Author Topic: How to burp/bleed gen 2 cooling system?  (Read 3317 times)

DR1665

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How to burp/bleed gen 2 cooling system?
« on: March 17, 2018, 03:07:42 PM »
Drained and refilled my cooling system earlier today. (New, OEM tstat and overflow bottle after running distilled water and a bottle of CLR for three weeks to clear out the rust water I'd been running since last summer.)

Parked on a slight incline in driveway, nose up.

Filled radiator, started engine with radiator cap off.

Heater on full blast, mix of idle and hand throttle to circulate.

Continued like this until coolant was steaming hot.

Revving the engine produced more bubbles, but doing so pushed coolant out, then the level dropped to below the filler neck, which introduced more air.

Put about 20 miles on it after this and the temp gauge still dropped a few times, suggesting I'm still low.



Coolant still isn't as clean as I would like, so I'll probably see more CLR (any threat to my new tstat?), but I'd really like to know how to do this right. Never needed one of those fancy funnels before, but never needed an OEM tstat or radiator cap before, either.

Cooling system health is damn important on these trucks. Especially for those of us in Phoenix. Appreciate the advice.
The Driggins | 98 Pajero | 11 Juke
(Previously: 89 Pajero 2.6, 92 GVR4, 91 GVR4, 97 Talon)

kalieracer

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Re: How to burp/bleed gen 2 cooling system?
« Reply #1 on: March 17, 2018, 11:23:01 PM »
It takes a couple of tries. Use the two bleeder bolts on the water outlet. You can see one of them have a yellow sticker with some writing next to it. If your truck has a body lift it make require a drive or two. Also make sure that the rubber hose for the over flow is there and working  (inside the bottle to the cap)


Drained and refilled my cooling system earlier today. (New, OEM tstat and overflow bottle after running distilled water and a bottle of CLR for three weeks to clear out the rust water I'd been running since last summer.)

Parked on a slight incline in driveway, nose up.

Filled radiator, started engine with radiator cap off.

Heater on full blast, mix of idle and hand throttle to circulate.

Continued like this until coolant was steaming hot.

Revving the engine produced more bubbles, but doing so pushed coolant out, then the level dropped to below the filler neck, which introduced more air.

Put about 20 miles on it after this and the temp gauge still dropped a few times, suggesting I'm still low.



Coolant still isn't as clean as I would like, so I'll probably see more CLR (any threat to my new tstat?), but I'd really like to know how to do this right. Never needed one of those fancy funnels before, but never needed an OEM tstat or radiator cap before, either.

Cooling system health is damn important on these trucks. Especially for those of us in Phoenix. Appreciate the advice.

CharlieN

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Re: How to burp/bleed gen 2 cooling system?
« Reply #2 on: March 18, 2018, 03:56:13 AM »
The bleeder on top of the water neck is the important one. Bleeding is best done with radiator cap on so pressure can build. Starting with a cold system back off the bleeder bolt or start with it out, put the bleeder bolt in place with just a few threads engaged till just water is trying to escape. Close it and run the engine up to full temp. No need to rev the engine at this point.
When at full temp if you do not feel all air is out, with engine idling crack the bleeder, do not back it out far. Do not rev the engine.
Close system up, make sure coolant reservoir is pretty full and shut down and let cool.

Do not open the system during cool down since the system will be drawing coolant from the overflow.

FWIW, this system is quite well designed in such there are bleeder hoses that come off the front of the heads, behind the Tbelt up into the thermo housing. it allows for a much more active bleeding system during the life of the vehicle.

I would also NOT run straight water in these, you need at least some sort of good corrosion inhibitor.
Regards, Charlie N

DR1665

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Re: How to burp/bleed gen 2 cooling system?
« Reply #3 on: March 18, 2018, 09:13:28 PM »
Thank you both kindly. Appreciate it. I'll try the bleeder as suggested.

My old expansion tank was cracked inside one of the grooves where it slides onto the bracket. Glad it was an easy, obvious fix. Got a new OEM unit from ADD.

Currently running 90c/10w mix and planning to drain and refill again next weekend.
The Driggins | 98 Pajero | 11 Juke
(Previously: 89 Pajero 2.6, 92 GVR4, 91 GVR4, 97 Talon)

CharlieN

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Re: How to burp/bleed gen 2 cooling system?
« Reply #4 on: March 19, 2018, 04:23:21 AM »
Draining is a bit of a PIA since both radiator hoses come off the engine up petty high, the lower part of the block will not drain unless the plugs are pulled from each side of the engine. Something most of us are reluctant to do.
So when flushing, multiple drain fill cycles through the radiator get a fair bit out but never a true flush. You do need to warm the engine each flush to open the Tstat. No need to bleed the system during flushing.
If the engine has lived with straight water for year I expect a chemical flush is needed to loosen crap that is settled in the block.
Warm or hot water fill makes the flushing go quicker with the final fill with coolant added is best with a cool fill just so the bleed cycle works properly.

Many years back when I built my 3.8 DOHC motor I bought many parts on Ebay, particularly cooling system so I had a selection to pick from. One of the large steel coolant pipes that come over the engine from the rear I got out of the LA area, sure was beautiful on the outside. But once I had it in hand it was rusted through from the inside. It was scrap.

In the race cars I build & maintain we run a bottle of RedLine water wetter in the system to prevent corrosion.
Regards, Charlie N

Se7en62

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Re: How to burp/bleed gen 2 cooling system?
« Reply #5 on: March 19, 2018, 02:28:03 PM »
I just did a 6 hours flush (over a week's time) on my 1999 Gen 2.5. I don't know if you know or not, but there's is a drain plug on the passenger-side lower-corner of the radiator. You just remove the intake and it makes it a lot easier to access. If you flush it again, I'd suggest trying Blue Devil. I've used it on all of my older vehicles and projects and have always had great results.
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1999 Montero "Winter Package" Overland - X3 / ADD / ADHD / ARB / AVN / OME / Bilstein / CVT / DFG / Dometic

RyanY

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Re: How to burp/bleed gen 2 cooling system?
« Reply #6 on: March 19, 2018, 04:08:42 PM »
Brian, when you do your final fill on your cooling system, I'd recommend running at least a 70/30 coolant to distilled water ratio, and a 50/50 would be even better. Coolant doesn't transmit heat very well, so the more water in your system the more efficient it will be. Even a 50/50 mixture should give you plenty of freeze protection for anything you're going to experience in AZ.

Don't forget to add a capful of dish detergent, the emulsifiers actually reduce the surface tension of the water which allows it to make "better" contact with the inner walls of the coolant passages and radiator. Same as what Water Wetter accomplishes for 1/10000 the cost.

Drew84

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Re: How to burp/bleed gen 2 cooling system?
« Reply #7 on: April 07, 2018, 04:59:39 AM »
https://www.amazon.com/Lisle-24680-Spill-Free-Funnel/dp/B00A6AS6LY/ref=sr_1_2?ie=UTF8&qid=1523102000&sr=8-2&keywords=radiator+funnel+fill+kit

I keep one of these funnels in my tool box. I use it for all my cars, you over fill it, run it up to temp and the bubbles come out of the funnel. On my 2.5 I swapped a replacement plastic tank radiator for an OEM metal one, then my heater hose burst a few weeks later. (Yeah I know, should have done those at the same time, it's a long story) I also had to do a coolant flush on my WRX this past year and my DSM needs a radiator, so I use it quite a bit.
Keep your cars analog.
1990 Talon TSi
1991 Galant VR4
1999 Montero "Cold weather"