1994 GMC Sonoma A/C repaired now overheating?

CAMODEREK

MEMBER
1994 GMC SONOMA
4 CYL
2WD
MANUAL
155,000 MILES

I have had my sonoma for 2/3 yr never had A/C this heat has been bad so I bring it to local shop the be fixed. They inform me it needs a hose then a evac and charge then taada I have ice cold air! The truck until this date always ran between 180-210 only 210 on really hot days. The same day I pickup my truck from A/C place I notice it's running around 210-220 until I stop in traffic then it gets to about 240 so I decide to replace thermostat from the 195 with a new 180tstat when I open her up there is NO Tstat! So I install the 180 and she overheats even faster so I remove Tstat again? I have nice green clean fluid no leaks fan clutch seems to be spinning just fine. A/C hose breaks the other day draining all ac juice and I notice over next 2 days while waiting for ac repair truck doesn't overheat. Even with ac off it still overheats. Please help.

1 Reply

HMAC300

MECHANIC
48,601 POSTS

First the fan clutch. If you see oil around it it probably doesn't work. When it is hot it should be hard to turn but check this with teh engine off. If it turns easy it's probably shot. There should be a shroud around the radiator as well that the very front of the fan should ride in so topull the air through the system. Then after the truck overheats or gets hot shut the engine off and feel the raidator in different spots. If you feel any cool or cold spots the radiator is shot. It should be the same or about the same temp all over.