Problem w/ temp. on startup?

[01EB5.0]

i have a problem wit my truck on startup after it sat for a few minuts (up to about 10 or so)when I start the truck sometimes the temp. gauge goes all the way into the red...even sometimes past and the check gauge light turns on. the first time this happened I put the truck in reverse and the needle immediatly dropped back down to where it normally sits. The second time it did same. Third time it sat in the red for about 1 1/2 miles...some even at 55MPH. Those 3 instances were last fall, then winter came...had no problems at all...until 2 days ago. We stopped at a rest area along the interstate and I went back to start the truck and the needle got pegged again....backed out put in drive started pulling away and it dropped real fast like it had before. Since then it has done it 2 more times. The thing that confuses me is why the needle just sits in the red (Or past it) for up to 1 1/2-2 miles and then it'll just drop in an instant back to where it normally is. WHat may help figure out the cause of the problem? I just replaced the T-stat and coolant 4K ago and replaced the radiator cap also. Please help!

 

[David Barnes]

guages

Hi -
Had the same problem with my oil pressure guage on my previous 95 sport. I just ignored it, it was there on and off (quite rare near the end) for 70,000 miles. Seemed to happen more in the spring. It would shoot up and stay pegged in the red when starting sometimes, then drop down after 10
minutes or so. I had 105,000 on my truck when I traded it in last week and got my 99 (woo hoo!). Dunno if this helps.

 

[CHH777]

Next time your temperature gauge needle pegs the red open the hood and (very carefully) check the upper radiator hose. It should be hot (too hot to touch for long) and hard to squeeze. If not, your thermostat is stuck.

BTW, it's not uncommon for new thermostats to be faulty. When mine failed I had to replace it three times (AutoZone sucks) before I got one (from NAPA) that worked properly. Damn near drove me crazy. Good luck…

 

[01EB5.0]

I will check that mext time..The T-stat is a stant and the old one was too...i always thoguht they would get stuck open from all the heat and then the coolant would flow to cool the engine thoguh....am I wrong?

 

[CHH777]

They can get stuck fully open, closed, or anywhere in between. The factory t-stat has a "weep" hole designed to allow some (very little) flow in the event it gets stuck in the closed position to prevent overheating. Did your replacement have this?

 

[01EB5.0]

The replacement had a little hole that it said was to let air out through...I mounted it woth the air hole up like it said. The one i put in was exactly same as one i took out except it's a 195 instead of 180