Overheating
QUESTION: Jeremy Reeln77 asks: I have a 89 iroc w/ a 350 it has a hypertech chip,edelbrock headers,b-m transpac,k-n filters,and a high flow exhaust system . now I had the heads milled 45 thousandths because when I got it they were warped not I put a 15 thou. gasket in there but I over heat sometimes... I mean I t will run 140 most of the time but will sometimes get up to 230 -235 before I shut it down and I am running the heat when I does this, I already had the radiator rebuilt, and new thermostat out in and the fans work.. I don't understand it if you can help me it would greatly be appreciated also I need a way to improve my fuel economy I am getting a pathetic 10-12 miles a gallon at highway travel and alot worse in town I need help to find my problem thank you.
| Jennifer Grant answers
Jeremy: If you exceed 11:1 compression your O2 sensor may not read right, exhaust on high compression engines changes to the point where it can be out of the O2 range. The water temp
going to 230-235 is within the factory's normal operating temp, note the red on the gauge is higher than that. The stock fan switch is set at about 235 degrees, try changing the fan switch to a GM #3053190
this switch setting is about 195 deg, NOTE: the fan switch is located on the right cylinder head just below the exhaust manifold between #6 and #8 spark plug. as far as the poor fuel economy check the |
| T89iroc@gateway.net
answers:
Just for info purposes i have an 89 5.7, k&n and hi flow exhaust I average 19-20mpg. |