Oil in coolant reservoir

[jakecorn]

Guys,



I have an early 1991 automatictransmission, non-intercooled, truck that is puking oil out the coolant reservoir, and when I checked the oil in the crankcase it was low. I can't find an oil cooler--did these trucks have one? My mechanic removed the head and couldn't find anything major wrong with the head or head gasket.



Thanks in advance for your help/ideas?

 

[RedRamAndy]

How low was the engine oil? Are you sure it was engine oil? We just had a truck at work towed off today that split the transmission cooler coil inside the radiator and it was doing the same thing. Pull the oil stick on your trans too and check that oil. Other than that, it's possible it's coming from soemwhere else in thoe engine. I'm no expert on where it could happen.

Good luck.

 

[cerberusiam]

We just had a truck at work towed off today that split the transmission cooler coil inside the radiator and it was doing the same thing.

Trans cooler is under the turbo, not in the radiator on these trucks.



The engine oil cooler is behind the oil filter mount assembly. Since it is low on engine oil its likely that cooler spring a leak.

 

[RedRamAndy]

Trans cooler is under the turbo, not in the radiator on these trucks.

Aaahhh. I see said the blind man. I was thinkin' in old-school typical car terms.

 

[Shadrach]

Since oil pressure is higher than coolant pressure when the oil cooler springs a leak the oil goes into the rad. Use a good heavy duty laundry detergent and flush out the rad several time after you change the cooler. Shadrach

 

[Bill Stockard]

Since oil pressure is higher than coolant pressure when the oil cooler springs a leak the oil goes into the rad. Use a good heavy duty laundry detergent and flush out the rad several time after you change the cooler. Shadrach

In our heavy truck shop, we used Cascade dishwasher detergent for removing engine oil from the cooling system after an oil cooler failure. It doesn't foam like laundry detergents.



Bill

 

[Shadrach]

Seen that too, or Fleetguard Restore Plus. Shadrach

 

[mwilson]

In our heavy truck shop, we used Cascade dishwasher detergent for removing engine oil from the cooling system after an oil cooler failure. It doesn't foam like laundry detergents.



Bill

Same here, I keep the Cascade in inventory.



Between 6 and 12 jugs here on hand at all times.



Works great.



Mike.

 

[RedRamAndy]

Ok, just to catch up here: There is a coil of sorts behind the oil filter carrying engine oil, and this is within the water jacket of the block? This is how the engine oil cooler is built? I've never been into this part of my engine and just want to learn.

I agree on using Cascade. Dawn dish detergent really works well too. We have used it in the D. O. T. to clean diesel spills from pavement. But, it would foam like was pointed out earlier. I like the dishwasher detergent alternative.

 

[cerberusiam]

There is a coil of sorts behind the oil filter carrying engine oil, and this is within the water jacket of the block? This is how the engine oil cooler is built?

Yep, that block hehind the filter is where the oil cooler is and has coolant circulated around it. Also source of oil leak on filter base.



Dawn works it just tends to foam too much when flushing and takes longer to clear from the block.