So I've noticed during the last month or two while bleeding the coolant system that as I put water into the overflow tank it would not bleed properly. It would not bleed up and through the bleeder hole on the "T". I tried to bleed with a cold and warm engine. same story. ( compared to the other times i have bled the system it would bleed just fine). I have the gray 180 t-stat but its a good 1 or 2 years old , cant recall. I'm going to test the t-stat later when i get to the truck. My question is this -- Has anyone else noticed this behavior right before a t stat going bad?

I have an ultara gauge and truck runs about 186 to 194, sometime will spike to 200 on a hot florida day at redlight. Wife was driving this morning and when she got to work it hit 221. I'm having it towed home and i over nighted a new 180 tsat.

 

In my experience the bleeding question does not point to a failed thermostat, but the overheating may. That's exactly what happened with my truck in January this year and the pre-failure performance was the same.

At first I wondered why it overheated with no loss of coolant but as I thought about what could have caused the sudden spike the first thing that came to mind was the thermostat stuck closed not allowing coolant through the radiator.

It's disappointing your 180 thermostat didn't last longer. Was it genuine or aftermarket?

Good luck, and let us know what happens.

 

When I fill my reservoir while bleeding the air out the bleed screw port, I put my finger over the reservoir drain tube, that way you can continually slowly pour anti-freeze into the reservoir and it will force the air up and out of the bleed port, I have never moved or raised the reservoir either, just filled it in the stock position....ONLY BLEED A COLD ENGINE.

 

I'm trying to remember where i bought it from. It was either from Atlantic British, Miami Rovers or Rovers North. I will dig around and look for receipts. The one I just overnight-ed is from Rovers North and is oem. One thing I tried to get a successful bleed was doing a pressure test and pumping to about 4 psi and that got fluid to come out at the " T " bleed hole. I cannot do a test drive until later, but i ran her at idle with ac on and at steady rev @ 2 grand (RPM), At idle with full AC she lingers at 197 -201 when revved up to 2 grand she would kick back down to 185 degrees.

 

On our D2's the thermostat is constantly opening/closing. Eventually depending on the condition of the coolant. It can stick fully open, fully closed, or in between.

The one thing I have seen time and time again is people spending $$$$ on new Head Gaskets, only to never spend the 80.00 on the actual cause = a stuck thermostat!!!!

On the 02 D2 I bought and quickly sold (didn't own it for 20 days). The so called LR tech had replaced the head gaskets, the water pump, and hoses, but he failed to replace the OEM stuck thermostat, or the clogged radiator.

The one time I forgot my Scangauge II and didn't know I was idling at 229F!! Once home and the issue was discovered I quickly replaced the thermostat and the radiator and idle temps went from 229F to 200F.

 

How do you dive into a headgasket job without verifying an actual leak with a pressure test or some other means? Oh wait, a head gasket job pays more than just changing the thermostat. That mechanic should be shot.

 

Reading other LR sites that recommend needing a block. Shallow dive into a HG sounds good.
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