I Have 1998 Chevy Blazer since 6 year. since last year I got problem with over heating. i clanged fan clutch and water pump but the over heating problem same as it is. then i notice while i am driving in after noon and outside temp around 45 degree centigrade so i notice my oil pressure gauge is going down and engine temperature goes to redline i checked many mechanics but they cant figure out whats the problem. please could some help in this page whats the realy problem so i can fix thanks

 

Hi welcome to the forum.

Several possible things coming to mind:

When possible using an IR thermometer

- Thermostat (check temp when warmed up of upper hose to radiator - does it open at all?)
- Routing of the V-Belt (Just to make sure fan AND water pump do not turn in the wrong direction)
- Radiator flush

Would be my first checks.

For the symptoms. How fast is this happening? Just after warming up? In your temperatures within say 5 - 6 minutes? Or can you drive for a long time o.k. and all on a sudden it heats up?

Has something been done on the Blazer before it started heating up?

 

Some other possibilities:

Check the temperature that the thermostat opens up. You can run without it temporarily to see if that's your problem.

Make sure that the cooling system does not have to be bled, it may have trapped air.

Do a compression check on the cylinders. Alternatively you gan put a pressure gauge on the radiator fill and watch for fluctuating pressures. You can also do a drop cylinder test - pull each plug wire in succession while at idle and listen for no rpm drop on one or more cylinders.

Your radiator can be blocked, internally or externally. What happens if you spray water on the outside of the radiator, does the temp improve?


George

 

Hi thanks for reply. i flush the radiator and clean the engine and before one year back i replace water pump and fan clutch but i have still same problem . when oil pressure gauge goes down to near 0 level and temperature goes to red line this happen when i stop car on signal or slow in heavy traffic when drive the car oil pressure gauge goes up and temperature gauge goes back to normal . please can you figure out what could be problem or i have to change oil pressure sending unit
thanks

 

Does your Blazer have an oil cooler (oil/water heat exchanger in radiator)?

Try with an IR thermometer (the handheld ones with a laser dot) when warming up.
Where does it become warm (radiator, heat exchanger cases)

How about the fan?
Does it have electrical fans? Is it damaged or has it been replaced with an incorrect part?
Is the v-belt routed correctly?