Radiator Cap selection

[cmayna]

I would like to replace the radiator cap on my 91'
4.0 engine. I believe I've read various threads saying to pick a 16lb cap, but the Stant book says that my engine uses a 13lb cap. Suggestion please.

Craig

 

[rjc]

I had a buddy with a V8, K5 Blazer. He could not understand why his car kept overheating so much. When I asked about his radiator cap he said he had changed out the 13 for a 16. I think the only time you might want to do that is if you live at high elevation where atmospheric pressure is less. Replace the 13 with a 13 Stant and you will have no problems with the system pressurizing. However, when you change a radiator cap that is not holding pressure on a high milage coolant system things can start Popping fast. I lost my Ranger radiator this way. No big loss as it would have eventually gone out anyway but if anything is weak presurizing it just speeds up the chance of a blow out. In my experience the hoses outlast the radiators because the rubber gasket goes between the mettle radiator and plastic tank.

 

[cmayna]

I just finished changing my manifold gaskets and Thermostat. The new stat seemed to be reading a little hotter that my previous one. Thought it was faulty so today I replaced it again and same reading (warmer than normal). My gauge is fluctuating a lot during a normal short distance drive. So I figured the last thing to replace is the radiator cap. Just went out and bought a Stant-13# as you suggested. I'm still not sold that this will resolve my problem though.....

 

[rjc]

There is one other problem that you can't see unless you take your radiator out and it might also be your problem. The way the 90-94 Explorers are set up to funnel air through the radiator debree gets caught between the air conditioning radiator and the engine radiator. Things will look fine from the front but the lower 1/3 could be totally blocked with leaves and dirt. On my 93 there is rubber spacer between the radiator and front body. If you have that remove it and look straight down. The corresponding rubber spacer on the bottom helps force air through the radiator and keep rocks from bouncing up into the fins but it also traps debree which cannot fall out of the bottom like on most cars. rc