vssman

Two days ago I changed the thermostat as it wasn't getting good heat anymore. Now the thermostat goes WAY up on the initial cycle (gauge goes up to 220*) then it works fine. Also at cold start up I can hear air bubbles in the heater (which now works great). So, I'm thinking I have air trapped in the cooling system - probably enough not to allow the jiggle pin to jiggle. Anyone ever experience this? Other than installing a flush tee, how do you get rid of the air? I'm not sure I want to run the truck at an elevated RPM while the front is on the jack. Any thoughts??

Dieseldude4x4

You mentioned the jiggle pin so I assume you put the t-stat in right.<br>Did you max out the cab heater to make sure the heater coil is full?<br>Try running for a while with the cap off and see if the level goes down. (in the drive way, not on the road)

Paul Winey

VSSMAN:<br><br>How hard was it changing out the t-stat? I'm also suffering with cold feet. Temp gauge never above 190 even with Lund grille covers. Any recommendations to prevent air entry? What temp t-stat did you put in?<br><br>Paul

mymaur

My 4x4 has always had the gurggle inside upon the first start in the morning. Have never changed the stat, but also it gets plenty warm, around 190 even on a day like today, 15*F this morning.<br><br>These trucks don't have a sealed cooling system so I do not believe you can get the air out.<br><br>Probably doesn't help you much.<br><br>2 cents<br>

pappyman

Any air traped in the system will work out thur the circulation after the stat opens..just watch your coolant level for a while...normaly with just a stat change you dont get any air trapped...unlike a complete system drain and refill

vssman

Pappy,<br><br>It was time to change the antifreeze too, so I drained it all out. Way back when I used to be a mechanic and we would let it run with the cap off on a high idle until the thermostat opened. That would drop the level - easy enough. The level won't drop even after I let it run at 1500 for a long time while watching the temp gauge cycle. A local shop told me today: 1)that gurgling is bad, 2)it can be pretty hard to eliminate the air 3)and jiggle pins really don't work well. Their take was that it is due to the rake on the nose placing the cap just slightly higher than the heater hose. They suggested I first try the flush tee approach (it's easiest to do) and if that doesn't work then remove the thermostat and prefill the block until it pours out the block - reinstall the tstat and pull a heater hose off and continue to fill.<br><br>Bubba - It's fairly easy to change. I used a 180* Stant tstat p/n 14248. I didn't change any of the seals, just put a light coat of black rtv on both sides of the lift bracket. You do have to remove the top alternator bracket. I found it easier with the belt removed to swing the alternator more out of the way. You'll need 10, 13, 15 mm sockets, 15mm wrench and a piece of hose to put on the petcock to cleanly drain the radiator.

BLK_RAM

I had a similar problem with air on my son's 94 12 valve... I just cracked the temp sender until I got a air bubble out and then the jiggling pin did the rest....

Paul Winey

Not to sound dumb, but -- what is a jiggle pin? Thanks for the help VSSMan

Dieseldude4x4

If you look at the t-stat, somewhere on the widest part or the flange area, there will be like a little rivet in a tiny hole that is loose to move around in the hole. This allows any trapped air to escape to the highest part of the cooling system so that the whole system will fill solid with water or coolant. This &quot;jiggle pin&quot; is normally placed so that it is in the upper or highest position when installed with the flange vertical. Hope this helps explain the jiggle pin.

TBGH

There is a little thing I do to help with getting rid of air in troublesome cooling systems. Drill a small hole in the thermostat (outer ring) before installation. The hole lets the air escape but the thermostat will still function normally.<br>John