whats up? This question involves my daily driver actually a '91 blazer, the car has been close to overheating lately. The car heats up within minutes to the 260' mark and the car blows cold air through the vents. Also periodically the car will go from 260' back down to normal temp of about 180'? Friend told me it's the head gasket, and to check oil to be certain, oil looks okay, its not milky white or anything else really, there wasnt Alot of oil on the stick but its wasn't whitish like i thought that would indicate.


Any help would be appreciated?

 

sounds like its just the temp. sending unit.

start it up and after the temp. starts to climb up,go put ur hard on the upper radiator hose. it will prob. still be cold,and if it is then it sounds like the temp. sending unit to me,its not expensive i dont think.

hope this helps

 

I guy I work with had a few problems with his S-10 Blazer a few months ago. I think it was an early 90's model, too. One of the issues was his temp guage. Every so often, when he used his turn signals the guage would deflect fully and then slowly come back down to what would be normal coolant temperatures.

He had to replace a few things (senders, guages) before everything was workning normal again. I don't remember what was replaced, but I can ask tomorrow.

 

hey dude, thanks for the quick response. Okay alittle more info, last night drove the car after it cooled down for about 12 minutes home soon enough it starts climbing fast, get home to check the oil like my buddy told me to, while i'm there i squeeze the top rad. tube, no pressure and not hot, so with that in my mind that supports your idea. Also with a recent water pump replacement, over heating issues periodically and the cold weather on us i have added more radiator fluid to make sure it was good, i seem to lose radiator fluid somewhere besides the ground it seems, cuz its never that full and the catch can is pretty much dry.

 

kool thanks Joe, i appreciate the quick responses...

 

Heater blows cold and the temp gauge fluctuates....generally that's caused by low coolant or sometimes a sticky thermostat. However, sicne you say you have to add coolant to it constantly, I'd suspect a bad intake/head gasket. Coolant doesn't just go away, it has to be leaking somewhere. If it's not going on the ground then it has to be going in the motor.

Check the inside of the oil cap for moisture....that's the first place it will show up if you have a bad head gasket.

 

Take the rad cap off and start the engine. A blown head gasket will usually force compression into the cooling system. You'll see lots of bubbles (big bubbles) in the coolent. The loss of coolent could be going out the overflow bottle from the excess pressure. The overflow bottle might be leaking and that's why you never see any coolent in it.

If the oil level is still the same then the coolent isn't going into the oil. The last place for it to go is out the exhaust.

With the engine hot and pressure in the rad, pull the spark plugs. You could find one that's wet with coolent.

With no heat from the heater and an overheating engine I'd suspect a stuck thermostat first.

 

well now that u said u had the water pump off not to long ago,than it also could be that u have an air lock in the cooling system. i just experienced this earlier this month and just now got it figured out a couple weeks ago.

heres a trick u can do to find out if it has a blown head gasket:

start it up and let it run for a couple min.

get a spray bottle of water and put it on "stream"

squirt it near every exhuast port on the exhaust monifold itself

might take a couple trys,but where ever it takes like a full second to burn away,thats where it is. if they all burn away fast,then thats a good sign.