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Old 10-27-2010, 06:28 AM   #1
Join Date: Oct 2010
Posts: 2
Identifying Engine

Beginning of the summer I bought a 99 wrangler with 62k on the odometer. Last week I went to replace the lower radiator hose for a 99 6 cyl. wrangler and the hose was too long. So I researched the old hoses number and it matches for a 97 wrangler 6 cyl. Upon further investigation on the valve cover sticker it says 97 also. Is there a stamp on the block similar to the vin that will tell me the engines history? Currently I have no idea what year of parts I should throw at this thing....for example spark plugs. Appreciate any help. Thanks.

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Old 10-28-2010, 01:29 AM   #2
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Location: sullivan IN
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id say your jeep has had the engine replaced

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Old 10-28-2010, 04:51 PM   #3

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The engine bulid code should be on a machined surface on the right side of the block, between cylinders 2 and 3

1st Digit - The year (8 = 1998)
2nd & 3rd Digits - The month (01 - 12)
4th & 5th Digits - The engine type/fuel system/compression ratio (MX = A 4.0 Liter (242 CID) 8.8:1 compression ratio engine with a multi-point fuel injection system)
6th & 7th Digits - The day of engine build (01 - 31)

FOR EXAMPLE: Code * 801MX12 * identifies a 4.0 Liter (242 CID) engine with a multi-point fuel injection system, 8.8:1 compression ratio and built on January 12, 1998.
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Old 10-29-2010, 05:12 PM   #4
Join Date: Oct 2010
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Thanks for the help. I've got
903mx25 on the left side and 53010449AA cast on the right. Both indicate it's a 99. Again...thanks.
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