So my R52 is fine when I am driving, but when I get to a light, the thermo-needle Max's Out. I ordered a new Thermostat, but was wondering if anyone has additional advice?

 

Water pump - water level - serpentine belt.

 

Thanks!

 

PS: The belt should be replaced about every 40K. Mine is due at next appointment in abt 120 miles.

 

Moving this to the Stock Problems/Issues section.

You sure your fan is working? A recent posting about overheating turned out to be the fan motors not working.

 

Fan is working.....too hard in fact. LOL

 

Check coolant expansion tank and/or cap. If it's leaking or cap isn't holding pressure, you'll overheat.

 

Belt was already replaced....thanks to a brother on the board that suggested it when I was having other engine work done. Caps are all on tight.

Solution: I read online that I should bleed out the line at the Thermo Housing Bleed Screw, before invest a bunch of cash. I filled the radiator and tank with anti-freeze. Then unscrewed, slightly, while engine running, until steam and bubbles started. Had my son maintain revs to about 1700. Only Anti-Freeze started escaping, and the fan stopped. I have not had a single event with the gauge since.

 

Next thing consider strongly replacing the plastic expansion tank. They eventually split at the seam at inappropriate times. A stainless tank can be found on ebay and just move the cap over. Use a baster to remove the coolant then replace it after. A little coolant on the nipples makes it easy to slide the hoses back on.