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Followup To
Question -
I have an 88 suburban 350tbi. I have noticed that the temp guage fluctuates between 180-260 when drving. I replaced the thermostat three times and there have been no signs of engine overheating. After removing the radiator cap I noticed that there was no movement of fluid through the radiator lattice. The temp was reading around 240 with a closed thermostat (the top radiator hose is cold.) After removing the thermostat the radiator moves fluid like niagra falls. I have not noticed in anti-freeze consumption. I have also replaced the temp sending unit. Could I have a bad guage? The system seems to be holding pressure. The trruck now has a failsafe 194 thermostat and the guage still reaches 260. Thanks, Chris
Answer -
IF this vehicle has the ORIGINAL radiator in the vehicle REPLACE it with a NEW one. I did NOT say to have your old one CLEANED, FLUSHED and or professionally REBUILT, I said a NEW one.
Yes, You can see coolant flowing thru the upper channels of the radiator via viewing thru the radiator cap opening BUT you can't see what the middle and lower channels are doing.
FLUSH out the entire cooling system AFTER you remove the OLD radiator and don't forget to flush out the heater core as well.
Install a NEW radiator and you should be all set PROVIDED you did your homework and tested for a possible head gasket(s) leaking EXTERNALLY and or INTERNALLY and also check the front corners of the intake manifold as these areas are prone to developing a leak where the intake bolts to the heads.
Also make sure you fan clutch is working OK.
autohelp
The truck has a new radiator replaced within the past year. I have not checked for a blown/leaking headgasket. How is the best way to check it. The system is holding pressure and the oil looks good. Also, with no thermostat the radiator moves fluid very well, (although I can't see the bottom channels). With no thermostat the truck never gets above 100 degrees by the guage. It is only when I place a thermostat that the truck starts to overheat. The truck also has a thermostat that is supposed to stick open if it overheats, but it has yet to do so. Another point is that the heater core lines seem much hotter than the rest of the lines. Thanks again for your help!
AnswerNormal operating teperature of the engine at which the vehicle is designed to operate is at 220 degrees. You CAN install an external temp gage on the vehicle just to make sure that your gage is accurate.
There si another test you can do, But you have to be VERY CAREFUL so as NOT to get burnt by HOT COOLANT.
With the engine at normal operating temp, SLOWLY remove the radiator cap and SLOWLY and CAREFULLY take it off.
Go swipe the wife's turkey thermometer and put it in the radiator cap opening and see what temperatures you get at idle. As the TOP of the radiator is the hottest point of the coolant because hot air always RISES. If your turkey thermometer remains below 300 degrees, I don't see any problem.
Since you did NOT say you installed a NEW radiator, I had to include it.
NEVER EVER run a computerized vehicle WITHOUT the proper thermostat or NO thermostat.
let me know.
autohelp
