How to clean oily gunk from coolant system.

So I had oil in the water, the oil was going down, no water in the oil, and no water in the exhaust. Spark plugs looked fine.

Did a chemical test for carbon monoxide, no carbon monoxide found as it did not turn from blue to pink. So indications are head gasket is fine.

WTF?


Turns out the the MOPAR oil / coolant heat exchanger was leaking oil into the coolant. with the engine running you can see the oil coming out of where the coolant hose is supposed to hook up.


so now I have to clean up the emulsified oil from the inside of the coolant system. every hose or fitting i have seen is just caked in this oily gunk. Dish washing liquid works of you scrub it off but otherwise does not touch it.


I ended up using petrol to clean out the radiator header tank!
I think the gunk coating the coolant galleries explains the massive heat spike.


I'm going to try this set up with some dish washer machine detergent. any other ideas/ comments welcome.

Will a standerd coolant flush get rid of that sort of gunk build up.
This is a one year old rebuilt engine. all the gunk is new.

Ive always used the detergent like you said, but it takes a ton of flushing to even make a dent on it. Its the absolute worst crap to get out. A coolant filter at this point may be a good idea for the long run. I always get the motor hot tho, and the open the radiator drain to try and blast as much out as I can.

Good luck.

What Mopar oil/coolant heat exchanger are you referring to?

garr said:

What Mopar oil/coolant heat exchanger are you referring to?

Click to expand...

aftermarket one, its not stock.

I've always used alcohol to cut oil out of heat exchangers, but unless you have access to a 55 gal drum paid for by the government, you might find it cost prohibitive.

The alcohol will cut the oil if you're willing to buy 3 or 4 gallons and fill the radiator up with it then flush it out.

Gonna follow this! Pretty sure this is what happened to my '90. I don't have an aftermarket oil/coolant exchanger, but the overflow bottle and radiator were full of a thick as molasses oily gunk the same color. Pretty sure the motor water jackets are plugged with it too. It overheats with antifreeze but not straight water. I'm to the point of pulling the motor and having it boiled out and do a mild build while out. ��

the pool pump did fvk all over night, got some out but the hoses were still caked.
seem to be moving some oil with powdered dishwasher detergent. I'm taking it up to about 95-98*c then taking the rad cap off blows out in a geyser about 5l of water and crud every cycle.
then replace with tap water and go again. done it about 4 times now going to give it another shot of dishwasher detergent.
Started to put in 2l of nearly boiling water mixed with 2 caps of dishwasher toped up with tap water. In the beginning the engine bay was covered in oil gloops but after a while the gloops stopped coming out and the hot detergent water geyser blowing all over the engine bay cleaned up the oil gloops. After a while i was able to run it, with the fans switching on and effectively cooling.
however at this stage the dash temp gauge was reading 10*c over the coolant temp reading from the PCM. (its a '95).
So the next stage was flushing all the water detergent out till it ran clear, then another 2 caps of dishwasher powder and run for 15 min or so. At this point i stopped with the hot water geyser and used the e-fans to pull the temp down to 90*c before switching off the engine and opening the rad cap, was just a bit of a burp at that temp.
The heater was not really responding, turns out low speeds there really is not that much flow / pressure generated by the water pump into the heater, hooking the garden hose direct to the heater hoses, resulted in half a cup of creamy gloop coming out the heater return hose.
After clearing the gloop and making sure there was a flow at idle from the heater hose another 15min run with 2 caps of dishwasher powder and the heater was working again.
Was pretty much a all day thing.
tomorrow will pull the bottom hose to drain / check for crud & fill with deionised water if all ok.

egotripp said:

Gonna follow this! Pretty sure this is what happened to my '90. I don't have an aftermarket oil/coolant exchanger, but the overflow bottle and radiator were full of a thick as molasses oily gunk the same color. Pretty sure the motor water jackets are plugged with it too. It overheats with antifreeze but not straight water. I'm to the point of pulling the motor and having it boiled out and do a mild build while out. ��

Click to expand...

before doing this suggest you find where/ how the engine oil is getting into the coolant.

Try your set-up with Dawn detergent-to cut the oil. And a weak acid solution-vinegar-to help with the build up in the heater core.
Removing the T-stat may help with the coolant movement.

thanks for the input guys,
for the last couple of flushes i switched to powdered front loader laundry detergent, apparently its what the CAT mechanics use to clean the coolant system when a heat exchanger leaks as the front loader detergent is gentler on seals and such.
By this stage enough oil had been removed that the vehicle had no problem maintaining safe operating temp,which was not the case when i started.I ran it for 30 min for each flush, with the laundry detergent.

I have no idear if the dish washing machine detergent actively destroys water pump seals, but it sure does move emulsified oil.
In this instance i have a high flow water pump and new thermostat, which will be going in after i have the rad professionally cleaned.

DO NOT USE DI WATER.

While it sounds good, it will try and steal ions from anywhere it can get it. Normally that will be from an aluminum or brass radiator. I have seen what it can do, when an engineer filled the cooling system for a very large generator with DI water and ended eating through the radiator and burning up the motor.

Distilled water is what you want.

ok just rechecked the bottles of water i bought its de-mineralised water.

old_man said:

DO NOT USE DI WATER.sx
While it sounds good, it will try and steal ions from anywhere it can get it. Normally that will be from an aluminum or brass radiator. I have seen what it can do, when an engineer filled the cooling system for a very large generator with DI water and ended eating through the radiator and burning up the motor.

Distilled water is what you want.

Click to expand...

I have seen deionized water repeatedly destroy big stainless steel sump pumps, requiring custom pumps, built of reinforced plastics.....nasty stuff.