Hi all: After reading about the ultraguage I bought one and dont know how I lived without it. Have a code reader but when I found out the guages ( as nice as they are ) are really idiot lights I thought they are really useless. Sexy looking fake analog eye candy !!!. Wow with the ultraguage now I can actually see what my coolant temp is etc ( around 208 to 213 usually ) as well when you get an intermittant fault is should tell you what it is. And the alarms that you can program. I have my coolant alarmed at 220 f. Have not played with it alot yet but when you buy one of these cars the sellar should put one in the deal. I see on the gorum where you can make the guages actually work but that will be a later date. Anywhoo just saying it takes a little stress away from driving these reliant automobiles !!
Howard 99xk8 convert

 

And here's your first bit of analysis from your temperature profile.

My 97 was operating in that temperature range, the higher end more often than not. Hot august afternoons with the AC on it would reach in the 230s. After 15 years and 175,000 miles the plastic tank on the radiator gave it up so I put in a new radiator. Temperatures dropped 20 degrees across all operating conditions. Now it runs in the low to mid 190s where it should. Prior to that the thermostat was new, good water pump, several chemical flushes didn't bring the temperatures down. I happen to have a ScangaugeII, the predecessor to your Ultra, so I could see the true temperature as well.

My point is, two things got cleaned in this radiator swap operation.

1. One of course was a fresh radiator core; the inside or water side.
2. The second was all the accumulated road debris that collects in between the radiator core and the AC condenser in front of it; the outside or air side. All sorts of leaves, fuzz, feathers, bugs, and other road crud that conspired to block a lot of the air flow through the core.

I should mention that in the 55k miles I've put on the car this was the only time I had the radiator out and it quite possibly had never been out of the car. The rat's nest between the cores comes from the miles, not the years. Any internal corrosion and loss of efficiency would come from the years.

Any of you seeing temps regularly above 200 should pop off the top plate over the radiator so you can see in between the cores (with a flash light) and see what's built up over the miles (see picture #1). YOU HAVE TO REMOVE the radiator to clean this out (picture #2). Reaching in with sticks and vacuum hoses will only flatten out the radiator fins and you'll just end up with a messed up radiator that still doesn't cool. Yes it's an all day job but worth it. You love working on these things anyway, right?

Isn't it nice what a decent temperature gauge can show you?

The third picture doesn't really show how clogged the radiator core is. You need to set it flat on saw horses front side down and NOT ON THE FINS. Soak it with something like Foamy Engine Brite or a good foaming cleaner, set down with a beer or beverage of your preference, rinse, and repeat until the space between the fins is shiny. Be very careful with compressed air and DO NOT use high pressure water to blast the core clean; you'll just flatten the fins. Of course, as I noted above, I just put in a new radiator. Nissen aftermarket, $500, but my tanks were shot and that took care of both the air side and the water side.

Mike

 

Mike, real pithy and great information. This will go on my PM to do list. Thanks for the post.

 

Yeah will have to check that out, it was hot today and she was staying around 207 and i did do a flush and fill earlier the year. I am wondering now I suppose with those temps its a stock thermostat ?? Anywhooo it is a nice thing knowing that all systems are monitored and alarmed eventually. Thks for the info and it is worth a look in there