thermostat change

[Andy_Disco1]

Hi everyone,

Once I changed the thermostat and I reconnected the plenum chamber do I fill up the header tank and keep plug open and top up as the radiator drinks up the reserve coolant? Or whats the procedure to fill up what has leaked out?

To remove the air from the system after, do I bleed by the radiator plug?

Thank you

 

[outono]

There are several ways to do it. For me, I fill through the radiator.

For best results, make sure your passenger side is a bit higher up (ramp or jack) since air will flow out of the highest point.

After you fill the radiator, keep the reservoir cap off (and rad cap) and fire the truck up, keeping an eye on your temp (use a Ultragauge or Scangauge). Turn the heater on full blast and let the vehicle come to operating temp. You'll see bubbles come out mostly from the reservoir, though there will be some from the rad. When coolant is about to overflow from the rad, I cap it off, but keep the reservoir cap off to allow any additional bubbles to escape.

You can keep it running for as long as you need, but it's easy to tell when most of the air is out because your vehicle temp will settle. Time wise, I usually run it 10 min, maybe 15. When you're done, turn it off and in the morning, check the coolant level in the reservoir. Top up if needed.

 

[Tugela]

As an alternative to jacking up the passenger side, you can also disconnect the hardware securing the coolant reservoir and elevate that. Same effect, different approach.

 

[mlnnc]

Hi Andy,

I see you are new to the forum. You don't say whether your truck is a D1 or a DII. If it's a DII, I recommend you download a PDF copy of the workshop manual, known here as the RAVE, using the link below.

http://l.b5z.net/i/u/6064257/f/D2_Workshop_Manual.pdf

The instructions for draining and refilling the cooling system begin on p.428 of the PDF. Ignore the parts about the cylinder block drain plugs. The procedure you want to follow begins at the top of p.429. Follow it as written and you'll be fine.

There are dozens of threads on this and other forums about other methods and how others have trouble bleeding the system. My advice is to ignore all that. I have had my DII over 20 years. I have always followed the procedure in the RAVE and I have never had a problem.

Good luck, and welcome to the forum.

 

[Blueboy]

As an alternative to jacking up the passenger side, you can also disconnect the hardware securing the coolant reservoir and elevate that. Same effect, different approach.

Yep. My approach as well for a 96 D1. Keeps the radiator level yet raises the reservoir.

 

[WaltNYC]

One technique that has helped me avoid air pockets.... fill it slowly. Pour in half a gallon, wait 30 secs. Repeat.