Suburban Problems

[Truck man]

I have a 98 suburban with the big block 454 that has started to use some oil about a quart to half quart a change, also some anti freeze.
It runs fine other than this. What could be causing this?
Head gasket??? Should I have it looked at right away??

[Eyez]

Check your oil to see if it looks milky, it could be a head gasket or cracked head or something nasty like that, or it could just be a couple of non-related leaks. If you don't see oil leaking anywhere on top of the motor, check the back, towards the tranny, could be a rear main seal.


Dusty

[Dave in Mpls]

Next time you do an oil change, look and see if there is any oil residue on the lower radiator hose and/or lower front of the block. 454s are prone to front seal leaks. As for the antifreeze, my money is on the intake.

Regards

[Dave in Mpls]

Another thought on the antifreeze - you can put tracer dye in the cooling system that is visible under black light. This would detect any leaks from the radiator, hoses, overflow tanks, etc. Another possibility is the heater core.

Regards

[RANGER]

All good advice! Additionally, look into your radiator reservoir and the radiator itself to see if there are any drops of oil floating around in there. Sorry, but I'm going to suggest a head gasket is starting to go, especially if you find water in the oil or oil in the water. It could be the seals but my guess is the gasket.

[TJTROLLER]

Truckman,

I had the same problem on my Chevy pickup,
It turned out to be the intake manifold gaskets.

[J.P.]

Having worked on GMC trucks for the last 17 yrs., I would bet your intake gaskets are leaking. Check all 4 corners for traces of coolant. The front and rear can also leak oil. If they are leaking the oil could be getting into the intake runners and would cause your consumption problem. These are a low torque gasket so care must be taken when assemling. Head gaskets were not a problem, not to say they couldn't leak. If you let them go too long, coolant can get into the oil and damage could result. Have it checked right away. Also check engine oil cooler hoses for oil leaks.

[AquaMan]

Dave, I think you are right on the money with the intake manfold gasket.

Truck Man, look around the top front edge of the motor where the intake meets the block. Look for any residue from dried antifreeze. Also look at the top of the manafold next to the carb and see if oil is weeping up from the bolt. It does not seal well as it passes through the intake to the block.

I replaced my gasket on the 350 last year and while doing that we put sealant on that bolt. She is dry as a bone now.

AquaMan~~~~~~~~~~~~~~~~~~~~~

It all begins and ends at the water's edge...

[Jerry]

A friend had these same symptoms on a Dodge 5.2L V8. Not the same engine but it was the intake gaskets.