VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc '37 216 - Water leak

I have a '37 216 original engine that seems to be running fine, however, I have a water leak from somewhere on the rear of the engine. I have looked all over as best as I can to see the leak, but can't find it. Is there a freeze plug on the rear of the block that could be leaking? Everything seems to be tight, no water in the crankcase and the temp sensor is not leaking. When the leak finally stops, it takes about a gallon of water to refill the cooling system.

By the way, the plug in the head that the temp sensor screws into is corroded, can anyone tell me where I can fine a replacement?

Thanks,

Rich

There is a 2 inch freeze plug on the rear of the block...

Rich:
There are two freeze plugs near the middle of the block. There is a drain cock near the rear on the left side of the block. If the leak is not apparent otherwise, using a dye and UV (black)light should help find the source. It worked for me in trying to find the source for a slight leak on Old Blue's 216. Turned out to be a cracked block, which a previous owner had repaired with cold weld epoxy material. The leak is not yet severe enough to require immediate repair. I am searching for a year correct engine replacement in the meantime.
Good luck,
37Blue

Is the rear freeze plug accessable if you remove the center floor pan from the passenger compartment?

Thanks,

Rich

Its almost accessable and at least you could do an inspection by removing the floor pan. Removing the pan is where I would start. Also possible that the head gasket is leaking at the rear corners. Gasket could have rotted away from long term storage.
I have a new heat indiactor fitting if you need one.

Gene,

Thanks for the offer of the fitting. Please let me know what you want for it. I will send you my address.

I am out of town on business today, but when I return home, I will remove the floor pan and "see what I can see."

Thanks,

Rich

Rich,
There is a good picture of the rear of the block. Go to the 1940 Block for sale on ebay post. Its picture #4, or 2nd row, picture to the right.

Gene,

Thanks for the clue. There are two freeze plugs on the rear of the engine. It appears that one or both of these could cause the problem. It also appears that at least the off center plug would be covered by the bell housing (maybe both.) Is that correct?

http://cgi.ebay.com/ebaymotors/1940...682QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


Thanks,

Rich

The off center one would be on the right side of the engine and the camshaft is behind it. If I remember correctly the cooling system one in the center is above the bell housing.

Gene,

I was looking at the alignment pins and the mating surface on the rear of the engine. It looks like the bell housing covers freeze plug. If so, that would stink. One thing that I did not mention, on Saturday afternoon I removed the bottom cover on the bell housing and there was a very small drip under it, right on the back of the engine. The clutch and flywheel were dry. This is what had me looking at the rear of the engine. However, since the rear of the engine is so close to the firewall, you can't really see anything.

I will get the floorboard cover removed shortly so I can take a close up look.

Rich

Well, this evening I did look at the back of the engine, without removing the floor boards. I can see that the top of the bell housing goes to the top of the block, just under the head. That means that the bell housing covers the rear freeze plug and it will take major surgery just to take a look at it. From looking at the picture of the rear of the engine, I am pretty sure that the flywheel does not cover the freeze plug. But to R & R the transmission and fix the plug feels like an all day job. Before that, I am considering throwing in a can of stop leak. Too dumb of an idea?

Comments?

Rich

AH!, come on Rich. You need to replace the clutch disc and grind the flywheel and pressure plate anyway. Then you can take a look and find/fix the leak.

Ray,

Deep in my heart I know you are right. I WANT a "mechanic in a can" cuz I'm lazy.

Also, I have never worked on the torque tube before. I was reading the service manual last night and some of the removal instructions were a little less than clear. When I had the cover off of the bell housing last weekend, everything looked very clean, almost new. This may be an area that a previous owner has done some work, I just don't know. I have only driven the car about 3 miles around the neighborhood these past two weekends, and the clutch seems to work just fine. The last time I had a transmission in my lap was in the late 80's when I replaced the clutch on a S-10 that I had.

With the floorboards removed, access to the bell housing may be pretty good. If the torque tube removal and replacement isn't too bad, then I suppose this is not too bad of a project. I have never replaced a freeze plug either, but I don't think they are that hard.

Are there any seals that I should get before I attack this? I did not see any mention of a seal for the torque tube where it connects to the rear of the transmission. From what I have read, oil from the transmission gets into the torque tube to lube the universal joint just aft of the transmission. I would think there would be a seal in this location.

I'll buy the beer and pizza if anyone wants to come over Saturday.

Rich

Here is a photo of that plug's location on my 51 216.
http://rides.webshots.com/photo/1316417356041873203xTDshC

Rich never did tell us what he found.

Well, because of a transmission problem, I removed everything aft of the engine block. The rear freeze plug was much corroded. It has a slot about 1/4" long and 1/16" wide. The back of the plug showed that in the not too distant future, I would have had a gusher. (I think this is the most work I have ever done to replace a part that only cost $1.89.) I guess I will now have to replace the other freeze plugs. I think that there are two on the left side of the engine. Is that correct?

And yes, I replaced the clutch while I was at it. This was just about at the limits of my strength. I did the whole project alone, and lifting the flywheel into place with one hand while trying to start a bolt was tough, but I got it done.

I still need to repair the transmission. I have a new second gear and I will order the rebuild kit from Chev's of the 40's. I still haven't decided if I am going to do this myself, or farm out the rebuild.

Rich

The two on the left side of the block are 1 5/8" cup type. The rear of the block is a 2 inch and If I remember correctly it is not a cup type. Use a sealer in the opening like #1 Permatex.
Would be a good move to flush out the block while the plugs are out if at all possible. Especially the side plugs. You will be suprised as to what you will finf in there.
Unless you find a person familar with that transmission I would recommend doing the job your self. You may find that the rear set of gears on the cluster gear that mesh with the 2nd speed gear may also have a problem. Would suggest replacing the front and rear ball bearings, the 14 rollers between the front main drive gear and the rear main shaft and checking out the bushings in the cluster gear and the shaft they ride on. Also check each tooth in all the gears for wear (the hardned surface chipping away).

Gene,

Yes, the rear freeze plug is a flat disk type. I used a cup type (all I could find) to replace it. I took a band saw and cut the side of the cup down so it would flush out with the rear of the block. I did put a thin film of permatex on the sides of the cup when I drove it in. There was a sholder in the hole to seat the disk type plug, but I just used that as a depth guide.

I have inspected the the gears as much as possible without a tear down on the transmission. The only thing I see is the broken tooth on the 2nd gear. The gear it meshes with may be damaged too. I will replace the bearings.

Rich

Rich
I would dobt that the cut down cup freeze plug will work properly. I would acquire the proper type plug and be sure it will stay there.
Tony

Tony,

The cut down freeze plug seated very solidly. My cooling system is zero pressure so I don't think it will be a problem. I appreciate the advice, but I am committed. It's all back together except for the transmission.

Rich

I yanked the engine this weekend so I could fix the front driver spring mount. In disassembling the engine-clutch-trans assembly to get the engine on a stand I discovered a nasty, leaky, and significantly corroded freeze plug at the back of my 235.

Thanks for the advice in this post - I will not use it to fix my own. Per Chev Nut's advice, I will remove all the freeze plugs, flush, and install new ones.

Wise move Lyn.
While the engine is out I would be inspecting everything else you removed and if it is suspect replace it (including the clutch). Beats doing all that work again a few weeks later.
Tony