1988 chevy k2500 silverado 3/4ton

[scornedlotus]

Hi all and another hopefully lovely evening for all. I have a question regarding my 350 small block chevy, I just acquired. All of the coolant system has been rebuilt by the previous owner. He got stranded in the mountains and rebuilt the coolant system there. I know everything is done properly. However after he stayed the night in the mountains over night got below freezing the next morning and ever since the temp gauge dosnt work. It will go up literally a quarter tick and stop there nothing more... however the thermostat is brand new and worked up to the point of the frozen night. After that night the temp gauge no longer works again. What would cause this?

Also the previous owner said that ever since he has owned the truck the oil pressure gauge has never been "setup" any ideas as to what he could mean by this? Like is it just basically not there? Or not plugged in? At all times when the truck is running or off the oil pressure gauge says its MAXED out on oil pressure and I would like to be able to monitor where it's actually at.

 

[evilunclegrimace]

Check on the left side of the block above the oil filter and see if the wire is connected to the sender. Also check to see if the wire is shorted to the exhaust or the block. Those senders were noted for a fairly high failure rate due to the proximity to the exhaust. If the sender is the problem make sure that you get the proper pressure range sender, there was a 60 psi and an 80 psi if I remember correctly.

 

[scornedlotus]

Check on the left side of the block above the oil filter and see if the wire is connected to the sender. Also check to see if the wire is shorted to the exhaust or the block. Those senders were noted for a fairly high failure rate due to the proximity to the exhaust. If the sender is the problem make sure that you get the proper pressure range sender, there was a 60 psi and an 80 psi if I remember correctly.

Thank you, you wouldn't happen to have any ideas on the thermostat or temp gauge would you? Because the only thing I can think of is the deep freeze in the mountains messed up the new thermostat. Seeing as how everything was working just fine till then

 

[someotherguy]

Driver side cylinder head between #1 and #3 the sender there is for your dash gauge. Check the wiring, replace the sender if it looks old and crusty. They operate on resistance and they go bad with age - reading colder than actual temp. Just be sure you get the sender for the dash gauge, there's also a sensor for the ECM and it lives on the intake next to the thermostat. People get 'em mixed up all the time. Different roles, different connectors.

Richard

 

[Schurkey]

1988 5.7L?

INFAMOUS for failed oil pressure sending units. The sending unit listed on some parts-store computers is the WRONG ONE. I wrote about those sending units on another forum, and I'm not going to repeat it all here.
www.automotiveforums.com/vbulletin/showthread.php?t=1136624

Oil Pressure Sending Unit--TBI V-8 dash gauge - Automotive Forums .com Car Chat

Oil Pressure Sending Unit--TBI V-8 dash gauge C/K

www.automotiveforums.com

There is nothing about cold weather than can damage a temp gauge sending unit, wire harness, or gauge unless we're talking about colder than -60F UNLESS there's no antifreeze in the coolant. In which case, cracked castings are more likely than a damaged sending unit. OTOH, I could imagine that ice might deform the thermostat leading to an engine that doesn't warm-up properly. Fairly unlikely, though.

I'd replace the thermostat with a verified-good 195 degree unit, and verify the temp sending system from sending unit to gauge. Ground the wire leading to the temp sending unit--gauge should go to the full "HOT" side of the gauge. If it does, replace the sending unit. If it does not, track down the problem in the harness or the gauge.