I'm surprised no one has commented that you apparently have Dexcool in your truck. The consensus here and in other forums is to avoid Dexcool.

 

Is there really a consensus? Or more like a forever war?

 

I would 100% get an aluminum expansion tank. I had a brand new tank (Behr) split at the seam one day driving. Miraculously it happened as I was pulling into my driveway. How the heck that worked out, no idea, but thankful.

Avoid Dexcool as others mentioned. I use BMW's blue coolant since it's formulated to specifically work with aluminum blocks. I'm sure others are great too. BMW's is re-branded Zerex, but the BMW one isn't expensive, so I just get that.

 

I am using orange-colored coolant, Prestone, I think it's for GM engines. I am not even sure, I think the previous owner had that in there, but... Am I doing something wrong? What's "Dexcool"? Lots of engines are built on aluminum blocks these days, not just old Rovers... Please clarify.
Yeah, went down to the garage, checked it out - it's Preston DEX-COOL for GM vehicles, orange stuff. Now, I had a serpentine belt brake on me a few months ago. The motor overheated a bit, I lost some coolant, and ended up replacing the temp sensor, bottom line is, my orange Preston Dex-Cool is practically new. I thought this was the correct type of coolant for this truck... I guess I was wrong...
Is it something that has to be addressed ASAP or can this wait a few more months?

 

Dexcool is mostly only a problem on cast iron engines, less of an issue with all aluminum engines and cooling system. No downside to changing to conventional coolant.

 

I avoid Dexcool, since I am using Land Rover XLC.

 

I have already learned, that most people in LR world are avoiding Dexcool. So, I now realize - that's what I have in my cooling system, and it's pretty new and fresh. Should I dump it as soon as possible as in an emergency, or should I just run it for a while and switch to something else later? Is Dexcool known to actually damage our engines or headgaskets somehow? That's what I am trying to ask at this point.
Thanks.

 

It's not an emergency having Dex-cool in the system. It's even claimed that Dex-Cool is compatible with our engines: https://www.fcpeuro.com/products/lan...-zxel1#fitment
Dex-cool and LR XLC are both OAT coolants, but LR XLC is the better choice because the additives are specifically made for Land Rover engines, while Dex-cool is made for US-cars. That's why I prefer LR XLC.