This Problem I believe I have inherited from previous owners of my vehicle so I am trying to figure out what has being done and what need to be done to fix it

What I get is that once I start the Van temperature will slowly build on the gauge reach higher than normal then will drop back to what should be the actual temp.

This problem has been worked around as the outside temperature is usually warm enough that the delay is not a problem, however it is currently freezing below zero outside and causing problems.

The temperature guage is now going up and down until it reaches a normal stable temperature.

The fix I see for this is that some Tstats are not up to the job and a better quality is needed. What Stat would you recommend I like some of the Stant options. Also I would not mind getting some extra heat to heat the vehicle as well

 

Considering that we're close to winter and changing the t-stat is no picnic, I suggest that you get an OEM t-stat and gasket from the dealer. You don't have a lot of good days left to be messing around with it.

 

Thanks for your answer, I have gone out and got a replacement from Stant using their premium unit. will put it in next week and let you know how it goes as for now the temps are ok to deal with.

 

Smart with the better Stant. It's chrome/nickle plated vs. the base Stant that's zinc plated and not worth the effort to even try.

I would also recommend looking at the water-pump and the fan-clutch assembly. Early this year, I had replaced my entire cooling system after 100,000+ miles. The water-pump was erratic for performance and had the symptoms you have described with your engine. If the Tstat goes, then the temp just keeps rising. What you are seeing is a water-pump, fan-clutch or a bad belt issue due to slippage.

What year and how many miles are on the engine and cooling loop?

 

so my Van is a 1996 B2500, 176,000 mile the current Stat is a few years old, along with all the pipes except for the top Rad hose which I replaced recently because it was so out of shape. How ever I have still not put in the new Stat. Why you may ask, well it is because I changed the oil filter. Go figure! and also using High Mileage Oil (Valvoline Nextgen), But I am putting it down to a Premium quaility Oil filter. The temp guage never gets too hot now it just rises normally and sits where it should. I still have to wait for another sub temperature day to fully test this theory out.