Packard Forum Index » Pre-War (1899-1942)

In working on my 1939 Super 8 that has not been driven since before 1970 I have been cleaning and servicing the engine oil system. I found that the oil cooler was completely clogged with old oil deposits. I tried brake cleaner, carb cleaner, old gasoline, and other cleaners. Nothing seemed to do the job. All the above even after soaking over night or for several days did not seem to work. Finally I put the oil cooler into a pot of water with detergent and some CLR cleaner and boiled it for a few hours. Finally I was able to get air or liquid to flow from one side to the other. So if yo are going to clean out your oil cooler I recommend boiling it in water with dish detergent (to cut the oil) several times. (I have a back up for this part and will clean it in the next couple of weeks and I will report if starting out with boiling water work as well as we think it does.)

YMMV,
Rick Mahaffey

I notice on the CLR it says not to use on aluminum, brass or copper..... I had considered using to clean the radiator, but decided against it.
John

The best and safest chemicals for use in cleaning brass and solder radiators are those that were used in commercial radiator cleaners of that era. DuPont's HD product used oxalic acid followed by a bicarbonate neutralized rinse.

This of course does not apply to oil cooler cores which is the subject here.

I forgot to mention that I used a 2.5 liter ultrasonic cleaner from Harbor freight. In the ultrasonic I used a bit of detergent and just a spritz of CLR so dilute it would not harm anything. I had to put the oil cooler on it's side at an angle and then after the 180 second run reversing the angle and doing the other side.

In the pan of water I used dish detergent and just a bit of CLR. not much at all. The detergent was poured down the oil passageways then the whole thing was then boiled for about 30 minutes and the cycle repeated.

The first two times in the ultrasonic the water turned brown from the fine slit (Maybe it was rust) came off the fins in the oil cooler.

The oil cooler in a 39 Super 8 is not like modern oil coolers, it has to withstand the oil pressure that averages well above 60 PSI and it is made of heaven metal when compared to the radiator which generally does not run much pressure at all in a modern car and even less if any in a '39.

It seemed that the boiling did the most to clean the internal passages.
compressed air was used to help clear out the last of the oil after boiling.

I think the dish detergent, heat, and boiling water was what did most of the cleaning.
YMMV

... it has to withstand the oil pressure that averages well above 60 PSI

I'd strongly recommend adjusting your oil pressure relief valve so you don't exceed a maximum of 55 or 60 psi (the factory recommendation) at the very most. There are two risks of continued excessive pressure, splitting the filter housing open and bursting thru two adjacent oil passages in the aluminum crankcase.

Thank you for the advice. I have cleaned and serviced the oil pressure regulator so that it can now function properly.

The only spec I have found for the oil pressure is 60 PSI at 30 mph. I wonder what RPM equates to 30 MPH in top gear so that the regulator can be adjusted without having to drive the car to find the pressure.

What should the oil pressure at idle be, does anyone know?

Rick M
'39 Super 8

You shouldn't have to drive 60 mph to reach max, typically it will reach max when cold and given a bit of throttle. Again from the shop manual Packard calls for 5 psi minimum at hot idle.

I suggest you buy the 37/38 Shop Manual reprint if the '39 isn't available, it will answer many such questions.

Thank you for the information. I will be checking the pressure as soon as we fire the engine which I hope will happen soon. We have many parts of this project to work on before we can fire the engine.

Rick M

Well, I just got the 1939 Super 8 running and the oil pressure went up to 75 PSI at ideal when cold so we shut it down and I backed off the pressure regulator a full turn and the pressure went up to 65 so I backed it down one half turn more and the pressure settled in at 55 PSI and did not go up past that when the engine was revved a bit so I think the pressure regulator is working as it should. I am happy with 55 on the pressure gauge I mounted on the firewall. The inside gauge is working and reading a bit lower than the engine compartment gauge.

The engine was very quiet with one tapped making a bit of noise (I removed the followers and checked them for wear and had to take my best guess on the clearance on the two I had to back off to get the lifters back in.).

As you might imagine it is a bit smokey because I had put some marvel mystery oil in the cylinders while it was laid up. I think that some of the rings are a bit gummed up as well.

The engine is very quiet and it started up right away on the remote tank we used. I will be working to run it longer next weekend and I hope that the smoking tones down as I get more time on the engine.

Thank you all for your input, it is greatly appreciated.
I will report back as I have more to say.

Thanks for reminding me about the oil cooler being mucked up inside! I totally forgot about it.