Dumb question

[blazinbg]

Wanted to know how accurate is the temp. gauges in my k5. I just finished doing the head gaskets and my temp. gauge is reading over the 210 mark I have 195 thermostat and after plugging a scanner to the computer it is reading that the truck is running at about 195-200 range. So ultimately wondering is my gauge bad or the sending switch bad?

 

[ttuburbo]

Head down to the parts house and get an manual temp gage. It should have a length 5-10' of temp coil on it. Screw that into one of the water ports on the front of the block, or anywhere you can find one, and use that to check against your electric gage. Do you have electric fan/ manual fan? Stock water pump etc?

 

[blazinbg]

I have elec. fans they are flex-a-lite dual set up and it is a stock water pump. before the head job it never went over the half way mark which is 210 degrees.

 

[ttuburbo]

Did you use a new thermostat after the head gaskets?

 

[toomany]

Did you check the timing when you put the distributor back in? Incorrect timing can cause it to run hot. Do you have the fans hooked up to a temp switch or a manual switch? Do you have them wired/installed correctly? I know it sounds stupid, but one of my friends put an electric fan on and used a puller infront of the radiator. Why did you swap the head gaskets in the first place?

It is possible that you still have an air pocket in the system and it needs to get pushed out.

 

[blazinbg]

I did use a new thermostat.

 

[ttuburbo]

X2 on what toomany said. I usually manually check my therms in a pot of water before installing them.

 

[blazinbg]

I had a blown head gasket, the fans are on a temp. switch, if there is an air pocket how do I get rid of it.

 

[toomany]

I had a blown head gasket, the fans are on a temp. switch, if there is an air pocket how do I get rid of it.

The radiator cap/fill point should be the highest point in the system....if it's stock it will be. Run the motor with the cap off untill it comes up to temp (thermostat opening). This should evacutate the air. It will probably be nesacary to add some water.

On another note...are you having to add water now? Did you have the heads checked for cracks when they were off? You could have a cracked head.

 

[blazinbg]

thanks for the tips gives me something to do tomorrow!!

 

[dyeager535]

If your scanner is reading 195*, that is likely what the temp is. Very unlikely the ECM temp sender is reading incorrectly as well, especially since it is higher up and less likely to be in contact with coolant if there is a problem with air in the system or lack of coolant. (in which case it would read low since air doesn't conduct heat well)

Gauge isn't a precision instrument, and I will say that unless a mechanical is tested, they too are no better than stock or any other electric.

If the gauge is steady and consistent, albeit off by a few degrees (tested via the scanner), you have a few options. My top two would be go get another stock gauge from the wrecking yard and swap, or live with it, knowing your coolant temp reading is off by X degrees.

If you really dig into it, you'd have a pretty good chance of finding that the volt and/or oil pressure gauges aren't precise either.