Crankcase oil contamination serial number help

[MyJD450]

Hello all! I'm brand new to this forum and to owning a JD450 dozer. I'm told it's a straight 450. I have 3 questions I hope to get some guidance on.
Question #1- I am losing coolant and the oil level has risen an inch or so on dip stick. I am assuming coolant is getting into crankcase after adding about 3 quarts of coolant to top it off. There is small amount of coolant exiting overflow tube, beginning after a few minutes of run time (idle), but can't imagine a lot escaping. No other leaks identified. Crankcase oil clings more to dipstick and is a greenish brown color. I don't notice any diesel smell from oil. I'm thinking bad manifold gasket or cracked head. Any suggestions on where and how to begin to troubleshoot?

Question #2- There are no serial number tags on this dozer or engine. There is an engine block casting number of T24961 and I was told that it may give a serial number range and date when JD started using this engine with this casting number, or at least starting number, but I can't seem to find that information. Any information would be helpful and appreciated.

Question #3- The crankcase drain plug is a recessed type with a torx socket, which is extremely shallow, (1/16" or maybe 3/32"). Is this original and is there a replacement drain plug?

Thank you in advance,

Wes

[Jim B]

Welcome to the Boards.

This really doesn't fit the FAQ status. Don't be surprised if you find your post has been moved to the Late Models Board. Things like this pertaining to the models, 350, 450, and newer should be on that board. Moderators generally move them to the correct Board.

Given you description I would not be running it until the problem is found. Get a radiator pressure tester. Drain the oil from the pan (watch what first comes out as you slowly remove the plug. If you get coolant before oil, you definitely have a problem. With the pan drained and plug out, pressurized the radiator to about 9 psi. It is likely that you will have coolant coming out the drain hole after a bit. That could mean a bad head gasket, a cracked head, failed liner seal, or a hole(s) eroded through the side of a liner(s). Opening it up and looking will be the only way to tell for sure.

You are talking about the drain plug in the bottom of the pan, not the pipe plug in the side, correct? As for the drain plug, I have seen some like you describe. Yes, I believe you can replace them with a hex head plug. It looks like the current JD part number is R515346 for the plug and the aluminum seal washer for it is T13213.

The straight 450 serial number tag was on the right side of the panel below the seat, about behind the operator's right calf when seated. If the tag is missing, you should find two 1/8" holes about 3 inches apart in that area. That is where the tag would have been riveted. In some cases, the block casting number can help with getting the right parts. Even the block serial number is not a sure thing to ID the crawler as over the years many engines have been swapped out. The casting number is for a diesel 4-202 engine from what I find which is the size the 450 had. It was also used in the 2020 and 2510 Ag tractors. The 450 and those tractors were built during the 1965-to-1971-time frame.

[MyJD450]

Thank you for the reply, Jim B.

I checked the other day and it is definitely coolant. I spoke to a guy that works on these and he said 90% of the time it's the piston liner that develops a hole and allows coolant in. Will have to start tearing into it.
Yes the drain plug in bottom of pan. The 2 holes are there where the VIN was. Thank you for the extra information on engine, will definitely use this.
I found the drain plug parts online. Much appreciated.