1991 Suburban 454 heat issues

[extd56]

I installed a 1991 Suburban motor in my 69 crew cab truck and put in Autometer gauges. I am having a problem with the temperature gauge reading hot. I had the sending unit in the right head and the gauge was showing that it is running 210 in the driveway but when I took it out on the freeway it went up to 250. I moved the sending unit to the thermostat housing and now it reads 180.00 all the time. Can the sending unit next to the exhaust make a differance in the reading? I am running a Edelbrock reverse flow water pump and a be cool radiator and it seems like it is running cool but I am worried about the reading from the head.

[tvblazer78]

Your header could make some dif with it, but I would not think that much.

[extd56]

Thanks, the motor was recently rebuilt and only has 80 miles on it and I am thinking it still might have an air pocket in it.

[BLOWN73]

try an infared gauge (point and shoot) to see what temps you are getting

[extd56]

I did that today and the temp on the heads was 185 and the radiator was 140 and the intake was 180. I put a sender in the thermostat housing and wired it to the temp gauge and it showed 180 and that was with it sitting for about a 1/2 hour. I moved it back to the head and the temp jumped to 250. I called Autometer about it and after following their suggestions it still does not work right.

[TLoz]

I had the same problem with my 454 with a stock temp gage. Moved the temp sensor from head to head. Even got a new sensor, nothing helped. Got a new gage and wired it in and verified it was the gage.

[extd56]

I am thinking of putting in a mechanical gauge and see what it says.

[BLOWN73]

well at least you know is a gauge issue and not an engine problem

[2tons of fun]

they like to trap air around the sendors and cause that problem. eventualy it will go away.

[extd56]

Thanks for the replies, it is driving me nuts trying to figure out why it will not read right from the head. Thanks

[tvblazer78]

Good luck with it..