bubbles/air pockets at the rad filler. Keep topping up until no more bubbles come up.

Here is what I do:

I drive it up on slope to make the radiator higher.

when I put in new thermostats I always drill a 1/8ish hole to add with air locks.

I run the motor with the cap off topping up until the thermostat opens with all heaters turned on (important on vehicles that turn off coolant flow to the heaters).

I will check it for a few days to make sure (I check my rad before every long trip).

thedjjack wrote:until the thermostat opens with all heaters turned on

Forgot to add this point as well. Important when bleeding the cooling sys. Thanks

Have I screwed things up by driving around before bleeding? Or is this just going to take more persistence as the air pockets can be anywhere in the system now?

What is the capacity of the cooling system on a l300 any how. I put in 8 liters so far and it still needs a tad more! I honestly thought 8 would cover it. Got more mopar on my lunch break for topping up when I bleed the system.

I'll let you know how it goes. Thanks for the feedback.

- Jason

you're fine driving around so long as your temps don't spike towards the red. just bleed it as soon as you can to be certain.

Ok cool. Will do that when I get home from work.

So as for the sounds I heard while I was driving. Was that the coolant returning to the radiator from the engine for the first time?

- Jason

can't tell from behind a keyboard

Ha, well after I bleed it and the sound persists I'm so not above recording the sound with a handheld and posting it. We'll see hopefully I don't have to.

Thanks again all.

I have this exact issue, although mine seemed to just start randomly - not after a coolant change or anything. Strange... I tried topping up the coolant and then running the engine with the van facing uphill in an attempt to burp out some possible bubbles, but it didn't seem to help. Does this mean I should drain my entire fluid or is there an alternate solution I could try???

Thanks!

Good call, I'll check the rad cap tomorrow! Please excuse my ignorance of this, but when burping the system of air bubbles, should I run from cold with the cap off, and keep filling the rad until I hear no more bubbles and I can't fit any more fluid in the rad? And from the sounds of it i may have to do this several times, correct? How long should I keep the engine running with the cap off? Thanks for the help - I'd love to figure this out without having to take it to a shop. (by the way the rad is about a year old, so it's not super old coolant).

I think what happened is that I filled up my rad and resevoir after completely draining the cooling system. I didn't take into account the engine block. So I'm pretty sure once the van ran for a bit the thermostat opened and filled the engine block. Once I topped up the rad again and bleed it everything looks/sounds good.

I used a napa part # 31333 for my rad cap.

Good luck with your troubleshooting.