1992 Mercury Sable temperature gauge

SISTERKATE

MEMBER
1992 MERCURY SABLE
6 CYL
FWD
AUTOMATIC
81,000 MILES

We purchased this vehicle yesterday. While driving it home, I noticed that the temperature gauge kept fluctuating from normal to cold. I checked the coolant when I got home and it was somewhat low. Add antifreeze. Mentioned this to a mechanic friend of mine and he said it was a blown head gasket. There appears to not be any water in the oil. No leaks are appearing on the ground. It doesn't appear to be running hot. Fan would come on but go back off. What possible could be the problem?

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Have it block and pressure tested-do the block first to pinpoint a combustion leaking into the cooling system or a gas analyzer to sniff for hydrocarbons at the radiator fill neck.

Pressure test: do not do a pressure test if there's leakage at the headgasket this might cause coolant into the cylinders and lock it up or bend a connecting rod if cranked thereafter. The headgasket should be repaired before doing the pressure test.

If the block and pressure test passes check the following: Thermostat, Pressure test the Rad. Cap, Clogged radiator, Fan clutch, Radiator electrical fan, collaspe hoses, water pump.