Beginning of the end, or end of the beginning?!?!

[spano]

Prior to me loosing the tranny as described in a earlier thread I am noticing what may be the beginning of the end or just my wicked imignation. During operation (both parked and running) I noticed the temp gauge doing a little jumping, not major swings from 190 to 210 but a notch here and it just bounces and spikes. This is both before and after the thermostat has opened. The vehicle dosn't get hot so the t-stat is function properly but just that little spike is got me concerned. Temps have ranged from 8 deg F to 30 in the past few weeks and it does it regurdless of outside temp. Removed cap and I am full on coolant and have no leaks that I can see. I plan on replaceing the sending unit as it may be faulty but should I go the distance and replace the T-stat and any thing else?
96 Blazer -

[billibong]

I would say to replace the T Stat. They're only a couple of bucks, and its very inexpensive insurance.
Do you have a stock Rad Cap, or did you get a Stant aftermarket? If you still have the original cap replace it with a Stant. There is a reason that everyone on this forum has gotten a Stant cap for their Blazer, and I don't think any of us own stock in them.

[Macgyver007]

HI Spano

I reiterate the point made by billibong. I had almost the same issue with my blazer. (including the tranny ) anyhow I did the Stat and the rad cap and finished it off with a flush and refill. Now its dead still once it warms up.

Jason

[Powerarranger]

If the needle is actually jumping around, you might have a short. Check the connection to the temp sensor (in the block on pass side?). Mine had chafing on the sensor wire and was intermittently shorting to ground. Splice, solder, shrink wrap, presto you're done.

Use a thermometer to check the temperature of your coolant to make sure the sensor itself isn't going bad. On a cool engine, pop the rad cap, insert thermometer, warm up the engine and note the temperature rise. Compare with what's on the gauge on the dash, and you'lll know where things stand. There are lots of threads on this topic that can help as well.

Good luck!