Coolant Passage Rust Removal on a 38-75

[RRT38-7519]

I have a 38 7519 that has been in storage for almost 30 years.  My problem is the coolant passages in the block are full of rust and other junk.  I removed the radiator to have it rebuilt and decided to rebuild the water pump while I was at it.  When I removed the water pump, that's when I found the problem inside the engine.  This engine runs perfectly and I really do not wish to dismantle it just clean that coolant passages.
 I thought of blocking off the intake on the water pump and filling the block with radiator flush or some other types of solvent to loosen the rust and then flush it with clean water.  Also thought about flushing the engine with water under pressure.  Does anyone have any suggestions???
Thanks,
Trey P.

[Otto Skorzeny]

You've got the right idea.

Too bad you have the pump off already because it's easier to flush the block with the water pump to circulate the water , etc. If you haven't rebuilt the pump yet, I'd put it back on the best you can  - along with the radiator. If it's as bad as your description sounds, you'll need to do this while the engine is running for a decent amount of time.

Clean out as much crud as you can with a garden hose and bottle brushes, etc. with the pump and radiator off. You may be able to get the water to move throught the galleries with just the pressure of the hose.

After you've done that, put it back together and flush it per the instructions on the flush kit. keep cycling the water through the  system - draining it with the petcock while keeping fresh water filling the radiator. Make sure the heater is running the whole time on high.

Run the water through until it's draining clear or as clear as you can get it.

Then, take off your pump and radiator as planned, have them repaired and re-install them. I'd then do another flush to make sure there's no more loose crap glugging around in there.

Ideally, the block would be boiled out during a rebuild.

I don't know of a better way to do this without disassembling the whole engine.

[Bob Hoffmann CLC#96]

I'd like to add to what Forrest said. While the water pump is off, get a piece of stiff metal & dislodge all the scale you can reach. Also pull the 2 lower drain petcocks. Get a stiff piece of thin rod or heavy wire. Stiffer than clothes hanger. Scrape what you can. Flush the block. Repeat several times. Especially try to get to the lower rear of the block.  Then go with Forrest's plan. HTH, Bob

[35-709]

The procedure for cleaning out rust and crud plugged coolant passages was written up in the Self-Starter sometime ago.  Part of the procedure is to remove the water pump and with water running into the block remove one head bolt at a time (start at the rear) and  use a long rod to break up the crud and then a long tube on a blow gun to blow and flush the crud out.  Replace and retorque that bolt and go to the next one.

[Bill Ingler #7799]

To add to what Geoff has said, that procedure of removing one head bolt at a time that apperared in the Selfstarter was probably the one that was in the Cadillac -LaSalle Service Man issue of August 1939. That procedure probably was OK for a few years after the car was new. OK to use if you know when the engine was last overhauled but the problem you might run into with an engine that has been sitting for 30 years, is breaking off a rusted head bolt. Now you have a problem.

[RRT38-7519]

Thanks for all the advice!

I wish I could run the engine now.  It is pretty crusty inside from what I can see, lots of scale and sediment.  I blew compressed air in through the upper hose outlets and some of the loose material came out.  I'm sure there is a lot more!  The radiator should be ready this week, it had to be completely rebuilt.  I'm going to put the water pump on today and fill the engine with water and a flush solvent and let it sit for few days.  I wish I could start it and let some heat get in it, but the carb is being overhauled along with the starter and will not be ready for a couple of weeks.  I'll try the soak first and see.  If it is still looking bad, I'll put everything back together and do a running flush.   

Does anyone have any thoughts as to how long I should let the engine soak with the solvent inside it?  I don't think it would hurt to leave it for a few days to let all the junk inside the best chance for loosen up and coming out! 

I will think about pulling one head bolt at a time.  The engine was rebuilt in the early 70's and probably only a 2 or 3 thousand miles put on it.  It runs very well, no smoke or noise.  I agree, bolts could snap!  Then I would be taking it apart! 

