I just took it out for a little drive on some dirt roads close by. I've never had an issue with getting hot on these roads but it got to the red again as soon as I pulled into my house. I was gone maybe 20 minutes. I put the purple ice in before I left, I figured I'd give it a shot but it didnt do anything. As soon as I pulled in I took some reading with my IR thermometer. full disclaimer; it's a harbor freight tool so I dont know how accurate it is but the temps I found were scary to say the least:
228 on the lower heater core hose that's metal
195 on the upper metal h.c. hose
222 on the small hose right off the radiator that goes to the tank
218 on the upper rad hose
160ish on the lower hose (cant remember)
230 on the hoses at the T on top
125 on one of the top rows of the radiator on pass side
165 on one of the top rows of the radiator on driver side
235 on the plastic tank

I also have a brand new coolant leak under my throttle body. It leaked about and inch of fluid out of the tank. I think it's safe to say there's a bigger problem than a tstat. Any suggestions? Anyone have a 4.6 block in the utah/arizona/nevada area?

 

I've got a scan gauge coming but it's not here yet. How accurate are those at reading temps? I also forgot to mention my hoses were swelled pretty bad this time

 

If you have the throttle body heater leak, that leak is also letting air into your system. You can't get the air out so it will get hot and overheat until you fix the TBH plate. Easy fix. You could still have other problems with the hoses looking like that. Something is pressurizing your system above spec... Possibly HG's.

 

I know head gaskets could be a very real possibility but I know that they were done on this engine within 50k miles ago. I think I have a set of clean heads, but I dont want to put them on quite yet until I'm certain. I dont have white smoke on start up, there's not coolant in my oil or vice versa. I do have an oil leak on the drivers side, the valve covers are seeping and there's another one lower that leaks close to the cat. I cant tell exactly cause the whole side of the engine is covered in atf from another mishap. It doesnt seem to be leaking from the heads though cause they are still pretty clean from whenever they got done. It also has a new tick that sounds like an exhaust leak but I cant find one, it's on the passenger side by the exhaust manifold. I read somewhere that that can also be a sign of head gasket failure. The odds arent looking good. Is there any other way to test if they have failed? Or test to see if the HGs are what's cause extra pressure in my system?

 

You can get a kit to test for exhaust gases in the coolant. Any auto parts store should have one. Based on those swollen coolant lines, that’s my bet.

 

Get the test kit or pay to have it tested but my bet is head gaskets, however with that much pressure you should have coolant spewing out the overflow hose on the coolant tank. So check your rad cap too.

I had a small head gasket leak and I lost fluid from the overflow every time I ran the engine, no overheat for me though

 

Ive tried 2 different caps. One stamped 200 and one stamped 140, the 140 seems to work a little better at keeping temps lower, but now I've got a bigger problem. I talked to my father in law who is a local mechanic, hes actually the one that gave me the rover too. We are going to take a look at it today but he says those tests are usually inconclusive and that hes had cars in the past pass the test even though he knew the HGs were bad. I'll probably just bypass that tbh so I dont have to worry about it leaking. Any other suggestions? Is there a way to see/test if I've got slipped sleeves if I do replace head gaskets? from what I've heard the only way to find out is to drive it after its put back together and see if it still has issues.

 

Why not pull the heads? When I did this, it was pretty apparent I had a slipped sleeve (and a number of other issues). If you look closely you can see the edge of the sleeve above the deck. Also a great big chunk of aluminum is missing!

 

If a sleeve has slipped, it will leave a ring impression on the bottom of the head gasket on that cylinder, where the sleeve itself has been hammering into the gasket.

 

I like to rule other things out but it's looking like I'm gonna have to anyways. Do they usually slip upwards or downwards? I can see in your picture it's slightly raised. Is that all I look for? And the damage to the gasket like sixpack mentioned?