The Stovebolt Site Forums The Shop Area Engine Shop rust inside engine

Moderator, I'm almost positive I read a thread on this topic in this section. I was searching for it again and could not find it. I started this new post, but please transfer it as you see fit.

I was working on my 59 bus (a 235) but don't see why this wouldn't apply to any engine. It was sitting over 10 years before I acquired it. I had to do several things to get it on the road, including a new water pump. When I was installing it, I noticed there was quite a bit of rust inside the block; at least what I could see with the pump removed. My focus was to get it running, so I proceeded with the pump install.

Forward ahead two years later. This bus has been on the road, but just for short distances (10-15 minutes road time) and doing just fine. One day I had a "bus load", and after being on the road about 20-25 minutes, I noticed my temp gauge continuing to climb; and it eventually over heated.

I figured it was the cooling system passages, either in the radiator or block or both. I had a good radiator in stock, but before replacing the old one, I was thinking of a way to clean the block out.

I've had pretty good results using vinegar to clean rusty things, so decided to use it before installing the new radiator. After the radiator was out, I turned the bottom radiator hose with the radiator connection end facing up, and filled the engine with vinegar-took about 2 gallons. I connected my fan belt only to the water pump pulley and used my Dremmel on it to rotate the pump so the vinegar would circulate through the engine water passages. Then I reversed the Dremmel (just put it on the other side of the belt) and turned the pump counter clock wise to circulate the other way. I did this 2-3 times a day for a week.

I drained and flushed the system thoroughly before installing the radiator. There was plenty of rusty colored vinegar that came out. I connected everything and took it out on the road. Went on a long drive with no problems.

Did the vinegar help? Would it have worked just fine if I had only replaced the radiator?....Maybe. But what I didn't want to happen is to just replace the radiator and still have the over heating problem...wishing I had cleaned the block. It took a little time but the cost was only for the vinegar.

Just thought I'd post this for your consideration if you are experiencing a similar problem.

That's an encouraging story. I've currently got the same thing going on with a long-idle 270 that's overheating. Right now I'm soaking the radiator and block with a commercial cleaning product to remove rust. Since I was going to change-out the thermostat from 180 to 160 anyway, this was the logical time to do it. Try the simple stuff first!

Yes Pinetree, the "KISS" principal is good if it works. I really wanted to locate that thread I read before doing what I did, because Bolters were talking about pulling their engines out and replacing them. I certainly didn't want to do that!

And again, there's no evidence that it was the only culprit, since I changed out the radiator too. But when I saw the color of the solution when I flushed the system, I believe it had to help.

Good luck with yours!

One can also use a weak HCl solution.

Not sure why change Tstat from 180 to 160, 180 or 195 make for a more efficient engine, make for warmer heater, better fuel mileage.

Any mild acid will work to get rusty deposits out of an engine. The one that's specific for rust is Oxalic acid, which used to be the active ingredient in the old DuPont powdered cleaner. With any sort of acid flush, it's imperative to follow up with a box or two of baking soda dissolved in water to neutralize the residue, followed by a clear water flush. About 3-4 ounces of the "muriatic acid" (technical-grade hydrochloric) used to clean up after masonry work will do, but don't use it on an engine with aluminum cooling system components, and neutralize it well after the flush.
Jerry