If this does not work, I guess I'll just have to pull the engine and tank it!  It was rebuilt in the early 70's and probably only had a couple of thousand miles put on it.  It does run great!  Quiet and no smoke!  I just really would hate to take it apart!  I can see it now, engine comes out and the next thing I know the body is on one side of the shop and the chassis is on the other side with all the body panels between...LOL!!!  I want to drive this car for a while before doing all that.  If I start another restoration before I finish the other two I am doing, I know my wife would kill me!

Does anyone have and idea as to how long I should let the engine soak with the solvent inside it?  I don't think it would hurt to leave it for a few days. 

Thanks for all the advice!

Trey 

[Bill Ingler #7799]

Hi Trey: There is another way you might try to clean out some of the crud in the block and that is knock out 2 of the 3 freeze plugs on each side of the engine. The front plug is behind the front engine mount and I would leave this one in place. The middle and rear plugs are easy to get too although you will have to pull the starter to get the right rear plug. With two plugs out and and some air and water, you will be able to remove some of the crud. I did this to my 41 engine. I had both my 41 and 47 radiators rebuilt which made both engines run much cooler. After pulling the top radiator tank on both radiators we found that each core was plugged over 40%. Since both cores were original, rodding the core was ruled out, new cores were installed. Depending on what you are having done to your radiator, removing head bolts or freeze plugs might not be necessary. Have fun.

[35-709]

"If this does not work, I guess I'll just have to pull the engine and tank it!"

If all else fails and you decide you are going to have to pull the engine anyway, at least try the "pulling one head bolt at a time" procedure.  A friend did that on his '41 60 Special engine that had never been apart before and had great success doing it.  Best of luck.

[CEC #20099]

CEC #20099
Any crud or rust you dislodge from the block will be deposited in the top tank & tubes of your newly rebuilt radiator. Sorry about that.
To answer your soaking question, I did a Dodge Hemi by using Oxalic acid flush/neutralizer And running it with NO RADIATOR. Connected top & bottom hoses with tubing, & ran it for 5 minutes or so, over a period of 3 days. Make sure to disconnect heater. After this and a thorough Reverse flush with compressed air, I installed the newly rebuilt radiator. Still runs cool & clean.
This may still not do the job in your case.

[Dave Leger CLC #19256]

CEC is right about crud ending up in the radiator.  There are a couple of companies that make filters to go in the upper radiator hoses.  It's be a worthwhile investment to catch the crud there, rather than plugging up a fresh radiator.  I put the Tefba filters in when I had my engine rebuilt. 

Dave

[Keith McGowan]

On the Model T Club forum people have reported good success in cleaning rust and crud out of the blocks by using either CLR or dishwasher detergent in the cooling system and running the engine until it gets hot. I would not do this with a newly rebuilt radiator as I would not want to get the junk in the new radiator. Do as suggested and connect the inlet and outlet pipes to each other so the junk just keeps circulationg through the engine. Just be careful not to overheat the engine, which should take a while if it is full of water.
Another possibility is take it to a repair shop with the rad off and let them run water under high pressure with compressed air in it backwards through the system. That will also remove a lot of crud. It worked great on my 1936 Packard and 1974 Pantera.

[RRT38-7519]

Thanks everyone!!!  I'm going to try running the engine with either CLR or dishwashing detergent without the radiator.  I was given bad news from the radiator shop today, they can't fix it.  Upper and lower tanks are too far gone and just keep coming apart the more they try to fix them.   I'll post the results sometime next week if I get a chance to try it this weekend.  My wifes is making me go to Canton, Texas for some outdoor trade show (flea market) Saturday, all day!!!  Hopefully I'll get time after chruch on Sunday!

Does anyone have any idea where I might find a replacement radiator???

Thanks again!!!

Trey 

[Otto Skorzeny]

Go to the sunrise service and get back home. You've got a whole day of work ahead of you!