Hey All,

I've been dealing with a problem the last month or two and the Jeep has been sitting because of this problem.

My radiator started leaking one day so I ordered a replacement radiator and put it in. I filled up the radiator with coolant and started it up without the radiator cap on to burp the system. Well long story short, coolant started coming out of the radiator neck and the thermostat never opened. I tried replacing the thermostat because they are cheap to replace and that could be a potential culprit. Now, I'm thinking maybe the thermostat is airlocked.

Brand new parts in the cooling system:
- Radiator
- Thermostat
- Water pump
- Coolant temperature sensor (For ECU)
- Coolant temperature sensor (For the gauge cluster)
- Valve cover gasket (Because I had to take the valve cover off to change the coolant temperature sensor)

Does anyone still drill a small hole in their thermostat to bleed air?

I have noticed one thing lately as well. You can see small bubbles trying to escape through the thermostat housing gasket while the Jeep is running. To me, this means the thermostat housing gasket isn't sealing like it's supposed to and air coming in could affect the thermostat? Reminds me of people spraying soapy water on an area looking for bubbles to find a leak.

Thoughts? Suggestions? Comments?

Bleeding the system. That is what happens.
You fill it up, you can add coolant for a bit, but then it gets to the point where is starts bubbling out.
That is when I cap it off. Run it for a bit more, shut her down, let her cool down completely, fill up the radiator
if you can, and get the overflow tank where I like it.
Then I drive around for a few days. Keep an eye on the overflow tank and radiator after it cools down from each time I drive it.
After a couple/three days the air is burped out and am good.

Now I just use this:


Hook all up, some coolant in the funnel, idle the Jeep at about 1500 rpm, and make sure that there is always some coolant in the funnel.
After about 1/2 hour maybe 45 minutes you will notice that she is not taking anymore coolant. Let here cool down, take the funnel off, double check the levels,
And am usually good to go.

Since I swap out my coolant every other year to me the price of the tool is worth it.

Now as far as the bubbles trying to escape the thermostat housing.
Maybe not tight enough but more likely this.
You have to be careful that the thermostat is seated in that little channel when you put on the housing.
While you are putting on the housing sometime the thermostat will slip out of place.
Then you tighten the housing not realizing it. And could crack the housing so....

I always recommend using a FelPro gasket there with no gunk. Or very little to try and hold everything in place.
Cause it can be awkward to do the job without gunk.
But can be done cause I just did mine about 2 years ago.

Oh and I never have drilled the hole in the thermostat.

Do our t-stats have vent holes that are supposed to be at the 12 o'clock position? Or am I thinking another vehicle I recently worked on hahaha.... (5.7 Hemi)

That is what I think I have read but not 100% sure.

A genuine MOPAR thermostat has the hole with a loose rivet at 12 o'clock. Desired but not required.

The new thermostat that I put in that wouldn't open was a Gates thermostat. It's possible that Gates thermostats are shotty or I got a bad one or it's airlocked.

I'll look at getting a Mopar thermostat.

I bought a cheap Stant or something from rock auto for like $1.12 and I dont THINK I have any issues. My temp gauge almost hits the 210° mark...

I've always had good luck with Gates and Stant products. I made sure to be careful when putting the thermostat in so it didn't fall off, but it's entirely possible it moved while tightening the bolts down. I also used Permatex water pump and thermostat gasket sealant on the Fel Pro thermostat housing gasket I used. This stuff
Not sure where I went wrong.

When one of you all have changed out a water pump in the past, did you fill the coolant passages in the block with fresh coolant through the heater hose?

A year ago I got a Gates, it failed the boil in a pot test. Rock Auto refunded the cost back to me. I bought a Murray at O'Reilly that appeared to pass, ran it for a year and engine was never heating up properly. Replaced it a few weeks ago with my factory original Chrysler thermostat and it is operating right now.

https://www.rockauto.com/RSS/vehicle...l=en&html=true

Here is the one I got. Looks like no vent hole.
Oh and it is only $0.88.
But read that description, that thing sounds state of the art....Hahahaha....
I ordered the gasket from that page as well, and they sent me 1 pack of 10 gaskets hahaha.... not just 1 gasket.

They have been many threads about bad out of the box thermostats.
When I first got my Jeep over 7 years ago the first thing I had to do was put in a new radiator.
Decided to do the thermostat too. Used the cheap Napa one.
Well when I did the water pump a couple years ago decided to buy a new thermostat housing, a Stant Superstat,
and the FelPro gasket. Also used a FelPro gasket instead of the supplied one with the water pump.
Well because of the bad out of the box threads despite having a brand new thermostat I reused the Napa one.
I am sure I will pay for that at some point.
But it still works like it should so far. LOL.