How can I easily confirm if there is oil in my coolant?

[rfishi]

I drain coolant only a week or less after adding new coolant, and it's already all brown. Maybe this is just rust from inside the engine? But yesterday I replaced a hose, spilling coolant in the process. The coolant dripped all the way down the engine bay until it landed in a bucket under the truck. I then noticed a layer of oil on top of the coolant in the bucket (you know that rainbow type of mirage).

But I think that oil was just from the coolant flowing down the grimy, oily engine bay before reaching the bucket. Like it just picked up so old oil sludge from past leaks.

But how can I 100% confirm there isn't oil in my coolant?

I was going to buy a combustion leak detector, the ones with blue water that changes colors if combustion gases are present in the coolant. But would this test actually detect oil on the coolant, or just combustion gases? These tests are made to check for blown head gaskets, but what if my oil cooler is what's causing the oil to be in coolant? Will those tests work for this?

 

[410Fortune]

Good question!!

It certainly sounds like you may have oil in your coolant and it could easily be the 5.0 oil cooler

Have you confirmed your 98 engine has the oil coolant? Some 98 do some do not

The hydrocarbon test kit is usually for detecting blown head gaskets but can also detect oil in coolant

After that it is up to you to determine the source either head gasket or oil cooler

Leaks down test/ compression test would be next after hydrocarbon tester

I personally would plan to remove the oil cooler, at this age they are prone to fail and the water and oil will mix

The 99-01 5.0 did not have one
You can install the 99 oil filter mount and lower radiator hose and ditch the cooler

Oily film and brown cloud on top of coolant is a sign of oil contamination

Oil and water do not mix
I would take a small clear jar and collect a sample of your coolant
Let it settle see if you have a layer of oil

Do the same for your crankcase oil, see if it contains any water

Either way that oil cooler would be on the chopping block
I have had them cost me an engine before

 

[rfishi]

When I inspected oil cooler area I noticed some drops of liquid coming from what looked like the oil pan. I couldn't tell if it was coming from the pan or from the cooler/oil filter housing. I tightened one of the oil pan gaskets and 1/8 of a turn or less where the leak appeared to be coming from, and also scrubbed the area with a dish scrubber to clean some grime off. 10 minutes later I came back and the leak had gotten worse and left a couple drops on the ground. I still can't visibly see the exact source of the leak, but I'm guessing its the oil pan gasket, and IDK if I have the tools or time to change that.

 

[C420sailor]

It may also be worth hooking up a coolant system pressure tester and checking to see if your system holds pressure. I like to do this periodically as part of my battery of regular maintenance tests—it can clue you in to tiny leaks that will become not so tiny leaks.

I’d imagine oil pressure at the cooler would be higher than cooling system pressure, but after shutting down a hot engine, you’d have a pressure differential in the other direction…coolant to oil. As mentioned above, it may also be worth looking at your oil to check for signs of water (milkshake, phase separation, etc).

 

[FordFlintrock]

I’d imagine oil pressure at the cooler would be higher than cooling system pressure, but after shutting down a hot engine, you’d have a pressure differential in the other direction…coolant to oil. As mentioned above, it may also be worth looking at your oil to check for signs of water (milkshake, phase separation, etc).

Just to add some very good info on detecting coolant in oil.

Glycol In Lubricating Oil - Detection, Analysis and Removal

Introducing glycol into lubricating oils exposes your machines to a powerful and poisonous mixture of chemicals. Unlike other harmful contaminants such as water and dirt, the destructive potential...

www.machinerylubrication.com

AGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - Coolant in engine oil

AGCO provides overall lowest costs of vehicle ownership. We do this by providing extremely high quality automotive service, following the theories and practices of Dr. W. Edwards Deming., the effects of glycol in engine oil

www.agcoauto.com

 

[rfishi]

I'm going to create a new thread about the leaking oil pan