Cooling system mess...help me out

[MLX10]

i have a new to me 89 k1500 manual. It's in decent shape I thought.... but the cooling system was a disaster. It thick brown with a lot of sediment. The previous owner did not touch it. The thermostat has been stuck open for god knows how long so it's been running around 100 degrees.

Today I began flushing out the system with water. Drained it, filled it, ran about 10 times. It is finally starting to come out "mostly clear". Now I will be replacing the radiator, hoses, thermostat, and overflow tank.

The problem is I noticed oil in the coolent every time I drained it. A big let down for me. My first thought was obviously the head gasket but there is just a little bit of oil each time. Cracked block? Sure hope not. Then I thought about the engine oil cooler.. could it be something not so serious? What steps should I take to figure out where the oil is coming from????

 

[Trucknut25]

I havent tried this this on our trucks, but have seen it done on a toyota.

Take the dip stick out, get a balloon and a zip tie and fasten the balloon over the dip stick tube. Start the truck, if it fills up with air you have pressure in the engine, good posibly of a blown head gasket/crack.

Worth a shot.

Joe

 

[BIG_KID]

If oil in the coolant I'd suspect the oil cooler. If coolant in the oil I'd suspect a gasket of some sort. You should be able to delete the cooler if there is an adapter sandwiched between the block and oil filter.

 

[shorepatrol]

I drained and filled mine about 5 times between intake gaskets, water pump, rad hoses and rad replace before it cleared up. That dex when air gets to it is sludgy and oily. Radiator was ******* full of that ****

 

[MLX10]

If oil in the coolant I'd suspect the oil cooler. If coolant in the oil I'd suspect a gasket of some sort. You should be able to delete the cooler if there is an adapter sandwiched between the block and oil filter.

I was hoping to hear something like this. I would be very happy if it was the oil cooler. If deleting the oil cooler would fix the problem I'd be all for it. I'd prefer to to fix it though. Fingers crossed on it being the oil cooler...

 

[MLX10]

I drained and filled mine about 5 times between intake gaskets, water pump, rad hoses and rad replace before it cleared up. That dex when air gets to it is sludgy and oily. Radiator was ******* full of that ****

I couldn't believe how sludgy it was. I can't believe the water pump is still working

 

[C30454]

Much of them remaining sediment is at the bottom of the block and in the heater core. Remove the heater hoses from the eng. and radiator and flush the heater core.

Also, and more important, there is a 9/16 hex pipe plug screwed into the block in the middle, one on each side, just above the oil pan rail. Pull both those plugs and flush until clean. If you pull either plug and nothing comes out, poke into the hole with a screwdriver.

DON'T put the balloon on the dipstick looking for a bad head gasket. That can NOT be determined in this manner.


Tom

 

[MLX10]

Much of them remaining sediment is at the bottom of the block and in the heater core. Remove the heater hoses from the eng. and radiator and flush the heater core.

Also, and more important, there is a 9/16 hex pipe plug screwed into the block in the middle, one on each side, just above the oil pan rail. Pull both those plugs and flush until clean. If you pull either plug and nothing comes out, poke into the hole with a screwdriver.

DON'T put the balloon on the dipstick looking for a bad head gasket. That can NOT be determined in this manner.


Tom

Thanks Tom!

I figured most of it was still in the block and I did not know about those drain holes. I will definitely check that out. Do you have any recommendations on how to flush the system? Besides draining, filling it with water, running it for ten minutes, then draining it again? I'm still concerned about the small amount of oil that's getting into the cooling system.

 

[MLX10]

Anything else I should know before I replace all hoses radiator and thermostat? I'm not seeing and plugs in the block. Still worried about the oil in my coolent

 

[C30454]

I'm not seeing and plugs in the block.

They are in the middle of the sides of the block, 2-3 inches above the oil pan/block. They are a little harder to see on a 4wd on the left side. Some years, the knock sensor is screwed in the block in place of the plug on some GM motors. Don't remember if the did it that way on this year for sure, but I don't think so.



Tom