Installed my two 2,000 cfm fans on my repaired radiator last night and got it all put back together. Today going to work (2,000 ft downhill from my house) it pegged the temp gauge and pushed antifreeze out of the overflow.
It was weird because the heater was blowing cold the whole time, so I'm thinking I may have lost another water pump, or the relatively new thermostat died. It cooled down during my first appointment, but started heating up right away again. This time the heater would work so I cranked it on high with the windows down to get it home.
Very frustrating.

 

T/stat or air pocket? Did you bleed the system?

 

It may or may not be your situation, but after putting the new water-pump on the wife's engine, it didn't come close to holding all the coolant I had just drained from it.

I had to break loose and remove that 1/2-NPT plug that is hidden behind the forward lift-hook, the one where some install a temperature sender, to allow the trapped air to escape; once the plug was loosened, the air came out so fast it whistled.

With that hole open, I was able to pour in all the coolant plus a half-gallon or so to top off.

I haven't yet done so, but a bleeder petcock would be a good addition where that plug resides.

 

Thanks, I will try that.

 

If you have never had it out before, it will take a 3-foot or longer breaker-bar and maybe even a pipe over that to break it loose.

There is no reason to reinstall it quite so tight; I just wrap the threads with Teflon-tape and torque them tight with a normal 1/2" ratchet.

 

Sounds definitely like an air dam...Mark

 

Like ^^^he^^^ said. If you don't burp that baby, it'll airlock on you and not cool. It can be really hard on the head.

 

My 82 MB 300D has to be burped as well when ever there is a coolant change, water pump change, etc.

Can the truck be burped by raising the front end up and pouring the replacement coolant through the upper radiator hose when the hose is detached from the radiator? That is how you burp the Mercedes.

 

I used a flushing "t" installed in the inlet hose to the heater. That has worked quite well through several flushes over the years. I did replace it this year with a new one. It also works for a system flush when replacing coolant. Just hook a hot water hose and watch the crud come out.

Bob

 

Turned out to be a stuck thermostat and an air bubble.
Seems fine now.

 

I read somewhere to put an aspirin in the thermostat, such that it holds the thermostat open, thus allowing both coolant and air to pass.

Once the aspirin has done it's job, it dissolves, disappears, and not even NCIS could ever detect that it was ever there.

 

I like that aspirin idea.

 

And it will keep your truck from getting a headache.

 

I always drill a tiny hole in the thermostat (if it doesn't already have a bleeder) to let the air pass.

 

There's a couple of vent holes in the stock Cummin's stat. Still needs burping because of the way the thermostat is mounted.

You can get it without bleeding it, but it takes about 3 rounds of fill-er-up, warm up engine, let it cool down, top it off, repeat. Until the bubble gets small enough so the vacuum formed when cooling is strong enough to pull fluid in from the overflow container, it won't fill the radiator on cooling, but leaves a bubble in it. Did that whole routine one time, then decided to read a little, found the vent. Next fill was one shot.